Bulk Handling Today Jan/Feb 2020

BULK

HANDLING Endorsed by: CMA l LEEASA l SAIMechE l SAIMH Jan/Feb 2020

BRAND-NEW CHUTE DESIGN TRAINING COURSE FIRST MACHINES IN SA FOR SCRAP APPLICATIONS

T O D A Y

BULK

HANDLING

T O D A Y

Endorsed by: CMA l LEEASA l SAIMechE l SAIMH Jan/Feb 2020

BULK

HANDLING Jan/Feb 2020

Contents

BRAND-NEW CHUTE DESIGN TRAINING COURSE FIRST MACHINES IN SA FOR SCRAP APPLICATIONS

On the cover: ASPASA Nico Pienaar Tel: (011) 791-3327 Email: nico@aspasa.co.za, Web: www.aspasa.co.za

T O D A Y

CMA News

Storage Solutions

Cover Story

37

Lifting Equipment

Endorsing Bodies

5 6

From the Desk

30 Solid Fertilizer Products

A Positive Approach

10 Scrap Processing Division Opts for a •

Green Solution

Beltcon 20

14 Pulley Designing Methodology in

South Africa

•

Conveying

22 From Leather to Intelligent Solutions •

Power Transmission

27 Refurbishment of Geared Units

Stockyard

28 Stacking up Efficiencies

Copyright

All rights reserved. No editorial matter published in “Bulk Handling Today” may be reproduced in any form or language without written permission of the publishers. While every effort is made to ensure accurate reproduction, the editor, authors, publishers and their employees or agents shall not be responsible or in any way liable for any errors, omissions or inaccuracies in the publication, whether arising from negligence or otherwise or for any consequences arising therefrom. The inclusion or exclusion of any product does not mean that the publisher or editorial board advocates or rejects its use either generally or in any particular field or fields.

Our e-mail address is bulkhandling@promech.co.za Visit our website on www.bulkhandlingtoday.co.za

•

Market Forum

CMA (Conveyor Manufacturers Association) LEEASA (Lifting Equipment Engineering Association of South Africa) SAIMechE (SA Institution of Mechanical Engineering) SAIMH (SA Institute of Materials Handling)

The monthly circulation is 3 673

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WORLD-CLASS performance requires speed, agility and endurance

STRATEGY

INFRASTRUCTURE

OPERATIONS

Planning strategic direction benchmarked to world-class standards

Development of world-class infrastructure from concept to realisation

Development of operations to best practice and world-class standards

Supply Chain Strategy

Facility Design & Development

Process & Operations Design

• Supply Chain network analysis & design • National & Regional DC strategy development • Facility Sizing and OPEX estimates • On-line fullllment • Slow vs. Fast movers network set-up • A Supply Chain that supports business strategy • Site development strategies • Technology, IOT and digitilisation strategy

• Greennelds site development

• Operations assessment and benchmarking • WMS / WCS review • WMS / WCS functional requirements • Process and operations optimisation • Long term operational development strategies • Process audit • Labour standards and incentive programs

planning • Brownnelds site development planning • Functional building requirements speciication • Technical liaison to professional / development team • Facility sizing requirements (short to long term) • Design to execution • Procurement, program and vendor management

In today’s competitive business world you need to focus on every opportunity to advance your company mission

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ils-ct@ils.co.za ils-jhb@ils.co.za www.ils.co.za

CONVEYOR MANUFACTURERS ASSOCIATION

From The Chairman’s Desk

W

e are starting the CMA off with a bang with the launching of a brand-new training course. The CMA Transfer Chute Design course will be held in March and all details can be found on the website www.cmasa.co.za in the Education and Training section.

Transfer chutes are used as a method to transfer bulk material from one conveyor to another. There are however many poorly designed chutes that cause plant downtime, spillages and generally low plant availability due to blockages, excessive wear, impact damage to conveyor belting, misalignment due to skew loading, etc. The majority of these problems can be prevented by correctly designing the transfer chute.

We present and explain the basic design principles of “guided flow” hood and spoon chutes, rock/dead box chutes and combinations of these two chute concepts.

The course also covers the use of Discrete Element Modelling as a tool to supplement the traditional calculation methods. Since DEM is widely used throughout the industry, this forms an important part of the course and we focus on DEM analysis and calibration methods.

The course also covers the practical aspects: • Understanding material properties – cohesion/ adhesion

• Minimising dust generation • Minimising spillages • Wear liner selection • Diverter gate selection / flopper gate design • Skirting and impact stations

Jay Pillay

The three days of theory are followed up with an (optional) assignment. Candidates who hand in the assignment may then write an examination. The course presenter is Henk Brink, who has had considerable experience in this field and is well respected in the industry. The assignments and examination are both moderated by an independent expert and successful candidates are eligible for a certificate of competency in the design of transