VOLUME 117
NO. 12
DECEMBER 2017
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The Southern African Institute of Mining and Metallurgy ) ) ) ) ) ) ! ! !" " Mxolis Donald Mbuyisa Mgojo President, Chamber of Mines of South Africa ! ! " !" " Mosebenzi Joseph Zwane Minister of Mineral Resources, South Africa Rob Davies Minister of Trade and Industry, South Africa Naledi Pandor Minister of Science and Technology, South Africa !" " S. Ndlovu !" " " A.S. Macfarlane " ! " !" " M.I. Mthenjane ! " !" " Z. Botha " " !" " C. Musingwini ! ! !" !"! J.L. Porter ! ! " "! V.G. Duke I.J. Geldenhuys M.F. Handley W.C. Joughin E. Matinde M. Motuku D.D. Munro
G. Njowa S.M Rupprecht A.G. Smith M.H. Solomon D. Tudor D.J. van Niekerk A.T. van Zyl
!" " "! N.A. Barcza R.D. Beck J.R. Dixon M. Dworzanowski H.E. James R.T. Jones G.V.R. Landman
R.G.B. Pickering S.J. Ramokgopa M.H. Rogers D.A.J. Ross-Watt G.L. Smith W.H. van Niekerk R.P.H. Willis
G.R. Lane–TPC Mining Chairperson Z. Botha–TPC Metallurgy Chairperson A.S. Nhleko–YPC Chairperson K.M. Letsoalo–YPC Vice-Chairperson ! ! "! Botswana DRC Johannesburg Namibia Northern Cape Pretoria Western Cape Zambia Zimbabwe Zululand
L.E. Dimbungu S. Maleba J.A. Luckmann N.M. Namate W.J. Mans R.J. Mostert R.D. Beck D. Muma S. Matutu C.W. Mienie
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!!" " "! Australia: I.J. Corrans, R.J. Dippenaar, A. Croll, C. Workman-Davies Austria: H. Wagner Botswana: S.D. Williams United Kingdom: J.J.L. Cilliers, N.A. Barcza USA: J-M.M. Rendu, P.C. Pistorius
W. Bettel (1894–1895) A.F. Crosse (1895–1896) W.R. Feldtmann (1896–1897) C. Butters (1897–1898) J. Loevy (1898–1899) J.R. Williams (1899–1903) S.H. Pearce (1903–1904) W.A. Caldecott (1904–1905) W. Cullen (1905–1906) E.H. Johnson (1906–1907) J. Yates (1907–1908) R.G. Bevington (1908–1909) A. McA. Johnston (1909–1910) J. Moir (1910–1911) C.B. Saner (1911–1912) W.R. Dowling (1912–1913) A. Richardson (1913–1914) G.H. Stanley (1914–1915) J.E. Thomas (1915–1916) J.A. Wilkinson (1916–1917) G. Hildick-Smith (1917–1918) H.S. Meyer (1918–1919) J. Gray (1919–1920) J. Chilton (1920–1921) F. Wartenweiler (1921–1922) G.A. Watermeyer (1922–1923) F.W. Watson (1923–1924) C.J. Gray (1924–1925) H.A. White (1925–1926) H.R. Adam (1926–1927) Sir Robert Kotze (1927–1928) J.A. Woodburn (1928–1929) H. Pirow (1929–1930) J. Henderson (1930–1931) A. King (1931–1932) V. Nimmo-Dewar (1932–1933) P.N. Lategan (1933–1934) E.C. Ranson (1934–1935) R.A. Flugge-De-Smidt (1935–1936) T.K. Prentice (1936–1937) R.S.G. Stokes (1937–1938) P.E. Hall (1938–1939) E.H.A. Joseph (1939–1940) J.H. Dobson (1940–1941) Theo Meyer (1941–1942) John V. Muller (1942–1943) C. Biccard Jeppe (1943–1944) P.J. Louis Bok (1944–1945) J.T. McIntyre (1945–1946) M. Falcon (1946–1947) A. Clemens (1947–1948) F.G. Hill (1948–1949) O.A.E. Jackson (1949–1950) W.E. Gooday (1950–1951) C.J. Irving (1951–1952) D.D. Stitt (1952–1953) M.C.G. Meyer (1953–1954) L.A. Bushell (1954–1955) H. Britten (1955–1956) Wm. Bleloch (1956–1957)
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H. Simon (1957–1958) M. Barcza (1958–1959) R.J. Adamson (1959–1960) W.S. Findlay (1960–1961) D.G. Maxwell (1961–1962) J. de V. Lambrechts (1962–1963) J.F. Reid (1963–1964) D.M. Jamieson (1964–1965) H.E. Cross (1965–1966) D. Gordon Jones (1966–1967) P. Lambooy (1967–1968) R.C.J. Goode (1968–1969) J.K.E. Douglas (1969–1970) V.C. Robinson (1970–1971) D.D. Howat (1971–1972) J.P. Hugo (1972–1973) P.W.J. van Rensburg (1973–1974) R.P. Plewman (1974–1975) R.E. Robinson (1975–1976) M.D.G. Salamon (1976–1977) P.A. Von Wielligh (1977–1978) M.G. Atmore (1978–1979) D.A. Viljoen (1979–1980) P.R. Jochens (1980–1981) G.Y. Nisbet (1981–1982) A.N. Brown (1982–1983) R.P. King (1983–1984) J.D. Austin (1984–1985) H.E. James (1985–1986) H. Wagner (1986–1987) B.C. Alberts (1987–1988) C.E. Fivaz (1988–1989) O.K.H. Steffen (1989–1990) H.G. Mosenthal (1990–1991) R.D. Beck (1991–1992) J.P. Hoffman (1992–1993) H. Scott-Russell (1993–1994) J.A. Cruise (1994–1995) D.A.J. Ross-Watt (1995–1996) N.A. Barcza (1996–1997) R.P. Mohring (1997–1998) J.R. Dixon (1998–1999) M.H. Rogers (1999–2000) L.A. Cramer (2000–2001) A.A.B. Douglas (2001–2002) S.J. Ramokgopa (2002-2003) T.R. Stacey (2003–2004) F.M.G. Egerton (2004–2005) W.H. van Niekerk (2005–2006) R.P.H. Willis (2006–2007) R.G.B. Pickering (2007–2008) A.M. Garbers-Craig (2008–2009) J.C. Ngoma (2009–2010) G.V.R. Landman (2010–2011) J.N. van der Merwe (2011–2012) G.L. Smith (2012–2013) M. Dworzanowski (2013–2014) J.L. Porter (2014–2015) R.T. Jones (2015–2016) C. Musingwini (2016–2017)
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VOLUME 117 NO. 12 DECEMBER 2017
Contents Journal Comment: The SAMREC/SAMVAL Companion Volume Conference by K. Lomberg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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President’s Corner: A Christmas gift for the Institute by S. Ndlovu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Naming of the Peter King Minerals Processing Laboratory by H. Potgieter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Gold Fields, Wits R6 m boost for mechanized mining in South Africa by S. Braham . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Mining research and development reborn – the Mining Precinct by A. Macfarlane and N. Singh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Camera Press, Johannesburg
The Secretariat The Southern African Institute of Mining and Metallurgy ISSN 2225-6253 (print) ISSN 2411-9717 (online)
THE INSTITUTE, AS A BODY, IS NOT RESPONSIBLE FOR THE STATEMENTS AND OPINIONS ADVANCED IN ANY OF ITS PUBLICATIONS. CopyrightŠ 2017 by The Southern African Institute of Mining and Metallurgy. All rights reserved. Multiple copying of the contents of this publication or parts thereof without permission is in breach of copyright, but permission is hereby given for the copying of titles and abstracts of papers and names of authors. Permission to copy illustrations and short extracts from the text of individual contributions is usually given upon written application to the Institute, provided that the source (and where appropriate, the copyright) is acknowledged. Apart from any fair dealing for the purposes of review or criticism under , of the Republic of South Africa, a single copy of an article may be supplied by a library for the purposes of research or private study. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means without the prior permission of the publishers. U.S. Copyright Law applicable to users In the U.S.A. The appearance of the statement of copyright at the bottom of the first page of an article appearing in this journal indicates that the copyright holder consents to the making of copies of the article for personal or internal use. This consent is given on condition that the copier pays the stated fee for each copy of a paper beyond that permitted by Section 107 or 108 of the U.S. Copyright Law. The fee is to be paid through the Copyright Clearance Center, Inc., Operations Center, P.O. Box 765, Schenectady, New York 12301, U.S.A. This consent does not extend to other kinds of copying, such as copying for general distribution, for advertising or promotional purposes, for creating new collective works, or for resale.
SAMREC/SAMVAL COMPANION VOLUME CONFERENCE The 2016 SAMREC Code by K. Lomberg and S.M. Rupprecht . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The objective of this paper is to inform the reader of the changes to the 2016 SAMREC Code and to re-emphasis best practice for the declaration of Exploration Results, Mineral Resources, and Mineral Reserves.
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Mineral Resource and Mineral Reserve governance and reporting for AngloGold Ashanti by R. Peattie, V. Chamberlain, and T. Flitton . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . This paper describes the steps that AngloGold Ashanti has put in place to ensure that the Executive Committee and the Board have line of sight to the annual Mineral Resource and Mineral Reserve public reporting, as well as the findings from a stringent internal and external review programme.
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Good reporting practices by S.M. Rupprecht . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Compliance of Public Reports and some of the common compliance issues currently being experienced are investigated. The paper also discusses methodologies to improve compliance and Public Reporting, such as self-regulation, coaching and training, and other means to promote good reporting practice.
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The new SANS 10320:2016 versus the 2014 Australian guidelines for the estimation and classification of coal resources—what are the implications for southern African coal resource estimators? by J. Hancox and H. Pinheiro . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The authors discuss the recent updates of the South African SANS 10320:2016 and the Australian Guidelines for the Estimation and Classification of Coal Resources, 2014. Unlike their respective parent codes (SAMREC and JORC), which have become increasingly similar, these guidelines have diverged and are different in a number of significant ways, which will have an impact on coal resource estimators working in the coalfields of south-central Africa.
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%'( $%&! $ ) # &"!( ) !$(# VOLUME 117
N O. 12
DECEMBER 2 017
R. Dimitrakopoulos, McGill University, Canada D. Dreisinger, University of British Columbia, Canada E. Esterhuizen, NIOSH Research Organization, USA H. Mitri, McGill University, Canada M.J. Nicol, Murdoch University, Australia E. Topal, Curtin University, Australia
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# '(%&"& ) ' ('"' %$%& ' Barbara Spence Avenue Advertising Telephone (011) 463-7940 E-mail: barbara@avenue.co.za
VOLUME 117 NO. 12 DECEMBER 2017
Contents
(continued)
SAMREC/SAMVAL COMPANION VOLUME CONFERENCE Exploration Results, Exploration Targets, and Mineralisation by T.R. Marshall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . This paper seeks to clarify the concepts and definitions of Exploration Results, Exploration Targets, and Mineralisation and to assist in clearing misconceptions. A number of case-study examples are presented in order to illustrate the differences between Exploration Targets that are purely conceptual and those which may be identified as Mineralisation. Development of a best-practice mineral resource classification system for the De Beers group of companies by S. Duggan, A. Grills, J. Stiefenhofer, and M. Thurston . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The authors present a review of a best-practice Mineral Resource classification system that takes into account the complexity and variability of diamond deposits, and which includes the ability to take cognisance of new data obtained during mining and production performance.
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PAPERS OF GENERAL INTEREST Development of a technology to prevent spontaneous combustion of coal in underground coal mining by A. Tosun. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The aim of this study was to develop cheap materials with very low oxygen permeability and high mechanical resistance for coating the walls of the coal mine galleries in order to prevent spontaneous combustion. Epoxy/fibreglass was identified as the material with the least oxygen permeability, and also has other desirable properties. An improved method of testing tendon straps and weld mesh by B.P. Watson, D. van Niekerk, and M. Page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A more representative test than the purely tensile test for tendon straps and weld mesh, which caters for a worst-case loading condition due to block rotation, is presented, together with an improved design of tendon strap to better cope with the actual underground loading environment. A stochastic mathematical model for determination of transition time in the non-simultaneous case of surface and underground mining by E. Bakhtavar, J. Abdollahisharif, and A. Aminzadeh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . This research introduces a stochastic mathematical model that uses open pit long-term production planning on an integrated open pit and underground block model to determine the optimal time for transition from open pit to underground mining. Near-surface wave attenuation (kappa) of an earthquake near Durban, South Africa by M.B.C. Brandt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The near-surface wave attenuation factor (kappa), which describes the attenuation of seismic waves over distance in the top 1–3 km of the Earth’s crust, was determined for eastern South Africa using data from a magnitude 3.8 earthquake that occurred off the coast near Durban.
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nal Jour t men Com
The SAMREC/SAMVAL Companion Volume Conference
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his edition of the Journal features papers that were presented at the SAMREC/SAMVAL Companion Volume Conference held on 17 and 18 May 2016 and attended by some 100 people. The intention of the conference was to provide Competent Persons and Competent Valuators with the opportunity to prepare and present details of recognized standards and industry benchmarks in all aspects of the SAMREC and SAMVAL Codes. These contributions were collated into a Companion Volume to provide a guideline for the declaration of Exploration Results, Mineral Resources and Mineral Reserves, and the Valuation of Mineral Projects for South Africa.
The purpose of international mineral reporting codes such as the SAMREC Code and the valuation codes such as the SAMVAL Code is to ensure that misleading, erroneous, or fraudulent information relating to mineral properties and mineral asset valuations is not published or promoted to investors on the stock exchanges. In preparing Public Reports for Exploration Results, Mineral Resources, and Mineral Reserves (SAMREC) and Mineral Asset Valuations (SAMVAL) the practitioner must satisfy the requirements of the SAMREC and SAMVAL Codes. The intention of the Companion Volume is to aid the Competent Person (CP) and Competent Mineral Asset Valuator (CV) when making these declarations. The objective of this conference and the Companion Volume was to provide a record of current industry benchmarks and best practice to be used or referenced when making a declaration. A best practice consistently yields superior results to those achieved with other means or techniques, and is used as a benchmark. Reporting in accordance with the guidelines of the Codes alone does not guarantee good reporting, as the nature of the mining industry changes over time due to developments in the economic, social, political, and technical environments. The Codes also cover a very broad spectrum in terms of commodities, geographies, and mineral deposit/mineralization types. It was therefore felt that more guidance was required for the CP/CV to assist with reporting and promote good reporting. It is acknowledged that no single document could cover all the accepted industry practices or assist with all possible situations. However, the aim of the Companion Volume is to represent the best current knowledge. A key strategic talent is still required when applying best practice as the Competent Person or Competent Mineral Asset Valuator must balance the unique situation with the practices that it has in common with others. The Codes are guidelines to assist Competent Persons and Competent Mineral Asset Valuators when declaring Exploration Results, Mineral Resources or Mineral Reserves and their valuations. The purpose of the Companion Volume is also to provide information that will be useful to mentor-less or inexperienced mineral industry professionals. Despite having these industry practices available, the Competent Person or Competent Mineral Asset Valuator is still required to be prepared to defend themselves to their peers and take responsibly for their work. In addition to the technical presentations, the recently developed and released guidelines for environmental, social, and governance reporting (SAMESG) were distributed at the conference. An aspect that also came out of the SAMREC Code update was the need for comprehensive guidelines for the reporting of diamonds resources and reserves. To this end, diamond reporting guidelines were also presented and distributed. Both the Diamond guidelines and the SAMESG guidelines are supplementary to the SAMREC Code. The Conference included three plenary addresses, a panel discussion, 29 papers about the SAMREC Code including three keynote addresses, and eight papers under the SAMVAL section with one keynote address. This edition of the Journal represents a selection of those papers presented. The SAMREC and SAMVAL Codes were officially launched at the opening bell of the JSE on the 17–18 May 2016. A period was allowed in which the previous Codes (SAMREC 2007 as amended in 2009) and SAMVAL (2008) were used in parallel to the Codes launched in 2016. The updated Codes became the prevailing Codes on 1 January 2017. We encourage CPs and CVs to review the papers presented so that they can be up to speed with the new developments in reporting and in the declaration of Exploration Results, Minerals Resources, and Mineral Reserves as well as when making a declaration of A Mineral Asset Valuation.
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K. Lomberg Chairperson Organizing Committee
Naming of the Peter King Minerals Processing Laboratory The School of Chemical & Metallurgical Engineering at Wits held a ceremony on 7 November 2017 to mark the naming of the Peter King Minerals Processing Laboratory in recognition of Peter King’s contribution to the field of minerals processing. A Wits alumnus, Peter King was an accomplished metallurgist who served as the head of the Department of Metallurgy and Materials Engineering for over a decade from 1976 to 1990 before accepting an appointment at the University of Utah. The ceremony was attended by industry, King’s former students, and guests of honour, his wife, Ellen and son, Andrew. Wits Professor of Hydrometallurgy and Sustainable Development, Prof. Sehliselo Ndlovu, also the current President of the Southern African Institute of Mining and Metallurgy said the laboratory would ensure the continuation of King’s vision, who was passionate about capacity building and world-renowned for developing useful techniques to quantify mineral liberation.
Mrs Ellen King and Andrew King, respectively widow and son of the late Prof. King unveiling the R. Peter King Minerals Processing Laboratory name plate in the School of Chemical and Metallurgical Engineering at Wits
Metallurgy is key to our economy. For more than 100 years, metallurgy at Wits has been inextricably linked to that of the mining industry, said Ndlovu. ‘Extractive metallurgy plays a critical role in maximising returns from the processing of mineral resources such as gold, platinum, and coal.’ A well-equipped laboratory for teaching and research is essential to continue producing experts in minerals processing. Former students described Prof. King as a great teacher who instilled confidence and a desire for continual progress. Some Wits graduates, who hold key positions in industry, reflected on Peter King’s flair with technology. Prof. King was among the first to incorporate technology in his teaching methods and provide online courses in response to the demands of the modern world. An all-rounder, professional staff also praised Peter King for his hands-on approach and open door policy. Bruce Mothibedi, a senior technician at Wits, recalls many moments when King would don an overall to lend a hand in some of the messy pilot plant projects. ‘Rarely do you find a man of Prof. King’s calibre sacrificing his time to lend a hand in plant processes, but he gladly did it. Staff development across different grades was also important to him and he would arrange appropriate training for his team, be it at industry, the mines or related fields, so that one could gain more understanding and passion for their work,’ says Mothibedi. King, who was born in Springs in 1938, left Wits and South Africa in 1990 to take up the post in Utah. His involvement with Wits continued across the seas. ‘Peter was very proud of the accomplishments of the department and took great interest in the progress of the students once they graduated,’ said Mrs King, who continued to give guests a glimpse into personal joys and loves of her husband. Ballroom dancing, which he took up in the 1960s during a sabbatical, and book-binding were his other passions. Head of School Professor Herman Potgieter said the lab was a fitting tribute to a ‘world-renowned member of our family’. The laboratory will be dedicated to technology-intensive extractive metallurgy that serves to meet the needs of industry locally and internationally, through training of undergraduate and postgraduate students by providing the tools necessary for high-level, applied research. The King family has donated R500 000 towards the fitting out of the laboratory. Alumni of the School and industry are encouraged to follow this sterling example. To make a donation, please contact the Wits Development and Fundraising Office. Prof. Peter King published more than 150 scholarly papers on fundamental aspects of mineral processing during his long and distinguished career. He authored or co-authored five books, the most recent of which are Introduction to Practical Fluid Flow (Elsevier, 2002) and Modeling and Simulation of Mineral Process Systems (Butterworth-Heinemann, 2001). Peter King sadly died at the age of 68 on 11 September 2006. At the time of his death, he was a professor of metallurgical engineering at the University of Utah in Salt Lake City. His accomplishments over his lifetime were truly remarkable. Peter King
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(Extracts from a memorial tribute published in Vol 11: National Academy of Engineering, National Academies (2007).
t’s iden s e r P er Corn
A Christmas gift for the Institute
I
t is the end of the year and Christmas is in sight. We have all had a busy year and thus look forward to a restful break, which we will fill with new memories with our families and friends. Above all, we all look forward to receiving that well-chosen wonderful gift from loved ones. A gift is always treasured. It might be something that we did not ask for but somehow our loved ones always manage to surprise us by recognizing our need or yearning for that particular item. The fact that they understand us, love and care enough to go out of their way to give us that special something is a gift in itself. They make a sacrifice for a greater return; our happiness. A gift does not have to be expensive, it does not have to be wrapped up in an expensive wrapping paper and tied with a costly ribbon. For most of us there is one gift that is more valuable than anything bought in a shop; more appreciated by its recipient than anything wrapped in pretty colourful paper; and sure to be remembered for years to come. This is the gift of time. Time is the most valuable gift because it is a portion of your life that you can never get back. Time freely given is truly priceless to those who receive it. As you tick your Christmas gift list, I ask that as a SAIMM member, you also think of the gift you could give to the Institute that you love this coming year. The SAIMM is a voluntary organization and as such, it depends mostly on volunteers who freely give of their time in order to advance the Institute’s missions and goals. There are quite a number of ways in which you could give your time. One way is by actively participating in your local branch activities. Branches usually organize different events aimed at benefiting all members. These include technical presentations on topics of interest, technical visits to mining operations, or even non-technical events such as wine tasting, hiking, or birdwatching. Lack of time is always the reason given by members for their absence from such events. Think about giving your time to branch events this coming year as your gift to the Institute. You could also become involved in organizing conferences through the Technical Programme Committees (TPCs). TPCs play a significant role in providing platforms for the dissemination of information in technological developments in the mining and metallurgical industries. They are also a platform for members in these sectors to meet and share experiences. The SAIMM has two TPCs, TPC Metallurgy and TPC Mining, which focus on organizing metallurgical- and mining-related events respectively. These committees are always in need of dedicated and committed members to identify relevant topics of interest in the industry and actively participate in translating these ideas into a conference, a school, a workshop, seminar or any other means of disseminating value. Alternatively, you could offer your services as a reviewer for the numerous papers submitted for conference proceedings and the SAIMM Journal. The SAIMM member database boasts members who have varied technical, operational, and academic expertise which ensures the high quality of SAIMM publications. And to top it all, your gift of time spent reading and reviewing these articles is acknowledged through the publication of your name as a reviewer in the special AGM issue every year. As a SAIMM member, you can also participate in the SAIMM mentoring programme. This programme is particularly valuable to the young professionals of the Institute. Give back by helping younger SAIMM members to set important life-goals and develop the skills they need to guide them to a successful career. You could also go big and run for the SAIMM Council. The Council serves as the heart of the SAIMM and as a Council member you have the opportunity to become actively involved in the management and administration of the Institute’s affairs. This is a major commitment which requires dedication and would be a commendable gift for the Institute. For the younger members of SAIMM, i.e. younger than 35 years, you could run for the Young Professionals Council and add value on issues that are pertinent to the younger members of the Institute. If, however, you still feel that you are time-constrained, that the gift of time is something you truly cannot provide this coming year, and you need a bit more time to think about it or to reorganize yourself, you could still give an alternative gift. A donation to the SAIMM Scholarship Trust fund is a precious and important gift. The Scholarship Trust fund was established in 2003 with the goal of ensuring that no deserving student registered for a Mining or Metallurgical Engineering degree programme at a South African tertiary institute is denied the opportunity of having a career in the minerals and metals industry as a technically qualified graduate because of financial challenges. The Fund provides assistance to a huge number of needy students who depend on personal or family funds for their educational needs. Your gift can be a donation to this worthy cause. As we enjoy the festive season celebrating Christmas and preparing for the New 2018 Year, let us remember that the greatest gift we can ever give is our time and our presence. It is a gift that leads to the most magnificent and truly priceless memories. A very merry and restful Christmas and a joyful New Year to you all!
The Journal of the Southern African Institute of Mining and Metallurgy
VOLUME 117
DECEMbEr 2017
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S. Ndlovu President, SAIMM
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Gold Fields, Wits R6 m boost for mechanized mining in South Africa old Fields is pleased to announce a R6-million, three-year partnership with the University of the Witwatersrand (Wits University) to further the academic knowledge of mechanized mining and rock engineering in South Africa.
• Two Geological Resource Modelling postgraduate research projects • Two postgraduate Drill and Blast improvement and other productivity-related research projects
The partnership agreement with Wits University’s School of Mining Engineering and the Wits Mining Institute was signed by Gold Fields CEO Nick Holland and Wits Vice-Chancellor and Principal, Professor Adam Habib, 22 November.
Gold Fields’ funding will also be used to cover the costs of about four to six 3rd and 4th year student research works a year. The post-graduate and under-graduate research projects will be in subject areas that are critical to South Deep as it ramps up to full production in 2022.
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Gold Fields’ funding seeks to fill the gap of mechanized mining skills in South Africa, with the company managing the country’s largest and deepest underground mechanized gold mine, South Deep. The skills and expertise required to bring the mine, with an expected life of over 70 years, to full production are not in abundant supply in South Africa. ‘With the Mining School’s long history of research-intensive higher education and the more recently launched Wits Mining Institute, with its focus on digital mining, it made for a natural partnership,’ says Holland. ‘Both Gold Fields and Wits University want to collaborate in developing young professionals with the knowledge and skills required to support mechanized, deep level gold mining. Through this we can undoubtedly assist the mining industry in general and play our part in bringing South Deep to full production,’ adds Habib.
As part of the partnership Gold Fields has been granted naming rights for the Genmin Laboratories building on the Wits Campus, which will now be known as the Gold Fields Laboratories building. The partnership between Gold Fields and Wits University goes back many years. Most recently, in 2010, the company pledged R18 million on a three-year sponsorship deal comprising a number of investments in the Faculty of Engineering and the Built Environment at Wits University. The last of these funds were spent in 2015. ‘Wits has for decades provided the skills needed to power South Africa’s mining industry. This latest sponsorship will ensure that they are in a position to do so for many more years to come,’ says Holland
A number of projects have already been identified for funding by Gold Fields during the three-year period. They are:
• Three postgraduate research projects linked to the Chair of Rock Engineering at the School
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S. Braham On behalf of the Wits School of Mining Email: sally@sbpr.co.za
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Mining research and development reborn – the Mining Precinct History tells us that, during the 1970s and 1980s, mining research and development in South Africa was at the global forefront, driven by the need to continue and grow mining, and gold in particular, at depths ‘way beyond where other mining countries dared to go’. South Africa, through the Chamber of Mines Research Organisation (COMRO) and other initiatives, became the leader in mining research in deep level, narrow-reef mining, as well as block caving mining in the diamond and copper industries. This was as a result of co-investment by Chamber of Mines member companies which, in today’s money terms, amounted to some R400 million a year. Unfortunately, during the 1990s and beyond, R&D funding reduced significantly, to the extent that, by 2014, only some R5 million was allocated by government to mining R&D. Part of the reason for this was that mining companies decided to ‘go it alone’, and set up their own R&D capacity and projects. Whilst this was in many cases successful, these initiatives inevitably became the victims of fluctuating price cycles, and budgetary constraints. The world is moving forward at an alarming pace. The term Industry 4.0 is a name for the current trend of automation and data exchange, particularly in the manufacturing industries. It includes the Internet of Things, which focusses on the integration of all data into platforms that allow real time decision making. Industry 4.0 is now upon us, and our mining industry, and if our industry does not join this innovation curve, it will be left behind. Our industry is faced not only with technological and economic challenges, but also challenges of the requisite skills, water supply, depleting reserves and environmental, health and safety issues. Nevertheless, we have opportunities, if R&D can find the answers, of mining the extensive resources that still exist unmined, either in deep operations, or in lower grades. These challenges can only be met if we establish a collaborative and enabling environment for mining R&D, innovation and the development of world-class manufacturing in the mining and beneficiation space. The Mining Phakisa was held in 2015, as a multi-stakeholder engagement that spanned some five weeks of intensive work and debate, aimed at finding ways to re-establish the mining industry in a sustainable manner as a significant contributor to GDP. The broad aim of Mining Phakisa was to foster growth, transformation, investment and employment preservation and creation along the entire mining value chain, in relevant input sectors and within communities affected by mining activities. This was to be achieved by conducting innovative research and development initiatives in collaboration with industry, the original equipment manufacturers (OEMs) within the mining supply chain, tertiary education institutions, government departments such as the Department of Science and Technology (DST) and Department of Trade and Industry (DTI), as well as other stakeholders in the industry. Prior to the Phakisa, the Council for Scientific and Industrial Research (CSIR) with the support of the DST developed the South African Mining Extraction Research, Development & Innovation (SAMERDI) Strategy. In parallel, following extensive discussions between Chamber of Mines members, through the Chamber Council, there resulted a breakthrough in terms of establishing an industry open innovation platform. A forum was established that identified the main research areas or programmes, and these were then meshed into the SAMERDI strategy, Thus, the SAMERDI strategy was adopted post-Phakisa as the mining R&D strategy that would achieve the outcomes of the Phakisa. The Mining Precinct@Carlow Road was established as the physical location from where R&D activities would be co-ordinated along with the Mining Hub to provide management oversight in the implementation of the SAMERDI strategy. The aims of the strategy is: ‘To maximize the returns from South Africa’s mineral wealth through collaborative, sustainable research, development, innovation and implementation of mining technologies in a socially, environmentally and financially responsible manner that is rooted in the wellbeing of local communities and the national economy’. Of great significance in these developments has been the financial commitment to the R&D programmes by the following: 1. The DST made the Carlow Road facility available which is now known as the Mining Precinct@Carlow Road for the coordination and facilitation of Mining R&D; 2. The DST granted, through National Treasury, an amount of R150 million over a three- year period, and which may be increased and certainly continued; 3. The DTI granted an amount of R8 million for the establishment of MEMSA (Mining Equipment Manufacturers of South Africa) as a development cluster to increase the capacity and capability of local mining equipment manufacturing, both for the local and export markets. MEMSA is housed within the Mining Precinct@Carlow Road; 4. The Chamber of Mines, in addition to initial seed funding in 2016 of some R10 million, has pledged support of R33 million for 2018. 5. Additionally, commitments have been made by the mining departments at Universities and the CSIR to participate in these programmes in a fully collaborative manner.
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As a result of these developments, mining R&D has been restarted, and the Mining Precinct@Carlow Road now has some 55 occupants, ranging from interns to researchers, principal investigators, programme managers and a Mining Hub directorate. Governance has been addressed through the establishment of a steering committee, with representation from key stakeholders, operating similar to that of a board.
The R&D programmes listed below are currently funded by the DST and participating mining companies and are co-managed by the CSIR and the Chamber of Mines. The CSIR is contracted by the DST to serve as an incubator of the Mining Hub and the lead implementer of SAMERDI. This is part of a strategic journey that aims to re-establish a world-class organization as a public-private partnership that will support the industry from now until 2030, and beyond. The SAMERDI Steering Committee is co-chaired by representatives from the DST and the Chamber of Mines, and includes the following programmes (each of which has many sub-projects): 1. Longevity of Current Mining operations (LoCM)—The focus is to increase the efficiency of extraction, improvement in occupational health and safety and reduction in costs in current mining operations. 2. Mechanized Drill and Blasting (MD&B)—To develop fully mechanized mining systems that will allow for remote drilling and blasting of narrow hard rock mines (in particular the gold and platinum mines). 3. 24/7 Non-Explosive Rock breaking (NERB)—To develop complete mining systems for continuous mining, allowing for ore extraction that is completely independent of the use of explosives. 4. Advanced Orebody Knowledge (AOK)—Mechanization and modernization of mining requires better knowledge of the orebody ahead of the mining face. This project aims to make ‘glass rock’ so that, instead of mining blind, an accurate 3-D real time model can be used for safety and planning. 5. Real Time Information Management Systems (RTIMS)—The inability to accurately monitor issues in real time poses a significant challenge across the entire mining process, even more so when using mechanized mining methods. Productionrelated issues have a direct impact on the efficiency of the mines. Using real time information for monitoring and control allows pro-active intervention that can correct deviations and unsafe conditions as they arise. Thus, the ‘Ă?nternet of Things’ becomes a mining imperative for the future. 6. Successful Applications of Technology MAP (SATMAP)—Modernization via automation and mechanization of South African mining processes will have significant implications on the number of people employed in the industry as well as the required skills level. This will also require significant attention to change management issues. The requirements for the upstream and downstream processes associated with mechanisation will have to be understood. These programmes extend well beyond pure technology implementation. They obviously include many people issues, and mining process and system issues, where radical, modern ideas are required. As such, the programmes focus on people-centric solutions, that will allow mining to be conducted in a safe, healthy and ergonomically friendly environment, whereby lower grade orebodies can be mined with minimal dilution, with order of magnitude improvements in efficiency and cost effectiveness. Less obvious, but equally important, is the need to engage with communities and other stakeholders, on issues of local industrialization, the establishment of local agri-business, and skills development. Skills development requires that not only are direct skills identified for the future, but also supervisory and management skills, as well as community skills development, and skills development within OEMs and small, medium and micro enterprises (SMMEs) are identified. The Southern African Institute of Mining and Metallurgy (SAIMM) has been kept abreast of the developments post-Phakisa, and has organized events that support elements of the R&D programmes. It now needs to become more involved in terms of providing platforms for dissemination of research and development information, in helping to develop new R&D skills and competencies, and in supporting R&D initiatives. A direct result of the demise of R&D over the last 20 years has been the loss of key research capacity and experience. Now that this new initiative is underway, there is a need to develop a new breed and critical mass of researchers, to take the programmes forward. These researchers are being drawn from research organisations, Universities, industry and interns. In the case of interns, these are being sourced through the databases of the Young (' * * &* ( Professionals Council, thus further increasing the support of the SAIMM. Here, the SAIMM can also assist through its members. Members who may wish to become involved in the activities at the Mining Precinct are encouraged to support the activities of the researchers and interns in an advisory, or mentorship role, so as to rebuild much-needed capacity and capability. These people will require guidance in how to conduct their research, as well as assistance in terms of linkages to industry and its needs, while at the same time being encouraged to engage in disruptive thinking and ideas
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Anyone who would like to pursue such an interest is encouraged to contact the Directors of the Mining Precinct@Carlow Road—Alastair Macfarlane (Amacfarlane@chamberofmines.org.za) or Navin Singh (NSingh1@csir.co.za) or telephonically via 011 358 0004.
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http://dx.doi.org/10.17159/2411-9717/2017/v117n12a1
The 2016 SAMREC Code by K. Lomberg* and S.M. Rupprechtâ€
$! The SAMREC Code is a guideline that stipulates the minimum standards for the reporting of Exploration Results, Mineral Resources, and Mineral Reserves; adds credibility to declarations by project promoters, and assists in comparisons due to the uniform basis of the declaration, assists professionals by providing guidance; assists the Competent Person to demonstrate the legitimacy of the declaration, and provides credibility to Public Reporting. The SAMREC Code provides guidelines and acts as one of the fundamental mechanisms to assist in the progression of mining projects. Importantly, it holds professionals accountable for their work, but does not specify the technical details relating to estimating Exploration Results, Mineral Resources, and Mineral Reserves. The SAMREC Code does provide guidance in the estimation and declaration of Exploration Results, Mineral Resources and Mineral Reserves; thus endorsing the sustainability of the mineral industry. A revision of the SAMREC Code was necessary because the mineral industry has advanced and has changed focus as the prevailing economic and political circumstances have changed. The manner in which projects and mines are funded, developed, and operated is continually altering; there are shifting requirements by the investment community, government, and society (social license to operate); there is a need to promote greater efficiency in capital raising and funding for exploration, mining, and production companies; and the SAMREC Code must keep abreast of the advances made by other international reporting codes and eliminate possible contradictory reporting practices. The aspects that have been addressed and updated in the 2016 SAMREC Code are as follows: The complete adoption of the Combined Reserves International Reporting Standards Committee (CRIRSCO) standard definitions Additional assistance with the understanding and reporting of Exploration Results The inclusion of a new table format and the adoption of the ‘If not, why not’ principle in reporting Further emphasis on economics and transparency/materiality Additional Technical Studies definitions and the inclusion of guidelines in terms of the composition of Technical Studies Provision of clarity as to the point of reference for a declaration Making a site visit by the Competent Person mandatory Revision of aspects relating to coal and improved alignment with SANS 10320 The provision of a more comprehensive diamond and gemstone section The introduction of a section on industrial minerals and metal equivalents Inclusion of recommendations for a table of contents, signature page, glossary of terms, and updating of definitions. The objective of this paper is to inform the reader of the changes to the SAMREC Code and to re-emphasize best practice for the declaration of Exploration Results, Mineral Resources, and Mineral Reserves. !" Reporting codes, SAMREC 2016.
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The development of the Combined Reserves International Reporting Standards Committee (CRIRSCO) family of international reporting codes is a response to a number of mining industry ‘bubbles’, e.g. the Poseidon nickel boom and bust of 1969/70 and the Bre-X scandal of 1997. Although the USA and Australia had already started developing their codes (1988 and 1989 respectively), the international initiative to standardize reporting definitions for Mineral Resources and Mineral Reserves began at the 15th Council of Mining and Metallurgical Institutions (CMMI) Congress at Sun City, South Africa in 1994. The ad-hoc International Definitions Group (later to become CRIRSCO) was tasked with the primary objective of developing a set of international standard definitions for the reporting of Mineral Resources and Mineral Reserves. Deliberations continued, with agreement being reached for the definitions of the two major categories, Mineral Resources and Mineral Reserves, and their respective sub-categories Measured, Indicated, and Inferred Mineral Resource, and Proved and Probable Mineral Reserves under the Denver Accord in 1997. Following these agreements, an updated version of the JORC Code was released in Australia in 1999 and the first SAMREC Code was issued in 2000. In 2002, the Combined Reserves International Reporting Standards Committee (CRIRSCO, now known as the Committee for Mineral Reserves International Reporting Standards) was formed, replacing the CMMI International Definitions Group with the mission to continue coordination between
* Coffey Mining (SA) Pty Ltd, South Africa. †University of Johannesburg, South Africa.
Š The Southern African Institute of Mining and Metallurgy, 2017. ISSN 2225-6253. This paper was first presented at the SAMREC/SAMVAL Companion Volume Conference ‘An Industry Standard for Mining Professionals in South Africa’, 17–18 May 2016, Emperors Palace, Johannesburg
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The 2016 SAMREC Code member countries for the development of international standards for the definition and reporting of Exploration Results, Mineral Resources, and Mineral Reserves. Subsequently, various other codes have been developed based on the CRIRSCO template. These now include nine national/regional reporting organizations (NROs): namely Australasia (JORC), Brazil (CBRR), Canada (CIM), Chile (National Committee), Europe (National Committee PERC), Mongolia (MPIGM), Russia (OERN), South Africa (SAMREC), and the USA (SME). The combined value of mining companies listed on the stock exchanges of these countries accounts for more than 80% of the listed capital of the mining industry (CRIRSCO website).
# $ # # $ ! " The mining industry is a vital contributor to national, regional, and international economies. There is a continuous demand for various mineral and metal commodities that necessitates finding new deposits, as well as developing more efficient, safer, and cheaper ways of mining and processing minerals. In an ever-changing world, new products are continuously being developed that require new commodities or the continued production of existing commodities. Commodities are frequently discovered in one area, beneficiated and refined in another, and sold or used in yet another location. The mining industry therefore transcends international boundaries and ‘depends on the trust and confidence of investors and other stakeholders for its operational well-being’ (CRIRSCO website). The process of developing a mining project or mine involves technical expertise, requires a substantial and longterm capital investment, and carries numerous uncertainties and risks. Unlike many other industries, mining is based on depleting assets, the knowledge of which is imperfect prior to the commencement of extraction. To mitigate the risks and obtain support (financial, political, social etc.) for the investment, a detailed technical, financial, environmental, governmental, and social understanding of the project/mine is required. It is therefore essential that the industry is able to communicate the investment risks effectively and thus provide a level of trust and confidence for investors and other stakeholders to allow project progression and a sustainable operation. Part of the communication is provided by the declaration of Mineral Resources and Mineral Reserves. The international codes provide significant guidelines that inter alia provide a common understanding of the project/mine. ‘The international mining industry has a need to communicate effectively. With meaningful standards in place and enforced, sound decision can be made by various stakeholders in their participation in a project, as well as the best way to progress it’ (Rendu, 2000). The aim of the SAMREC Code is to contribute to gaining and maintaining the trust of potential investors and other interested parties and stakeholders by promoting high standards of reporting of mineral estimates (Mineral Resources and Mineral Reserves) and of exploration progress (Exploration Results). Furthermore, the SAMREC Code contains specific guidelines for the Public Reporting of Exploration Results, Mineral Resources, and Mineral Reserves for mineral projects and mines. The SAMREC Code:
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Provides minimum standards for reporting of Exploration Results, Mineral Resources, and Mineral Reserves Adds credibility to declarations by project promoters and assists in the comparison with similar projects due to the uniform basis of declaration Assists professionals by providing guidance Assists the Competent Person to demonstrate the legitimacy of the declaration and provides credibility to the Public Report.
# ! The SAMREC Code does not specify the technical details relating to estimating Exploration Results, Mineral Resources, and Mineral Reserves. The interpretation of the raw data, the geological interpretation, engineering design, infrastructure requirements, and governmental, social, and environmental inputs are all required to be based on the contribution of specialists and signed off by a Competent Person. Because the geological model is open to interpretation and has a huge influence on the mine design and associated financial outlook of the mine or project, there is a need for guidelines. The SAMREC Code provides these guidelines and a mechanism to assist in the progression of mining projects, which includes holding professionals (Compentent Persons) accountable for their work. Over and above the technical work, the SAMREC Code requires the Competent Person to justify and document the technical inputs and the process underlying the declaration of Exploration Results, Mineral Resources, and Mineral Reserves. This approach relies on the Competent Person being prepared to face his/her peers and willing to take responsibility for the result. The aim of the SAMREC Code is to develop and maintain the trust of investors and other interested and affected parties by promoting high standards of Public Reporting. The SAMREC Code represents the minimum reporting standard and compels the Competent Person to rather report ‘more information than the barest minimum’. The SAMREC Code provides the guiding principles that support these declarations.
$ " # # ! As a result of increasing professionalism and updated methodologies, it is necessary to regularly review and update the SAMREC Code because: The minerals industry has advanced and changed focus as the prevailing economic and political circumstances have evolved The manner in which projects and mines are funded, developed, and operated is continually changing The requirements of the investment community, government, and society (social licence to operate) are shifting There is a need to promote greater efficiency in capital raising and utilization of funds for exploration, mining, and beneficiation The SAMREC Code must keep abreast of the advances made by other international reporting codes and eliminate possible contradictory reporting practices.
The 2016 SAMREC Code )"$#' #! ) ( &'&$&%'")# % $( In recent years, CRIRSCO has worked towards aligning all the international reporting codes so that the definitions used in the extractive industries are globally consistent. This consistency is based on insisting that the 15 standard definitions are commonly applied to all the international Codes (CRIRSCO, 2013). The following are the standard definitions commonly applied by CRIRSCO members: Public Reports Competent Person Modifying Factors Exploration Target Exploration Results Mineral Resource Indicated Resource Inferred Resource
Measured Resource Mineral Reserve Probable Reserve Proved Reserve Scoping Study Pre-Feasibility Study Feasibility Study
Consequently, the definitions in the SAMREC Code are required to be either identical to, or not materially different from, the other international definitions.
%!#$&%') (" $" The reporting of Exploration Results has occasionally been misused (or abused) as some Competent Persons have tended to be selective in their reporting. Because reporting of Exploration Results represents the entry level to declarations, a lot of effort has been made to ensure that these declarations are considered balanced reporting. Clause 18 of the SAMREC Code has been updated with the intention that Exploration Results must not be ‘presented in a way that unreasonably implies the discovery of potentially economic mineralisation’ and should include relevant data and information relating to the mineral property (both positive and negative). The SAMREC Code further advises that ‘historical data and information may also be included if, in the considered opinion of the Competent Person, such is relevant, giving reasons for such conclusions’. Guidance has also been
provided that ‘the data and information may be derived from adjacent or nearby properties if the Competent Person can provide justification of continuity for such an association’ (Rupprecht, 2015). Also, the deposit is referred to as ‘Mineralisation’ so as not to imply any degree of technical or economic study. The reporting of Exploration Targets in the updated 2016 SAMREC Code has not changed in that a range of tons and grade has to be reported. However, guidance is provided in the use of the data maxima and minima being required, and the requirement that an Exploration Target cannot be tabulated together with Mineral Resources and Mineral Reserves. It is hoped that this will clearly indicate the low level of confidence in the information and ensure that a reported Exploration Target cannot be misconstrued or misrepresented as a Mineral Resource or Mineral Reserve.
( )!( %!$&' ) %! #$ The 2016 SAMREC Code provides a comprehensive checklist for the Competent Person in the form of Table I. One of the criticisms of the previous SAMREC Code has been the formulation of this table. The revised Table I is now in a ‘landscape’ format with each section numbered with Arabic numerals. Each sub-section that existed in the 2009 Table I has been included in the various sections and numbered using Roman numerals (Figure 1). Additional information was sourced from the other international reporting codes and, where appropriate, the sub-sections of the original Table I reworded. It is believed that the new referencing will be easier for, inter alia, the JSE Reader requirements, and will assist Competent Persons to ensure they have addressed all the necessary reporting aspects. The structure attempts to follow the logical project progression from the scientific aspects relating to the geology in the first few sections to the engineering aspects in the later sections. The structure also cascades from Exploration Results to Mineral Resources and then to Mineral Reserves (proceeding left to right in the table).
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The 2016 SAMREC Code )'%$ ) )'%$ )!( %!$&' ) !&' & ( Table 1 in the 2016 SAMREC Code provides a comprehensive checklist of the various technical aspects that are required for an Exploration Results, Mineral Resources, or Mineral Reserve declaration. The use of the checklist for every declaration is considered best practice and if completed properly it can provide the Competent Person with assurance that no technical inputs or practices have been omitted. It also provides users with confidence that the declaration is fully compliant and can be relied upon. The revised SAMREC Code has included a requirement to report against Table 1 on an ‘if not, why not’ basis for maiden declarations and when a material change in the declaration has occurred for a significant project/mine. The reader is referred to the SAMREC Code glossary of terms for the definition of ‘material’ and a ‘significant project’. The 2016 SAMREC Code requires that every aspect of the Table 1 (checklist) must be answered by the Competent Person so as to adequately address all key elements of the reporting of Exploration Results, Mineral Resources, and Mineral Reserves. Where aspects of this table are not included in the Public Report, the Competent Person is required to comment as to why they have not been addressed. The motivation for this requirement is to improve ‘transparency’ and ‘materiality’, as well as making it more difficult to be ‘opaque’ or present ‘selective’ reporting in market releases or other Public Reports. ‘If not, why not’ reporting increases confidence in Public Reporting, as well as assisting the Competent Person to include all aspects that a reasonable stakeholder, investor, and advisors would expect to find in a Public Report. Furthermore, the reporting mechanism assists the Competent Person to provide all relevant details, whether they are perceived as positive or negative, in the Public Report.
#"&")%') %'% & ")#' ) !#'" #!(' #$(!&# &$ An ‘if not, why not’ approach is required in recognition of a perceived lack of transparency and/or materiality in Public Reporting. The SAMREC Committee felt that it was important that the aspects of balanced reporting are emphasized. An aspect often lacking in Public Reporting is the demonstration of ‘reasonable prospects for eventual economic extraction’. To this end, various points have been added to Table 1 to provide more detail to stakeholders, investors, and advisers, and which are aimed at improving the communication of results and engendering trust and confidence in the industry.
( '& # )"$ &(" The previous code contained definitions for Pre-Feasibility Study and Feasibility Study. This is appropriate, as the minimum requirement for the declaration of a Mineral Reserve is a Pre-Feasibility level study. The detailed requirements, although broadly understood, are frequently selectively considered. To assist in providing a common understanding, Table 2 has been included in the 2016 SAMREC Code to provide some detail and reduce the ambiguity of the definitions. It must be noted that these are generally recognized definitions and not mandatory. Since the previous edition of the SAMREC Code the concept of Preliminary Economic Assessment (PEA) has become increasingly popular in Canada. This is a synonym for a Scoping Study. As a result, and following the CRIRSCO
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lead, the definition of ‘Scoping Study’ is provided and supported by information provided in Table 2. It must be emphasized that a Scoping Study is not sufficient grounds to allow for the declaration of a Mineral Reserve.
' ( (' (' ( Independence of the Competent Person has been a topic of debate within the mineral industry. The SAMREC Code allows employees and people who have a vested interest in a project to sign off as the Competent Person. However, the relationship with the commissioning entity must be clearly stated. Defining independence can at times be extremely difficult and complex and it is therefore left to the commissioning entity to define if independence is a requirement.
%&'$)% )!( (!(' ( The declaration of a Mineral Resource and Mineral Reserve is linked to various common practices and economic realities. A declaration for precious and base metals typically reports grade as a head grade, i.e. prior to processing. However, the economics of bulk commodities and industrial minerals are linked to the saleable specification. Therefore, the concept of defining the point of reference has been introduced in the 2016 SAMREC Code to improve transparency and enhance communication and understanding.
&$() &"&$ Until now, the necessity of a site visit has not been definitive. The SAMREC Code now requires a site visit to be undertaken by a Competent Person. This is without a doubt best practice and assists the Competent Person in fully appreciating the technical complexities of the assignment. However, where a site visit is impractical or impossible due to, for instance, political unrest, this should be declared. In this case, the Competent Person cannot abstain from taking responsibility, although a caveat may be appropriate.
( &"&%')% )#" ( $")!( #$&' )$%) %# In parallel with the SAMREC Code update there has been a revision of the SANS coal standard (SANS 10320: South African Guide to the Systematic Evaluation of Coal Resources and Coal Reserves). It must be noted that this is a standard under the South African Bureau of Standards (SABS) and covers a slightly different ambit, which includes national reporting of Coal Resources and Coal Reserves. Nonetheless it includes various valuable aspects that are relevant to the declaration of Coal Resources and Coal Reserves. The SAMREC Code therefore requires that SANS 10320 is considered when preparing reports for Coal Resources or Coal Reserves. This has allowed the coal section of the 2016 SAMREC Code to be revised and abbreviated. It must be noted that some aspects of coal reporting were previously not fully consistent with the SAMREC Code; for example, the requirement for a Feasibility Study to be completed in order to declare a Proved Coal Reserve. The classification of Proved and Probable Coal Reserves has been modified to reflect a minimum requirement of a PreFeasibility Study or Life of Mine Plan, which now aligns this definition with international requirements. An additional change to coal reporting is the removal of reporting of In-Situ Coal Reserves in the 2016 SAMREC Code. It should be noted that this later concept is not lost and is still part of the SANS standard – but is no longer included in the SAMREC Code.
The 2016 SAMREC Code %!() % !( ('"& () &# %' )#' ) ( "$%'()"( $&%'
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The 2009 SAMREC Code had a diamond section. However, the section was not considered adequate in terms of the requirements of Public Reporting, and a significant revision was undertaken to include a set of guidelines for consideration when a Competent Person makes a public declaration. Ten additional clauses, as well as a diagram to demonstrate the relationship between Diamond Exploration Results, Diamond Resources, and Diamond Reserves, have been included in the 2016 SAMREC Code. Due to the number of changes in the diamond section of the Code and the specific nature of diamond reporting, readers are referred to the 2016 SAMREC Code for elaboration of these changes. Key areas discussed are:
The Competent Person must take responsibility for his/her work. The guidance provided in the form of a suggested signature page is aimed at identifying the Competent Person, noting their qualifications, affiliations, and relevant experience, as well as demonstrating that the Competent Person has indeed taken responsibility for their work or their contribution to the Public Report.
Stone size distribution Diamond price Geological domains Minimum representative parcel or samples for various deposits Use of kimberlitic indicator mineral chemistry in grade and value estimation Valuation of microdiamonds and sampling protocols Relationship between the micro- and macro-diamond portions of the size frequency distribution curve Recovery factors.
( &"&%')% )$ () #""& & #$&%') &# !# The classification diagram has been revised and although the change is minimal, the diagram (Figure 1 of the 2016 SAMREC Code) is now virtually the same as the CRIRSCO diagram. The important inclusion is Infrastructure as a Modifying Factor. In addition, specific diagrams have been drafted for coal and diamond classifications.
)!( # ( During the last few years the legislation affecting surveying has been revised in the form of the Geomatics Profession Act 19 of 2013. A consequence of this has been the disbanding of PLATO and the establishment of the South African Geomatics Council (SAGC) (statutory body) and the Institute of Mine Surveyors of South Africa (IMSSA) (learned society) to replace PLATO. These bodies have the necessary disciplinary codes and codes of ethics.
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The reporting of industrial minerals is a new section in the SAMREC Code. The broadening of the ambit of Exploration Results, Mineral Resources, and Mineral Reserves has necessitated that more specific information be provided when dealing with industrial minerals. Aspects mentioned include the importance of a market and the saleable specifications.
The designated Competent Person must be sure that they understand fully the meaning of the Competent Person designation and the responsibilities that go with it. Being a Competent Person is not only about the professional training a person has received, nor simply a matter of being in a supervisory role and certainly not just a matter of being designated – it means the person takes responsibility for their part of the Public Report. The responsibility of deeming oneself as a Competent Person lies with the individual as the ‘Competent Person must be clearly satisfied in their own mind that they are able to face their peers and demonstrate competence in the commodity, type of deposit and situation under consideration’ (SAMREC Code Clause 10). It is the responsibility of the Competent Person to be fully aware of all applicable rules and regulations before a signing off on a Public Report. The key professions in Public Reporting and declarations in terms of the Code are geology, surveying, and mining engineering. They are, naturally, supported by a number of other professionals such as economists, metallurgists, engineers (geotechnical, ventilation, civil, mechanical, electrical etc.), environmentalists, social scientists/ practitioners, and lawyers.
'$!% $&%')% ) ($# )( & # ('$" Metal equivalents are a contentious issue. However, some guidance is required and specifically the minimum requirements of grades, recoveries, and metal prices are emphasized. These have been included as a separate section in the SAMREC Code to provide better understanding and communication to the various stakeholders and interested and affected persons or parties.
# ()% ) %'$('$" Canadian National Instrument (NI) 43-101 is often considered a superior form of reporting due to its structure. The structure, like the guidelines in the SAMREC Code, does not guarantee the quality of the Public Report, which remains the responsibility of the Competent Person. However, the 2016 SAMREC Code now includes a suggested table of contents to assist the Competent Person in providing a readable document and improve communication of the technical aspects.
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Key changes to the SAMREC Code include the updating of the glossary of terms to provide a minimal consistency with the CRIRSCO Reporting Template. For instance, the definition of a Recognised Overseas Professional Organisation (ROPO) was updated to Recognised Professional Organisation (RPO). Other terms, such items as review, Competent Person’s Report, and audit have been added to the glossary of terms.
Geologists bring a range of important skills to the estimation of Mineral Resources, notably the discipline and rigor of science. Their interpretation of the often sparse data results in geological understanding and interpretation in the form of geological models. An important aspect of science is the ability to predict beyond the data. Geologists are able to assist in presenting the scientific aspects of a project/mine that allow the engineers to provide a technical solution for the exploitation of the mineralisation. The tool used is the geological model and associated grade or block model. The
The 2016 SAMREC Code value of the block model is that it provides the information necessary for mine and infrastructure design, supports the development of the mining schedule and informs mineral processing strategies, and underpins the declaration of Mineral Resources and Mineral Reserves.
! ( %! The mine surveyor is one of the key contributors to the mining industry. Surveyors are responsible for maintaining accurate plans of the mine. More importantly, the surveyor is responsible for the measuring process that keeps account of the monthly production (tonnage and grade) of the operation. In addition to this, the volumes of the waste dumps and other surface stockpiles are frequently determined. Mine surveying is considered to be a branch of mining science and technology and includes all measurements, calculations, and mapping that serve the purpose of ascertaining and documenting information at all stages from prospecting to exploitation and utilizing of mineral deposits by both surface and underground workings (International Society for Mine Surveying). Mine surveyors therefore work hand-in-hand with geologists and mining engineers, especially as regards the geometry of the deposit/orebody and the associated quality/grade. Mine surveyors assist with, and are an integral part of, the estimation of Mineral Resources and Mineral Reserves.
&'&' )(' &'((! The role of the mining engineer is to design, develop, and operate safe and efficient mines, whether surface or underground operations. Their role is to combine an understanding of the deposit with the various engineering disciplines by applying their technical knowledge and management skills. The mining engineer will assess the technical, engineering, and commercial viability of a project or mine. This requires the design of a possible mine, including geotechnical engineering, production requirements/profiles, equipment specifications, ventilation, health and safety, etc. These technical aspects may be reported in a Scoping Study, Pre-Feasibility Study or Feasibility Study, or Life of Mine Plan for an existing mine and will form the basis of the declaration of a Mineral Reserve. Mining engineers are able to undertake the various technical or engineering aspects of a mining operation, which are a series of very complex tasks, and formulate a mine plan and schedule that can be executed. The financial valuation of a project or mine relies on geological and grade models that are the result of scientific modelling, together with engineering skills provided by the mining engineer and other experts and specialists.
! $! # # The way forward for Competent Persons is to embrace the 2016 SAMREC Code and appropriately apply the guidelines. It is safe to assume that increased attention will be given to Public Reporting in the future, partly in response to the launch of the revised SAMREC Code. Use of the SAMREC Code should be motivated by the desire to provide the best technical output possible rather than by a fear of the consequence of making a mistake or being found on the wrong side of the SAMREC Code’s guidelines. By complying with the SAMREC Code, Competent Persons can enhance their reputation and the reputation of the mining industry.
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Although the revised SAMREC Code came into effect on 1 January 2017, there remain some unresolved issues, for example, the reporting of Mineral Resources inclusively or exclusively of Mineral Reserves, and the registration of Competent Persons. These are complex issues that will require further discussion. Other issues can be expected to arise in the future and will also need to be discussed. It is hoped that the solution to these issues and new issues can be resolved through public debate or articles on best practice rather than having to revise or update the Code in the near future.
$ " $ In preparing a Public Report the practitioner must satisfy the requirements of the SAMREC Code. The intention of the SAMREC Code is to aid the Competent Person in the declaration of Exploration Results, Mineral Resources, and Mineral Reserves. The authors acknowledge that no single document could cover all accepted industry practices or assist with all possible situations. However, the aim of the SAMREC Code is to provide guidance that represent the best current knowledge in terms of reporting practices. Competency and diligence are still required when applying the SAMREC Code, as the Competent Person must balance the unique situation of a deposit with best practices. Despite having the SAMREC Code available, Competent Persons are still required to be prepared to defend themselves to their peers and take responsibly for their work. The amount of effort that may be required in complying with the revised Code must not be underestimated. However, the hope is that the industry will see improved communication and the positive progression of projects and mines as a result of these changes.
$ ! $#" This paper could not have been written without the contributions made by the many friends and fellow professionals who have contributed to the writing and revision of the SAMREC Code over the last 15 years. Although the authors have been involved only in the last six years, we owe them an immense debt. Naming them all would be impossible.
$ " BIRCH, C. 2014. New systems for geological modelling – black box or best practice? Journal of the Southern African Institute of Mining and Metallurgy, vol. 114. pp. 993–1000. BLUMER, J.M. 2000. The Valmin Code – Bible, Roadmap or Signpost? International Aspects of Resource and Reserve Reporting in MICA. The Codes Forum, Sydney. RENDU, J.M. 2000. International aspects of Resource and Reserve Standards. International Aspects of Resource and Reserve Reporting in MICA. The Codes Forum, Sydney. RUPPRECHT, S.M. 2015. The SAMREC Code 2105 — some thoughts and concerns. Journal of the Southern African Institute of Mining and Metallurgy, vol. 115, no. 11. pp. 987-991. SAMREC. 2009. South African Mineral Resource Committee. The South African Code for Reporting of Exploration Results, Mineral Resources and Mineral Reserves (the SAMREC Code). 2007 Edition as amended July 2009. http://www.samcode.co.za/downloads/SAMREC2009.pdf SAMREC. 2016. South African Mineral Resource Committee. The South African Code for the Reporting of Exploration Results, Mineral Resources and Mineral Reserves (the SAMREC Code). 2016 Edition. http://www.samcode.co.za/codes/category/8-reportingcodes?download=120:samrec
http://dx.doi.org/10.17159/2411-9717/2017/v117n12a2
Mineral Resource and Mineral Reserve governance and reporting for AngloGold Ashanti by R. Peattie, V. Chamberlain, and T. Flitton
Mineral Resource and Mineral Reserve governance is the comprehensive, overarching management process by which the Mineral Resource and Mineral Reserve is estimated, managed, and reported. Mineral Resource and Mineral Reserve governance provides the Board of Directors and investors with assurance on the integrity of the reported Mineral Resource and Mineral Reserve, which is the primary asset of the company and upon which investment decisions are based. The framework for Mineral Resource and Mineral Reserve governance of a company must be compliant with all regulatory codes as well as internal company policies and procedures. It is critical to ensure that reporting is transparent, appropriate, timeous, and reliable. Good Mineral Resource and Mineral Reserve governance should also ensure that all components in the estimation (from exploration to processing) of the Mineral Resource and Mineral Reserve are auditable and defendable. AngloGold Ashanti (AGA) is acutely aware that its primary asset is its Mineral Resource and Mineral Reserve, and has therefore established a formal Mineral Resource and Mineral Reserve governance process that has been structured to ensure that the Executive Committee and the Board have line of sight to the annual Mineral Resource and Mineral Reserve Public Reporting, as well as the review findings from a stringent internal and external review programme. SAMREC, governance, Mineral Resource, Mineral Reserve, Competent Person.
AngloGold Ashanti (AGA) has a number of operations across ten countries (Figure 1) and is listed on four stock exchanges, therefore its public reporting must comply with the requirements of a number of different regulatory bodies across multiple jurisdictions. With the first publication of the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves (‘the JORC Code’) in 1989 and the subsequent publishing of the South African Code for the Reporting of Exploration Results, Mineral Resources and Mineral Reserves (the SAMREC Code) in 2007, AGA quickly recognized that the processes in place within the company for the reporting of Mineral Resources and Mineral Reserves were inadequate for the evolving regulatory environment. In response, the company embarked on a 10-year journey to develop a far more formalized, structured, and standardized approach to reporting.
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* AngloGold Ashanti, South Africa. Š The Southern African Institute of Mining and Metallurgy, 2017. ISSN 2225-6253. This paper was first presented at the SAMREC/SAMVAL Companion Volume Conference ‘An Industry Standard for Mining Professionals in South Africa’, 17–18 May 2016, Emperors Palace, Johannesburg
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To simplify this process and provide standardization, AGA manages its Mineral Resource and Mineral Reserve reporting in terms of the SAMREC Code, supported by internal guidelines. The internal guidelines are set out to ensure the reporting of Exploration Results, Mineral Resources, and Mineral Reserves is consistently undertaken in a manner in accordance with AGA’s business expectations and also in compliance with internationally accepted codes of practice adopted by AGA. The document outlines the minimum requirement for reporting to ensure that the process is consistent and transparent across AGA. AGA follows a process-driven approach to the reporting of its Mineral Resource and Mineral Reserve. The lead is taken by the AGA Mineral Resource and Ore Reserve Reporting Committee (RRSC), whose membership and terms of references are mandated under a policy document signed off by the Chief Executive Officer. Its primary function is as a facilitator of the process, setting the requirements and the standards of quality. AGA recognizes that the reporting of AGA’s Mineral Resource and Mineral Reserve is the responsibility of the company acting through its Board of Directors; with access to the Board being through the Board Audit Committee. The final published outcome is based on Mineral Resource and Mineral Reserve reports and supporting documentation prepared by Competent Persons (CPs). To achieve this outcome and ensure regulatory approval, all CPs are members of SACNASP, ECSA, or SAGC, or are a Member or Fellow of the SAIMM, the GSSA, IMSSA, or a Recognized Professional Organization (RPO).
Mineral Resource and Mineral Reserve governance and reporting for AngloGold Ashanti
The CPs also need to have a minimum of five years’ relevant experience in the style of mineralization and type of deposit under consideration and in the activities they are undertaking. Appointment of the individual CPs is by the General Manager, with oversight and ratification by the RRSC. Two CPs are appointed for each operation, one for Mineral Resources and the other for Mineral Reserves.
The RRSC, which meets at least once a quarter, comprises representatives from the relevant technical disciplines as well as regional representatives. The Senior Vice President: Strategic and Technical chairs the RRSC to ensure the requisite level of authority is assigned to the Committee. The RRSC is responsible for setting and overseeing the company’s Mineral Resource and Mineral Reserve governance framework and for ensuring that it meets the company’s goals and objectives while complying with all relevant regularity codes. Its primary function is corporate assurance and its terms of reference and composition are fixed through a policy document approved by the Chief Executive Officer. They include: Providing Group guidelines for the reporting of Mineral Resources and Mineral Reserves Compilation of the Group’s annual Mineral Resource and Mineral Reserve statement Engagement with external regulatory bodies such as JORC, SAMREC, and the SEC to ensure that AngloGold Ashanti’s interests are protected
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Providing assurance that all Mineral Resource or Mineral Reserve reporting complies with the relevant reporting codes as well as internal Group guidelines The ratification of CPs Ensuring regular external reviews of Mineral Resources and Mineral Reserves. The key outputs of the RRSC are the annual Mineral Resource and Mineral Reserve report and the requisite internal Group guidelines for the reporting of Mineral Resources and Mineral Reserves. Due to the ever-evolving regularity environment, a key aspect of the RRSC is to continuous align itself to the changes and ensure the timeous briefing and training of the CPs.
# " # " # The Group guidelines for the reporting of the Mineral Resource and Mineral Reserve is an annual document that formalizes AGA’s interpretation of the various listing requirements, regulatory frameworks, and reporting codes, including the Johannesburg Stock Exchange (JSE) and the Securities and Exchange Commission (SEC), SAMREC, and JORC, and provides the necessary company context and detail required for the estimation and reporting of Mineral Resources and Mineral Reserves on an annual basis. It is a live document that is reviewed on an annual basis and whose owner is the RRSC. To ensure compliance with internationally accepted codes of practice adopted by AngloGold Ashanti, the main principles inherent in the language of the document are transparency, materiality, and competence. To consistently achieve these principles across the
Mineral Resource and Mineral Reserve governance and reporting for AngloGold Ashanti company, the guidelines provides the standardization and necessary detail regarding the material assumptions used in the declaration of the Mineral Resource and Mineral Reserve, including: Gold price and other critical economic parameters such as exchange rates Minimum reporting requirements for a new Mineral Resource and Mineral Reserve Detailed definition and work flows for Mineral Resource classification Guidelines for reporting reconciliation, cut-off grades, modifying factors, Inferred Mineral Resource in the business plan, Mineral Resource and Mineral Reserve below infrastructure, Mineral Resource sensitivities Guidelines for Competent Persons Reports (CPRs).
Competency and the competent person (CP) are an integral part of all of the reporting codes. AGA has recognized the importance of selecting the appropriate individuals with the relevant experiences and expertise to become CPs at its operations and projects across the world, and therefore has a formalized approach to the appointment of its CPs. CPs are appointed by the relevant manager of the operation in question and the appointments are ratified by the RRSC. CPs are preferably employed by AGA and are selected based on relevant experience with the style of mineralization and type of deposit under consideration and with the activity that they are undertaking. To ensure that the CPs consent to the inclusion of Mineral Resource and Mineral Reserve information in the annual report, they sign a letter of consent once they have reviewed the information in the form and context in which it appears. A critical aspect of this approval is ensuring that the legal tenure of each operation and project has been verified to the satisfaction of the accountable CP and all Mineral Reserves have been confirmed to be covered by the required mining permits or there is a realistic expectation that these permits will be issued. Due to the different experience and skills sets required for the estimation and evaluation of Mineral Resources and Mineral Reserves, AGA has separate appointments for Mineral Resources and for Mineral Reserves. This is reinforced by a professional development and support structure to ensure that the CP is fully briefed on the evolving external governance and has the necessary network and training to ensure best practice. A key aspect of the management of the CPs is the training and succession planning required to ensure the skills and experiences remain in-house to allow the ongoing reporting of the Mineral Resources and Mineral Reserves.
that each operation or project will be reviewed by an independent third party on average once every three years. The external reviews focus on the identification of fatal flaws, and through impartiality they provide an independence verification that the reporting is in terms of the requirements of the various codes. Internal peer reviews are completed on an annual basis before all annual information is captured by the CPs. This review consists of an informal process that involves the relevant CP having to defend their work to their peers, and a formal process where the reviewer will attempt to replicate aspects of the work independently. The peer review process is seen as an integral aspect of the audit and review process in ensuring consistency, in propagating best practice across the company, and for the personal development of the individuals involved. In addition, all variation in excess of 10% (net of depletion) in the individual operation or project’s Mineral Resource and/or Mineral Reserve statement) requires a formal review by the RRSC.
AGA makes use of a web-based group reporting database called Resource and Reserve Reporting System (R3) for the compilation and authorization of Mineral Resource and Mineral Reserve reporting. R3 is a fully integrated system for the reporting and reconciliation of Mineral Resources and Mineral Reserves that supports various regulatory reporting requirements, including the SEC and the JSE under SAMREC. AGA uses R3 to ensure that a documented chain of responsibility exists from the CPs at the operations to the company’s RRSC. The web-based reporting system provides a platform that ensures a single version of the truth is captured in a secure, auditable database that is workflow-enabled. The system has a comprehensive set of validation rules that include, but are not limited to, the following: The Mineral Resource needs to be captured/imported before the Mineral Reserve can be captured Mineral Reserve content cannot be greater than Mineral Resource content per project area Inclusive Mineral Resource content must always be greater than or equal to exclusive Mineral Resource context The previous year and all changes in the reconciliation capture must sum up to the current year total for tons and grams The Inferred Mineral Resource in a business plan content cannot be greater than the inclusive Inferred Mineral Resource content.
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Over more than a decade, AGA has developed and implemented a rigorous system of internal and external reviews aimed at providing assurance in respect of Mineral Resource and Mineral Reserve estimates. External reviews are done on selected operations, in line with AGA’s policy
This system is compliant with the guiding principles of the Sarbanes-Oxley Act of 2002 (SOX) and forms the supporting database from which the Mineral Resource and Mineral Reserve report is published on an annual basis. To support the reporting process, the system also contains a database of the various technical specialists and CPs, together with a record of their experience and qualifications. A clear division of responsibilities is assigned within the system that
Mineral Resource and Mineral Reserve governance and reporting for AngloGold Ashanti
requires a rigid hierarchy of work flow sign-offs; this ensures that the relevant people have access to the information for review and approval before it is made publicly available (Figure 2). R3 assigns individual responsibilities that can be tracked and managed and allows remote access for data upload by the relevant technical specialists and approvals and consent by the CPs. Access, authorizations and work flow sign-off is through a unique secure login that allows a full audit trail. R3, first conceptualized in 2003 and rolled out in 2004 as a data capture and company database of the Mineral Resource and Mineral Reserves, immediately proved itself by providing a single source of the truth and minimizing human error involved in handling large data-sets. Since then it has evolved into a fully integrated system for the reporting and reconciliation of Mineral Resources and Mineral Reserves that supports reporting to the SEC and the JSE under SAMREC. It achieves this by providing the relevant details, summaries, and reconciliations for end-of-year reporting, together with the necessary consents. For any particular year of consideration, R3 provides the following information: Mineral Resource (inclusive and exclusive of Mineral Reserve) and the Mineral Reserve statement
and Mineral Reserve governance and reporting process is to ensure that the right people are doing the right work and that the information that is being made publicly available is fully vetted, compliant, and transparent, and therefore meets the guidelines in the South African Code for the Reporting of Exploration Results, Mineral Resources and Mineral Reserves (SAMREC Code). To achieve this end, AGA has developed a rigorous Mineral Resource and Mineral Reserve governance and reporting process that is supported by a set of internal Group guidelines, a structure for the management of the process, and an integrated Group reporting database. This is complemented by a combination of internal and external audits and reviews to ensure independence and impartiality and that the individual operations and projects are estimating and compiling their Mineral Resources and Mineral Reserves in accordance with the company guidelines and external regulatory requirements. The sum result is a process that ensures that the Executive Committee of AGA and the Board through the Board Audit Committee have line of sight to the annual Mineral Resource and Mineral Reserve public reporting as well as the review findings from a stringent internal and external review programme, and thus the assurance in the integrity of the reported Mineral Resource and Mineral Reserve, which is the primary asset of the company and upon which investment decisions are based. AGA recognizes that both the regulatory framework and the definition of best practice are continuously evolving, and that therefore it is important that the governance framework is sufficiently dynamic to respond to the ever-changing environment. Through the RRSC, AGA has the structure to both manage the Mineral Resource and Mineral Reserve governance and reporting process and react to these changes in a timely manner. The current process is a work in progress, and while it currently meets the corporate and governance requirement it is continuously being improved to keep pace with the regulatory changes and increases in corporate expectations.
Inferred Mineral Resource used in business plan Mineral Resource and Mineral Reserve below infrastructure By-product information Reconciliations details Mineral Reserve modifying factors Professional details of all CPs Letters of appointment Letters of consent for publication Tenement information CP Reports (CPRs) Statement of competence Documented chain of responsibility JORC Table 1 and the SAMREC Table 1.
The foundation of AngloGold Ashanti’s Mineral Resource
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# ANGLOGOLD ASHANTI. 2014. Mineral Resource and Ore Reserve Report. 192 pp. ANGLOGOLD ASHANTI. 2015. Guidelines for the reporting of Mineral Resources and Ore Reserve. Internal report. 57 pp. CANADIAN SECURITIES COMMISSIONS (CSA). 2005. National Instrument 43-101. Standards for disclosure for mineral projects. JORC. 2012. Australasian Joint Ore Reserves Committee. Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves. The Joint Ore Reserves Committee of the Australasian Institute of Mining and Metallurgy, Australian Institute of Geoscientists, and Minerals Council of Australia. http://www.jorc.org/docs/JORC_code_2012.pdf SAMREC. 2009. South African Mineral Resource Committee. The South African Code for Reporting of Exploration Results, Mineral Resources and Mineral Reserves (the SAMREC Code). 2007 Edition as amended July 2009. http://www.samcode.co.za/downloads/SAMREC2009.pdf SAMREC. (2016). South African Mineral Resource Committee. The South African Code for the Reporting of Exploration Results, Mineral Resources and Mineral Reserves (the SAMREC Code). 2016 Edition. http://www.samcode.co.za/codes/category/8-reportingcodes?download=120:samrec
http://dx.doi.org/10.17159/2411-9717/2017/v117n12a3
Good reporting practices by S.M. Rupprecht
The SAMREC Code sets out the minimum standard for the Public Reporting of Exploration Results, Mineral Resources, and Mineral Reserves. When making a declaration the Competent Person (CP) must disclose relevant information concerning the status and characteristics of a mineral deposit that could materially influence the economic value of the deposit and promptly report any material changes. The Johannesburg Stock Exchange (JSE) Listing enlists Panel Readers to review all CP Reports and annual reports for their compliance with the SAMREC Code and Section 12 of the JSE Listing Requirements. The JSE Readers Panel assists in achieving reporting compliance. However there are still many Public Reports that are not formally reviewed. Thus, the SAMREC Code is largely reliant on self-regulation. Although Clause 11 of the SAMREC Code makes provision for complaints made in respect of Public Reporting, complaints are rarely made. Yet, noncompliant reporting remains an issue within the southern African mineral industry. This paper investigates compliance of Public Reports and some of the common compliance issues currently being experienced. The paper also discusses methodologies to improve compliance and Public Reporting, such as self-regulation, coaching and training, and other means to promote good reporting compliance. '! * Public Reporting, good practice, self-regulation.
% The South African Code for the Reporting of Exploration Results, Mineral Resources and Mineral Reserves (The SAMREC Code) contributes to promoting the minimum requirements of Public Reporting. A declaration in terms of The SAMREC Code requires the Competent Person (CP) to be prepared to defend themselves to their peers. The Code relies on this peer review process and is therefore effectively self-policing. The effectiveness of this self-policing has been debated since the inception of the Code, and although it is sometimes seen as ineffective, self-regulation is the preferred method to monitor Public Reporting. The Poseidon Nickel bubble of 1970 and the Bre-X scandal of 1997 motivated the creation of international reporting codes, which provide investors, potential investors, and other stakeholders with a sense of confidence in statements made by promoters
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* University of Johannesburg, South Africa. Š The Southern African Institute of Mining and Metallurgy, 2017. ISSN 2225-6253. This paper was first presented at the SAMREC/SAMVAL Companion Volume Conference ‘An Industry Standard for Mining Professionals in South Africa’, 17–18 May 2016, Emperors Palace, Johannesburg
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and owners of mineral projects. Consequently, the aim of the SAMREC Code is to maintain the trust of investors and other interested parties by promoting high standards of Public Reporting. The SAMREC Code is meant as a minimum reporting standard and advises CPs to report ‘too much information rather than too little’ (Clause 32 of the SAMREC Code). Opponents to the monitoring of Public Reporting practices are of the opinion that the Code is presented as a guideline and therefore regulating reporting practices is not necessary. Furthermore, opponents feel that some responsibility must be placed on the investor to be diligent when investing in an exploration or mineral company. The author does not concur with the above opinions, as the mineral industry relies on investments to support project development and, furthermore, the industry historically had a tarnished reputation. Mark Twain in the 1880s famously defined a mine as ‘a hole in the ground with a liar on top’. Events such as the 1970s Poseidon Nickel boom-to-bust, Bre-X, and Enron highlight unscrupulous or fraudulent behaviour. In South Africa, recent failures such in coal, platinum, and gold projects and other commodities have eroded investor confidence, for example the delisting of Miranda Coal and closure of Burnside gold mine. In an industry that requires investor capital, often as seed money to fund early exploration or development projects, ensuring investor confidence is paramount. Public companies listed on the Johannesburg Stock Exchange (JSE) must adhere to the ongoing reporting requirements in terms of Section 12.11 of the JSE Listing Requirements. When a company reports
Good reporting practices according to the SAMREC Code, the public should have a sense of confidence that the information that has been reported is relevant, factually correct, and provides full disclosure. Fortunately, most companies adhere to the principles and guidelines of the SAMREC Code. In some cases, minor oversights may occur but generally companies observe the underlying values of the Code. Regrettably, there is a minority of companies that do not understand the importance of good ongoing reporting and fail to adhere to industry best practice. In these cases, Exploration Results, Mineral Resources, and Mineral Reserves are reported in an inappropriate manner, leaving the public uninformed as reporting fails to comply with the Code fully, misinterprets data, distorts information, or fails to disclose material information fully. The mineral industry is a difficult enough investment without being encumbered by poor disclosure, non-transparency, and poor quality and/or incompetent reporting. This paper discusses the issues around compliant Public Reporting and the SAMREC Code. The paper also discusses the governing principles of the Code, self-regulation and complaints procedures, and provides examples of noncompliant reporting. Reference is made to the revised 2016 SAMREC Code and recommendations made going forward regarding Public Reporting, self-regulation, and teaching and mentoring of industry professionals.
$ ! " ! " " !" ! In the course of Public Reporting, CPs sometimes overlook the governing principles of the SAMREC Code, i.e. Transparency, Materiality, and Competence (Figure 1). Materiality signifies that all relevant information should be made available and that reasoned and balanced reporting should be undertaken. One of the main purposes in developing the Codes was to ensure that various stakeholders, investors, and their professional advisors would be provided with sufficient information for the purpose of making a reasoned and balanced decision. Critical to Public Reporting is the principle that any material aspects for which the presence or absence of comment could affect the public perception or value of the mineral occurrence must be disclosed.
Transparency requires that the CP provide sufficient information, which is clear and unambiguous, and that the CP does not mislead or omit material information. As a rule, it is better for the CP to provide too much information rather than too little. Transparent reporting provides the public with confidence. Competency requires that all technical work conducted is done by suitably qualified and experienced persons who are subject to an enforceable professional code of ethics and rules of conduct. It is important that the CP is not unduly affected by outside influences and remains able to present a fair and accurate report. Persons undertaking the role of a CP must be capable of defending their professional opinions and not be intimidated by interested parties. CPs, executives, and other interested parties of publicly listed companies are reminded that the Code sets out the required minimum standards for Public Reporting. CPs, as authors, must insist that they provide written approval (JSE Listing Requirement) of specific documentation that is referred to in a Public Report or statement. The CP must be satisfied as to the form, content, and context in which that documentation is to be included in a Public Report. As a reminder to the reader, the Code (Clause 3) defines Public Reports as follows: Public Reports are all those reports prepared for the purpose of informing investors or potential investors and their advisers and include but are not limited to companies’ annual reports, quarterly reports and other reports included in JSE circulars, or as required by the Companies Act. The Code also applies to the following reports if they have been prepared for the purposes described in Clause 3: environmental statements; information memoranda; expert reports; technical papers; website postings; and public presentations. And T8 (A)(ii) Announcements by companies should comply with the SAMREC Code, where applicable, and insofar as they relate or refer to a Competent Person’s report they should: (a) Be approved in writing in advance of publication by the relevant Competent Person. Unfortunately, Clause 3 is often overlooked by companies. Some Public Reports fail to comply with the above clause and a number of public statements fail to gain approval from the responsible CP prior to the announcement.
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Good reporting practices In the context of complying with the principles of the Code, the CP is required to comment on the relevant sections of Table 1 of the SAMREC Code. The 2016 SAMREC Code introduces, similar to the 2012 JORC Code, an ‘if not, why not’ approach to the reporting as per Table 1. This necessitates that each item listed in the table be discussed, and if not discussed then the CP must explain why it has been omitted from the documentation. This additional requirement to the Code improves transparency and ensures that the Public Report is clear to the reader (public) and that all items have been considered and have been addressed or resolved.
! In terms of Public Reporting, compliance requires reporting in accordance with the principles and guidelines of the SAMREC Code. The importance of compliance is the underlying requirement to provide the public with confidence. Based on discussion held within the SAMREC Committee, some mining professionals believe that the Codes are becoming overly onerous, while others believe that CP Reports (CPRs) should be made simpler and easier to complete, advocating the use of a ‘short form’ CPR. The author rejects the above premise and stresses the need for comprehensive and fully disclosed Public Reporting. CPRs and other Public Reports, including news releases, should not be taken lightly, noting that Public Reports must ensure that information provided is unambiguous and provide sufficient information for a reasonable person to make an informed decision on the viability of a project and whether to invest or disinvest. A short form report, basically equivalent to an executive summary, is incapable of providing sufficient detail to sufficiently inform an investor.
registration has not materialized, as many CPs believe that there is sufficient regulation or guidelines in place to ensure competence – the real issue is non-compliance in reporting and the lack of discipline for poor reporting practices. Selfregulation is seen as the preferred method of control, but it requires peers to monitor CPs’ work and to report noncompliance. Some professionals believe that the onus on competency should lie with statutory registration bodies such as SACNASP, SAGC, IMSSA, or ECSA. The issue of competency is sometimes confused with the fact that a CP must be a member of ECSA, SACNASP, SAGC, IMSSA, or member/fellow of the SAIMM, GSSA or a recognized professional organization (RPO), all of which have enforceable disciplinary processes including the power to suspend or expel a member/fellow. This is important in that these professional organizations provide an enforceable Professional Code of Ethics, which is a basic requirement for a CP. Although these organizations have disciplinary powers, they in themselves do not determine whether a person is competent. The responsibility of deeming oneself as competent relies on the individual as the ‘Competent Person should be clearly satisfied in their own mind that they could face their peers and demonstrate competence in the commodity, type of deposit and situation under consideration’ (SAMREC Code, Clause 10). It is up to a CP’s peers to ensure that indeed authors of technical (Public) reports act in a competent, responsible, and ethical manner. The CP must demonstrate their own competency applying to a Code of Ethics and if in doubt a person should either seek the opinion from appropriately experienced peers or should decline to act as a CP for that specific job.
!" " !"& " ! ! "( ! " #! " " ! !
The role of the JSE Reader is to ensure that a CPR or annual report is conducted in accordance with the requirements of the SAMREC and SAMVAL Codes, and the JSE Listing Requirements, indicate errors in the text, and indicate whether plans and diagrams accompanying the Public Report support the content of the report. The JSE Reader must be satisfied that the Competent Person or Competent Valuator complies with the professional registration requirements and experience as set out in Clause 7 to 10 of the SAMREC Code and/or Clause 9 and 10 of the SAMVAL Code. The JSE Reader also must ensure that the Competent Person/Competent Valuator, in terms of a CPR, has correctly referenced the SAMREC and SAMVAL Code (Table 1) or JSE Listing Requirements in the CPR or annual report. The Reader’s job is not to provide sign-off on the technical aspects of the work nor validate the conclusions of the CPR. It must be acknowledged that there is an element of peer review in the process of ensuring that technical work makes sense and is fair and reasonable. For example, the JSE Readers guidelines state that ‘the Reader should comment on issues which, based on his/her experience appear technically incorrect or inadequately covered’. However, in the end the CPR remains the responsibility of the author(s). The JSE Readers Panel review process is viewed by other countries as a good process. However, JSE Readers Panel reviews are only activated in certain situations and not all
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One cannot discuss compliance with the SAMREC Code without discussing competency of the CP. The glossary of terms as provided in the SAMREC Code has no definition provided for competency, yet competency is one of the fundamental components of the Code. Competency, as described in Clause 4 of the SAMREC Code, is as follows: ‘The Public Report is based on work that is the responsibility of suitably qualified and experienced persons who are subject to an enforceable Professional Code of Ethics’. Although Clause 9 of the Code does provide clarity on the definition of a CP it relies on the individual to act competently. ‘A Competent Person is a person who is registered with SACNASP, ECSA or SAGC, IMSSA, or is a Member or Fellow of the SAIMM, the GSSA or a RPO’. ‘A Competent Person must have a minimum of five years’ experience relevant to the style of mineralisation and type of deposit or class of deposit under consideration and to the activity he or she is undertaking’. For a number of years the JSE has been requesting a registration list for CPs. The reasoning behind this drive is to improve the quality of Public Reporting, the objective being that only persons that have demonstrated their ‘competency’ would be able to provide CPRs to the JSE. To date this
Good reporting practices published CPRs are reviewed, especially those conducted for companies not publicly listed. The reader must understand that many CPRs have not been formally reviewed. Furthermore, the JSE Readers review process is not without its problems. One of the dilemmas with the Readers review process is that a CPR encapsulates a number of areas that may stretch the capabilities of a single Reader. For example, the Reader may be required to be knowledgeable in mineral resources, geotechnical engineering, mine engineering, ventilation, metallurgical processes, environmental, infrastructural, marketing, governmental and social aspects, as well as the valuation of mineral projects. It may be prudent for the JSE to introduce more than one reader to conduct reviews of CPRs, thereby improving the overall review process. However, it must be recognized that ultimately the CPR remains the responsibility of the CP(s). As of 2014, the JSE Readers Panel has also begun to review annual reports of mineral and exploration companies to ensure compliance with the ongoing reporting requirements in terms of Section 12.11 of the JSE Listing Requirements. The second year of reviewing annual reports has generally seen an improvement in compliance with the JSE Listing Requirements [SAMREC Code], however, compliance still can improve.
" ! ! Professionals when coming across noncompliant Public Reports need to consider if the breach warrants action. The SAMREC Code provides a means to make formal complaints, and Clause 11 states ‘complaints in respect of the Public Report of a Competent Person will be subject to the complaints procedures of the [The SAMCODE Standards Committee] SSC.’ The written complaint will be referred to the Complaints Sub-committee, which will review the complaint with the complainant so as to best define the nature of the alleged breach; identify the correct professional/statutory/certifying organization where the complaint needs to be lodged; and assist the complainant to lodge their grievance in the prescribed manner of the applicable organization. The relevant body may be any of the following: SACNASP, ECSA, PLATO (now the South African Geomatics Council (SAGC), the Institute of Mine Surveyors of South Africa (IMSSA), GSSA, SAIMM, or other Recognized Professional Organization (RPO) to which the CP or Competent Valuator is affiliated (Learned Society or Statutory Body). The Complaints Sub-committee will also be available to assist the ethics/disciplinary committee of the professional/statutory/certifying organization in understanding and/or investigating the nature of the alleged SAMCODES-related violation, if requested to do so by that organization. The difficulty in managing the quality of Public Reports has been the reluctance of mining professionals to regulate their peers and to ensure that Public Reports properly adhere to the Code. The number of noncompliant Public Reports observed by the author indicates that there are members of the mineral industry that are not concerned with compliance. Perhaps this is due the fact that over the past 15 years there have only been a few complaints made to the SSC and
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therefore there is an attitude that little, if any action is taken for noncompliant reporting. Based on the author’s experience, it appears that there are a few CPs, mining executives, and senior managers that project a laissez faire attitude toward Public Reporting and that for some there is a resistance to change reporting practices. A general review of exploration and mining company’s web sites will support the above statement. Although the author could reference several indiscretions, it is not the intention of this paper to embarrass individuals or companies but rather highlight the issue.
The need for self-regulation and action on noncompliant reporting has been an issue and a matter for debate since the inception of the SAMREC Code. There are many reasons for a general lack of discipline in the industry, one being that CPRs are often under confidentiality agreements. Another is the reluctance of practising CPs to make formal complaints against peers – justifying the lack of criticism under the proverb ‘persons who live in glass houses shouldn’t throw stones’. Non-compliance in reporting is not limited to South Africa but is a problem for all reporting countries. A general consensus is that more focus should be on coaching and mentoring of CPs. Rather than viewing complaints as a process of taking disciplinary action or sanctions against CPs, there should be a move towards coaching and mentoring. It is proposed that the SSC, through each of the Code Committees, form a subcommittee whose primary objective is to promote short courses through the GSSA and/or SAIMM to improve knowledge of the Code and its reporting requirements. Similarly, it may be prudent for the learned societies to publish (anonymously) corrective actions taken for noncompliant reporting. The AusIMM successfully does this and the author believes that this approach should be adopted in South Africa. It is interesting to note that if noncompliance is established, the AusIMM may impose a penalty, which may include a reprimand, mediation, and/or counselling. However, suspension of membership to the AusIMM is not imposed by the Complaints Committee, as may be the case with some of the South African professional/statutory bodies. The Canadian Ontario Securities Commission in 2013 undertook a compliance review of 50 Technical Reports that represented approximately 10% of the NI43-101 Technical Reports submitted over the period 30 June 2011 to 30 June 2012 (Ontario Securities Commission, 2013). The review found that 40% of the CPRs required significant changes and a further 40% were also noncompliant, requiring minor changes. Only 20% of the reports were considered compliant. It should be noted that professional organizations do not take legal responsibility for a CP or a CPR. Professional membership does not guarantee competency for any specific technical report, nor do qualifications necessarily guarantee competency. The onus of conducting competent technical work remains with the CP. Professional organizations are legally liable for ensuring that a person who applies for and is accepted for membership satisfies the requirements of the organization’s constitution and by-laws. In doing so the
Good reporting practices professional organization affirms that the individual satisfies the requirements for, and has the qualifications required to be, a member and ensures that the member complies with the code of ethics of the organization. These organizations have no liability for the negligent activities of their members. This is one of the reasons for not having a register of CPs, as the holders of the list could be held liable if a CP does not conduct compliant work. One thing is for certain – if the mineral industry does not self-regulate its reporting then some other agency will and that could lead to non-mineral experts reviewing technical reports; an outcome that will not be good for the mining industry as a whole.
The following section highlights some of the more common or serious mistakes in reporting. Figure 2 depicts a public Coal Resource and Reserve statement, which provides an example of a number of common compliance issues observed by the author. Although this statement is dated 2013, the issues highlighted remain relevant. The author has removed the project names as not to embarrass the company or the CP purposely.
# ! "! " # # # The Coal Reserve is not subdivided in order of increasing confidence into Probable and Proved Reserves. Clauses 32, 33, and 34 of the Code highlight the requirements when
reporting reserves. Although not the case in this example, CPs continue to incorrectly use the term ’Proven’ instead of ’Proved’. Furthermore, when reporting Coal Reserves, Mineable Tons In-situ (MTIS), ROM, and Saleable Tonnages must be reported. In the above example the Saleable Tonnage has been left out of the report, and therefore the reader is uninformed of the coal beneficiation efficiency and the planned market for the sale of the washed coal.
# ! "! " ! " Figure 2 highlights another common occurrence in the declaration of Coal Resources and Reserves – the failure to report the quality of the coal. The above example only reports coal tonnages. According to Clause 52 of the Code, appropriate coal qualities must be reported for all Resources and Reserve categories. The selection of the quality parameters is the responsibility of the CP and should include parameters such as ash, volatile matter, sulphur, coking properties, calorific value, etc. The coal quality parameters also should include the basis of reporting (air-dry or dry basis, etc.), and where applicable Saleable Coal Reserves should be subdivided into the relevant coal product types. This information is critical and without reporting coal qualities the Coal Reserve is almost useless to an investor. This reporting trend must be stopped immediately; unfortunately, many coal companies observe this trend as being sanctioned. Hopefully, through the JSE Readers Panel’s review of annual reports and ongoing training this poor reporting practice will be corrected over the next couple of years.
# ! " ! ! " # When reporting Exploration or Reconnaissance Results (Clause 20 of the SAMREC Code) the potential quantity, quality, and content should be reported as a range and should include a detailed explanation of the basis for the statement and a proximate statement that the potential quantity, quality, and content are conceptual in nature. Failure to report as a range of values and not providing a detailed explanation may be misleading to the investor, as it may appear that there is greater confidence associated with the project than actually exists. Failure to comply with Clause 20, as seen in the provided example, remains a common oversight by some CPs and Public Reports.
#" "# #"
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!" !" " " " " ! !" " ! ! !" ! !
When both Mineral Resources and Mineral Reserves are reported the Public Report must include a statement that clearly indicates whether the Mineral Resource is inclusive of, or exclusive to those Mineral Resources that have been modified to estimate a Mineral Reserve (Clause 39). The debate on whether Mineral Resources should be reported inclusive or exclusive of the Mineral Reserve is a decade-long debate that probably will never be resolved. However, whatever the reporting position, a statement is required to avoid confusion and the possibility of the inaccurate valuation of the Mineral Resources. The above example, like many other Resource–Reserve statements, fails to disclose whether the Coal Resources are inclusive or exclusive of the Coal Reserve.
Good reporting practices ! " # ! #" ! #
! # " #"! " #" # " ! #
Although Figure 2 is only a summary of the Coal Resource and Coal Reserve, the CP’s report also failed to provide commentary on the reasonableness of the projects. For example, on the only operating mine, no comment is provided whether a Life Of Mine (LOM) plan has been completed or any other commentary to support the declaration of a Coal Reserve. For other projects with Coal Reserves, no mention is made if a Feasibility Study or Pre-Feasibility Study (PFS) has been conducted – a requirement in order to declare a Reserve. The Public Reporting of a Mineral Resource estimate must provide sufficient information on how the projects have reasonable prospects for economic extraction, assumptions made to estimate economic viability, and the cut-off grade used to estimate the Mineral Resource.
The terms ‘ore’ or ‘orebody’ should be used only when a Mineral Reserve has been completed, and should be associated with Mineral Reserves and not Mineral Resources. For example, the following excerpt from a recent news release is incorrect. The Zone 5 resource (JORC 2012 compliant) now totals an estimated 100.3 million tonnes of measured, indicated, and inferred ore grading 1.95% copper and 20 grams per tonne silver.
# ! "! " # # # " # "! " ! # !
In the above example more than two of the project areas declared a reserve; however the CP declared ’The [deleted] pillar project is still in a planning phase’. In order to declare a Reserve the company should have either conducted a PFS or a LOM Plan. This was not the case at the time of the declaration, and therefore the project should only be classified as a Coal Resource as per Clauses 33 and 34 of SAMREC Code read with Clauses 47 and 48. A Mineral Reserve must be based on a minimum assessment of a PFS for a project or a LOM Plan for an operation, and the modifying factors applied must be realistically considered (Clause 32). On occasion, Mineral Reserves are declared without a PFS being completed, which can have a material effect on the project’s valuation. In terms of compliance, this is one of the biggest mistakes a CP can make.
! #" Mineral/exploration companies are required to disclose the full name, address, professional qualifications, and relevant experience of the Lead CP authorizing publication of the information disclosed. Informing the investor of the CP’s details and experience is also important to provide the investor with confidence that the CP is competent. For the informed investor, knowledge of the responsible CP may influence the decision to invest or not to invest in a project.
# " ! ! It is common for exploration/mineral companies not to include a statement that they have written confirmation from the Lead CP that the information disclosed is in accordance with the SAMREC Code and, where applicable, the JSE Listing Requirements. Again, it is hoped this poor habit will be rectified in the short to medium term.
# # " # ! # Many Public Reports fail to comment on whether the Inferred Mineral Resource category has been included in Feasibility Studies, and if so, the impact of such inclusion. The use of large portions of Inferred Resources in a PFS is also incorrect, and can falsely elevate the value of a mineral project.
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! # " #"! " # A common reporting mistake is the use of ‘calculated’ instead of ’estimated’ when referring to Mineral Resource and Mineral Reserve statements.
! ! "! " # ! " # "# # The Code requires that a comparison of the Mineral Resource and Mineral Reserve estimates with the previous financial year/period’s estimates is provided and an explanation provided of the material differences between the two declarations. This remains a common oversight by CPs.
# # " " # ! " " #" # Public Reports often provide no description of future exploration activities, exploration expenditures, exploration results, and feasibility studies undertaken. Directors are required to state (or include an appropriate negative statement) on any legal proceedings or other material conditions that may impact on the company’s ability to continue mining or exploration activities. Again, this statement is often overlooked in Public Reporting.
! ! " ! " Optimistic assumptions in terms of mining rates, capital expenditure, operating costs, and revenue factors are required. Problems encountered in technical reports include the inadequate disclose of the main components of the capital cost estimate. Also, economic analysis information such as cash flows and or sensitivity analysis is sometimes omitted or lacks detail. Many of the reports do not clearly disclose the assumed metal price or factors related to the mining scenario or mineral processing recovery. Failure to provide this type of information prevents the public from conducting their own techno-economic analysis of the project.
! " # ! " # # # When reading an annual report, often one will come across the following or a similar statement - ‘A resources and reserves summary, which is SAMREC compliant and JSE approved, is carried in full on the [deleted] website.’ The annual report must contain the full information, as required by Section 12.11, within the annual report itself. Reference to other documentation providing further detailed information for the public is fine, but should not be used to provide primary information to the public.
# # The identification of risk is mentioned in several areas of the
Good reporting practices Code, with a dedicated section (T6) in Table 1. Although CPs may comment on risk, seldom is the analysis conducted with the intent of truly identifying risk in the Mineral Resource and Mineral Reserve estimation. A risk assessment should incorporate all technical specialists involved in the Mineral Resource and Mineral Reserve estimation process. For example, Public Reports fail to disclose project-specific risks and uncertainties, such as the availability of infrastructure, government approvals, use of novel mining/mineral processing technology, or the potential impact of regional unrest or civil war, e.g. Central Africa. Environmental and social issues have become increasingly important in recent years and remain an area of poor commentary. Based on the guiding principles of the Code, environmental and social issues require appropriate commentary in Public Reports.
A general consensus is that more focus should be on coaching and mentoring of CPs in order to improve reporting compliance. Coaching and mentoring should be seen as the preferred method, rather than using disciplinary action or sanctions against CPs. Ongoing training for CPs and CVs needs to be actively pursued by professional organizations, with the price of such training kept to a minimum so that costs do not become prohibitive. Some universities, such as the University of Johannesburg, include tuition in the area of the SAMREC and SAMVAL Codes. The Geological Society of South Africa (GSSA) conducts CPs courses once or twice a year. The JSE also has in the past provided reporting compliance courses and the SAIMM provides ad hoc presentations on the varied topics on the codes: recent examples include un update of the 2016 SAMREC and SAMVAL Codes, the application of Modifying Factors, and the Companion Volume published to coincide with the launch of the 2016 SAMREC and SAMVAL Codes. As peers we must play a more active role in regulating our own industry. As a general observation, the mining industry needs to implement a coaching and mentoring approach, thereby uplifting reporting standards. Coaching and mentoring must not be limited to only CPs, but must also extended to exploration and mineral companies who must also abide by the SAMREC Code as well as the JSE Listing Requirements
reputation of the CP but also the reputation of the mining profession. The mineral industry must self-regulate, otherwise others will conduct this regulatory process and almost certainly this will not be to the industry’s liking or satisfaction. Along with self-regulation, more teaching and mentoring is required to improve the overall quality of Public Reporting. A number of companies and organizations conduct training courses on a regular basis; some for commercial purposes while other learned societies such the GSSA and SAIMM present courses on a non-profit basis. In the future, courses need to focus on compliance issues, the underlying meaning and intent of the Code, and examples of good and poor reporting practices. When CPs fail to comply with the Code and a complaint is raised, corrective action must be taken. The process should focus on corrective action rather than punishment. The process should be geared to improve reporting standards, with severe retribution served only to those individuals acting in a fraudulent or incompetent manner. Part of the process must involve educating the mining fraternity on the shortcomings in Public Reporting practices so that deficiencies can be shared and the lessons learned made public. Any learning outcome must provide a foundation to the intent of the Code. Currently, CPs see the Code as a hurdle to be met in order to complete an assignment. All too often there appears to be a disjoint between creating a report and protecting the interests of investors. Furthermore, CPs must be capable of preserving their professional opinions and not be intimidated by interested parties.
) * ! ! ! " The author would like to acknowledge the assistance and guidance provided by Mr Ken Lomberg of Pivot Mining Consultants (Pty) Ltd.
! ! ! ! ONTARIO SECURITIES COMMISSION. 2013. OSC Staff Notice 43-705 - Report on Staff’s Review of Technical Reports by Ontario Mining Issuers. June 2013. RUPPRECHT, S.M. 2014. The SAMREC Code 2015 – Some thoughts and concerns. Proceedings of Surface Mining 2014 . Southern African Institute of Mining and Metallurgy, Johannesburg. SAMREC. 2009. South African Mineral Resource Committee. The South African
The SAMREC Code already provides guidelines to reporting, as presented in Table 1. The difficulty is that Table 1 is not properly used, as authors of CPRs fail to comply fully with the provided checklist, choosing rather to omit certain clauses of the Code. The updating of the Code should improve compliance with the introduction of the ‘if not, why not’ approach to reporting. However, updating of the Code addresses only one aspect of Public Reporting compliance. The implementation of selfregulation and peer review will go a long way towards improving reporting compliance. CPs, as well as the mining industry, must realize that failure to comply with the guiding principles of the SAMREC Code not only damages the
SAMCODE. 2009. The South African Mineral Codes.
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Code for the Reporting of Exploration Results, Minerals Resources and Mineral Reserves (the SAMREC Code). 2007 Edition as amended July 2009. Prepared by the South African Mineral Resource Committee (SAMREC) Working Group. http://www.samcode.co.za/downloads/SAMREC2009.pdf
http://www.samcode.co.za/SAMCODE/SSC/Disciplinaryprocedures [Accessed: 15 April 2015]. WIKIPEDIA. 2014. Regulatory compliance. http//www.en.wikipedia/regulatory compliance. [Accessed 16 April 2015].
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SCHOOL OF CHEMICAL & METALLURGICAL ENGINEERING MSC ENGINEERING/MENG PROGRAMME – 2018 ELEN7067A CHMT7008A
Research Methodology Research Project
Course Co-ordinator
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Compulsory to all MSC 50/50 (ECA00) students + 4 courses totalling 80 credits from each branch of study / 80% from branch + 20% from any other engineering branch/school in the Faculty of Engineering & the Built Environment = 6 courses
Course Presenter
Course Code
Course Name
Attendance Dates
The Future of the Automotive Industry and Fuels Process Instrumentation and Control in Refining Oil Products and Refining Introduction to Oil and Gas Offshore platforms/ pipelines Nanotechnology in Petroleum Reservoir Research Methodology - Compulsory course (10 credits) Research Project - Compulsory course (90 credits)
16–20 April 14–18 May 19–23 February 12–16 March 11–15 June
OIL AND GAS ENGINEERING Dr Diakanua Nkazi
Jean Marie Bottes (TOTAL/ TPA) Nicolas Caillet (TOTAL/ TPA) Dr Diakanua Nkazi Dr Fidelis Wopara Prof Abhijit Dandekar Prof Hofsajer Ivan
Dr Kevin Harding
Antony Higginson Paul Chego Prof Jean Mulopo Prof Geoffrey Simate Dr Shehzaad Kauchali
CHMT7062A CHMT7063A CHMT7065A CHMT7066A CHMT7070A ELEN7067A CHMT7008A
CHEMICAL ENGINEERING CHMT7072A
Advanced Biochemical Engineering
h 12–16 Marc
CHMT7037A
Distillation Synthesis
09–13 July
CHMT7038A ELEN7067A CHMT7008A
Applied Thermodynamics Research Methodology - Compulsory course (10 credits) Research Project - Compulsory course (90 credits)
10–14 September
CLEAN ENERGY AND SUSTAINABLE TECHNOLOGIES Dr Shehzaad Kauchali
Dr Shehzaad Kauchali Prof Michael Daramola Dr Shehzaad Kauchali Mr Sehai Mokhahlane Dr Diakanua Nkazi
CHMT7076A CHMT7069A CHMT7059A CHMT7068A CHMT7065A ELEN7067A CHMT7008A
Synthetic Fuels & Processes CO₂ Capture in Power Plants Coal Conversion and Gasification Underground Coal Gasification Oil Products and Refining Research Methodology - Compulsory course (10 credits) Research Project - Compulsory course (90 credits)
21–25 May 23–27 April 19–23 March 16–20 April 19– 23 February
Sehai Mokhahlane
Dr Shehzaad Kauchali Dr Elias Matinde Sehai Mokhahlane Prof Michael Daramola
CHMT7059A CHMT7060A CHMT7068A CHMT7069A ELEN7067A CHMT7008A
Dr Elias Matinde
Paul den Hoed Prof Eriç Hürman Dr Elias Matinde Prof Serdar Kucukkaragos Dr Elias Matinde
CHMT7011A CHMT7016A
Physicochemical principles of refractories Selected/ Special Topics in Pyrometallurgy
23–27 April 28 May–01 June
CHMT7013A
Solid, Liquid and Gaseous state in Pyrometallurgy
16–20 July
CHMT7060A ELEN7067A CHMT7008A
Coal & Carbon in the Metal Industry Research Methodology - Compulsory course (10 credits) Research Project - Compulsory course (90 credits)
17–21 Sep
COAL ENGINEERING Coal Conversion & Gasification Coal & Carbon in the Metal Industry Underground Coal Gasification CO₂ Capture in Power Plants Research Methodology - Compulsory course (10 credits) Research Project - Compulsory course (90 credits)
19–23 March 10–14 September 16–20 April 23–27 April
METALLURGICAL ENGINEERING
Dr Elias Matinde
MINERALS PROCESSING AND EXTRACTIVE METALLURGY Prof Vusumuzi Sibanda
Prof Sehliselo Ndlovu Dr Murray Bwalya Prof Vusumuzi Sibanda
CHMT7030A CHMT7028A ELEN7067A CHMT7008A
Leaching Operations in Hydrometallurgy Physical Processing of Ores Research Methodology - Compulsory course (10 credits) Research Project - Compulsory course (90 credits)
25–29 June 26–30 March
MATERIALS SCIENCE AND ENGINEERING Dr David Whitefield
Dr David Whitefield Prof Iakovos Sigalas Prof Iakovos Sigalas Prof Lesley Chown Prof Natasha Sacks
CHMT7019A
Advanced Materials Processing
2–6 July
Principles of Ceramic Materials Structure and Properties of Engineering Materials Tribology of Materials Research Methodology - Compulsory course (10 credits) Research Project - Compulsory course (90 credits)
30 July–3 August 11–15 June 14–18 May
Dr David Whitefield
CHMT7020A CHMT7024A CHMT7071A ELEN7067A CHMT7008A
Dr Lesley Chown
CHMT7045A CHMT7049A CHMT7050A CHMT7051A CHMT7073A CHMT7074A ELEN7067A CHMT7008A
WELDING ENGINEERING (MSc 50/50) Dr Lesley Chown
Advanced Welding Processes Welding Metallurgy of Steels Weldability of alloy steels & stainless steels Weldability of ferrous & non-ferrous materials Design and Construction of Welded Structures under Static Loading Design and Construction of Welded Structures under Dynamic Loading Research Methodology (10 credits) (Optional for Welding Engineering) Research Project - Compulsory (90 credits)
16–20 April 14–18 May 04–08 June 25–29 June 16–20 July 13–17 August
MASTER OF ENGINEERING (MENG) EC001 TIMETABLE WELDING ENGINEERING Dr Lesley Chown
CHMT7043A CHMT7044A CHMT7045A CHMT7046A CHMT7047A CHMT7049A CHMT7050A CHMT7051A CHMT7052A CHMT7053A CHMT7073A CHMT7074A
Welding Processes & Equipment Other Welding Processes Advanced Welding Processes Fabrication, applications engineering Non-destructive testing methods & economics Welding Metallurgy of Steels Weldability of alloy steels & stainless steels Weldability of ferrous & non-ferrous materials Case Studies for Welding Engineers Practical Education – Welding Processes Design and Construction of Welded Structures under Static Loading Design and Construction of Welded Structures under Dynamic Loading
12–16 March 02–06 April 16–20 April 10–14 September 01–05 October 14–18 May 04–08 June 25–29 June 22–26 October 19–24 February 16–20 July 13–17 August
http://dx.doi.org/10.17159/2411-9717/2017/v117n12a4
The new SANS 10320:2016 versus the 2014 Australian guidelines for the estimation and classification of coal resources–what are the implications for southern African coal resource estimators? by J. Hancox* and H. Pinheiroâ€
& 6<-9;9 The past three decades have witnessed the publishing of reporting codes for all the main stock exchanges, as well as the evolution of a uniform international standard covering the definition, estimation, and public reporting of Mineral Resources. Many of these reporting codes have commodity-specific reporting sections for coal, but only two countries (Australia and South Africa) have specific guidelines for reporting on coal resources. Both of these companion documents (SANS 10320:2016 and the Australian Guidelines for the Estimation and Classification of Coal Resources, 2014) have recently been updated. Unlike their parent codes, which have become increasingly similar, these new guidelines have diverged and are different in a number of significant ways, which in turn will have an impact on coal resource estimators working in the coalfields of south-central Africa, particularly in countries where no commodityspecific guidelines for coal exist. ?= )<8/9 Reporting codes, coal resources, estimation, classification.
and Canada) and two are descriptive (South Africa and Australia) and are considered as guidelines. Though termed â&#x20AC;&#x2DC;guidelinesâ&#x20AC;&#x2122;, most institutions involved in the business of coal resource estimation, evaluation, and ultimately with the goal of raising funding, consider these guidelines as prescriptive, and as a set of standards that must be addressed for a Coal Resource to be considered as being reported in accordance with the required code. While most of the internationally recognized reporting codes have become very similar, including the South African Code for Reporting Mineral Resources and Mineral Reserves (the SAMREC Code, 2007 as amended 2009; 2016) and that of the Joint Ore Reserves Committee (JORC, 2012), their coalspecific guidelines have recently diverged and differ in a number of significant ways.
97;1:7;<6><0> <:5> =9<384=9>;6>&<372 %08;4: Due to various reporting irregularities and the need to protect the investing public, the past three decades have witnessed the publication of reporting codes for all the worldâ&#x20AC;&#x2122;s main stock exchanges, as well as the release of an international reporting template for the public reporting of Exploration Results, Mineral Resources, and Mineral Reserves by the Combined Reserves International Reporting Standards Committee (CRIRSCO). Many of the codes now have commodity-specific reporting sections for coal. However, due to the fact that the governing codes have developed to such an extent, some have questioned the need for coal-specific standards. We would argue that coal resource estimation does require commodity-specific guidelines, as the processes of coal formation include aspects that are unique and which are fundamentally different from those that apply to most other mineral deposits. In addition, certain coal qualities may be of special interest for specific uses and technological applications, and may require very specific analytical work. Of the codes that have commodity-specific sections for coal, two are prescriptive (the USA
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Coal occurs in South Africa in 19 separate coalfields (Figure 1), each of which has unique characteristics relating to coal formation, and the Competent Person should take due consideration of these characteristics when estimating, classifying, and reporting Coal Resources in South Africa. Currently, Coal Resources in South Africa must be estimated in accordance with the SAMREC Code (2009), with additional guidelines deemed necessary to standardize the reporting of Coal Resources for securities exchange requirements, being supplied by the South African guide to the systematic evaluation of Coal Resources and Coal
* CCIC Coal (Pty) Ltd, South Africa. â&#x20AC; Ariy Consulting and Advisory, South Africa.
Š The Southern African Institute of Mining and Metallurgy, 2017. ISSN 2225-6253. This paper was first presented at the SAMREC/SAMVAL Companion Volume Conference â&#x20AC;&#x2DC;An Industry Standard for Mining Professionals in South Africaâ&#x20AC;&#x2122;, 17â&#x20AC;&#x201C;18 May 2016, Emperors Palace, Johannesburg
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The new SANS 10320:2016 versus the 2014 Australian guidelines
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Reserves (SANS 10320:2004). The standard was originally prepared in conjunction with the SAMREC Code by the SAMREC Coal Commodity Specific Sub-committee. Although not yet published, this guideline has recently been updated as SANS 10320:2016 and has passed the Committee draft stage. Both authors of this paper were involved with this process and were provided with a final draft of the document for use in writing this paper. Once ratified, the new standard will supersede the first edition, and will serve to provide further alignment, clarification, and best practices in terms of the reporting of Coal Deposits, Coal Resources, and Coal Reserves. Dingemans (2015) and van Deventer (2015) have both provided overviews of what the main changes in the new guidelines will be, and these are documented and discussed below. One of the most significant aspects of the new SANS 10320:2016 standard is that it applies to all Coal Exploration Results, Inventory Coal, Coal Resources, and Coal Reserves within South Africa, irrespective of the jurisdiction within which the reporting is undertaken. This means that the application of other codes and guidelines to South African coal deposits will no longer be allowed, which will prevent the previous poor practice of using the larger drill-hole spacing that other codes allow in delineating South African deposits. SANS 10320:2016 will provide the methodologies and definitions of the relevant terms that should be considered when preparing Public Reports on Coal Exploration Results, Coal Resources, and Coal Reserves. In terms of the new standard a Coal Resource is defined as â&#x20AC;&#x2122;coal of economic interest in or on the Earth's crust in such form, quality and quantity that there are reasonable prospects for eventual economic extractionâ&#x20AC;&#x2122;. Tonnage and coal quality must be reported for all entries in a Public Report, per classification
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category, in order of increasing confidence in respect of geoscientific evidence, into Inferred, Indicated, and Measured categories. The moisture content for all tonnages and coal qualities must be reported. The determination of reasonable and realistic prospects for eventual economic extraction is fundamental to the definition of a Coal Resource. Under the new standard, in order to classify a Coal Resource, the Competent Person (CP) shall identify that part of a coal deposit for which there are reasonable and realistic prospects for eventual economic extraction, and that will be economically viable to mine and produce a raw or beneficiated saleable coal product. Consideration must also now, for the first time, be given to Conversion Factors, which are considerations used in a geological study to convert Coal Exploration Results to Coal Resources. These include, but are not restricted to, mining, processing, metallurgical, infrastructure, economic, marketing, legal, environmental, social, and governmental factors. Although these factors are similar to the Modifying Factors used to convert Coal Resources to Coal Reserves, they may be more conceptual in nature. Under the new standard a Coal Resource risk assessment must be undertaken, and any risks that may affect the potential economic viability of the Coal Resource must be clearly stated. If any key variable or combination of variables of the coal deposit under consideration does not meet a level for which there are reasonable and realistic prospects for eventual economic extraction, then Coal Resources cannot be declared, and must be reported only as Inventory Coal. While SANS 10320:2004 allowed for a Gross Tonnes in situ (GTIS) resource to be publicly stated, the new standard will allow such figures for internal calculation purposes only, and not for Public Reporting. Under SANS 10320:2016, for the Public Reporting of Coal Resources, all tonnages and coal
The new SANS 10320:2016 versus the 2014 Australian guidelines
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qualities must be reported on a Mineable Tonnes in situ (MTIS) basis, with the associated yield, coal quality, and moisture content clearly stated. According to Dingemans (2015) the lowest level of Resource that may be publically reported under the new standard would be an Inferred, MTIS Coal Resource. A MTIS Resource is the tonnage and coal
quality, at a specified moisture content, contained in the coal seam, or section of the coal seam, which is proposed to be mined, at the theoretical mining height, adjusted by the geological loss factors and derating for previous mining activities, but excluding contaminant material, with respect to a specific mining method, and after the relevant minimum and maximum mineable thickness cut-offs and relevant coal quality cut-off parameters have been applied. SANS 10320:2016 will still recognize two different types of South African coal deposits (multiple seam and thick interbedded deposit types) and will still allow for resource category confidence to be assessed based on the density (per 100 hectares) or spacing of cored boreholes with quality data. A difference to the previous SANS 10320:2004 guidelines is that the new guideline specifically mentions that different coal deposit types within the same coalfield must be reported separately. In addition, the new guidelines will allow for a maximum 500 m borehole spacing for the Measured Resource category of thick interbedded coal deposit, as opposed to the 350 m required in SANS 10320:2004 (Figure 2). Typically in South Africa, the Free State, VereenigingSasolburg, South Rand, Witbank, Highveld, Ermelo, Klip River, Utrecht, Vryheid, Springbok Flats, lower Waterberg, Somkhele, and Molteno coalfields are multiple seam deposit types, whereas the upper Waterberg (Grootegeluk Formation), Springbok Flats, Limpopo, Soutpansberg (Mopane, Tshipise, and Pafuri) are thick interbedded seam deposit types. The Nongoma and Kangwane coalfields may contain both coal deposit types (Figure 1). SANS 10320:2016 will supply a list of which coalfields contain which types of coal deposits.
97;1:7;<6><0>4<:5>8=9<384=9>;6>%3978:5;: The productive coalfields of Australia occur mainly on and around the east coast (Figure 3), predominantly in Queensland and New South Wales, where the coal-bearing sequences show extreme lateral continuity and continuous geometry (Allen and Fielding, 2007).
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The new SANS 10320:2016 versus the 2014 Australian guidelines Prior to September 1999 the estimation and reporting of Coal Resources in Australia was prescribed by the Australian Code for Reporting Identified Coal Resources and Reserves (February 1986). The first direct references to coal are found in clauses 38 to 40 of the 1999 JORC Code. Until October 2014, the JORC (2012) Code required that Coal Resources be reported on the same basis as any other mineral commodity, with cognisance taken of the guidelines contained in the Australian Guidelines for Estimating and Reporting of Inventory Coal, Coal Resources, and Coal Reserves (2003). These guidelines (2003) stated that a Measured Coal Resource may be estimated using data obtained from Points of Observation usually less than 500 m apart, an Indicated Coal Resource from Points of Observation less than 1000 m apart, and an Inferred Coal Resource from Points of Observation less than 4000 m apart. These recommended spacings were based on historically proven continuity of coal seams in the Hunter Valley and the Bowen Basin. Unlike in the SANS 10320:2004 document, only one set of spacings was used no matter what the type of coal deposit. Subsequent geostatistical work by Bertoli et al., (2013) showed that the use of a â&#x20AC;&#x2DC;one size fits allâ&#x20AC;&#x2122; classification scheme (even in the well-documented Bowen Basin) may result in inappropriate resource classification (Table I), and as such the use of fixed drill-hole spacing for resource classification was not good practice. In October 2014 the new Australian Guidelines for the Estimation and Classification of Coal Resources (Australian Guideline 2014) were ratified. This document represents a significant update and marks a major change in the role of the CP in coal resource estimations in Australia. Probably the most important aspect of this revision is the fact that the concept of defining Resource categories in terms of distance around Points of Observation (which was introduced in 1971 in the first edition of the Code for Calculating and Reporting Coal Reserves by the Geological Survey of New South Wales) has been removed. Instead, the CP must now assess the
Table I
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1116
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6/;4:7=/
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550 800 500 1100 650 650 1100 350 750 700 850 400 750 250 500
1050 1400 1000 1900 1250 1250 1900 700 1450 1300 1700 750 1400 500 1000
2100 2800 2450 3600 2800 3150 3600 1850 3550 2600 4200 1800 2500 1000 4000
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confidence in the estimate of all significant variables, and the most applicable methods and criteria to demonstrate such confidence should be used to support the classification assigned. Such criteria and methods include statistical and geostatistical analyses, as well as the definition of geological domains, and geological modelling. The estimator must also identify any critical parameters that might affect the eventual economic extraction test, or those that may result in contractual penalties. The use of geostatistical methodology, whereby the classification of the resource is driven by the actual in situ variability (or conversely spatial continuity) of the resource, is strongly recommended. The Australian Guidelines (2014) include a Glossary of terms, which is surprisingly short, and does not include important terms such as â&#x20AC;&#x2DC;plyâ&#x20AC;&#x2122;, â&#x20AC;&#x2DC;seamâ&#x20AC;&#x2122;, and â&#x20AC;&#x2DC;zoneâ&#x20AC;&#x2122;. Yet the concept of ply in particular is vital to the exercise of Australian resource assessment. While the words â&#x20AC;&#x2122;shouldâ&#x20AC;&#x2122;, â&#x20AC;&#x2DC;canâ&#x20AC;&#x2122;, â&#x20AC;&#x2DC;mayâ&#x20AC;&#x2122;, â&#x20AC;&#x2DC;may notâ&#x20AC;&#x2122;, and so on are typical and rather common throughout the guidelines, occasionally â&#x20AC;&#x2DC;mustâ&#x20AC;&#x2122; enters the fray. For example, â&#x20AC;&#x2122;seam thickness and location must be unambiguousâ&#x20AC;&#x2122;, in which case it is prescriptive. For the first time the new Australian Guidelines (2014) recommend that the geotechnical conditions of the overburden, interburden, roof and floor strata, the seam gas content and composition, the propensity of the coal for spontaneous heating, the potential of relevant materials for frictional ignition, and any other parameters pertinent to the consideration of reasonable prospects for eventual economic extraction, should be assessed. Furthermore these guidelines suggest that a CP must assess all relevant aspects of (and risks to) mining, processing, metallurgical, infrastructure, economic, marketing, legal, environmental, social, governmental, and regulatory factors. It notes that while the assessment can in part be qualitative in nature, there generally needs to be at least a basic quantitative evaluation that considers financial indicators and consideration should be given to whether the tonnage and coal quality are sufficient to ensure satisfactory returns over a reasonable life of mine. These guidelines do not, however, prescribe: a specific approach to arriving at the key assumptions; the level of detail required; the economic indicators that need to be satisfied; the level of satisfaction that needs to be achieved for the coal to be said to have reasonable prospects, and hence be classified as a Coal Resource.
<1-:8;9<6><0>72=>&<372>%08;4:6>:6/>%3978:5;:6 .3;/=5;6=9>0<8>4<:5>8=-<87;6. There are a number of instances where the two parent codes (JORC and SAMREC) and coal guidelines are now similar, yet different from their previous versions. The most significant of these are that: The controlling Code now requires that Table 1 is completed in both instances All reporting must be on an â&#x20AC;&#x2DC;if not â&#x20AC;&#x201C; why notâ&#x20AC;&#x2122; basis The basis for quality and tonnage reporting must now be in-situ moisture, with the Preston and Sanders (1993) formulae applied for density in tonnage calculations
The new SANS 10320:2016 versus the 2014 Australian guidelines
The Australian Guidelines (2014) require the CP to assess the likely mining scenario (open cut/cast or underground). For a potential open cut mining scenario, emphasis must be placed on strip ratio, minimum mineable seam thickness, maximum non-separable parting thickness, pit wall stability, and depth of weathering. In an underground mining scenario, aspects such as depth, faulting, igneous intrusions, working section thickness, seam dip, physical properties of roof and floor lithologies, hydrogeology, stress regime, gas content, lithological composition, and permeability should be considered. SANS 10320:2016 will also place more emphasis on geotechnical work, specifically as to how such parameters may influence the potential for eventual economic extraction. Both documents also place more emphasis on the role of the CP, often extending outside of such personâ&#x20AC;&#x2122;s normal sphere of expertise, with the Australian Guidelines (2014) going as far as noting that these matters are normally considered in concert with engineers and other specialists and that it may be necessary to seek expert comment on these factors. The impact of the latter on the cost of exploration cannot be underestimated, and will be significant, especially for junior miners seeking to operate and deliver against such guidelines. Neither guideline requires the lodging of the CP Report with the controlling exchange, an area which should be addressed. There are, however, also several differences between the forthcoming SANS 10320:2016 revision and the Australian Guidelines (2014), the main ones being: SANS 10320:2016 will still allow the use of maximum distances between Points of Observation for defining resource categories per coal deposit type in South Africa, whereas the concept of defining resource categories on distance around Points of Observation has been removed from the Australian Guidelines (2014), which prefers that the resource classification be founded on the assessment of the confidence in the estimate of all significant variables, based on a series of methods and criteria, such as geostatistical analysis SANS 10320:2016 will still prescribe core recovery in excess of 95% by length within the coal seam intersection of a drill-hole, whereas the Australian Guidelines (2014) state that sample recovery must be considered representative, and that potential loss of material from within a sample may be critical, irrespective of the relative percentage lost; and that downhole geophysical data should be used to confirm the location and nature of any core loss in the coal seam. The use of downhole geophysical data is not prescribed in the new SANS 10320:2016 standard The Australian Guidelines (2014) also note that the analysed sample should be representative of the in-situ material within the interval of interest, and as such hints that it is in fact the percentage of material that makes it to the laboratory that is important. SANS 10320:2016 does not state that the received sample at
the laboratory must represent 95% of the recovered material SANS 10320:2016 refers to both Coal Resources and Coal Reserves, whereas the Australian Guidelines (2014) is now only applicable to Coal Resources In SANS 10320:2016 the only level of tonnage reporting is MTIS; the Australian Guidelines (2014) makes no distinction between GTIS, TTIS, and MTIS and do not mention that geological losses need to be specified SANS 10320:2016 specifically mentions that different coal deposit types within the same coalfield (e.g. for the Waterberg Coalfield) must be reported separately, whereas this is not required by the Australian Guidelines (2014), other than as stipulated in section 5.2.2 of the guidelines SANS 10320:2016 must be applied to all Coal Exploration Results, Inventory Coal, Coal Resources, and Coal Reserves within South Africa, irrespective of the jurisdiction within which the reporting is undertaken; whereas the Australian Guidelines (2014) are intended for use in Australian coalfields The revised SANS 10320:2016 guidelines for Coal Resource estimation do not require the reporting of tonnages beyond the in situ stage. Where the Coal Resource is deemed suitable to be exploited for a washed coal product, the associated theoretical yield and washed target product shall, however, be stated. In the case of the Australian Guidelines (2014) the application of certain quality and potential utilization factors is required, thereby allowing for reporting of a coal quality that is closer to a saleable product For the Australian Guidelines (2014) a CP must at least undertake a basic quantitative evaluation of financial indicators, whereas this is not a requirement of the SANS 10320:2016 guidelines. Despite the Australian Guidelines (2014) stating that it is intended for use in Australian coalfields, it also follows with the wording â&#x20AC;&#x2122;but may also provide guidance internationallyâ&#x20AC;&#x2122;, thus leaving the door open for its use elsewhere, such as is the case in the coalfields of Mozambique.
97;1:7;<6><0>4<:5>8=9<384=9>;6> < :1+;@3= >: 9<372=86>%08;4:6>= :1-5=><0>72=>:--5;4:7;<6><0>72= 7)<>/;00=8=67>4<:5>.3;/=5;6=9 The coalfields of the Tete Province of Mozambique occupy an area stretching over 350 km, from Lake Cahora Bassa in the west to the Malawi border in the east (Figure 4). From west to east these are variously termed the ChicĂ´a-MecĂşcoè (including the Mucanha-Vuzi sector), Sanângoè-MefĂdĂŠzi, Moatize (or Moatize-Benga), Muarazi, and Minjova subbasins, with northwest and southeast extensions Ncondezi (Nâ&#x20AC;&#x2122;condezi) and Mutarara (Vasconcelos, 2012). In the past decade a lot of exploration focus has been placed on the coalfields of Mozambique. However, at present Mozambique does not have its own reporting code or commodity-specific coal reporting guidelines. The JORC Code has mostly been used by companies active in the coalfields, VOLUME 117
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More importance must be placed on the conversion factors in the stating of a Coal Resource A risk assessment is now required.
The new SANS 10320:2016 versus the 2014 Australian guidelines
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and prior to October 2014 this meant that the more loosely constrained maximum distances between Points of Observation allowed for by the 2003 Australian Coal Guidelines could be used to define Coal Resources. As an extreme example of how things stood prior to the new codes and coal guidelines, consider a South African CP utilizing the SAMREC Code (2009) and SANS 10320:2004 to define a coal resource in Mozambique. Based on a drill-hole spacing of 500 m and raw coal quality data, the CP would be able to disclose an Indicated GTIS Coal Resource, with no geological losses required. Even considering the changes proposed in the SANS 10320:2016 update that GTIS may not be reported, a 1.5 billion ton (Gt) opencastable GTIS Resource may drop by only 10â&#x20AC;&#x201C;20% (geological losses) if full seam extraction is considered, to give an MTIS Resource of 1.2â&#x20AC;&#x201C; 1.35 Gt. An Australian geologist considering the same resource and reporting in terms of the JORC (2012) code and 2003 Australian Guidelines (prior to October 2014) would be able to define a similar resource estimate in the Measured category and would not have to apply any geological loss. Strict application of the Australian Guidelines (2014) may mean that many such publicly stated coal resources in Mozambique may have to be re-defined based on a geostatistical evaluation of the density and variability of their Points of Observation, as well as on all critical variables. Given that coal represents a heterogeneous mixture of constituents there is a large range of coal quality parameters that would have to be considered by the CP, and geostatistical analysis on a ply-by-ply and variable-by-variable basis (as may be required in the Tete Province coalfields of Mozambique) would be extremely onerous and costly. Under the more stringent requirements of the Australian Guidelines (2014) it is also highly likely that several of the resource estimations made public prior to the new guidelines may have to be downgraded in tonnage and resource category, and that some isolated deposits in remote areas may not make it into the Resource category at all. Since many of the coal deposits of Mozambique consist of thick interbedded seams, the application of the new SANS 10320:2016 guidelines would allow a spacing of 500 m for the Measured category (as for the 2003 Australian Coal
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Guidelines), and we may in future therefore see previously JORC-compliant resources turning to the SAMREC Code (2016) and SANS 10320:2016 guidelines. The new SANS 10320:2016 guidelines, however, specifically mention that different coal deposit types within the same coalfield must be reported separately, and this would impact on the reporting of Mozambique coal resources, where both thick interbedded and multiple seam styles may occur within a coalfield or subbasin. Additionally, in structurally complex deposits, such as those found in Mozambique, it is structure (and not only coal quality) that can often be the critical resource-limiting determinant. Mozambique should therefore be considered to be a unique setting, with structural complexity far greater than seen in Australia or most of South Africa. As has been shown above, the rigid application of either the SAMREC (2016) or JORC Code (2014) may not be best practice, and Mozambique desperately requires a set of coal reporting guidelines of its own.
;94399;<6 There is no doubt that the revised Australian Coal Guidelines (2014) and SANS 10320:2016 guidelines are superior to their predecessors. The authors, however, contend that there is still one glaring omission in both the guidelines and controlling codes, and that is the failure to ensure a requirement for the lodging of the CP Report with the controlling exchange (such as is the case for the Toronto Stock Exchange). While both the Australian Guidelines (2014) and the SANS 10320:2016 revision place more emphasis on the role of the CP, neither address how to gauge (or maintain) the level of competency. Both the proposed SANS 10320:2016 update and the Australian Guidelines (2014) require that a Coal Resource geologist (whose core skills should be coal geology, modelling, and resource estimation) must also be familiar with Conversion (SANS 10320:2016) or Modifying Factors (Australian Guidelines, 2014). The Australian Guidelines (2014) further require the CP to be conversant with the potential product qualities, potential utilization,
The new SANS 10320:2016 versus the 2014 Australian guidelines the two are not. In the case of the revised Australian Guidelines (2014) there is a significant increase in certain requirements, which include the application of geostatistical parameters to resource classification criteria, as well as expert knowledge of coal beneficiation, utilization, and mining practices. While this places an increased burden on the Competent Person (and, the authors believe, moves into the territory of reserving), the new codes and guidelines do at least mean that seeing a 1.5 Gt Coal Resource reported with Reserves of only 200 Mt will be a thing of the past.
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product yields and value, and mining horizon/target, which will undoubtedly require at least a mine plan and more realistically a pit shell for opencast mining. These aspects are more traditionally defined as the Modifying Factors, and fall within the realm of the mining engineer. It is therefore evident that the lines are becoming blurred in both codes, more notably so in the case of the Australian Guidelines (2014). The SANS 10320:2016 update could also benefit from various considerations found in the new Australian Guidelines (2014), such as the geostatistical analysis of drillhole data. There are, however, some concerns with a geostatistical approach to resource classification in South Africa, the main one being that the creation of a robust semivariogram requires sufficient data-points, and that one cannot create a robust semivariogram if the data has a mix of different populations. Small Coal Resource areas, such as are often found in South Africa, would require data-sets with drill-holes numbering far in excess of what is currently required for Resource reporting. The authors also note that while the level of recovery through the seam is mandated in the revised SANS 10320:2016 guidelines, the level of that material reporting to the laboratory is not. We have come across many a South African example when it is stated that 95% recovery was obtained through the coal seam, yet less than 50% of the mass has been delivered to the laboratory. One last point of discussion that arises from the new Australian Guidelines (2014) is the death of the spotted dogâ&#x20AC;&#x2122; (Figure 5) â&#x20AC;&#x201C; the poor practice of estimating Measured, Indicated, and Inferred Resources over disconnected circles of influence around individual Points of Observation or along a line of Points of Observation (Stephenson et al., 2006). The exclusion of such practice means that the new Australian Guidelines (2014) directly contradict the USA (USGS Circular 891) and Canadian (GSC Paper 88-21) systems, which are rules-based and prescriptive and which rely on the use of spotted-dog methodologies.
<64539;<69
ALLEN, J.P. and FIELDING, C.R. 2007. Sequence architecture within a lowaccommodation setting: an example from the Permian of the Galilee and Bowen basins, Queensland, Australia. American Association of Petroleum Geologists Bulletin, vol. 91, no. 11. pp. 1503â&#x20AC;&#x201C;1539. AUSTRALIAN GUIDELINES FOR ESTIMATING AND REPORTING OF INVENTORY COAL, Coal Resources and Coal Reserves. 2003 Edition. Coalfields Geology Council of New South Wales and the Queensland Mining Council, 2003. 8 pp. AUSTRALIAN GUIDELINES FOR THE ESTIMATION AND CLASSIFICATION OF COAL RESOURCES. 2014 Edition. Coalfields Geology Council of New South Wales and the Queensland Resources Council. 16 pp. BERTOLI, O., PAUL, A., CASLEY, Z., and DUNN, D. 2013. Geostatistical drillhole spacing analysis for coal resource classiďŹ cation in the Bowen Basin, Queensland. International Journal of Coal Geology, vol. 112. pp. 107â&#x20AC;&#x201C;113. DINGEMANS, D. 2015. The update of the SAMREC & SAMVAL Codes and SANS 10320: Progress and Changes. Presentation at the Witbank Recreation Club, March 2015. HANCOX, P.J. and GĂ&#x2013;TZ, A.E. 2014. South Africa's coalfields â&#x20AC;&#x201D; a 2014 perspective. International Journal of Coal Geology, vol. 132. pp. 170â&#x20AC;&#x201C;254. JORC. 2012. Australasian Joint Ore Reserves Committee. Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves (The JORC Code, 2012 Edition). The Joint Ore Reserve Committee of the Australasian Institute of Mining and Metallurgy, Australian Institute of Geoscientists and Minerals Council of Australia (JORC), (Effective 20 December 2012, mandatory 1 December 2013). 44 pp. http://www.jorc.org/docs/JORC_code_2012.pdf PRESTON, K.B. and SANDERS R.H. 1993. Estimating the in-situ relative density of coal. Australian Coal Geology, vol. 9. pp. 22â&#x20AC;&#x201C;26. SAMREC. 2007. South African Mineral Resource Committee. The South African Code for the Reporting of Exploration Results, Mineral Resources and Mineral Reserves (The SAMREC Code). 2007 Edition as Amended July 2009 . 61 pp. http://www.samcode.co.za/downloads/SAMREC2009.pdf SAMREC. 2016. South African Mineral Resource Committee. The South African Code for the Reporting of Exploration Results, Mineral Resources and Mineral Reserves (the SAMREC Code). 2016 Edition. http://www.samcode.co.za/codes/category/8-reportingcodes?download=120:samrec SANS 10320:2004. South African guide to the systematic evaluation of coal resources and coal reserves. Standards South Africa, Pretoria. 140 pp. SANS 10320:2016. Systematic evaluation of coal exploration results, inventory coal, coal resources and coal reserves. Standards South Africa, Pretoria. [in press]. STEPHENSON, P.R., ALLMAN, A., CARVILLE, D.P., STOKER, P.T., MOKOS, P., TYRRELL, J., and BURROWS, T. 2006. Mineral Resource classification â&#x20AC;&#x201C; itâ&#x20AC;&#x2122;s time to shoot the â&#x20AC;&#x2DC;spotted dogâ&#x20AC;&#x2122;! Proceedings of the Sixth International Mining Geology Conference, Darwin, NT, 21â&#x20AC;&#x201C;23 August 2006. Australasian Institute of Mining and Metallurgy, Carlton, Victoria, Australia. pp 91â&#x20AC;&#x201C;95. VAN DEVENTER, K. 2015. Update of the Resource and Reserve Reporting Codes and Guidelines for the Coal Industry with specific focus on the SAMREC and SANS 10320 update. Progress and changes and the practical application thereof. Presentation for the SAMCODE Committee, September 2015. VASCONCELOS L. 2012. Overview of the Mozambique coal deposits. Proceedings of the 34th International Geological Congress, Brisbane, QLD, Australia, 5â&#x20AC;&#x201C;10 August 2012. Australian Geosciences Council. 25 pp.
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This paper has shown that while the parent codes (JORC and SAMREC) are very similar, the coal reporting guidelines for
Infacon XV: International Ferro-Alloys Congress 25–28 February 2018 Century City Conference Centre and Hotel, Cape Town, South Africa The 15th International Ferro-Alloys Congress (Infacon XV) will be held at the Century City Conference Centre in Cape Town, South Africa from 25-28 February 2018. INFACON (International Ferro-Alloys Congress) was founded in South Africa in 1974 by the SAIMM (Southern African Institute of Mining and Metallurgy), Mintek (then the National Institute for Metallurgy), and the Ferro Alloys Producers' Association (FAPA) when the first INFACON was held in Johannesburg. The intention of INFACON is to stimulate technical interchange on all aspects of ferro-alloy production.
Topics for discussion: Topics include but are not limited to Operational updates from ferro-alloy producers Technical aspects of ferro-alloy production Status of the ferro-alloys markets FeCr, FeMn, FeNi, FeV, FeSi, SiMn, etc. Effects of electricity cost and availability Energy efficiency and recovery Pre-treatment technologies
The impact of UG2 chromite from the PGM industry Fines, tailings, and low-grade ores Volatility of ore and ferro-alloy prices Approach to a circular economy How to extract maximum value from resources Other topics of relevance to ferro-alloy production
Who should attend?
Metallurgists
Ferro-alloy producers
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New technologies and processes
Plant general managers
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Environmental issues Carbon dioxide emissions and climate change Government policies affecting ferro-alloys
Process engineers Engineering companies
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Use of natural gas Sale of ore versus ferro-alloy production Market supply and demand Future of the ferro-alloys industry in South Africa
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For further information please contact: Gugu Charlie • Conference Co-ordinator • E-mail: gugu@saimm.co.za Website: http://infacon15.com
http://dx.doi.org/10.17159/2411-9717/2017/v117n12a5
Exploration Results, Exploration Targets, and Mineralisation by T.R. Marshall
While the original intent of all of the international reporting codes was to regulate the Public Reporting of Mineral Resources and Mineral Reserves only, many jurisdictions have seen the need to provide guidance for the reporting of Exploration Targets, which are the lifeblood of junior exploration and mining companies and private operators alike. In harmony with this trend, the SAMREC Code 2016 has greatly expanded the issues surrounding Exploration Results and Exploration Targets and has also introduced the concept of Mineralisation. This document seeks to clarify the concepts and definitions and to assist in clearing misconceptions before they arise. A number of case-study examples are presented in order to illustrate the differences between Exploration Targets that are purely conceptual and those which may be identified as Mineralisation. Public Reporting, Resource classification, Exploration Results, Exploration Targets, Mineralisation.
The original purpose of the international reporting codes was to regulate the public reporting of Mineral Resources and Mineral Reserves. This is highlighted by the titles of the original codes â&#x20AC;&#x201C; for example, the 1999 JORC Code is entitled â&#x20AC;&#x2DC;Australasian Code for reporting of Mineral Resources and Ore Reservesâ&#x20AC;&#x2122; and the 2000 SAMREC Code is â&#x20AC;&#x2DC;South African Code for reporting of Mineral Resources and Mineral Reservesâ&#x20AC;&#x2122;. In both of these codes, issues were confined to reports compiled for the relevant securities exchange. Very little attention was paid to the preresource space, with no more than a few lines dealing with the reporting of exploration results, called â&#x20AC;&#x2DC;prospecting informationâ&#x20AC;&#x2122; in the 2000 SAMREC Code. By the mid-2000s, both codes had changed their titles. The 2004 version of JORC had become â&#x20AC;&#x2DC;Australasian Code for reporting of Exploration Results, Mineral Resources and Ore Reservesâ&#x20AC;&#x2122; and the 2007 SAMREC Code was entitled â&#x20AC;&#x2DC;South African Code for the reporting of Exploration Results, Mineral Resources and Mineral Reservesâ&#x20AC;&#x2122; (italics added). It is noteworthy that, although the emphasis is still on listed company reporting,
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* Explorations Unlimited, South Africa. Š The Southern African Institute of Mining and Metallurgy, 2017. ISSN 2225-6253. This paper was first presented at the SAMREC/SAMVAL Companion Volume Conference â&#x20AC;&#x2DC;An Industry Standard for Mining Professionals in South Africaâ&#x20AC;&#x2122;, 17â&#x20AC;&#x201C;18 May 2016, Emperors Palace, Johannesburg
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the definition of â&#x20AC;&#x2DC;Public Reportsâ&#x20AC;&#x2122; has been expanded significantly to include all reports that may be of use to investors and potential investors. This migration appears to be, partially, in recognition of the increasing role played by junior exploration and mining companies and their need to report on strategic exploration targets for continued financial support. In addition to the needs of junior companies, large mining companies need to continuously assess long-term development opportunities in the exploration areas surrounding their operations (Mullins et al., (2014). The objectives of these programmes are to develop a thorough understanding of the mineral inventory so that the full mineral endowment potential of an area can be considered under multiple scenarios and long-term investment decisions taken to optimize the development potential of the province. It was argued that such objectives require a consistent approach to evaluating the nature and extents of potentially economic mineralisation. While guidelines such as the JORC Code (and, by extension, the SAMREC Code) adequately address this for Public Reporting purposes, internal strategic decisions often require a less conservative, but similarly rigorous, approach so that projects and increasingly competitive budgets can be prioritized before all of the information needed for formal resource estimation and classification is available. Similar to other codes, the 2007/2009 SAMREC Code did not place much emphasis on the definition of Mineral Resources, beyond the statement that there were to be reasonable expectations for eventual economic extraction. Apart from recognizing that it is common practice for a company to comment on and discuss its exploration in terms of target size
Exploration Results, Exploration Targets, and Mineralisation and type, guidelines for anything in the pre-resource space were even more vague and, consequently, reporting of exploration results, exploration targets, mineralisation, and inventory became highly suspect in terms of credibility. The emerging importance of Exploration Results as a defined term was, however, seen in the fact that an entire column in Table 1 of the SAMREC Code (â&#x20AC;&#x2DC;Exploration Results (A)â&#x20AC;&#x2122;) was dedicated to the discussion of exploration data and information, where applicable. â&#x20AC;&#x2DC;Exploration targetâ&#x20AC;&#x2122; became a sack term for anything that did not meet the requirements of a Mineral Resource and included everything from pure conceptual models to properties where the amount of data and/or the level of confidence in the results fell just short of â&#x20AC;&#x2DC;Resourceâ&#x20AC;&#x2122;. Since it is not a Resource, according to the Codes an Exploration Target could not form part of a Mineral Resource statement or tabulation, nor be included in any techno-economic assessment, however preliminary. An unintended consequence of the inclusion of both early and more advanced reconnaissance-stage exploration programmes was that many that of the more advanced reconnaissance-stage properties were shoehorned into the Inferred Resource category because that was the lowest classification that credited the company with having done any exploration on the target property. The latest versions of the JORC, PERC, and SME codes all define an Exploration Target as â&#x20AC;&#x2DC;a statement or estimate of the exploration potential of a mineral deposit in a defined geological setting where the statement or estimate, â&#x20AC;Ś relates to mineralisation for which there has been insufficient exploration to estimate Mineral Resourcesâ&#x20AC;&#x2122; (same or similar wording). Both JORC and PERC note that all disclosures of an Exploration Target should clarify whether the target is based on actual exploration results completed or on proposed exploration programmes yet to commence, implying that Exploration Targets can be both conceptual or advanced. The provisions of SME indicate that only properties where actual exploration results have been obtained can be described as Exploration Targets. Although CIM makes no mention of either of the terms Exploration Results or Exploration Target, the National Instrument 43-101 Companion Policy of 2011 gives limited guidelines on what might constitute such information and how it may be reported publicly in a manner that does not misrepresent the potential prospectivity of the property. It is in recognition of these matters that the SAMREC Code 2016 has greatly expanded the issues surrounding Exploration Results and Exploration Targets, and has also introduced the concept of Mineralisation (as opposed to mineralisation as a geological term, which SAMREC defines as â&#x20AC;&#x2DC;The process or processes by which a mineral or minerals are introduced into a rock, resulting in a potentially valuable deposit. It is a general term, incorporating various types, e.g. fissure filling, impregnation, replacement, etc.â&#x20AC;&#x2122;). The Code has also seen the migration from reports that deal with purely listed entities to any document that may find its way into the public domain, and even includes statements on social media. In addition to the requirements of the various securities exchanges with respect to public reporting by listed companies of all sizes, industry best practice strongly recommends that reports compiled for â&#x20AC;&#x2122;privateâ&#x20AC;&#x2122; companies also be compiled in accordance with the SAMREC Code â&#x20AC;&#x201C; the primary argument being that investors in non-listed entities
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deserve the same level of professionalism in reporting and valuation standards as for listed companies. In recent years there has been an upsurge in the number of Public Reports associated with non-listed companies. The reasons for this are many and varied, but the most common involve the many private companies that are looking to obtain finance for very early-stage exploration projects from financial institutions (such as the Industrial Development Corporation, banks, and/or mining funds), from established (listed) exploration and mining companies, or from high-wealth individuals. In most of these situations, the potential investor requires a Competent Personâ&#x20AC;&#x2122;s Report (CPR) before being willing to commit to commercial terms. This paper seeks to clarify the thought processes by the Exploration Results subcommittee of the SAMREC Working Group in developing the definitions and concepts integral to the pre-resource space and to assist in clearing misconceptions before they arise.
The 2016 SAMREC Code (Clause 20) defines Exploration Results as data and information generated by exploration programmes that may be of use to investors, but which do not form part of a declaration of Mineral Resources or Mineral Reserves. The reporting of such information is common in the early stages of exploration when the quantity of data available is generally not sufficient to allow any reasonable estimates of Mineral Resources. What is vitally important in the reporting of such Exploration Results is that they must not be presented in such a manner so as to unreasonably imply that potentially economic mineralisation has been discovered. Reports of Exploration Results must contain sufficient information to allow for a considered and balanced judgement of their significance and the reporting should be structured to include both positive and negative relevant data and information relating to the mineral property. The overriding emphasis is on balanced reporting, providing relevant information relating to prospecting activity that has taken place on the property of interest. Such Exploration Results may include survey, geological, geophysical, geochemical, sampling, drilling, trenching, analytical testing, assaying, mineralogical, metallurgical, and other data and information, where available. Exploration Results may also include historical data/information as well as data/information from adjacent or nearby properties, if the CP can provide justification for its inclusion. Such justification must include at least some physical evidence of assumed continuity of the mineralisation on the property of interest. With the rise of the junior exploration company, it has become common practise to comment on and discuss Exploration Results in terms of size and type, even at a very early stage of prospecting, before formal Mineral Resources have been identified. There is a long history of mining projects where the mineral endowment of a district or province is underestimated and careful consideration of the full potential for economic mineralisation in the early stages of assessment could have significantly improved development decisions and long-term profitability (Mullins et al., 2014). Likewise, examples of overestimating the potential size of a mineral district have been equally disastrous for shareholder
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The term â&#x20AC;&#x2DC;exploration targetâ&#x20AC;&#x2122; in the 2007/2009 SAMREC Code (Clause 20) had no formal definition, but was included as a way of reporting Exploration Results that might be of interest to investors. The governing principles of reporting exploration targets was that any statement referring to potential quantity, quality, and content of the target was to be expressed as ranges (to emphasize the lack of confidence in the data) and that they were to be accompanied by various cautionary statements. The definition of the term â&#x20AC;&#x2DC;Exploration Targetâ&#x20AC;&#x2122; in Clauses 21/22 of the 2016 SAMREC Code has retained these essential elements. In harmony with other international codes, Exploration Target is defined as a statement, or estimate, of the exploration potential of a mineral deposit in a defined geological setting where the statement or estimate, quoted as a range of tons and a range of grade or quality, relates to mineralisation for which there has been insufficient exploration to estimate Mineral Resources. The essence of an Exploration Target is that, at one extreme, it can refer to a concept of mineralisation. It does not necessarily require that any mineralisation be identified or even that the company has identified specific properties for acquisition. A (conceptual) Exploration Target, therefore, need not, imply reasonable prospects for eventual economic extraction (RPEEE). Notwithstanding, there must be a likelihood that this exploration target occurs in an area of geological prospectivity for that commodity and mineralisation type. For example, a diamond company might target a property located on the Kaapvaal Craton in a region where kimberlite pipes are known to occur. The known kimberlite cluster may or may not include a pipe that is currently being mined, or that was mined in the past. The Exploration Target might be associated with the occurrence of an indicator mineral anomaly or a geophysical anomaly, or perhaps artisanal miners are recovering alluvial diamonds downstream from the property. At the other extreme, an Exploration Target may refer to a specific area in a property held under licence that has been subject to an advanced reconnaissance exploration programme, but where either the amount of data or the level of confidence in the data is insufficient for classification as a Mineral Resource or where RPEEE have not yet been established for the specific property. So, the company in the example above might have drilled a number of holes into one of the geophysical anomalies and identified the presence of kimberlite. The systematic drilling was able to identify an initial volume of some 20 Mm3 of kimberlite down to a depth of 60 m. Each intersection may have been sampled for microdiamonds which indicated potential grades in the order of 30-40 carats per hundred tons (the bulk density was assumed from a regional average average). However, to date, only 25 macrodiamonds have
been recovered from the initial bulk sampling programme. While this data will fall short of allowing the project being classified as a Resource, it can be classified as an Exploration Target (with identified Mineralisation). In terms of Clause 21, anything classified as an Exploration Target must not be expressed so as to be misrepresented or misconstrued as an estimate of a Mineral Resource or Mineral Reserve. Details of the Exploration Target may not form part of a Resource statement or be included in a tabulation of Mineral Resources or Mineral Reserves. Exploration Targets may not be included in a Technical Study (at Scoping, Pre-Feasibility, or Feasibility level) and may not be converted to Mineral Reserves (Clauses 21, 43-46). They may not be included in economic assessments or discounted cash flow (DCF) models, nor be included in valuations based on Income Approaches. Given the levels of uncertainty surrounding the supporting data, the quantity (volume or tonnage) or quality (grade and value) of an Exploration Target may not be reported as a â&#x20AC;&#x2DC;headline statementâ&#x20AC;&#x2122; in a Public Report (Clause 22). When discussing Exploration Targets, the CP must clearly describe the rationale for such selection, including the geological model on which it is based. Any statement referring to potential quantity, quality, and content, as appropriate, must be substantiated and include a detailed explanation of the basis for the statement. This must be followed by a proximate statement, with the same prominence, that the potential quantity, quality, and content, as appropriate, are conceptual in nature, that there has been insufficient exploration to define a Mineral Resource and that it is uncertain if further exploration could result in the determination of a Mineral Resource. â&#x20AC;&#x2DC;Same prominenceâ&#x20AC;&#x2122; is defined as the same font type and size and â&#x20AC;&#x2DC;proximate locationâ&#x20AC;&#x2122; is defined as the cautionary statement being included in the same paragraph as, or immediately following, the reported statement. The cautionary statement may not be by way of a footnote, nor will a general disclaimer elsewhere in the disclosure document satisfy this requirement. This cautionary statement must, further, be made each time the statement of potential quantity, quality, and content is presented. Any statement referring to quantity and quality must reflect the lack of reliable data. Where the statement includes information relating to ranges of tonnages and grades, these must be represented as approximations. The conceptual nature of the statements must be expressed either through the use of â&#x20AC;&#x2DC;order of magnitudeâ&#x20AC;&#x2122;, including appropriate descriptive terms (such as â&#x20AC;&#x2DC;approximatelyâ&#x20AC;&#x2122;, â&#x20AC;&#x2DC;in the order ofâ&#x20AC;&#x2122;, etc.) or as â&#x20AC;&#x2DC;rangesâ&#x20AC;&#x2122;, which is defined as the variation between the lowest and highest relevant Exploration Results â&#x20AC;&#x201C; the use of ranges in this context has no statistical relevance. Estimates of potential quantity and quality should, preferably, be made in terms of volume (or area) and not mass/tonnage. If, however, target tonnages are reported, then the preliminary estimates, or the basis of assumptions, made for bulk density must be stated. The explanatory text must include a description of the process used to determine the grade and tonnage ranges describing the Exploration Target or Mineralisation. Appropriate rounding should be used to express the level of uncertainty of the estimates. By way of example, â&#x20AC;&#x2DC;approximately one to two million tons at a grade of 3-5% Cuâ&#x20AC;&#x2122; or â&#x20AC;&#x2DC;an Exploration Target of more than 100 million tons of
value. Historically, this is where many (listed and private) companies have misused and abused reporting standards, resulting in, at best, the obfuscation of the situation so as to imply better results than actually exist and, at worst, the gross misrepresentation of the potential of projects (probably the most infamous example of this in modern times is the Bre-X fiasco in 1995-1997).
Exploration Results, Exploration Targets, and Mineralisation coal in excess of 16 MJ/kg for power generation marketsâ&#x20AC;&#x2122; would be acceptable, but not â&#x20AC;&#x2DC;2 Âą0.2 million tonsâ&#x20AC;&#x2122;. When estimates are quoted, statements of both quantity and quality must be provided. It is not permissible to quote one without the other. In addition, any discussion of Exploration Targets must include the intended exploration work programme to explore for the target, detailing the extent of the proposed exploration activities, the planned timeframe, and the anticipated costs. Public Reporting of an Exploration Target shall not be done unless supported by exploration. Without an explicit exploration work programme, Public Reporting of an Exploration Target must be regarded as being solely speculative (Clause 21). Clause 20 further notes that in discussions of Exploration Targets on properties adjacent to, or nearby, properties of known mineralisation, at least some physical evidence of assumed continuity of the mineralisation on the property of interest must be presented by the CP.
A new term, Mineralisation, (Clause 21/22) has been introduced (as a subset of Exploration Target) to deal with the situation where the Exploration Target is no longer purely conceptual, but where actual data has been obtained on the property and where mineralisation of significance (as opposed to a mineral occurrence) has been identified (see example above). Mineralisation refers to the situations where insufficient data has been acquired to estimate a Mineral Resource, where the existing data is of insufficient confidence to allow the classification of a Mineral Resource, or where RPEEE have not yet been demonstrated. In this respect, the concept of Mineralisation is similar to the term
â&#x20AC;&#x2DC;depositâ&#x20AC;&#x2122; in the previous SAMREC Codes. It can be roughly correlated with the concept of Inventory Coal (SANS 10320, 2nd Edition â&#x20AC;&#x201C; note, however, that the term â&#x20AC;&#x2DC;Inventory Coalâ&#x20AC;&#x2122; is not recognized by the SAMREC 2016 Code, nor shall it to be included or presented in Public Reports). The term Mineralisation has been introduced in deference to the proliferation of both private and junior exploration companies whose continued financial backing depends on the presentation of exploration results in the public domain. It was noted that, unless terminology was introduced and strictly controlled, then the current Resource definitions (especially the Inferred Mineral Resource category) would be adulterated by individuals/companies seeking the highest classification for their projects. It would not be sufficient to simply prohibit the reporting of anything that did not meet the requirements of the â&#x20AC;&#x2DC;Resourceâ&#x20AC;&#x2122; definition â&#x20AC;&#x201C; the necessity to publicize results would still result in further abuse of the codes. For an Exploration Target where Mineralisation has been identified based on Exploration Results, a summary of the relevant exploration data/information and the nature of the results should also be presented, including a disclosure of the current drill-hole or sampling spacing and relevant plans or sections. In any subsequent upgraded or modified statements on the Exploration Target, the CP should discuss any material changes to potential scale or quality arising from completed exploration activities. Typically, the phases of an exploration programme, and the subsequent classification, can be defined by the activities carried out in that phase (Table I). Depending on the mineral commodity and/or style of mineralisation, the activities undertaken in each exploration phase may differ significantly. The list included in this table is not meant to be exhaustive and is for illustrative purposes only.
Table I
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Exploration Results, Exploration Targets, and Mineralisation A number of case studies might be considered, which will help to highlight the differences between conceptual Exploration Targets and Mineralisation. Irrespective of the commodity and/or mineralisation type described in the specific case study, the principles are applicable to all commodity and deposit types.
BHP Billiton, as one of the largest mining companies in the world, is committed to developing large, long-life, low-cost expandable operations. An appreciation of this long-term potential in the earliest stages of development is critical for profitable long-term investment. To estimate this long-term potential, the company has developed a rigorous in-house method to assess the mineral endowment potential of a province that is unconstrained by current markets, technology, and the detailed requirements for Resource classification. Exploration Targets (potential mineralisation) are estimated from a limited set of geological information and are reported as a range to reflect different interpretations and the higher level of geological uncertainty. The geological information can be a combination of geophysical, mapping, and sampling data. Such targets (Mullins et al., 2014) capture the essence of â&#x20AC;&#x2DC;what we think will be there when the area under consideration is fully exploredâ&#x20AC;&#x2122; and contribute to the total mineral inventory to consider and prioritize longterm development options for a given orebody or mineral province.
grades for the Kwango River (and, therefore the project property) are 0.8-1â&#x20AC;&#x201C;5 carats per cubic metre (ct/m3) and average sales values in the region of US$90â&#x20AC;&#x201C;140 per carat. For the sake of the example, if it is assumed that the company proceeded to prospect this property; that a number of bulk sample pits were excavated on the floodplains and terraces and a small dredge was installed on the river itself; also a RC drill-rig was employed to drill on a wide grid spacing (as defined in the exploration programme outlined in the abovementioned geological report). As a result of this programme, 250 ct of diamonds were recovered and valued at US$120 per carat. The next Public Report or news release, if done in accordance with the 2016 SAMREC Code, would indicate that Mineralisation (no longer simply a concept) had been identified on the property in the amount of some 8.5â&#x20AC;&#x201C; 9.5 Mm3 of gravel in the present river and approximately 3638 Mm3 in the floodplain/terrace environment, at sample grades of 0.8-1 ct/m3 and an average diamond value of around US$90-140 per carat. The news release would not have the headline â&#x20AC;&#x2DC;47.5 Mm3 of diamondiferous gravel identified on the Midamines Concessionâ&#x20AC;&#x2122;.
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The Midamines Concession is located along the Kwango River in the Democratic Republic of Congo (DRC). Diamonds have long been associated with alluvial sediments within this river system both in Angola and the DRC. Historical data (primarily pre-1980s) regarding diamond recoveries covers an area of some 600 km, both up- and downstream of the project concession; however, no formal resource statements compatible with any international code were ever issued. Major prospecting/mining activity in this area ceased after independence in 1960, although low-level artisanal activity continued in various locations along the river, and even on the concession itself. A site visit confirmed that extensive river, flats were located on each side of a meandering river as well as the presence of several levels of higher terraces. An interpretation of available satellite data suggested that some 50 km2 (river channel, floodplain, and terrace) was potentially underlain by gravels. Information gleaned from the artisanals operating on the site indicated that the basal gravels in the present river bed (the primary target) were some 1 m thick. Limited information was also obtained regarding average diamond size and sales value. The only formal mining activity in the Kwango valley was located some 135 km upstream in a different geomorphological setting. A resource statement from this operation was obtained for comparison. At this stage of knowledge, the first Public Report on the property identified an (early stage, conceptual) Exploration Target of approximately 8â&#x20AC;&#x201C;10 Mm3 in the present river and an additional 35-40 km2 of abandoned river channel, floodplain, and terrace deposits (De Decker, 2005). Target
A number of kimberlite dykes are known to exist on the Bobi concession in CĂ´te dâ&#x20AC;&#x2122;Ivoire. Volumes were estimated from drilling during 1993-1995 â&#x20AC;&#x201C; the exact locations of the holes as well as the original core were destroyed during the civil war of 1999-2011. It is unknown how much material was processed from the different kimberlites over the years or how many diamonds were recovered. Historical documents indicate anecdotal grades of 0.15â&#x20AC;&#x201C;0.3 ct/m3 based on the recovery of an unknown number of carats from an unknown volume of material by artisanals. Diamond values are based on a report by Reuters (in 2014) which indicates that before the embargo, some 300 000 ct a year were being exported from the Ivorian diamond fields, worth around US$25 million (estimated US$83 per carat). Current sales (by small-scale artisanals) to local diamond buyers indicate prices of some US$50-200 per carat On the same property, a detailed ground geophysical survey (magnetics) was completed during 1974. Seven geophysical targets were identified from this data. No drilling has taken place to confirm whether they represent kimberlite. Based on this information, this project may be classified as containing identified Mineralisation as well as conceptual Exploration Targets. With respect to the Mineralisation, although some useful information is available from sampling on the property itself, it is totally inadequate to be stated as a Resource (Marshall, 2014). In addition, RPEEE have not been demonstrated at any scale. In a Public Report, a statement might indicate the identification of Mineralisation of some 300 000â&#x20AC;&#x201C;400 000 m3 of kimberlite to a depth of 60 m at sample grades of 0.15â&#x20AC;&#x201C;0.3 ct/m3 and US$50â&#x20AC;&#x201C;200 per carat. The geophysical anomalies, while occurring on the property, spatially related to the known kimberlites, and having similar (geophysical) characteristics, have not yet been verified as representing kimberlite. These anomalies have geological merit and would be classified as conceptual Exploration Targets. Again, the news release might indicate that the company is pursuing kimberlitic Exploration Targets with a combined volume in excess of 500 000 m3, where regional grades and values are in the range of 0.15â&#x20AC;&#x201C;0.3 ct/m3 and US$50â&#x20AC;&#x201C;200 per carat.
Exploration Results, Exploration Targets, and Mineralisation A company holds rights to a chrome project in the eastern limb of the Bushveld Complex. The project area is covered by recent sediments, with minimal outcrop of the underlying geology. The regional and local geology is well known, with current activity on nearby properties â&#x20AC;&#x201C; one is an underground mining operation with identified Mineral Resources and Mineral Reserves; and another project (adjacent to the project property), has been the subject of recent exploration, No historical mining has been known on the project property and the only documented historical exploration is for adjacent projects, including two percussion boreholes that were drilled into the suboutcrop area (LG6 chromitite unit) near the southern boundary of the farm. An initial exploration programme was conducted by the company, which included an aeromagnetic survey (including 5 m contours for a detailed digital terrain model), as well as the drilling of 10 diamond and reverse circulation drill-holes. The regional geology of the Bushveld Complex is very well known and it might be tempting on the part of a CP to extrapolate a Mineral Resource based on limited data from the property itself. In this case, the limited exploration borehole information and geophysical data, combined with extensive regional information resulted in the CP declaring an Exploration Target (Clay et al., 2014). The provisions of the 2016 SAMREC Code would add that the Exploration Target could be further described as Mineralisation.
SAMREC (and other CRIRSCO codes) adequately addresses the consistent approach required to evaluate and report the nature and extents of potentially economic Mineral Resources. However, limited guidelines exist for the Public Reporting of material that cannot be described as a Mineral Resource. As a result of these inadequacies, many junior/private exploration companies have misused and abused the Resource classification category (especially the Inferred Mineral Resource category). In an attempt to prevent such abuse and regulate the reporting of the pre-resource space, the 2016 SAMREC Code has greatly expanded on the concept of Exploration Targets â&#x20AC;&#x201C; what they may include and how they may be reported in the public domain in a manner that is not misleading, but is useful for potential investors and other stakeholders, in assessing the exploration potential of a specific property of even of an entire mineral province. The term â&#x20AC;&#x2DC;Mineralisationâ&#x20AC;&#x2122; is introduced as a variety of Exploration Target where the target is no longer purely conceptual, but where actual data has been obtained on the property and where mineralisation has been identified (based on actual Exploration Results). It refers to the situation where insufficient exploration data has been acquired to estimate a Mineral Resource, where the existing data is of insufficient confidence to allow the classification of a Mineral Resource or where reasonable prospects for eventual economic extraction (RPEEE) have not yet been demonstrated. When discussing Exploration Targets (either conceptual or with identified Mineralisation), the CP must clearly describe the rationale for such selection, including the geological model on which it is based. Any statement referring to potential quantity, quality, and content, as
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appropriate, must be substantiated and include a detailed explanation of the basis for the statement. This must be followed by a proximate statement, with the same prominence, that the potential quantity, quality, and content, as appropriate, are conceptual in nature, that there has been insufficient exploration to define a Mineral Resource, and that it is uncertain if further exploration could result in the determination of a Mineral Resource. Exploration Targets (conceptual or with identified Mineralisation) may not be included in a Technical Study (at Scoping, Pre-Feasibility, or Feasibility level) and may not be converted to Mineral Reserves. They may not be included in economic assessments or discounted cash flow (DCF) models, nor be included in valuations based on Income Approaches. Given the levels of uncertainty surrounding the supporting data, the quantity (volume or tonnage) or quality (grade and value) of an Exploration Target may not be reported as a â&#x20AC;&#x2DC;headline statementâ&#x20AC;&#x2122; in a Public Report. It is apparent that, in each of the examples or case studies presented, the Exploration Targets have merit, based on their regional setting, association with known deposits and/or limited prospecting data. However, the paucity of sample data, lack of confidence in the data or lack of demonstrated RPEEE means that they cannot be classified as Mineral Resources.
CIM. 2014. Definition Standards for Mineral Resources and Mineral Reserves 2014. Prepared by the Standing Committee on Reserve Definitions. Adopted by CIM Council on 10 May 2014. http://www.cim.org/~/media/Files/PDF/Subsites/CIM_DEFINITION_STAND ARDS_20142 CIM. 2011. Companion Policy 43-101CP to National Instrument 43-101 Standards of Disclosure for Mineral Projects. http://web.cim.org/standards/documents/Block484_Doc111.pdf CLAY, A.N., ORFORD, T.C., DYKE, S., MYBURGH, J.A., and MPHAHLELE, K. 2014. Independent Competent Persons' Report on the Moeijelik Chromite Mineral Asset prepared for Bauba Platinum Limited. Venmyn Deloitte, Johannesburg. DE DECKER, R.H. 2005. Report on a field visit to the Midamines Concession on the Kwango River, DRC to assess the potential for Diamond Mining. De Decker and Associates Consulting Services, Noordhoek. JORC. 2012. Australasian Joint Ore Reserves Committee. Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves. The Joint Ore Reserves Committee of the Australasian Institute of Mining and Metallurgy, Australian Institute of Geoscientists, and Minerals Council of Australia. http://www.jorc.org/docs/JORC_code_2012.pdf MARSHALL, T.R. 2014. Desktop study of the Bobi Diamond Project, Seguela, Cote d'Ivoire. Explorations Unlimited, Johannesburg. MULLINS, M., HODKIEWICZ, P., MCCLUSKEY, J., CAREY, C., and TERRY, J. 2014. Estimating and reporting potential mineralisation at BHP Biliton - the unconstrained view. Monograph Series 30. Australasian Institute of Mining and Metallurgy, Melbourne. pp. 791-798. PERC. 2013. Pan-European Reserves and Resources Reporting Committee. PERC Reporting Standard 2013. Pan European Standard for Reporting of Exploration Results, Mineral Resources and Reserves (â&#x20AC;&#x2DC;The PERC Reporting Standardâ&#x20AC;&#x2122;). 15 March 2013 (revision 2: 29 November 2013). http://www.vmine.net/PERC/documents/PERC_REPORTING_STANDARD_ 2013_rev2.pdf http://www.vmine.net/PERC/documents/PERC_REPORTING_STANDARD_ 2013_rev2.pdf SME. 2014. The Resources and Reserves Committee of the Society for Mining, Metallurgy and Exploration, Inc. The SME Guide for reporting Exploration Results, Mineral Resources and Mineral Reserves. June 2014. Society for Mining, Metallurgy and Exploration Inc., Englewood, CO.
http://dx.doi.org/10.17159/2411-9717/2017/v117n12a6
Development of a best-practice mineral resource classification system for the De Beers group of companies by S. Duggan*, A. Grills*, J. Stiefenhoferâ&#x20AC; , and M. Thurstonâ&#x20AC;
The De Beers Group of Companies has operating diamond mines and exploration projects in numerous countries including South Africa, Namibia, Botswana, and Canada. Diamond deposits are often geologically complex and typically characterized by significant variability in terms of grade and other variables. In addition, diamond revenue also needs to be estimated. These issues make evaluation sampling difficult and accurate Mineral Resource estimation problematic. De Beers identified the need for sound Mineral Resource classification that highlighted areas of uncertainty in the Mineral Resource. As a result De Beers has invested considerable time in developing a best-practice Mineral Resource Classification System (MRCS). In 2004 De Beers developed a prototype that identified the five key Mineral Resource criteria of geology, grade, volume, revenue, and density. A set of key questions and associated answers was developed for each criterion and a scoring system introduced. The MRCS prototype was tested on a wide range of De Beers diamond deposits. Critically, this extensive database of deposits allowed the questions, scoring, and priorities to be adjusted until representative and consistent classifications were produced. The MRCS has evolved through time and, more recently, significant changes have been made that include the ability to take cognisance of new data obtained during mining and production performance. The process involves the project geologist completing the five scorecards, which are reviewed internally prior to an independent review and final ratification by a Competent Person (CP). De Beers is of the opinion that the system is leading practice and provides a repeatable and constant depiction of the confidence in the Companyâ&#x20AC;&#x2122;s mineral resources. 1. ,* ) diamonds, mineral resource classification, geology, grade volume, revenue, density.
'(*, $&(-,' Diamond deposits are often geologically complex and typically characterized by significant variability in terms of diamond content (grade), diamond value, and other estimation parameters. The particulate nature of diamonds, their size distribution in the deposit, shape, quality, and colour also impact on the estimation and classification of diamond resources. This can lead to high levels of uncertainty during evaluation compared to other mineral deposits. Sampling to define grade variability on a local scale is often problematic as diamond deposits generally have very low grades (in terms of parts per million or ppm) when compared to
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%+))-"-&+(-,'/,"/ -+#,' / . ,)-() In the authorsâ&#x20AC;&#x2122; experience there are many cases where insufficient diligence is applied to the Mineral Resource classification process relative to the completion of the Mineral Resource estimate. This lack of thoroughness is often related to a poor understanding of the classification categories and/or the ability to interpret the various classification code guidelines. However, the need for an Indicated Mineral Resource in order to conduct a Feasibility Study requires the classification process to be thorough and justifiable. As highlighted in the introduction, the classification of a diamond resource is typically more complex than for other mineral resources for a number of reasons.
* Z Star Mineral Resource Consultants (Pty) Ltd, South Africa. â&#x20AC; De Beers Group Services (Pty) Ltd, South Africa. Š The Southern African Institute of Mining and Metallurgy, 2017. ISSN 2225-6253. This paper was first presented at the SAMREC/SAMVAL Companion Volume Conference â&#x20AC;&#x2DC;An Industry Standard for Mining Professionals in South Africaâ&#x20AC;&#x2122;, 17â&#x20AC;&#x201C;18 May 2016, Emperors Palace, Johannesburg
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other mineral deposits, as illustrated in Figure 1. These factors make the accurate estimation of diamond resources challenging and dictate that a significant quantity of optimized sampling is required to minimize risk. It follows that an accurate view of the level of uncertainty in the Mineral Resource estimate is critical in terms of obtaining a representative Mineral Resource classification for diamond deposits. The classification plays a critical role in terms of the status of a diamond deposit in the project delivery pipeline and the associated investment decisions. As a result, De Beers has invested considerable time in devising a best-practice classification methodology and subsequently developing an appropriate software package, the Mineral Resource Classification System (MRCS).
Development of a best-practice mineral resource classification system
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In-situ diamond grade can be highly variable within a single rock type and can vary significantly between rock types in the same deposit In the kimberlite environment the explosive volcanic nature of the pipes often leads to extensive dilution, which adds to the complexity of the grade estimate Diamond deposits are particulate and characterized by extremely low grades, typically less than 1 ppm. (Figure 1). This makes representative sampling extremely difficult and expensive. In many cases, due to cost, a move has been made to micro-diamond sampling, i.e. the sampling of a particular portion of the size frequency distribution (SFD) to estimate the diamond grade for the entire SFD Diamond revenue is typically estimated from a SFD and an assortment. The assortment provides an average US dollar value per carat per size class based on modelling valuation results. This is combined with the SFD to provide an overall average US dollar per carat estimate. This estimate may be for the entire pipe, or for a particular rock type within the pipe. The accuracy of the assortment, in particular, is often dependent on acquiring a sufficiently representative diamond parcel (e.g. >5000 carats) Being particulate in nature, diamond resources must be quoted at a defined bottom cut-off, e.g. a nominal square mesh cut-off of 1.15 mm. The grade and bottom cut-off are typically determined by economic studies that optimize these parameters for the resource in question. Should the production plant have a different bottom cut-off (e.g. 1.40 mm) or treatment process, e.g. re-crush to a different particle size, Resource to Reserve modifying factors are required. In 2004, based on the above reasons, De Beers identified the need to develop an appropriate classification methodology (and associated system) to categorize diamond deposits. The methodology had to accommodate three primary requirements: To enable mineral resource managers across the De Beers Group to refer to a standard system of classification across all deposit types (kimberlites, placers, and tailings) and thus ensure compatibility across the Group To consistently and accurately assess the diamond resource risk
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To undertake a classification compatible and compliant with generally accepted international reporting codes.
0-)(,*-&+%/&%+))-"-&+(-,'/+(/ ./ ..*) The methodology devised for classifying De Beers mineral resources involved the development of prototype scorecards for each of the five key mineral resource variables: Geology (the thinking behind the emplacement or deposition model) Grade (the data integrity, estimation methodology and process, and validity of results) Volume (the constructed 2D or 3D representation of the geological thinking) Revenue (the data integrity, SFD and assortment modelling, and validity of results) Density (the data integrity, estimation methodology and process, and validity of results). The process started with the development of the prototype scorecard based on a set of key questions and associated range of answers for each variable. The scoring associated with each question ranged from low for a negative outcome through medium for a partial outcome to high for a positive outcome. The questions in each of the variable scorecards were grouped into sets, e.g. data integrity or estimation methodology, and a priority assigned to the group of questions. The ability to assign priorities to each of the variables (geology, grade etc.) was also introduced as some variables, e.g. grade, were deemed to be more important than others, e.g. density. Importantly, the prototype scorecard system was tested on a wide range of De Beers diamond deposits, i.e. kimberlites, placers, and tailings mineral resources. Critically, this extensive database of deposits allowed the questions, scoring, and priorities to be adjusted until representative and consistent classifications were being produced. Once the scorecard methodology had been approved and implemented, the formal classification of all diamond deposits across the De Beers Group of Companies was undertaken by a Mineral Resource Classification Committee (MRCC) in 2004. The committee comprised De Beers specialists representing the mineral resource disciplines of geological modelling, grade and density estimation, and diamond revenue modelling. The committee mechanism assisted in ensuring consistency and compatibility of classification across all
Development of a best-practice mineral resource classification system operations and deposit types; the chairman of the committee was responsible for the final sign-off of a classification. The classification scorecard can also be used in a proactive sense to analyse the work undertaken on a deposit and identify the risks (areas outstanding) that require addressing prior to attaining a particular confidence level, e.g. Indicated.
1. /.%.#.'()/,"/(!./&$**.'(/ ./ ..*)/&%+))-"-&+(-,' #.(!, ,%, The formal classification at De Beers was initially undertaken by the MRCC. Typically, the project geologist or relevant mineral resource manager would present a preliminary scorecard to the MRCC for review. The scorecards would be interrogated and modified during the meeting, if required. At a later stage the MRCC would meet to ratify the scorecard. This process involved checking the classification database to ensure that question scores were compatible with deposits elsewhere in the Group where a similar amount and quality of work had been undertaken. Once ratification was complete the scorecard was signed off by the chairman of the MRCC. More recently the emphasis has moved towards ownership on the operations with the relevant Competent Person (CP) approving the final classification. However, the current classification process does require a peer review on the operation and, in addition, an independent external review. To this end there are four key steps in the current De Beers classification process: An initial classification by the project geologist, i.e. based on the project work undertaken, a series of questions are answered for each of five scorecards and scores assigned An on-site peer review by a committee, i.e. answers and scores are amended where applicable according to group consensus
An independent external review (i.e. different company and external to the mine) â&#x20AC;&#x201C; no changes are implemented, but recommendations are made regarding questions and scores for the CPâ&#x20AC;&#x2122;s consideration Finalization by the De Beers-appointed CP (may include the external reviewâ&#x20AC;&#x2122;s recommended changes if deemed appropriate). This best-practice approach to mineral resource classification ensures good governance by providing a representative semi-quantitative view on the level of confidence, thus ensuring adherence to the various international reporting guidelines (e.g. SAMREC, JORC, and NI 43-101). The methodology developed comprises four main processes (Figure 2): A preparation phase where the deposit to be classified is defined and information required collated A set-up phase which requires the user to select the appropriate De Beers company and operation in the MRCS and create a Resource, group, and classification A completion phase where a preliminary scorecard is completed, reviewed by the operation, and finally submitted for external review (i.e. by a different company) A final ratification and sign-off by the CP. In terms of the MRCS a typical classification will require eight steps as illustrated in Figure 2.
One of the most important tasks in the classification process is the subdivision of the deposit prior to completing the scorecards. It is often the case that a portion of the deposit may have a higher sampling density; this may be a higher grade area that was found first or it may simply be the part of the resource that is closer to surface and has been easier to drill. The higher sampling density will typically facilitate a better understanding of the geological model and thus improved definition in the volume model, the interpolation of local block grades and density estimates, and the recovery of more diamonds, resulting in a higher confidence revenue estimate. When an area or volume is delineated for classification it is critical that a similar level of evaluation work has been undertaken on the entire portion. If this is not the case, the questions become problematic as there can be more than one answer to each question. In summary, it is very important that, having taken the geological model into consideration, the deposit is carefully subdivided into portions with reasonably equal levels of evaluation work prior to classification.
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An individual score is assigned to each of the 84 questions in the scorecards. Within each individual scorecard, e.g. geology, the assigned scores within each group of questions are averaged. These average scores are then added to provide an overall score for the criteria out of a maximum of 100. The scorecards for the five key criteria are summarized in Table I in terms of the priority assigned to various groups of questions.
Development of a best-practice mineral resource classification system
Table I
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In Table I, the knowledge techniques relate to the application of appropriate methods, the sample (and data) integrity is associated with procedures, security issues, logging methods, positioning accuracy, etc. The sampling accuracy with respect to the grade scorecard relates to how the sample area and/or sample volume was measured. The original De Beers classification committee determined that three of the five variables â&#x20AC;&#x201C; geology, grade, and revenue â&#x20AC;&#x201C; are critical and should be assigned the highest weighting (3). Volume was viewed as being slightly less important as it is a constructed representation of the geology, and was hence assigned a lower weighting (2), and density was assigned the lowest weighting (1). These weightings are applied to the relevant scorecard and a final average classification score calculated. Classification limits were assigned as follows: â&#x20AC;˘ 0-30 â&#x20AC;&#x201C; Deposit (excluded from the resource) â&#x20AC;˘ 30-70 â&#x20AC;&#x201C; Inferred Mineral Resource â&#x20AC;˘ 70-90 â&#x20AC;&#x201C; Indicated Mineral Resource â&#x20AC;˘ 90-100 â&#x20AC;&#x201C; Measured Mineral Resource.
The De Beers classification methodology calls for each classification to be independently reviewed prior to final sign-off by the CP. The external reviewer is given access to the MRCS and is required to comment on the answers and the scores but has no permission to change the original entries. The external reviewer documents appropriate comment and the Microsoft WordTM file is stored in the MRCS.
De Beers officially appoints a CP for each Anglo American reporting cycle (typically a year), and this person is responsible for mineral resource classification on a specific operation or project. The MRCS has been designed with this structure in mind, and represents a change from historical classifications, where the final responsibility rested with a classification committee. In keeping with international reporting codes, the CP is ultimately accountable for the classification of mineral resources on an operation and must ensure that correct procedures have been followed during the classification process. The company letter of appointment, signed by the CP and the mine general manager, includes an abridged CV indicating the number of years of relevant experience that the CP has in terms of the type of deposit and style of mineralization. It includes proof of membership of a designated professional organization (e.g. SACNASP) and the letter is stored on the MRCS.
!./ -'.*+%/ .),$*&./ %+))-"-&+(-,'/ )(.#/ The methodology has evolved through time, and recently significant changes have been made to the scorecard and the MRCS. For example, the ability to take cognisance of production history has been introduced as an accurate assessment of performance that shows the resource is performing as expected will result in reduced risk and therefore enhance the resource confidence. The software application has a number of attributes that simplify the classification process, namely, an SQL sequel database facility that stores a list of documents and information associated with the particular resource being classified, a help facility to explain the meaning of each question, and a user-friendly â&#x20AC;&#x2DC;front endâ&#x20AC;&#x2122; that streamlines the process. The MRCS includes a hierarchical structure that enables users to easily select (or create) the company, operation, resource, group, and classification. Permission to create a new company or operation is restricted but most users may create and edit a resource, group, or classification (Figure 3). Each of these operations is briefly explained below: A Resource is named by the user and is defined by the geology (e.g. kimberlite, dyke, aeolian placer, beach placer, deep-water marine placer, fluvial placer,
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Development of a best-practice mineral resource classification system
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shallow-water marine placer, tailings mineral resource, stockpile) and the deposit type (e.g. primary, secondary, tertiary) A Group constitutes a user-defined group of classifications in a particular Resource, named by the user and including a brief description and spatial definition (e.g. a â&#x20AC;&#x2DC;from-toâ&#x20AC;&#x2122; elevation in the case of a kimberlite) The Classification scorecard status could be preliminary, internally reviewed, externally reviewed, or ratified depending on how far the Mineral Resource has moved along the classification process. Once the hierarchy has been appropriately defined, the classification scorecard is created and the user answers the questions appropriately based on his knowledge of the Mineral Resource (Figure 4). Hints are provided for uninitiated users as a guide to understanding the questions and comparative scoring functionality aids the user in selecting an appropriate score.
,# +*+(- ./)(+(-)(-&) The De Beers classification method remains a subjective process, and therefore it is useful to provide a guideline related to how questions should be interpreted. To this end the MRCS includes functionality that enables the user to compare scores and answers from other classifications across the De Beers Group of companies. This is achieved by a selection process that enables the user to compare scores for a specific question, a group of questions on a scorecard, an entire scorecard, or the whole classification. This process is extremely useful, as De Beers has a vast array of diamond resources that have been classified, and enables new resources to be benchmarked. The comparative statistics module is user-friendly and provides rapid graphic solutions, as illustrated by the example in Figure 5. The upper portion of this figure shows a number of options for selecting classifications for the comparison, which include selection by company, mine, Resource, group, deposit type, and geology type.
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Development of a best-practice mineral resource classification system %+))-"-&+(-,'/ ,&$#.'(/#+'+ .#.'( The MRCS includes a facility to store and manage documents associated with each classification. By way of example, it is important for users to have access to the documented sampling procedures, the geological models, the estimation reports, and review or audit documents. All versions of the classifications are stored, and therefore the MRCS document management component provides a record of the estimation process for each Mineral Resource, thereby creating an historical record for future users. Files of any format can be stored in the MRCS, e.g. ArcInfoTM files, WordTM documents, GemcomTM. Files, and ExcelTM spreadsheets.
-'-' / .*",*#+'&./ In the latest MRCS, mining performance has been introduced as a method for assessing the level of confidence in a small part of the Resource close to existing production. This approach, documented by NoppĂŠ (2014) and others, is intended for a relatively small part of the Resource, for example the next two years of mining. By way of example, for a typical kimberlite Mineral Resource the performance documentation may include a model like the one illustrated schematically in Figure 6. In this example of a kimberlite mine a few benches have been included below the current mining level. The decision as to what is included is documented in the MRCS, e.g. three benches falling within the vertical variogram range. Should the business rules be met, the dark green portion shown in Figure 6 would be upgraded to an Indicated category. In assessing confidence in this local resource the MRCS requires the user to answer a number of questions (all of which should be affirmative), including the following: Has face mapping, blast-hole chip sampling, field observations etc. been undertaken? Is the change in geology insignificant in adjacent mining? Is the orebody envelope changing insignificantly? Do the density estimates correlate with geology? Finally, as a measure of grade and value consistency, the following ratios are also considered:
RsCR: the average Resource carat ratio by year, defined as the carats expected from the Resource divided by the carats recovered RvCR: the average Reserve carat ratio by year, defined as the carats expected from the Resource after applying modifying factors divided by the carats recovered Rv$R: the average Reserve revenue ratio by year, defined as the value (in US dollars) expected from the Resource carats after applying modifying factors divided by the value of the carats recovered (in US dollars). For an Indicated Mineral Resource, these ratios should meet the so-called 15% rule (CaĂąas, 1995; Dohm, 2004; and others), meaning that the standard error of a given ratio measured over a period of one year should be 15% or less (90% confidence limits).
,'&%$)-,') The De Beers semi-quantitative approach to classification is robust and satisfies the key components of the international reporting codes, i.e. transparency, materiality, and competence. The classification method is not focused on specific estimation variables, such as kriging variance, but rather covers the five key criteria that combine to produce a diamond Mineral Resource estimate: geology, grade, volume, revenue and density. The classification approach is standardized and semi-quantitative and enables CPs on the operations to make informed decisions in terms of confidence. The comparative statistics is a powerful tool that allows classifications to be benchmarked against a large database of De Beers diamond Mineral Resources. The introduction of a performance module to incorporate information from mining is an important addition. The MRCS is a user-friendly and flexible system and ensures that a robust record of the classification process on all De Beers operations is stored electronically. Importantly, the MRCS provides De Beers with a best-practice documented and justifiable classification for all types of deposits: kimberlites, placers, and tailings. Although the MRCS continues to change, the essence of the scorecard approach has been applied to successfully produce several hundred De Beers classifications.
.".*.'&.) CAĂ&#x2018;AS, J.D. 1995. Salobo ore reserve model review. Letter from MRD (Mineral Resources Development Inc.) to Dr Alvaro Tohar (Anglo American Corp.), 30 July 1995. DOHM, C.E. 2004. Quantifiable mineral resource classification: a logical approach. Proceedings of Geostatistics Banff 2004. Springer, Dordecht:. pp. 399â&#x20AC;&#x201C;341. JORC. 2012. Australasian Joint Ore Reserves Committee. Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves. The Joint Ore Reserves Committee of the Australasian Institute of Mining and Metallurgy, Australian Institute of Geoscientists, and Minerals Council of Australia. http://www.jorc.org/docs/JORC_code_2012.pdf NOPPĂ&#x2030;, M.A. 2014. Communicating confidence in Mineral Resources and Mineral Reserves. Journal of the Southern African Institute of Mining and Metallurgy, vol. 114. pp. 213â&#x20AC;&#x201C;222.
- $*./ &!.#+(-&/)!, -' /(!./+ %-&+(-,'/,"/ .*",*#+'&. +)).))#.'(
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SAMREC. 2009. South African Mineral Resource Committee. The South African Code for Reporting of Exploration Results, Mineral Resources and Mineral Reserves (the SAMREC Code). 2007 Edition as amended July 2009. http://www.samcode.co.za/downloads/SAMREC2009.pdf
http://dx.doi.org/10.17159/2411-9717/2017/v117n12a7
Development of a technology to prevent spontaneous combustion of coal in underground coal mining by A. Tosun
Top and bottom roads, as well as the production areas in underground coal mining, are continually in contact with oxygen supplied by the mine ventilation system. These areas are at risk of spontaneous combustion, depending on various environmental conditions and characteristics of the coal seam. The formation of toxic gases as a result of spontaneous combustion of the coal and exposure of employees to these gases are the most important causes of coal mining accidents. To avoid the risk of spontaneous combustion, contact of the coal with oxygen must be prevented during production. The literature mentions various studies based on the use of fillers on small areas to control or delay spontaneous combustion. In this study, the aim was to develop cheap materials with very low oxygen permeability and high mechanical resistance for coating the walls of the mine galleries. Epoxy/fibreglass was identified as the material with the least oxygen permeability, and also has other desirable properties. 1. +( ) Coal mining accidents, spontaneous combustion of coal, polymer composite materials, oxygen permeability.
0'-(+ $ -,+' In recent years, deaths occurring as a result of underground coal mining have increased, due to serious accidents in certain regions. These accidents are mostly due to firedamp explosions and spontaneous combustion of the coal. Toxic gases are formed as a result of spontaneous combustion and many deaths may ensue due to exposure of employees to these gases. The spontaneous combustion of coal is an serious event that must be taken into consideration since it impedes production and has adverse occupational health consequences in underground mines. Spontaneous combustion is caused by selfheating of the coal through slow oxidation, and with sufficient heat accumulation it can develop into actual combustion with open flames. Top and bottom roads as well as the production areas in underground coal mines are continually in contact with the oxygen supplied by the mine ventilation system. The coal adsorbs the oxygen, and once the the temperature reaches over 40°C, the process transforms into a reaction and the ambient temperature increases further (Saraç, 1992). If this temperature cannot be reduced, after
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* Dokuz Eylul University, Department of Mining Engineering and Bergama vocational school Bergama-Izmir, Turkey. Š The Southern African Institute of Mining and Metallurgy, 2017. ISSN 2225-6253. Paper received Mar. 2016; revised paper received May. 2017.
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approximately 70°C the concentrations of CO and CO2 in the environment increase, and steam is evolved at 125°C. When the temperature reaches the ignition temperature, the coal starts burning. Therefore, the galleries and the roads opened inside the coal faces are continually at risk of spontaneous combustion, depending on the environmental conditions and characteristics of the coal seam. To avoid this risk, contact between coal seams and oxygen must be prevented during production. Various studies have been carried out based on the use of fillers, generally consisting of cement and nitrogen, in small areas prone to fire risk to control or delay the advent of spontaneous combustion by preventing contact of the coal with oxygen. However, these studies were limited to very small areas due to the cost of the cement and nitrogen used to inertize the voids. Also, scientific studies have shown that cement cannot completely prevent the ingress of the oxygen. In the scope of this study, the aim was to develop different materials with much lower oxygen permeability for coating the walls of the galleries in coal mines. Bearing in mind the size of the galleries, ensuring that the cost of this material is very low has been among the targets of this study. Therefore, the gas permeabilities of various cheap polymer composite materials were determined. The mechanical characteristics of the composite materials, such as stroke and friction, were also determined. The materials developed can be used to ensure that the coal seam doesn't contact with oxygen throughout the entire production process. Thus, it will be possible to minimize the occupational accidents occurring as a result of the oxidation of coal in underground mines.
Development of a technology to prevent spontaneous combustion of coal 2,-.(*-$(./)-$ ,.)/ The presence of coal and sufficient oxygen to initiate oxidation and sustain the oxidation at ambient temperature will lead to heat accumulation (Karpuz et al., 2000), depending on the characteristics and geological structure of the coal, and the mining conditions and environment (Feng, Chakravorty, and Cochrane., 1973; Kucht, Rowe, and Burgess, 1980). Generally, low-rank coals with a high pyrite content or high ratio of oxygen to moisture (semibituminous and lignites) are more prone to self-heating. Pyrite increases the risk if it is fine grained and present in sufficient quantity (Didari, 1986). The total surface area of the coal makes an important contribution to the self-heating propensity. The heating rate is directly proportional to the cube of the surface area. Thus, the more friable the coal the higher the risk of spontaneous combustion, due to the increased quantity of coal fines. Since a large amount of coal fines is produced at mechanized mines, accumulation of this material poses a potential risk. In thick seams, poor roof conditions may also create danger since the roof becomes unstable and coal accumulates on the floor. Generally, subsidence leads to cracks above the mine workings close to the surface and provokes the development of combustion by causing air leakage. Similarly, fractures in closely spaced seams cause air to leak between the seams. A high pressure difference in the ventilation is also an important factor provoking the development of self-heating. With an increase in the ventilation pressure, the possibility of heating is increased since the air leakage to a cracked coal mass or cave-in will increase. Main ventilation ways, regulators, and leakages in the gates are also a source of danger. Ground heave and roof falls also cause air leakage. If the regulators and the doors are not placed properly, they may cause air leakage into the cracks inside the coal around them due to increased pressure differential. The greater the pressure difference, the greater the risk of combustion. The amount of air in circulation in the mine is also important. As a general rule, the amount of air supplied to the oxidation zone must be sufficient to prevent the accumulation of the heat released. If a large amount of air flow is applied, the heat of oxidation is carried away but the increased oxygen supply will facilitate combustion (Demirbilek, 1986). On the other hand, if air flow is low, the heat released as a result of oxidation cannot be removed from the environment and will remain in the coal. If the fissure density, degree of cracking, and amount of broken coal are excessive, the rate of oxidation and subsequently the rate of heat production will be excessive. Therefore, it is useful to know the mine conditions inducive to self-combustion. As soon as the coal contacts the open air, it reacts with the oxygen even at low temperatures. Besides the physical and chemical changes in the coal, the heat is released depending on absorption and adsorption capacity of each coal type. The rate of oxygen comsumption during oxidation varies depending on the time and the phase of the oxidation. In the first phase of oxidation, the oxygen intake is very rapid and peroxide complexes are formed. The oxygen consumption decreases over time due to the coating of the coal surface with oxygen compounds and the temperature approaches a constant value. However, if the coal reaches the temperature of self-heating, oxygen consumption and temperature increase rapidly. Wade (1988) indicated that the
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factors affecting the physical oxidation ratio of the coal are particle size, temperature, moisture, pre-heating, oxygen partial pressure, volatile substance content, internal moisture, carbon content, degree of carbonization, and methane content. Studies on the prevention of spontaneous combustion are also reported in the literature. Millions of dollars have been spent on research related to this subject in Australia (Cliff, Brady, and Watkinson, 2014). A method based on monitoring the distribution of oxygen in the coal seams was developed (Balusu et al., 2002, 2010; Ren, Balusu, and Humphries, 2005). A simulation model showing the oxygen distribution inside the coal seam can be constructed by this method, as seen in Figure 1. Thus, precautions can be taken in cases where there is a high self-heating risk. The data for the simulation model is provided through sensors located at crirical places. However, owing to breakdown of the sensors, correct readings cannot be obtained in adverse conditions. Also, the method doesn't control or prevent combustion. The source of oxygen in the case of an underground coal mine is the mine ventilation. One aeration ventilator is generally placed at the mine entrance. Ventilator pressure varies depending on the depth of the mine and the length of the galleries. This pressure is high at mines with deep and long galleries. High air pressure creates high oxygen concentrations underground. Luxbacher and Jong (2013) reduced the ventilation pressure by using more than one ventilator. Thus, the contact of the coal with less oxygen gas is ensured, delaying spontaneous combustion. Certain filling materials were injected into the zones with a combustion risk in order to prevent spontaneous combustion (Humphreys, 2013). Filling materials were used in the form of resin, foam, and cement. These materials reduced the passage of oxygen. The injection of nitrogen and carbon dioxide under pressure into the zones at risk of combustion has also been successful (Ray and Singh, 2007). The abovementioned studies were based on the coating of only small areas at fire risk with various substances. Preventing contact of the entire coal seam with oxygen couldn't be ensured, except for the production area during the production period. Also, due to high cost of the nitrogen to prevent combustion and the cement filler, the coating of all coal surfaces in the underground mine with these materials is not possible. On the other hand, studies have shown that cement cannot completely exclude oxygen.
Development of a technology to prevent spontaneous combustion of coal
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Based on this previous work, studies were carried out at Omerler underground coal mine in Tunçbilek district, Kßtahya Province of Turkey. A method that would prevent spontaneous combustion of the coal seam was developed during this research (Onur et al., 2012). The mine galleries were coated using a mixture of ash, cement, and water in certain proportions and efforts were made to prevent oxygen from contacting the coal (Figure 2). It was determined that the mixture of ash, cement, and water reduced the oxygen permeability. Polymers are materials with a low oxygen permeability. The development of polymer composite materials as a barrier layer between the coal surface and the ambient air of the mine was therefore investigated in this study. Fibre-reinforced polymers consist of a polymer resin impregnated with low-cost fibreglass or high-cost aramid/carbon fibre materials. Fibres may be short or long, continuous or discontinuous, and single or multi-ply. Materials of this type have advantages compared with steel, aluminum, and other isotropic metals, having high stiffness, low weight, good fatigue characteristics, and corrosion resistance. Additionally, the characteristics of the materials can be tailored to the requirements of special designs by changing the orientations of the fibres. Typically the matrix materials, which harden by the evolution of heat, consist of epoxy, epoxy-based vinyl ester, and polyester resin and are used for the production of fibre-reinforced layers. However, vinyl esters modified by more flexible urethane are also used in the production of composites. These resins are normally hardened by a peroxide-based catalyser and a cobalt-based accelerator. To improve the characteristics of the composite material, the resin may be subjected to different curing procedures after the hardening process. Different fibreglass types can be used as reinforcement, including E-glass and boron-free E-glass. These materials differ in their corrosion reistance towards acid and basic substances and their tensilecorrosion strengths. Fibre-reinforced polymer materials can be produced by manual spreading or by continuous processing methods such as filament winding, spraying, and centrifuging, depending on the structure and geometry of the fibre materials. The focus in this project was to obtain high strength values and to avoid the use of easily flammable materials such as wedge-brush. Polymers are widely used in packaging, especially for food and medicine where gas permeability, optical, and
mechanical characteristics become important. These must meet challenging needs such as moisture, oxygen permeability, carbon dioxide permeability under pressure, and high-temperature sterilization. Different polymers such as polyolefin and polyethylene terephthalate (PET) are generally used in multi-layer structures to integrate their desirable characteristics (Lee, 2002). In general, these layers consist of a polyolefin folio serving as a moisture barrier and a PET folio functioning as an oxygen barrier. If adhesive material contributes to the oxygen barrier characteristic of polyolefin/PET layers, this will be advantageous. The barrier characteristics of the polymer are generally developed by obtaining a composite material through impregnation of the fibre materials not having good permeability characteristics with the polymers. Thus, the possibilities of the small oxygen molecules being able to diffuse to the other side of the composite layer by passing around the fibre materials will be minimized. Fibre-reinforced polymer materials are used in the reinforcement and the repair of structures, and many independent studies have shown that these materials are impermeable to oxygen. These applications have been effective in the repair of corrosion damage since the mid1990s (Alampalli, 2001; Pantazopoulou et al., 2001; Debaiky, Green, and Hope, 2002; Sen, 2003; Wang and Shih, 2004; Badawi and Soudki, 2005; Suh et al., 2007, 2008; Winters et al., 2008). Various studies have also shown that fibre-reinforced polymer materials do not prevent corrosion entirely, but reduce the corrosion rate considerably (Baiyasi and Harichandran, 2001; Berver et al., 2001; Wootton, Spainhour, and Yazdani, 2003; Wheat, Jirsa, and Fowler, 2005). Figure 3 shows the corrosion of an abutment caused by oxidation and the process of coating with a polymer composite material.
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Coal is a fragile and pervious material. The oxygen gains entrance to the coal either through fissures or by diffusion from the coal surface. This situation causes the spontaneous combustion of the coal. Because oxygen molecules are very small and also undergo rapid diffusion, their permeability inside fibre-reinforced polymeric materials is critical. In the scope of this study, the oxygen permeability of the fibrereinforced polymer was investigated experimentally. This study is the first international study of the oxygen
Development of a technology to prevent spontaneous combustion of coal
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permeability of polymer composite materials for underground coal mining applications. Several types of polymer composite materials were prepared experimentally. Fibreglass produced in the form of a felt was used as an additive, since it is very cheap compared to the alternatives, namely carbon and armide, and has been very effective. Three types of polymeric resins â&#x20AC;&#x201C; epoxy, polyester, and vinyl ester resins â&#x20AC;&#x201C; were investigated to ascertain the effect of the polymer material
used in the production of the composite material on the oxygen permeability. A few methods are available for the determination of the oxygen permeability of polymers, but these are not suitable for thick materials. The oxygen permeabilities of the composite material samples produced at laboratory scale were determined using the system developed by Chandra (2011) (Figure 4). In this test device, a stream of oxygen gas is directed on the surface of the material and the amount of oxygen that diffuses to the opposite surface of the material is determined by an oxygen sensor. The volume of oxygen gas passing from the material during the test is recorded continually. The material tested was placed in the test cell. Oxygen gas was streamed onto the sample from the oxygen tank. The oxygen gas sensor in the test cell transmitted the data on the amount of oxygen passing through the material to the data collecting device, and the data was stored in the data recorder. Thus, the degree of oxygen permeability of the material tested could be measured precisely. Each test lasted for three or four hours. The oxygen gas permeabilities determined for the materials are listed in Table I.
Table I
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Epoxy/fibreglass
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4.29Ă&#x2014;10-11
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Development of a technology to prevent spontaneous combustion of coal Table II
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A composite polymer material intended for application in underground working conditions must also be strong. Therefore, it is also important to determine the mechanical characteristics of the composite polymer materials. The elastic modulus and the Poissonâ&#x20AC;&#x2122;s ratios were determined by means of the tensile test, using the apparatus shown in Figure 5. Strain gauges were fixed to the material with adhesive. The strain gauges consisted of fine washers on an elastic carrier and connected to each other in parallel. These washers extend or shorten in proportion to the load applied on the material. Deformation was recorded continually by the data recorder. The first increase in the force applied on the material must be regular. Therefore, pre-loading was carried out and the force was increased slowly. At the end of the test, the elasticity modulus and the Poissonâ&#x20AC;&#x2122;s ratio were determined for each material by averaging the longitudinal and axial deformations measured continually (Table II). The following relationships were used in the determination of these values.
The epoxy/fibreglass composite was identified as having the least oxygen permeability of the materials tested. All gallery surfaces in the underground coal workings can be coated with this material to impede the permeation of oxygen gas during production and prevent spontaneous combustion of the coal. Thus, reduced levels of dangerous gases can be ensured inside the mines through minimized spontaneous combustion reactions. The permeability constant is defined as the rate per unit area at which a gas passes through a material of unit thickness under one unit pressure difference, expressed in units of mol.m2/m3.atm.sec. Thus underground coal mining companies can calculate how much oxygen gas will enter the coal seam by substituting their ventilator pressure, the size of coal seams, and time. This will indicate when the spontaneous combustion of the coal will start according to the combustion properties of the particular coal. The materials used in the study were produced in the solid state in the laboratory environment. For use in underground conditions, they must be produced in liquid form so that they can be sprayed onto the gallery surfaces. The surfaces of coal galleries are generally very irregular, and it will be necessary to ensure thorough coating of all surfaces and discontinuities. The application of the materials in underground conditions and the determination of the performances of the materials under these conditions should be investigated in future studies.
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[3] where = Tensile strength (MPa) E = Elastic modulus (MPa) v = Poissonâ&#x20AC;&#x2122;s ratio = Lateral deformation
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= Vertical deformation
The aim of this study was to develop cost-effective materials with very low oxygen permeability and high mechanical resistance for coating the walls of the galleries in underground coal mines in order to prevent spontaneous combustion of the coal. Three types of composite material were manufactured for testing. All of them were found to have good mechanical properties as well as being cheap to manufacture. The epoxy/fibreglass composite was identified as the material with the lowest oxygen permeability. The cost of this material (weight of 80 g/m2) is US$0.124-0.209 (https://cnxinghao.en.alibaba.com/product/60601388436219 069229/80g_m2_fiberglass_price_epoxy_fiberglass_resin_bit umen.html). This study is the first international study to determine the oxygen permeability of polymer composite materials for use in underground coal mining.
Development of a technology to prevent spontaneous combustion of coal 3.!.(.' .) ALAMPALLI, S. 2001. Reinforced polymers for rehabilitation of bridge columns. Proceedings of the 5th National Workshop on Bridge Research in Progress, 8-10 October. University of Minnesota. pp. 39â&#x20AC;&#x201C;41. BADAWI, M. and SOUDKI, K. 2005. Control of corrosion-induced damaged in reinforced concrete beams using carbon fiber-reinforced polymer laminates. Journal of Composites for Construction, vol. 9, no. 2. pp. 195â&#x20AC;&#x201C;201. BAIYASI, M. and HARICHANDRAN, R. 2001. Corrosion and wrap strains in concrete bridge columns repaired with FRP wraps. Proceedings of the 80th Annual Meeting, Transportation Research Board, Washington, DC. Paper no. 012609. BALUSU, R., REN, T., SCHIEFELBEIN, K., Oâ&#x20AC;&#x2122;GRADY, P., and HARVEY, T. 2010. Proactive strategies to prevent fires and explosions in longwall mines. A century of Mining Research. SME, Littleton, CO. pp. 408â&#x20AC;&#x201C;417. BALUSU, R., HUMPHRIES, P., HARRINGTON, P., WENDT, M., and XUE, S. 2002. Optimum inertisation strategies. Proceedings of the Queensland Mining Industry Safety and Health Conference, Townsville. pp. 133â&#x20AC;&#x201C;144.
ONUR, A.H., KĂ&#x2013;SE, H., YALĂ&#x2021;IN, E., KONAK, G., YENICE, H., KARAKUĹ&#x17E;, D., GĂ&#x2013;NEN, A., TOSUN, A., and Ă&#x2013;ZDOÄ&#x17E;AN, M. V. 2012. TĂźrkiye kĂśmĂźr i letmeleri-gĂźney linyitleri i letmesi (TK -GL ) mĂźessesesi Ă&#x2013;merler yeraltÄą oca Äą tavan kontrolĂź-tahkimat tasarÄąmÄą ve ocak yangÄąnlarÄą Ar-Ge Projesi. PANTAZOPOULOU, S.J., BONACCI, J.F., SHEIKH, S., TOMAS, M.D.A., and HEARN, N. 2001. Repair of corrosion-damage columns with FRP wraps. Journal of Composites for Construction, vol. 5, no. 1. pp. 3â&#x20AC;&#x201C;11. RAY, S.K. and SINGH, R.P., 2007. Recent developments and practices to control fire in underground coal mines. Fire Technology, vol. 43. pp. 285â&#x20AC;&#x201C;300. REN, T.X., BALUSU, R., and HUMPHRIES, P. 2005. Development of innovative goaf inertisation practices to improve coal safety. Proceedings of Coal 2005: Coal Operators' Conference, University of Wollongong. Aziz, N (ed). Australasian Institute of Mining and Metallurgy, Melbourne. pp. 315â&#x20AC;&#x201C;322. RESTREPOL, J.I. and DEVINO, B. 1996. Enhancement of the axial load carrying capacity of reinforced concrete columns by means of fiberglass-epoxy jackets. Proceedings of the First International Conference on Composites in Infrastructure, Montreal. Canadian Society for Civil Engineering. pp. 547â&#x20AC;&#x201C;553.
BERVER, E., JIRSA, J., FOWLER, D., WHEAT, H., and MOON, T. 2001. Effects of wrapping chloride contaminated concrete with fiber reinforced plastics. Report no. FHWA/TX-03/1774-2. enter for Transportation Research, University of Texas, Austin.
SAMAAN, M., MIRMIRAN, A., and SHAHAWY, M. 1998. Model of concrete confined by fiber composites. Journal of Structural Engineering, ASCE, vol. 124, no. 9. pp. 1025â&#x20AC;&#x201C;1031.
CHANDRA, K.K. 2011. Oxygen diffusion characterization of FRP composites used in concrete repair and rehabilitation. Doctoral thesis, University of South Florida..
SARAĂ&#x2021;, S., and SOYTĂ&#x153;RK, T. 1992. Tunçbilek kĂśmĂźrlerinin kendili inden yanmaya yatkÄąnlÄąklarÄąnÄąn ara tÄąrÄąlmasÄą. (An Äąnvestigation on the liability of Tunçbilek coals to spontaneous combustion.) TĂźrkiye 8. KĂśmĂźr Kongresi Bildiriler KitabÄą. pp. 141â&#x20AC;&#x201C;152.
CLIFF, D., BRADY, D., and WATKINSON, M. 2014. Developments in the management of spontaneous combustion in Australian underground coal mines. Proceedings of the 2014 Coal Operatorsâ&#x20AC;&#x2122; Conference, University of Wollongong. Australasian Institute of Mining and Metallurgy, Melbourne.
SEN, R, MULLINS, G., and SNYDER, D., 1999. Ultimate capacity of corrosion damaged piles. Final Report submitted to Florida Department of Transportation.
DAVID, C., DARREN B., and MARTIN W. 2014. Developments in the management of spontaneous combustion in Australian underground coal mines. Proceedings of the 2014 Coal Operators' Conference, University of Wollongong. Australasian Institute of Mining and Metallurgy, Melbourne.
SEN, R. 2003. Advances in the application of FRP for repairing corrosion damage. Progress in Structural Engineering and Materials, vol. 5, no. 2. pp. 99â&#x20AC;&#x201C;113.
DEBAIKY, A., GREEN, M., and HOPE, B. 2002. Carbon fiber-reinforced polymer wraps for corrosion control and rehabilitation of reinforced concrete columns. ACI Materials Journal, vol. 99, no. 2. pp. 129-137.
SHEIKH, S., PANTAZOPOULOU, S., BONACCI, J., THOMAS, M., and HEARN. N. 1997. Repair of delaminated circular pier columns with advanced composite materials. Report no. 31902. Ontario Joint Transportation Research, Toronto, Ontario, Canada.
DEMIRBILEK, S. 1986. The development of a spontaneous combustion risk classification system for coal seams. PhD thesis, University of Nottingham, UK. DIDARI, V. 1986. YeraltÄą ocaklarÄąnda kĂśmĂźrĂźn kendili inden yanmasÄą ve risk indeksleri. (Spontaneous combustion and risk indices in underground mines). Madencilik, vol. 15, no. 4. pp. 29â&#x20AC;&#x201C;34. FENG, K.K., CHAKRAVORTY, R.N., and COCHRANE, T.S. 1973. Spontaneous combustion - a coal mining hazard. CIM Bulletin, vol. 66. pp.75â&#x20AC;&#x201C;84. HUMPHREYS, D. 2013. Scoping Study: Application of new forms of fire suppression and hydrocarbon absorption materials to underground coal mines. Final Report C21015. Australian Coal Industry Research Program, Brisbane. KARPUZ, C., GĂ&#x153;YAGĂ&#x153;LER, T., BAÄ&#x17E;CI, S., BOZDAÄ&#x17E;, T., BAĹ&#x17E;ARIR, H. and KESKIN, S. 2000. Linyitlerin kendili inden yanmaya yatkÄąnlÄąk derecelerinin tespiti: bĂślĂźm 1 â&#x20AC;&#x201C; risk sÄąnÄąflamasÄą derlemesi. (The determination of liability Äąndex for spontaneous combustion of lignite: Part 1- Risk classification review). Madencilik dergisi SayÄą, vol. 39, no. 3-4. pp.3-13. KUCHTA, J.M., ROWE, V.R., and BURGESS, D.S. 1980. Spontaneous combustion susceptibility of U.S. coals. Report of Investigation RI8474. US Bureau of Mines. LEE, S. 2002. The Polyurethane Book. Wiley, New York. LUXBACHER, K. and JONG, E. 2013. Development of a passive tracer gas source for mine ventilation applications. Proceedings of the 24th Annual General Meeting of the Society of Mining Professors, Milos Island, Greece. pp. 26â&#x20AC;&#x201C;99.
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SUH, K., MULLINS, G., SEN, R., and WINTERS, D. 2007. Effectiveness of FRP in reducing corrosion in a marine environment. ACI Structural Journal, vol. 104, no. 1. pp. 76â&#x20AC;&#x201C;83. SUH, K.S., SEN, R., MULLINS, D., and WINTERS, D. 2008. Corrosion monitoring of FRP repaired piles in tidal waters. Special Publication 252. American Concrete Institute. pp. 137â&#x20AC;&#x201C;156. TARRICONE, P. 1995. Composite sketch. ASCE, Civil Engineering Magazine. pp. 52â&#x20AC;&#x201C;55. WADE, L. 1988. The propensity of South African coals to spontaneously combusti. PhD thesis, University of the Withwaterstrand, Johannesburg. WANG, C. and SHIH, C. 2004. Rehabilitation of cracked and corroded reinforced concrete beams with fiber-reinforced plastic patches. Journal of Composites for Construction, vol. 8, no. 3. pp. 219â&#x20AC;&#x201C;228. WHEAT, H.G., JIRSA, J.O., and FOWLER, D.W. 2005. Monitoring corrosion protection provided by fiber reinforced composites. International Journal of Materials and Product Technology, vol. 23, no. 3-4. pp. 372â&#x20AC;&#x201C;388. WINTERS, D., MULLINS, G., SEN. R., and STOKES, M. 2008. Bond enhancement for FRP pile repair in tidal waters. ASCE, Journal of Composites for Construction, vol. 12, no. 334. 10 pp. WOOTTON, I., SPAINHOUR, L., and YAZDANI, N. 2003. Corrosion of steel reinforcement in CFRP wrapped concrete cylinders. Journal of Composites for Construction, vol. 7, no.4. pp. 339â&#x20AC;&#x201C;347.
http://dx.doi.org/10.17159/2411-9717/2017/v117n12a8
An improved method of testing tendon straps and weld mesh by B.P. Watson*, D. van Niekerkâ&#x20AC; , and M. Pageâ&#x20AC;
There is currently no standard method of evaluating tendon straps and weld mesh for underground excavation support in South Africa. At the request of suppliers, the CSIR has been conducting pure tensile tests on these elements with all the strands clamped in a jig. Even though the actual in situ loading is usually quite different, the manufacturers have required pure tensile results. In an underground situation, these support units are loaded by a block or set of blocks perpendicular to the strands under the influence of gravity. This loading results in a combination of tensile stresses and bending moments at the point of fixture, which is not adequately represented by a pure tensile test. In this paper we describe a more representative test which caters for a worst-case loading condition due to block rotation. An improved design of tendon strap to better cope with the loading environment is also described. 84 15-2 eccentric loading, load-bearing capacity, bending moments, strength requirement, realistic laboratory test.
7/051-,$0.1/ The mechanized deep-level mines in South Africa have been using tendon straps (locally referred to as Osro straps) together with weld mesh for the support of longer term excavations. Traditionally, the Osro straps are 300 mm wide and consist of five 10 mm diameter strands along the length (Figure 1). The connecting strands are generally 6 mm in diameter and spaced 150 mm apart along the width, as shown in the figure. The five-strand geometry encourages eccentric loading underground, with clamping of different strands along the length of the strap (Figure 2). The Osro strap is normally installed with long anchors and dome washers over the existing primary support. The primary support commonly consists of 5.6 mm diameter weld mesh with 100 mm apertures, installed with tendons. One deep-level gold mine reported a dramatic drop in injuries since the introduction of the mesh and straps (Pretorius, 2010). In the absence of a documented standard on how to test mesh and Osro straps, the manufacturers of these products requested the CSIR to perform a tensile pull-test to determine strength and quality (Bergh, 2016). The strands are clamped on either end as shown in
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.04530,54654 .4 6 Mesh research was undertaken in South Africa by Rand Mines limited (Ortlepp, 1983) and in Canada by the Ontario Ministry of Labour (Pakalnis and Ames, 1983) in the early 1980s. Large-scale mesh tests were conducted by Tannant, Kaiser, and Maloney (1997) and Thompson, Windsor, and Cadby (1999) to determine the force-displacement reaction properties of mesh when loaded perpendicular to the strands. In 2005, a large-scale static testing facility was designed and built by the
* Visiting Professor - School of Mining Engineering, University of the Witwatersrand, South Africa. â&#x20AC; Private Consultant. Š The Southern African Institute of Mining and Metallurgy, 2017. ISSN 2225-6253. Paper received Sep. 2016; revised paper received Sep. 2017.
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Figure 3 and the element is loaded in tension until failure. However, a significant overestimation of the load-bearing capacity is provided by this test due to the disparate loading condition underground. In underground applications, clamping is provided by tendons located on the corners of the mesh (usually 150 mm in from the corners for mesh overlap) and the ends of the Osro straps, and loading takes place perpendicularly to the strands. A typical dome washer is 200 mm in diameter and can load a maximum of only two or three strands due to its size (Figure 4) and the uneven rock surface. Generally, two of the strands are doing little work during loading underground. This paper investigates whether the quoted tensile strengths are sufficient, or could the support elements be over- or under-designed? A suitable testing apparatus was therefore constructed to cater for a worst-case, underground loading environment, and tests were conducted at the CSIR in Johannesburg. The load demand requirements were calculated assuming the maximum likely dead-weight load of loose rock between support tendons.
An improved method of testing tendon straps and weld mesh
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Western Australian School of Mines, based on insights provided by the previous research. Two test programms were undertaken by Player et al. (2008) to assess the static and dynamic properties of welded wire and chain link meshes. The WASM static test facility is shown in Figure 5. It comprises two steel frames, which provide a loading condition perpendicular to the mesh or surface support. The mesh sample is restrained within a stiff frame that rests on the support frame. The restraint system consists of highstrength eye nuts, D-shackles, and threaded bar passing through a perimeter frame at allocated points as shown in Figure 6.
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An improved method of testing tendon straps and weld mesh This system, although providing repeatable results, does not fully represent the loading dynamics underground. In particular, Osro straps are generally clamped by dome washers and bolts that are pre-tensioned to 18 t. Loading would subsequently cause bending moments at the washer and edge of the loading block. Numerical analysis was performed to determine the effects of such a loading configuration on a strap.
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Finite element modelling (Solidworks, 2014) was carried out to determine the stress distribution along an Osro strap during loading. The results clearly show the tensile and compressive stresses resulting from the bending moments at the edge of the loading block and dome washer (Figure 7). These stress concentrations do not develop in a standard pull-test and therefore the standard test over-estimates the strength of the strap. Thus the modelling shows the importance of using the same loading configuration as underground to establish true strap and mesh strengths. Shackles do not provide a true boundary constraint as the bending moments are less pronounced. A test rig was therefore designed to load against a dome washer. &.+,546 % *3/-4-6 .4 62'1 ./+60'4624$1/-35 62,**1506$1/#.+,530.1/
*.$3(6,/-45+51,/-62,**1506$1/#.+,530.1/ The current primary support in the access and infrastructure excavations of South African mechanized gold mines generally consists of 2.4 m long split sets, spaced about 1.2 m Ă&#x2014; 1.5 m, and weld mesh (Figure 8). Both the mesh and split sets are installed remotely using twin-boom drill rigs or bolters. In the more permanent ramps and haulages, secondary support is installed in the form of 4.5 m long, 38 t anchors, spaced about 2 m Ă&#x2014; 2 m apart, with Osro straps across and along the direction of the tunnels (Figure 9).
/-45+51,/-6(13-./+64/ .51/)4/0 Assuming that the secondary support anchors are installed deep enough to anchor into competent ground, the mesh and
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Oslo straps need to contain the loose rock between the tendons. The size and mass of the unstable rock requiring containment can be approximated by a square pyramid, with a height of half the spacing between the tendons (Figure 10). The strength requirements of the mesh and Osro strap support elements are therefore calculated assuming the weight of loose rock within this shape: [1] where: L = Weight = Density g = Gravitational acceleration (9.81 m/s2) l,w, and h are the dimensions of the pyramid assuming h= ½l (Figure 10).
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A test rig has been designed to cater for the worst-case loading scenario. It includes the bending moments shown in the model results and the guillotine effects of the dome washer on the outer strap. (There will almost always be a
An improved method of testing tendon straps and weld mesh connecting or crossing strap that will not be exposed to the guillotine effects of the washer.) In addition, the sharp edges of loading blocks, typical of the Witwatersrand quartzites in the gold mines, are also considered. Typical blocks observed in falls of ground on the intermediate- to deep-level gold mines are relatively small (approx. 1 m Ă&#x2014; 0.5 m Ă&#x2014; 0.3 m). The commonly observed sharp edges are shown in Figure 11. Worst-case loading conditions would be caused by the acute bending that occurs along the edges of these blocks. The rig design consisted of a rectangular frame of the same length as a standard length of weld mesh (3.4 m) or tendon spacing along an Osro strap. The element is attached to the base of the rig by short bolts and washers to replicate the conditions underground (Figure 4). The assembly is loaded from the top by a line-shaped plunger (Figure 12 and Figure 13). The loading shape represents a block of rock that has rotated and is loading the support element along its edge. The length of the loading line was 0.5 m to coincide with a typical block size. Peak failure Loads of 18 kN and 44 kN were typical for the mesh and straps strands, respectively. A common tensile test on the same Osro strap will provide loads of about 170 kN.
Using the pyramid model, the strength requirement of such mesh where the support elements are spaced 2 m Ă&#x2014; 2 m is 35 kN (ignoring the support effects of the split sets). Obviously, the mesh on its own is insufficient, requiring straps as additional reinforcement. A similar test performed on a normal four-strand Osro strap with 10 mm strands will provide 44 kN (Figure 15). The significant safety factor allows for some corrosion. Note that only two strands were clamped during the test, as shown in Figure 4. Conventional tensile testing of the strap provides strength results that are â&#x20AC;&#x2122;not applicableâ&#x20AC;&#x2122; for estimating load resistance in an underground mine situation, as shown in Figure 16. Apart from ignoring the bending moments, it is impossible for all the strands to be equally loaded and to contribute to the overall element strength in the underground environment.
4206)40'1-6$1)*35.21/ A typical load-deformation curve for weld mesh under the described line-loading condition with a 0.5 m long plunger is shown in Figure 14. Note that the first strand failed at about 18 kN.
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An improved method of testing tendon straps and weld mesh An 8 mm diameter strand strap was tested and the strength was shown to be adequate for the described tendon spacing (Figure 21).
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&.+,546" % 1/ 4/0.1/3(604/2.(46042061/6360 *.$3(6 2053/-6!25162053*
An underground trial was initiated on a deep-level gold mine to determine any installation difficulties (Figure 22). The limited tolerance on the position of a tendon in the standard hammock design meant that tendons could not be moved to avoid bridging across ridges in an uneven hanging- or sidewall. However, this problem can be resolved by increasing the length of the hammock neck for straps used in uneven and blocky ground conditions.
&.+,546" % /-45+51,/-6./203((30.1/61#636'3))1$ 2'3*4-6!25162053*
&.+,546" % 3))1$ 2'3*4-6!25162053*
&./3/$.3(6.)*(.$30.1/2 A normal 300 mm wide Osro strap will cost about R280, but a two-strand strap will do almost the same work for R100. However, the areal coverage is small, with a possibility of falls of ground (FOGs) between the straps. Nonetheless, a wider strap can be designed with a hammock shape to cater for the area of the clamping washer. In this instance the washers would be located in the narrow ends.
3))1$ 2'3*4-6!25162053*
&.+,546" 3% 13-./+61#636/15)3(6!25162053*
The hammock shape (Figure 17) allows a 200 mm washer, located in the narrow end, to load over all four strands and maintain the standard 300 mm strap-width. An underground installation of the strap is shown in Figure 18.
Strength tests were performed on the normal and hammockshaped straps using the suggested testing apparatus (Figure 19a and Figure 19b). The results of the investigation are shown in Figure 20. As expected the hammock shape is stronger and stiffer than the normal shape. The hammock-shaped strap in Figure 20 is significantly over-designed for a 2 m Ă&#x2014; 2 m tendon spacing and a narrower gauge strand can therefore be considered, which would reduce costs and be easier to install around corners.
&.+,546" % 13-./+61#636'3))1$ 2'3*4-6!25162053*
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3 153015 60420261/60'46'3))1$ 6-42.+/
An improved method of testing tendon straps and weld mesh Osro strap designed in the form of a hammock, however, improves clamping and ensures that all the strands are loaded. Using this design, it is possible to reduce the strand thickness to 8 mm and still maintain sufficient load-bearing capacity. The mass of such a strap is considerably less and it is also easier to bend around corners. It should be noted that the analysis presented here deals only with static loading conditions, and does not consider dynamic loading in rockbursting situations.
1/$(,2.1/2 &.+,546 % 1)*35.21/6 40 44/60'46$1/ 4/0.1/3(63/-6'3))1$ 62'3*4 !25162053*6-42.+/
&.+,546 "% 13-6542,(0261#63/6 6))62053/-6 './162053*
It has been shown that in tests simulating underground loading conditions, Osro straps and weld mesh fail at significantly lower loads than predicted by the standard tensile tests. A test frame that creates a more realistic loading condition has been developed to simulate actual loading conditions. The research showed that the standard 5.6 mm diameter weld mesh is insufficient on its own if the secondary support tendons are installed at the common 2 m Ă&#x2014; 2 m spacing. Osro straps are thus required to strengthen the areal coverage support. Normal Osro straps with 10 mm diameter strands are sufficient to carry the unstable load. However, there are strands that are not clamped due to the size of the dome washer, uneven surface underground, and eccentric loading. Such strands are carrying little load and most of the work is done by one or two strands at the centre of the strap. A hammock-shaped strap with four strands has been designed to better accommodate the underground constraints. Tests have proved that such a design significantly increases the strength and stiffness of the strap. The current 10 mm diameter longitudinal strands are an over-design if this shape is employed. Under such conditions, 8 mm diameter strands are sufficient to provide the required load-bearing capacity on a 2 m anchor spacing. This will bring down the mass and make the strap more user-friendly. The paper deals only with static loading conditions, and may not be applicable to dynamic loading in rockbursting situations.
4#454/$42
&.+,546 % 3))1$ 2'3*4-62053*26./203((4-6,/-45+51,/-
.2$,22.1/ A more realistic laboratory test shows that the standard South African tensile testing of Osro straps and weld mesh provides strength values that are not applicable for establishing load-bearing capacity in underground mine situations. However, the mesh and Osro straps only need to contain the loose rock between properly installed tendons. The required strength is therefore relatively small and easily achieved if two strands are clamped. The standard 10 mm thick Osro strap could be considered as over-designed because only two of the five strands are carrying the load. It should also be remembered that there is a risk, in an underground environment, for only one strand to be properly clamped due to the uneven surface and eccentric loading. An
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BERGH, R. 2016. Personal communication. CSIR, Johannesburg, South Africa. Ortlepp, W.D. 1983. Considerations in the design of support for deep hard rock tunnels. Proceedings of the 5th International Congress on Rock Mechanics, vol. 2. Balkema, Rotterdam. pp. 179â&#x20AC;&#x201C;187. PAKALNIS, V and AMES, D. 1983. Load tests on mine screening. Underground Support Systems. Udd, J. (ed.). Special Volume 35. Canadian Institute of Mining Metallurgy and Petroleum, Montreal. pp. 79â&#x20AC;&#x201C;83. PLAYER, J.R., MORTON, E.C., THOMPSON, A.G., and VILLAESCUSA, E. 2008. Static and dynamic testing of steel wire mesh for mining applications of rock surface support. Proceedings of the 6th International Symposium on Ground Support in Mining and Civil Engineering Construction, Cape Town, 30 March â&#x20AC;&#x201C; 3 April 2008. Southern African Institute of Mining and Metallurgy, Johannesburg. pp. 693â&#x20AC;&#x201C;706. PRETORIUS, W. 2011. Personal communication. Randfontein, South Africa. SOLIDWORKS. 2014. www.solidworkstutorials.com TANNANT, D, KAISER, P.K., and MALONEY S. 1997. Load - displacement properties of welded - wire, chain - link and expanded metal mesh. Proceedings of the International symposium on Rock Support - Applied Solutions for Underground Structures, Lillehammer, Norway, 22â&#x20AC;&#x201C;25 June 1997. Broch, E., Myrvang, A., and Stjern, G. (eds.). Norwegian Society of Chartered Engineers. pp. 651â&#x20AC;&#x201C;659. THOMPSON, A.G., WINDSOR, C.R., and CADBY, G.W. 1999. Performance assessment of mesh for ground control applications. Rock Support and Reinforcement Practice in Mining. Villaescusa, E., Windsor, C.R., and Thompson, A.G. (eds.). Balkema, Rotterdam. pp. 119â&#x20AC;&#x201C;130.
http://dx.doi.org/10.17159/2411-9717/2017/v117n12a9
A stochastic mathematical model for determination of transition time in the non-simultaneous case of surface and underground mining by E. Bakhtavar*, J. Abdollahisharif â&#x20AC; , and A. Aminzadeh*
This research introduces a stochastic mathematical model that uses open pit long-term production planning on an integrated open pit and underground block model to determine the optimal time for transition from open pit to underground mining. In the model, ore grade is considered a random parameter in objective function and ore grade blending constraints. The objective function is modelled as the maximization of net present value in the mode of non-simultaneous combined open pit and underground mining. Moreover, the most important and conventional constraints in open pit long-term production planning are developed for non-simultaneous combined mining. Finally, information on an iron ore deposit is used to evaluate the results of the model. ,( #$ ! stochastic programming, transition time, non-simultaneous, combined mining.
+'"$# "%#' The problems of non-simultaneous combined mining by open pit and underground methods and transition from open pit to underground mining are among the most important challenges in mining engineering, and have been recently considered in many research investigations. Different researchers have attempted to solve these problems and presented solutions based on empirical, heuristic, and mathematical programming methods. In these works, the transition problem has been examined in three modes: (1) optimizing transition from open pit to underground mining, (2) determining the point, depth, or limit of transition from open pit to underground operation, and (3) determining the time of transition. Bakhtavar, Shahriar, and Mirhasani (2012) reviewed the solutions proposed for the transition problem, a summary of which is given in Table I, together with the most recent solutions. It can be seen from Table I that few of the solutions have an empirical basis, ultimately leading to only an estimated response. The main weaknesses of the empirical solutions are ignoring the time value of money, production planning, and uncertainties. Most of the solutions for the transition problem have a heuristic basis and follow a similar process by use of the cash flow
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* Department of Mining and Materials Engineering, Urmia University of Technology, Iran. â&#x20AC; Faculty of Engineering, Urmia University, Iran. Š The Southern African Institute of Mining and Metallurgy, 2017. ISSN 2225-6253. Paper received Feb. 2017; revised paper received Aug. 2017.
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/ '# !%!
solution introduced by Nilsson (1982). They make an economic comparison among different options, including open pit and underground mining. Some other heuristic solutions, such as the algorithms proposed by Bakhtavar and Shahriar (2007) and Shahriar (2007) and Bakhtavar, Shahriar, and Oraee (2008a, 2008b) are based on an economic comparison of open pit and underground mining methods at different levels of an ore deposit. The main drawback of the heuristic solutions is their complete dependence on the optimization algorithms of surface and underground mining. For this reason, they cannot solve the transition problem independently. Another deficiency of the heuristic solutions, excluding the research presented by Opoku and Musingwini (2013), is failure to consider uncertainty. This deficiency leads to the small difference between their responses and the reality. The working steps of the solution presented by Opoku and Musingwini (2013) are mostly similar to the solution by Visser and Ding (2007), except that Opoku and Musingwini emphasized uncertainties during geological simulation (in kriging) and prepared production planning and economic models employing conventional mining software. Among the solutions for the transition problem, studies by Bakhtavar, Shahriar, and Mirhasani (2012), Newman, Yano, and Rubio (2013), Chung, Topal, and Ghosh (2016), and MacNeil and Dimitrakopoulos (2017) have a mathematical basis and are more stable than others. These methods can be considered a foundation and then developed or modified to achieve an optimum solution to the transition problem, similar to the development of the optimization models of final pit limits and production planning.
A stochastic mathematical model for determination of transition time Table I
( )!"$&"( ) &!( )#') %'&$ )%'"( ($) $# $& %' ) #$)" ()$(!(&$ ) ) ' ) # & )&' ) #! )
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A stochastic mathematical model for determination of transition time
by use of a two-stage process of open pit and underground production scheduling. In the present study, attempts are made to introduce a stochastic binary integer programming model, which not only eliminates the deficiencies of other methods but also incorporates their benefits as far as is possible. Therefore, the model follows the following objectives: Determining the optimal time for transition from open pit to underground mining based on maximizing NPV Searching three-dimensional block models based on a detail-oriented trend Independence from the software and algorithms of production planning and pit limit and underground layout optimization (i.e., independent working) Considering ore grade uncertainty in mathematical planning of the model Considering technical and economic criteria (constraints). For these purposes, the stochastic model presented by Gholamnejad, Osanloo, and Khorram (2008) for optimal long-term production planning for open pits, which was originally introduced by Rao (1996), is the basis for the present research.
/"# &!"% ) &" ( &"% & ) # ( %' This research aims to maximize the overall NPV obtained from combined open pit and underground mining. Thus, in mathematical modelling, the objective function is defined as the maximization of the combined NPV resulted from both open pit and underground operations. To this end, the following requirements are taken into account. First, the economic net values of combined open pit and underground blocks are determined. In the transition problem, the main objective is to identify levels, and consequently blocks, extractable by open pit or underground methods so that an economic comparison is made for each block and level between open pit and underground methods. Then, the mining method with a higher NPV is selected as the superior option. This research uses the concept of the priority of open pit to underground mining. In this case, the combined economic value for each block is calculated by subtracting open pit and underground block net values. This concept has been used in some solutions for the transition problem, such as the work by Camus (1992) and Tulp (1998). Open pit and underground economic net values for each block are calculated by use of Equations [1] and [2], respectively. Moreover, according to Equation [3] and by subtraction of open pit and underground block net values, combined (subtracted) block net value can be calculated using Equation [4]. It should be noted that block caving is the most practicable underground method in the case of nonsimultaneous open-pit and underground mining. In block caving, ore recovery can usually be close to the open pit recovery, approaching 100%. Therefore, in Equation [4], ore recovery (r) is considered to be 100% for both open pit and underground methods (rop = rug = 1). [1] VOLUME 117
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The model by Bakhtavar, Shahriar, and Mirhasani (2012) started to apply mathematical programming in combined mining by open pit and underground methods and in solving the transition problem. It has some deficiencies, such as failure to consider production planning and net present value (NPV), presentation on a two-dimensional block model, limitation in the number of decision variables, and ignoring uncertainties such as ore grade. Among the important advantages of this model are its detail-oriented trend (on blocks with economic value) and its independence from other pit limits and production planning optimization algorithms. This model uses binary integer programming to maximize the profit from combined open pit and underground mining. A computerized tool was developed based on the model established by Bakhtavar, Shahriar, and Mirhasani (2012) for simple applications (Bakhtavar, 2015). The model introduced by Newman, Yano, and Rubio (2013) follows a holistic trend based on investigating various strata of an ore deposit at different levels using network programming. In this model, which is stated by schematic networks, the method of determining deposit boundaries in each stratum was not specified. Using strata instead of blocks in a block model can reduce the number of decision variables and investigations; however, this may not lead to an accurate response compared to blocks. The strata were considered due to the large size of the deposits with combined open pit and underground mining potential. In these cases, using conventional ore blocks would limit problem-solving using the available solvers and personal computers. Since each stratum is mined during two or more scheduling periods, mining sequence and production planning cannot determine which part of the stratum must be mined in the first place. To solve this problem, the strata must include ore blocks with a grade or economic net value. The main weakness of the network model by Newman, Yano, and Rubio (2013) is failure to consider uncertainty. This model is primarily based on maximizing NPV and decision-making based on production planning, which is a benefit of this model. An integer programming-based model was developed by Chung, Topal, and Ghosh (2016) to determine the transition point from open pit to underground mining in threedimensional space. Some strategies for shortening the solution time were attempted in order to deal with the problem of a large number of variables. This research focused on the optimal mining strategy, in addition to the optimal determination of the transition point from open pit to underground mining. MacNeil and Dimitrakopoulos (2017) developed a twostage stochastic integer programming model by use of geological uncertainty and managing technical risk to determine the transition from open pit to underground mining. The discounted cash flow values of different transition depth alternatives are calculated after optimizing the production schedules of each depth for open pit and underground operations. The most profitable transition depth alternative is determined by comparing the sum of both open pit and underground mining values. This base concept of making a comparison among a set of transition depth alternatives is similar to the work by Bakhtavar, Shahriar, and Oraee (2008a, 2009). The only deficiency of the model is holistically investigating and solving the transition problem
A stochastic mathematical model for determination of transition time [2] [3]
[4] where BEVop: P: CS: rop: g: TO: Cop: CW: TW: BEVug: rug: Cug: B:
Open pit economic net value for each block Unit selling price of metal Unit selling cost of metal Total metal recovery in open pit mining Block grade Total amount of ore in each block Unit open pit cost of ore extraction Unit open pit cost of waste removal Total amount of waste in each block Underground economic net value for each block Total metal recovery in underground mining Unit underground cost of ore extraction Open pit and underground combined economic net value for each block. In Equations [1] to [4], the economic net value of a waste block is negative, since a waste block imcurs removal cost without any profit. The NPV resulting from combined open pit and underground mining is obtained by Equation [5]. [5] In certainty mode, based on Equations [1] to [5], the objective function can be defined as Equation [6] in the form of a programming model using (0-1) integer decision variables. All the model variables, parameters, indices, counters, and indicators are defined in Appendix 1.
[6]
The most important uncertainties should be involved to minimize the errors of the optimization process and to achieve the optimal response, especially in specific mining situations that are greatly influenced by uncertainties. Simulating a deposit and preparing a geological block model with block grade estimation are the basis for the optimization of production planning and mining layout. These simulations and grade block models, which are constructed using exploration data, particularly from exploration boreholes, contain estimation errors. As a result, these errors are incorporated directly into all the processes based on using data on grade (geological) block models in optimizing production planning. Therefore, block grade is randomly considered with uncertainty in the optimization of production planning to minimize the impact of grade error resulting from exploration phase and block model simulation. In this case, the objective of maximizing NPV is accompanied by minimizing risks arising from the uncertainty in block grade.
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The random grade parameter is imported to the objective function and the related constraints of the model. Accordingly, the objective function of maximizing NPV as given in Equation [6] is randomly formulated in the following stages. After applying changes associated with the random variable to the objective function and constraints, they are non-linearized. They can be converted into linear mode using linear approximation methods, or the model can be solved in the same nonlinear mode. When a parameter is randomly considered in stochastic programming, some changes are made to the objective function and constraints. Assuming that a random variable has a normal distribution, a specific probability is considered for a constraint, and then the expected values and the variance are calculated. Given that the random variable has a normal distribution, the objective function would also have a normal distribution, and the expected value and variance would be calculated in the objective function. In such a case, a new objective function is defined in two stages: the first stage consists of maximizing the average of NPV, and the second is minimizing deviation from the main objective, which is the maximization of NPV. Now that ore grade is considered as a random variable, a confidence level is first assumed based on Equation [7] for the constraint related to the average grade as given in Equations [8] and [9]. [7]
[8]
[9]
Then, the expected value and variance of a random variable are calculated. The calculation results for expected value (average) and variance on the constraint with ore grade random variable are applied as given in Equations [10] to [14]. [10]
[11]
[12]
[13]
[14]
A stochastic mathematical model for determination of transition time Given that the random variable of ore grade exists in the objective function, the expected value and variance of the objective function by the random variable of the ore grade are calculated by Equations [15] and [16].
[22] The normal distribution function of the ore grade random variable is converted into a standard normal distribution by use of Equations [23] and [24].
[15]
[23]
[24] [16]
where
is a standard normal random variable
associated with ore grade which has an expected value (average) of zero and variance of unity. In this case, St is the value of a random variable that is true in Equation [25]. [25] According to Equation [17], the new objective function maximizes the average NPV resulting from combined mining and minimizes the deviation from grade distribution where optimal production planning is applied only to open pit mining in the combined block model. [17] Equation [18] indicates that values for the expected value and variance of the objective function are imported to Equation [17].
Equation [26] can be derived from Equations [23] and [25]. [26]
According to Equation [26], the following certain and nonlinear inequality (Equation [27]) can be fixed. Thus, the constraint of the problem changes from random and uncertain mode to certain but nonlinear. [27]
[28] [18]
Now, the values for the expected value and variance of a random variable are substituted into Equation [28], and the grade-related constraints are given by Equations [29] and [30].
[19]
[29]
[20]
The average ore grade of materials that are sent to the processing plant in each period is different, and has upper and lower bounds, as given in Equations [21] and [22] by Gholamnejad, Osanloo, and Khorram (2008).
[30]
Equation [33] shows the constraint related to the lower bound of the grade blending constraint. The values of St and St' are calculated by taking the integral of standard normal distribution function as given in Equations [31] and [32]. [31]
[32]
[21]
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Consistent with the long-term production planning model presented by Gholamnejad, Osanloo, and Khorram (2008), the following constraints are considered for the problem of transition from open pit to underground mining.
A stochastic mathematical model for determination of transition time
The tonnage of ore and waste materials mined in one period cannot exceed the maximum capacity or be less than a minimum capacity of equipment available in that period. Accordingly, the constraints of the maximum and minimum capacity of equipment can be formulated as Equations [33] and [34].
Equations [18], [29], and [30], instead of covariance, the product of the variance of two variables is imported, yielding Equation [39].
[39]
[33]
[34]
All blocks above the desired block must be extracted so that, for the stability of the pit wall, a cone with at least three blocks would comprise the desired block. This constraint also indicates that all rows of the pit limit should be assumed continuous in mining. This constraint is mathematically defined by Equation [35].
Now, the certain and nonlinear equations are linearized and rewritten as in Equations [40] and [41].
[40]
[35] [41]
According to the constraints of reserve extraction, any block in the block model can be extracted only once, in one period and using only one method (open pit or underground mining). This constraint is mathematically modelled using Equation [36].
In Equation [29], changes are applied as Equation [42].
[42]
[36] According to Equation [18], this can be written as:
The objective function of the model (Equation [18]) and the constraints of the upper and lower bounds of grade (Equations [29] and [30]) are certain but nonlinear. They are linearized by use of a linear approximation method. If xi and xj are assumed as two interdependent random variables, a parameter can be defined as a correlation coefficient between these two variables as given in Equation [37].
[43]
[44]
These values are substituted in the objective function, which is written as Equation [45].
[37] [45] Since the correlation coefficient is between 1 and -1, Equation [38] can be applied.
[38]
Using the linear approximation method, the objective function and the constraints for grade blending become linear. Finally, the model for determining the transition time in non-simultaneous combined mining is formulated employing ore grade uncertainty based on binary (zero and unity) integer programming as follows:
Therefore, the maximum amount of covariance can be equal to the product of the variance of two variables. In
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A stochastic mathematical model for determination of transition time s.t.
It is noteworthy that the determination of the transition time from open pit to underground mining is a very complex multi-attribute decision-making (MADM) process. Mathematical modelling of the transition problem based on the MADM concepts is very complicated, especially in the case of a detail-oriented trend as was considered in this research by searching for blocks on a block model with combinational economic values. The current research focused only on the technical and economic parameters (attributes) to avoid the complexity of modelling the transition problem as a multi-attribute system. The transition problem is similar to other mining problems based on strategic planning and asset management, which are long-term processes. Komljenovic, Abdul-Nour, and Popovic (2015) explained that the strategic planning and asset management models in mining projects should incorporate all related economic, operational, technical, engineering, organizational, natural, and other important factors in a systematic manner. The impacts of uncertainties and operational complexities should also be considered.
Table II
.(! "!)&' ) %! !!%#'
( '% & )&' )( #'# % ) &"&) #$)'#' !% "&'(# !) # %'( ) %'%' )& % &"%#'
An iron ore deposit with potential for mining by a combination of open pit and block caving is used to apply the introduced stochastic programming model. The size of the ore deposit was estimated at approximately 160 Mt at an average grade of 51%. According to the mine design parameters, the height of the benches in the open pit part was to be 15 m. It should be noted that in addition to block caving, sublevel caving can also be used as an alternative the case of nonsimultaneous underground and open pit mining. A geological model of the iron ore deposit that includes blocks with Fe grades is first created. The model consisted of 11 023 blocks with an average grade of 51%. The block size is 15Ă&#x2014;15Ă&#x2014;15 m. Table II summarizes some essential technical and economic parameters for applying the presented stochastic model in the non-simultaneous case of open pit and block caving mining. The grade value of each block that resulted from the kriging-based geostatistical process is imported to the stochastic model. A normal distribution function is assumed by the mean (kriging estimate) and variance (estimation variance) values of the grade parameter taken from the kriging process. The normal distribution function of the ore grade random variable was also considered by Gholamnejad, Osanloo, and Khorram (2008) and Halatchev and Lever (2005) for simplifying the calculation procedures. Then, the stochastic mathematical model of the studied case with 22046 decision variables is solved in approximately 55 minutes, and the optimal solution obtained. As shown in Figure 1, the results indicated that the optimal transition time is when the pit depth reaches the 1765 m level in the case of non-simultaneous combined open pit and block caving mining. According to the optimal transition time, a total NPV of $5159.7 million is determined. In the optimal case, the iron ore deposit should be mined by open pit to the 1765 m level, and the rest of the ore deposit between levels 1765 m and 1630 m by block caving.
% $() (') %") &''%' ) ( ( !)&' )" ()"$&'!%"%#') ( ( )#')&) $#!! !( "%#')# )" ()%$#')#$() ( #!%")
VOLUME 117
#'# % ) &$& ("($!
( '% & ) &$& ("($! & (
&$& ("($) '%"
& (
Processed ore price ($ per ton)
69
Annual working days
355
Open pit stripping cost ($ per ton)
1.5
Processing recovery (%)
80
Open pit mining cost ($ per ton)
1.75
Open pit recovery (%)
100
Open pit capital cost (million $)
109
Underground recovery (%)
90
Block caving cost ($ per ton)
4.25
Discount rate (%)
20
Underground capital cost (million $)
430
Maximum open pit mining capacity (t/a)
8 000 000
Processing cost ($ per ton) Additional costs ($ per ton)
8 4.5
Maximum underground 8 000 000 mining capacity (t/a) Mine life (years)
20
1151
&$& ("($) '%"
A stochastic mathematical model for determination of transition time Accordingly, mining problems and challenges are quite complex with a multidimensional space because of major uncertainties arising through the complexity of the system. The traditional models in strategic planning, asset management, and decision-making in the case of mining problems have some limitations which make it difficult to deal with the complexities adequately. For this reason, many mining organizations have employed the strategic planning and management models that decrease uncertainties to increase the overall efficiency of the system. In this case, the new approaches are required to model and analyse mining problems as complex adaptive systems (Komljenovic, AbdulNour, and Popovic, 2015).
#' !%#' A mathematical model was presented utilizing open pit longterm production planning and the stochastic effect of ore grade to determine the optimal transition time from open pit to underground mining. The objective function of the model is based on the maximization of NPV in the case of nonsimultaneous combined open pit and underground mining. The most important constraints are developed for the nonsimultaneous combined mining based on open pit long-term production planning. A database from an iron ore deposit of about 160 Mt was used to implement the model in detail. The deposit is suitable for mining by a combination of open pit and block caving. The proposed model was developed and solved considering the essential technical and economic data for the mining system. The results indicate that a total NPV of $ 5159.7 million is obtained based on the 1765 m level being selected as the optimal level for the transition from open pit to block caving.
.( ($(' (! BAKHTAVAR, E. 2013. Transition from open-pit to underground in the case of Chah-Gaz iron ore combined mining. Journal of Mining Science, vol. 49, no. 6. pp. 955â&#x20AC;&#x201C;966. BAKHTAVAR, E. 2015. OP-UG TD optimizer tool based on Matlab code to find transition depth from open pit to block caving. Archives of Mining Science, vol. 60, no. 2. pp. 487â&#x20AC;&#x201C;495. BAKHTAVAR, E. and SHAHRIAR, K. 2007. Optimal ultimate pit depth considering an underground alternative. Proceeding of the Fourth Aachen International Mining Symposium - High Performance Mine Production, Aachen, Germany. RWTH Aachen. pp. 213â&#x20AC;&#x201C;221. BAKHTAVAR, E., SHAHRIAR, K., AND MIRHASANI, A. 2012. OPTIMIZATION OF THE TRANSITION FROM OPEN PIT TO underground operation in combined mining using (0-1) integer programming. Journal of the Southern African Institute of Mining and Metallurgy, vol. 112. pp. 1059â&#x20AC;&#x201C;1064. BAKHTAVAR, E., SHAHRIAR, K., and ORAEE, K. 2008A, A MODEL FOR DETERMINING OPTIMAL TRANSITION DEPTH OVer from open pit to underground mining. MassMin 2008: Proceedings of the 5th International Conference and Exhibition on Mass Mining, LuleĂĽ, Sweden, 9â&#x20AC;&#x201C;11 June 2008. Schunnesson, H. and Nordlund, E. (eds.). LuleĂĽ University of Technolog. pp. 393â&#x20AC;&#x201C;400. BAKHTAVAR, E., SHAHRIAR, K., and ORAEE, K. 2008b. An approach towards ascertaining open-pit to underground transition depth. Journal of Applied Sciences, vol. 8, no. 23. pp. 4445â&#x20AC;&#x201C;4449. BAKHTAVAR, E., SHAHRIAR, K., and ORAEE, K. 2009. Transition from open-pit to underground as a new optimization challenge in mining engineering. Journal of Mining Science, vol. 45. pp. 485â&#x20AC;&#x201C;494. CAMUS, J.P. 1992. Open pit optimization considering an underground alternative. Proceedings of 23th International Symposium on the Application of Computers and Operations Research in the Mineral Industry (APCOM), Tucson, AZ, 7â&#x20AC;&#x201C;11 April 1992. Kim, Y.C. (ed.). Society of Mining Engineers of AIME. pp. 435â&#x20AC;&#x201C;441.
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CHEN, J., GUO, D., and LI, J. 2003. Optimization principle of combined surface and underground mining and its applications. Journal of Central South University of Technology, vol. 10, no. 3. pp. 222â&#x20AC;&#x201C;225. CHEN, J., LI, J., LUO, Z., and GUO, D. 2001. Development and application of optimum open-pit limits software for the combined mining of surface and underground. Proceedings of CAMI Symposium. Sweets & Zeitlinger, Lisse, The Netherlands. pp. 303â&#x20AC;&#x201C;306. CHUNG, J., TOPAL, E., and GHOSH, A.K. 2016. Where to make the transition from open-pit to underground? Using integer programming. Journal of the Southern African Institute of Mining and Metallurgy, vol. 116, no. 8. pp. 801â&#x20AC;&#x201C;808. GHOLAMNEJAD, J., OSANLOO, M., anD KHORRAM, E. 2008. A chance constrained integer programming model for open pit long-term production planning. Scientific Information Database, vol. 21. pp. 407â&#x20AC;&#x201C;418. HALATCHEV, R. and LEVER, P. 2005. Risk model of long-term production scheduling in open pit gold mining. Proceedings of the CRC Mining Technology Conference, Fremantle, WA, 27â&#x20AC;&#x201C;28 September 2005. KOMLJENOVIC, D., ABDUL-NOUR, G., and POPOVIC, N. 2015. An approach for strategic planning and asset management in the mining industry in the context of business and operational complexity. International Journal of Mining and Mineral Engineering, vol. 6, no. 4. pp. 338â&#x20AC;&#x201C;360. MACNEIL, J.A.L. and DIMITRAKOPOULOS, R.G. 2017. A stochastic optimization formulation for the transition from open pit to underground mining. Optimization and Engineering. https://doi.org/10.1007/s11081-0179361-6 NEWMAN, A., YANO, C.A., and RUBIO, E. 2013. Mining above and below ground: timing the transition. IIE Transactions. pp. 865â&#x20AC;&#x201C;882. NILSSON, D. 1982. Open pit or underground mining, Underground Mining Methods Handbook. AIME, New York. pp. 70â&#x20AC;&#x201C;87. NILSSON, D. 1992. Surface vs. underground methods. SME Mining Engineering Handbook.Hartman, H.L. (ed.). Society for Mining, Metallurgy and Exploration, Littleton, CO. pp. 2058â&#x20AC;&#x201C;2068. NILSSON, D. 1997. Optimal final pit depth once again. International Journal of Mining Engineering. pp. 71â&#x20AC;&#x201C;72. OPOKU, S. and MUSINGWINI, C. 2013. Stochastic modelling of the open pit to underground transition interface for gold mines. International Journal of Mining, Reclamation and the Environment, vol. 27, no. 6. pp. 407â&#x20AC;&#x201C;424. RAO, S.S. 1996. Engineering Optimization (Theory and Practice). Wiley, New York. p. 903. SODERBERG, A. and RAUSCH, D.O. 1968. Pit planning and layout. Surface Mining. Pfleider, E.P. (ed.). American Institute of Mining, Metallurgical, and Petroleum Engineers, New York. pp. 142â&#x20AC;&#x201C;143. TULP, T. 1998. Open pit to underground mining. Proceeding of Mine Planning and Equipment Selection (MPES) 1998. Balkema, Rotterdam. pp. 9â&#x20AC;&#x201C;12. VISSER, W. and DING, B. 2007. Optimization of the transition from open pit to underground mining. Proceeding of the Fourth Aachen International Mining Symposium - High Performance Mine Production, Aachen, Germany. RWTH Aachen. pp. 131â&#x20AC;&#x201C;148.
* (' %i: N: t: T: d: t xi : Toi: Twi: Copi: CWi: Cugi: Pt:
Index for blocks (i=1,2,â&#x20AC;Ś,N) Total number of blocks Index for planning period (t=1,2,â&#x20AC;Ś,T) Total number of planning periods Discount rate A binary integer variable; 1, if block i to be planned for extraction, and 0, otherwise Total amount of ore in block i to be extracted in period t Total amount of waste in block i to be removed in period t Unit open pit cost of ore extraction for block i Unit open pit cost of waste removal for block i Unit underground cost of ore extraction for block i Unit selling price of metal in period t
A stochastic mathematical model for determination of transition time t
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cov(g~ti, g~tj): Covariance between g i and g j
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http://dx.doi.org/10.17159/2411-9717/2017/v117n12a10
Near-surface wave attenuation (kappa) of an earthquake near Durban, South Africa by M.B.C. Brandt
The near-surface wave attenuation factor (kappa), which describes the attenuation of seismic waves over distance in the top 1â&#x20AC;&#x201C;3 km of the Earthâ&#x20AC;&#x2122;s crust, was determined for eastern South Africa using data recorded by five stations of the South African National Seismograph Network. The author carried out the analysis on data from an earthquake with magnitude 3.8 that occurred off the coast of Durban on 6 February 2016 at 09:00:01 GMT. For the analysis, the author selected a 30-second window for the S-phase portion of the vertical component seismogram. The result was an average = 0.021 Âą 0.0007 seconds, which is lower than = 0.048 seconds for micro-events in the Far West Rand and much lower than = 0.098 seconds for explosions at Sasolburg coal mines (Brandt, 2017). Kappa was found to be higher than for a stable continental region ( = approx. 0.0006 seconds). This is likely due to the narrow frequency range between 4 Hz and 9 Hz, as well as the small data-set employed during this analysis. D14>@:A kappa, near-surface seismic attenuation, tectonic earthquake, spectral analysis.
E?C@>:59C=>? Brandt (2017) recently undertook a study to determine the near-surface wave attenuation factor (kappa) of Far West Rand microevents and Sasolburg coal mine explosions. The values of = 0.048 seconds (microevents) and = 0.098 seconds (explosions) were found to be much higher than for a stable continental region where = approximately 0.0006 seconds (e.g. Atkinson, 1996; Douglas et al., 2010). Brandt (2017) ascribed this higher value obtained for to (1) additional near-surface wave attenuation at the shallow focus of both micro-events and explosions; and (2) the effect of the implosive component (micro-events) or explosive component (explosions) not accounted for in the Brune source model (Brune, 1970, 1971). These two factors differentiate mining-related events and explosions from tectonic earthquakes that have (1) deeper focal depths (Brandt, 2014) and (2) a source mechanism that may be described by a double couple (McGarr, 2002). The purpose of the initial investigation by the author (Brandt, 2017) was to derive a value for mining-related that will be useful in
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* Council for Geoscience, Geophysics Competency, South Africa. Š The Southern African Institute of Mining and Metallurgy, 2017. ISSN 2225-6253. Paper received Jul. 2016; revised paper received Aug. 2017.
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determining the attenuation relation required by spectral analysis when calculating moment magnitude, Mw, for S-waves using the seismograms recorded by the South African National Seismograph Network (SANSN). However, no analyses are available for from tectonic earthquakes in South Africa for comparison. Some doubt remains whether the value of = 0.048 seconds for mining-related events is appropriate for shallow, non doublecouple sources. Recently, a unique opportunity presented itself when the seismic waves, originating from a magnitude 3.8 earthquake off the coast of Durban on 6 February 2016 at 09:00:01 GMT, were clearly recorded by five stations of the SANSN, including station Parys (PRYS), with which Brandt (2017) had previously determined for micro-events and explosions. In this study, the author used the SEISAN earthquake analysis software (Havskov and OttemĂśller, 2010) and Scilab open-source software (2012) to determine for eastern South Africa using data from this earthquake. The author employed a Fourier acceleration spectral analysis of the seismic signals in eastern South Africa recorded by nearby regional, suitably calibrated seismograph stations that had been properly installed on bedrock. This study follows the method by Douglas et al. (2010), who derived a kappa model for France, but has adapted this approach for vertical component seismograms. The advantage of using this adapted approach is that the spectral analysis will be backwardly compatible to the 1990s, when waveform recording by the SANSN was carried out on vertical-component seismographs only (Saunders et al., 2008). It was envisaged that the resultant would be useful for a
Near-surface wave attenuation (kappa) of an earthquake near Durban, South Africa comparison with the of Far West Rand micro-events and Sasolburg coal mine explosions, as well as for the calculation of Mw for tectonic earthquakes in South Africa. However, owing to the limited frequency range of 4â&#x20AC;&#x201C;9 Hz of the authorâ&#x20AC;&#x2122;s analysis, this derived should not be extrapolated for strong ground motion engineering applications.
The first step in the analysis was to select suitable signals recorded by nearby regional stations for further processing. Examples of the semi-automatic selection procedure are shown Figure 2. The S-phase portion of the vertical component seismogram was identified and the corresponding Fourier acceleration spectra calculated. The Fourier acceleration S-spectrum and noise spectrum for a 30-second
DC<>: The present study is a continuation of the work previously completed by Brandt (2017). The reader is referred to that article for the definition of near-surface wave attenuation, , the two routine methods used to determine , the advanced method to determine , and how shapes the source spectrum of a small earthquake. In this study, is determined by means of definition (1) in Brandt (2017). This is the original definition given by Anderson and Hough (1984), but modified here for signals originating from a moderate size earthquake of ML 3.4 rather than for events larger than magnitude 5. Figure 1 is a map showing the epicentre of the magnitude 3.8 earthquake off the coast of Durban that occurred on 6 February 2016 at 09:00:01 GMT, together with the seismograph stations that recorded the signals at the time. The analyses were performed using the signals recorded by seismograph stations in eastern South Africa with epicentral distances of 271â&#x20AC;&#x201C;640 km. The stations were suitably calibrated up to a maximum frequency of 9 Hz (beyond which the anti-alias filter influences the signal, which is difficult to calibrate). Moreover, the stations had been properly installed on bedrock, the purpose of which was to ensure that no unwanted signal distortions or amplifications would occur at the site. Station Parys (PRYS) had been used in the previous study to derive for Far West Rand micro-events (Brandt, 2017) and is included in the present data-set for comparison.
&=75@D ">9BC=>? >8 C<D D6=9D?C@D >8 C<D 3B7?=C5:D DB@C<%5B D =? C<D 5@2B? B@DB B?: C<D AD=A3>7@B6< ACBC=>?A BC ->3D@ADC !BAC /- !., 'B@1A /' -., -=;0D@C>? /-" ., D49BAC;D / "., B?: '>?7>;B /' . $<D B?B;1A=A 4BA 9B@@=D: >5C >? 4B0DA @D9>@:D: 21 C<D ACBC=>?A /C@=B?7;DA 4=C< ACBC=>? 9>:DA. C<BC <B: C@B0D;;D: B;>?7 @B1 6BC<A /;=?DA. >@=7=?BC=?7 8@>3 C<D D0D?C ?DB@ 5@2B? >? &D2@5B@1 BC (
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Near-surface wave attenuation (kappa) of an earthquake near Durban, South Africa window preceding the P-phase were plotted together to identify signals with a signal-to-noise ratio of at least 2. Next, the high-frequency linear downward trend (above 4 Hz) in the acceleration spectrum was identified visually by comparing this spectrum to the theoretical signal spectrum that had not been corrected for near-surface attenuation. Based on this comparison, Fourier acceleration spectra without an obvious high-frequency linear trend were rejected. Finally, three lines were semi-automatically fitted (with a linear regression) over the high-frequency linear trend between 4â&#x20AC;&#x201C;9 Hz, 5â&#x20AC;&#x201C;9 Hz, and 4â&#x20AC;&#x201C;8 Hz, with = - / , where is the measured slope of the fitted line. Kappa was determined over the frequency range 4â&#x20AC;&#x201C;9 Hz. Signals with an unacceptable high-frequency linear downward trend were rejected from further processing if the standard deviation / of the three slopes exceeded 0.01. Figure 3 demonstrates how a signal recorded at station Senekal was rejected. The noise spectrum displayed unwanted signal distortions at 1 Hz, 2.5 Hz, and 8 Hz, which were attributed to a local factor (man-made or geological) that distorted the signal acceleration spectrum. The average spectrum of all five selected Fourier acceleration spectra (in view of deriving the average = 0.021 Âą 0.0007 seconds) is shown in Figure 4, together with the linear fits to the acceleration spectra for those seismograph stations not included in Figure 2. Three lines were again semi-automatically fitted over the average spectrum high-frequency linear trend to derive average kappa. Lines were also fitted over the standard deviation per frequency of the average spectrum and compared with the
arithmetic mean of for stations SOE, PRYS, SLR, NWCL, and POGA to test the consistency of average (i.e. the slope of the fitted line) with individual analyses. This test required the normalization of the different signal amplitudes to a common level to account for the attenuation over the epicentral distances ranging from 271â&#x20AC;&#x201C;640 km.
=A95AA=>? B?: 9>?9;5A=>? Determining average from a tectonic earthquake has provided a viable comparison to evaluate whether the value of = 0.048 seconds is appropriate for mining-related events with shallow, non double-couple sources. The result of this analysis has yielded a = 0.021 seconds, which is lower than for micro-events in the Far West Rand, and much lower than for explosions at Sasolburg coal mines. However, kappa is higher than for a stable continental region where = approximately 0.0006 seconds (Atkinson, 1996; Douglas et al., 2010). This may be ascribed to the narrow frequency range between 4 Hz and 9 Hz as well as the small data-set employed during the present analysis. Douglas et al. (2010) determined over a broad frequency range between 3 Hz and 50 Hz. For their study, the start of the linear downward trend in the acceleration signal spectrum (fE) was generally at 3 Hz, but with a large scatter within the 2â&#x20AC;&#x201C;12 Hz range, as had originally been observed by Anderson and Hough (1984). However, it would appear from the present study that fE is
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Near-surface wave attenuation (kappa) of an earthquake near Durban, South Africa consistently at 4 Hz for all five the stations and that the narrow frequency range between 4 Hz and 9 Hz is likely detrimentally affected by broad, local signal distortions (in comparison to the 2 Hzâ&#x20AC;&#x201C;50 Hz range). Nevertheless, since the moment magnitude for regional earthquakes is calculated by means of a spectral analysis of the S-wave using frequencies below 9 Hz, Mw for tectonic earthquakes can now be assigned with more confidence than before. The result of = 0.024 seconds for a tectonic earthquake, derived by station Parys (PRYS), as shown in Figure 2b, is in agreement (i.e. is lower) with the analysis of Brandt (2017), which yielded a value of = 0.048 seconds for Far West Rand micro-events, using the same station. The result of the present study is based on a small dataset derived from one earthquake with hypocentre near Durban, South Africa, and narrow frequency range signals recorded by five nearby regional stations. However, the comparison of derived before for Far West Rand microevents and Sasolburg coal mine explosions with derived in this study for the tectonic earthquake using the same station, PRYS, indicates that the analysis techniques are sound. Once more earthquake signals are analysed, and specifically when signals over the frequency range between 3 Hz and 50 Hz become available for analysis from suitable tectonic and mine-related events, a more accurate understanding of nearsurface wave attenuation for South Africa will emerge.
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D8D@D?9DA ANDERSON, J.G. and HOUGH, S.E. 1984. A model for the shape of the Fourier amplitude spectrum of acceleration at high frequencies. Bulletin of the Seismological Society of America, vol. 74. pp. 1969â&#x20AC;&#x201C;1993. ATKINSON, G.M. 1996. The high-frequency shape of the source spectrum for earthquakes in eastern and western Canada. Bulletin of the Seismological Society of America, vol. 86. pp. 106â&#x20AC;&#x201C;112. BRANDT, M.B.C. 2014. Focal depths of South African earthquakes and mine events. Journal of the Southern African Institute of Mining and Metallurgy, vol. 114. pp. 1â&#x20AC;&#x201C;8. BRANDT, M.B.C. 2017. Near-surface wave attenuation (kappa) of Far West Rand micro-events. Journal of the Southern African Institute of Mining and Metallurgy, vol. 117. pp. 511â&#x20AC;&#x201C;516. BRUNE, J.N. 1970. Tectonic stress and the spectra of seismic shear waves from earthquakes. Journal of Geophysical Research, vol. 75. pp. 4997â&#x20AC;&#x201C;5009. BRUNE, J.N. 1971. Correction. Journal of Geophysical Research, vol. 76. p. 5002. DOUGLAS, J., GEHL, P., BONILLA, L.F., and GĂ&#x2030;LIS, C. 2010. A kappa model for mainland France. Pure and Applied Geophysics, vol. 167. pp. 1303â&#x20AC;&#x201C;1315. doi. 10.1007/s00024-010-0146-5 HAVSKOV, J. and OTTEMĂ&#x2013;LLER, L. 2010. SEISAN earthquake analysis software for Windows, Solaris, Linux and Macosx. Ver. 8.3. University of Bergen, Norway. MCGARR, A. 2002. Control of strong ground motion of mining-induced earthquakes by the strength of seismic rock mass. Journal of the South African Institute of Mining and Metallurgy, vol. 102. pp. 225â&#x20AC;&#x201C;229. SAUNDERS, I., BRANDT, M.B.C., STEYN, J., ROBLIN, D.L., and KIJKO, A. 2008. The South African National Seismograph Network. Seismological Research Letters, vol. 79. pp. 203â&#x20AC;&#x201C;210. doi: 10.1785/gssrl.79.2.203 SCILAB ENTERPRISES. 2012. Scilab: Free and open source software for numerical computation (Windows, version 5.5.2). http://www.scilab.org
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VOLUME 117
NATIONAL & INTERNATIONAL ACTIVITIES
2018 25â&#x20AC;&#x201C;28 February 2018 â&#x20AC;&#x201D; Infacon XV: International Ferro-Alloys Congress Century City Conference Centre and Hotel, Cape Town, South Africa Contact: Gugu Charlie Tel: +27 11 834-1273/7 Fax: +27 11 838-5923/833-8156 E-mail: gugu@saimm.co.za Website: http://www.saimm.co.za
9â&#x20AC;&#x201C;12 July 2018 â&#x20AC;&#x201D; Copper Cobalt Africa in association with The 9th Southern African Base Metals Conference Avani Victoria Falls Resort, Livingstone, Zambia Contact: Gugu Charlie Tel: +27 11 834-1273/7 Fax: +27 11 838-5923/833-8156 E-mail: gugu@saimm.co.za Website: http://www.saimm.co.za
12â&#x20AC;&#x201C;14 March 2018 â&#x20AC;&#x201D; Society of Mining Professors 6th Regional Conference 2018 Overcoming challenges in the Mining Industry through sustainable mining practices Birchwood Hotel and Conference Centre, Johannesburg, South Africa Contact: Camielah Jardine Tel: +27 11 834-1273/7 Fax: +27 11 838-5923/833-8156 E-mail: camielah@saimm.co.za Website: http://www.saimm.co.za
6â&#x20AC;&#x201C;8 August 2018â&#x20AC;&#x201D;Geometallurgy Conference 2018 Johannesburg, South Africa Contact: Camielah Jardine Tel: +27 11 834-1273/7 Fax: +27 11 838-5923/833-8156 E-mail: camielah@saimm.co.za Website: http://www.saimm.co.za
11â&#x20AC;&#x201C;14 June 2018 â&#x20AC;&#x201D; SAIMM: Diamonds â&#x20AC;&#x201D; Source to Use 2018 Conference â&#x20AC;&#x2DC;Thriving in Changing Timesâ&#x20AC;&#x2122; Birchwood Conference Centre (Jet Park) Contact: Camielah Jardine Tel: +27 11 834-1273/7 Fax: +27 11 838-5923/833-8156 E-mail: camielah@saimm.co.za Website: http://www.saimm.co.za
15â&#x20AC;&#x201C;17 October 2018 â&#x20AC;&#x201D; Furnace Tapping 2018 Conference Nombolo Mdhluli Conference Centre, Kruger National Park, South Africa Contact: Gugu Charlie Tel: +27 11 834-1273/7 Fax: +27 11 838-5923/833-8156 E-mail: gugu@saimm.co.za Website: http://www.saimm.co.za
VOLUME 117
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6â&#x20AC;&#x201C;7 June 2018 â&#x20AC;&#x201D; Digitalization in Mining Conference â&#x20AC;&#x2DC;Mining business make-over â&#x20AC;&#x201C;Exploiting the digital resolutionâ&#x20AC;&#x2122; Johannesburg, South Africa Contact: Camielah Jardine Tel: +27 11 834-1273/7 Fax: +27 11 838-5923/833-8156 E-mail: camielah@saimm.co.za Website: http://www.saimm.co.za
10â&#x20AC;&#x201C;11 September 2018 â&#x20AC;&#x201D; ASM Conference 2018 â&#x20AC;&#x2DC;Fostering a regional approach to ASM transformation in sub-Saharan Africaâ&#x20AC;&#x2122; Nasrec, Johannesburg (Electra Mining) Contact: Camielah Jardine Tel: +27 11 834-1273/7 Fax: +27 11 838-5923/833-8156 E-mail: camielah@saimm.co.za Website: http://www.saimm.co.za
Company Affiliates The following organizations have been admitted to the Institute as Company Affiliates
3M South Africa (Pty) Limited
Expectra 2004 (Pty) Ltd
Ncamiso Trading (Pty) Ltd
AECOM SA (Pty) Ltd
Exxaro Coal (Pty) Ltd
New Concept Mining (Pty) Ltd
AEL Mining Services Limited
Exxaro Resources Limited
Northam Platinum Ltd - Zondereinde
Air Liquide (Pty) Ltd
Filtaquip (Pty) Ltd
PANalytical (Pty) Ltd
AMEC Foster Wheeler
FLSmidth Minerals (Pty) Ltd
AMIRA International Africa (Pty) Ltd
Fluor Daniel SA (Pty) Ltd
Paterson & Cooke Consulting Engineers (Pty) Ltd
ANDRITZ Delkor(Pty) Ltd
Franki Africa (Pty) Ltd-JHB
Anglo Operations Proprietary Limited
Fraser Alexander (Pty) Ltd
Polysius A Division Of Thyssenkrupp Industrial Sol
Anglogold Ashanti Ltd
Geobrugg Southern Africa (Pty) Ltd
Precious Metals Refiners
Arcus Gibb (Pty) Ltd
Glencore
Rand Refinery Limited
Atlas Copco (SA) (Pty) Ltd
Hall Core Drilling (Pty) Ltd
Redpath Mining (South Africa) (Pty) Ltd
Aurecon South Africa (Pty) Ltd
Hatch (Pty) Ltd
Rocbolt Technologies
Aveng Engineering
Herrenknecht AG
Rosond (Pty) Ltd
Aveng Mining Shafts and Underground
HPE Hydro Power Equipment (Pty) Ltd
Royal Bafokeng Platinum
Axis House (Pty) Ltd
Impala Platinum Limited
Roytec Global (Pty) Ltd
Bafokeng Rasimone Platinum Mine
IMS Engineering (Pty) Ltd
Runge Pincock Minarco Limited
Barloworld Equipment -Mining
Ivanhoe Mines SA
Rustenburg Platinum Mines Limited
BASF Holdings SA (Pty) Ltd
Joy Global Inc. (Africa)
Salene Mining (Pty) Ltd
BCL Limited
Kudumane Manganese Resources
Becker Mining (Pty) Ltd
Leco Africa (Pty) Limited
Sandvik Mining and Construction Delmas (Pty) Ltd
BedRock Mining Support (Pty) Ltd
Longyear South Africa (Pty) Ltd
Bell Equipment Limited
Lonmin Plc
BHP Billiton Energy Coal SA Ltd
Lull Storm Trading (Pty) Ltd
Blue Cube Systems (Pty) Ltd
Magnetech (Pty) Ltd
Bluhm Burton Engineering (Pty) Ltd
Magotteaux (Pty) Ltd
Bouygues Travaux Publics
MBE Minerals SA (Pty) Ltd
CDM Group
MCC Contracts (Pty) Ltd
CGG Services SA
MD Mineral Technologies SA (Pty) Ltd
Chamber of Mines
MDM Technical Africa (Pty) Ltd
Concor Opencast Mining
Metalock Engineering RSA (Pty)Ltd
SMS group Technical Services South Africa (Pty) Ltd
Concor Technicrete
Metorex Limited
Sound Mining Solution (Pty) Ltd
Council for Geoscience Library
Metso Minerals (South Africa) (Pty) Ltd
SRK Consulting SA (Pty) Ltd
CRONIMET Mining Processing SA( Pty) Ltd
Minerals Operations Executive (Pty) Ltd
Technology Innovation Agency
CSIR Natural Resources and the Environment (NRE)
MineRP Holding (Pty) Ltd
Time Mining and Processing (Pty) Ltd
Mintek
Timrite Pty Ltd
MIP Process Technologies (Pty) Ltd
Tomra (Pty) Ltd
Modular Mining Systems Africa (Pty) Ltd
Ukwazi Mining Solutions (Pty) Ltd
MSA Group (Pty) Ltd
Umgeni Water
Data Mine SA Department of Water Affairs and Forestry Digby Wells and Associates DRA Mineral Projects (Pty) Ltd Duraset Elbroc Mining Products (Pty) Ltd eThekwini Municipality
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Perkinelmer
Sandvik Mining and Construction RSA(Pty) Ltd SANIRE Sasol Mining Sebilo Resources (Pty) Ltd Sebilo Resources (Pty) Ltd SENET (Pty) Ltd Senmin International (Pty) Ltd Smec South Africa
Multotec (Pty) Ltd
Webber Wentzel
Murray and Roberts Cementation
Weir Minerals Africa
Nalco Africa (Pty) Ltd
Worley Parsons RSA (Pty) Ltd
Namakwa Sands (Pty) Ltd
VOLUME 117
The Society of Mining Professors (SOMP) in collaboration with the Mining Engineering Education South Africa (MEESA) and The Southern African Institute of Mining and Metallurgy (SAIMM) is proud to host
Society of Mining Professors 6th Regional Conference 2018 Overcoming challenges in the Mining Industry through sustainable mining practices
12â&#x20AC;&#x201C;13 March 2018 â&#x20AC;&#x201D; Conference 14 March 2018â&#x20AC;&#x201D; Technical Visit Birchwood Hotel and Conference Centre, Johannesburg, South Africa
The Mining Engineering Education South Africa (MEESA) will host the Society of Mining Professors (SOMP) 6th Regional Conference with the theme: Overcoming challenges in the Mining Industry through sustainable mining practices. The Society of Mining Professors is a vibrant Society representing the global academic community and committed to making a significant contribution to the future of the minerals disciplines. The main goal of the Society is to guarantee the scientific, technical, academic and professional knowledge required to ensure a sustainable supply of minerals for mankind. The Society facilitates information exchange, research and teaching partnerships and other collaborative activities among its members. MEESA is comprised of the School of Mining Engineering at the University of Witwatersrand, the Department of Mining Engineering at the University of Pretoria, the Department of Mining Engineering at the University of Johannesburg and the Department of Mining Engineering at the University of South Africa. The 6th Regional Conference gives a platform to academics, researchers, government officials, Minerals Industry professionals and other stakeholders an opportunity to interact, exchange and analyse the challenges and opportunities within the Minerals Industry. For any country to develop technologically and economically there must be a strong link between its industry, government & academic institutions. This conference will put together the role-players of the Mineral Industry from within and outside South Africa. The main aim of this conference is to facilitate information exchange. It is known that the mining industry is currently faced with big challenges ranging from the technical skills shortage, deep ore bodies, declining ore grades, challenges linked to processing ores with complex mineralogy, water quality and supply to the ever escalating energy costs and sustainability amongst others (Musiyarira et al., 2014). To address some of these challenges there must be a strong link between its industry, government & academic institutions. This will only happen when all the role-players collaboratively work together. The set-up of this conference is such that it allows the interaction between the Minerals Industry players and the academics.
The conference will feature peer reviewed technical presentations from academic, government and Industry professionals on a wide range of topics. While outlining the Conference programme, great emphasis is laid on participantsâ&#x20AC;&#x2122; interaction in addition to the presentations. The conference will be structured as follows:
Two-day technical programme with peer-reviewed papers Relevant discussion workshops Field trips and site tours Networking opportunities Keynote lecturers
The Conference is being organised by Society of Mining Professors (SOMP) in collaboration with the Mining Engineering Education South Africa (MEESA) and The Southern African Institute of Mining and Metallurgy (SAIMM). The Conference presenters are well-known and highly respected experts in their fields, and will cover a wide range of topics. Presentations will be followed by discussions. The Conference will be of benefit to the Minerals Industry professionals, academics, non-government, government officers and other stakeholders. For all enquiries please contact: Chair: Associate Prof Rudrajit Mitra Telephone: +27 (011) 717 7572 | Email: rudrajit.mitra@wits.ac.za Head of SOMP Committee on Capacity Building: Dr Harmony Musiyarira Head of Conferencing: Camielah Jardine SAIMM, Pâ&#x20AC;&#x2C6;Oâ&#x20AC;&#x2C6;Box 61127, Marshalltown 2107 Tel: +27 (0) 11 834-1273/7 ¡ E-mail: camielah@saimm.co.za Website: http://www.saimm.co.za
S ociety of Mining Professors Societät der Bergbaukunde
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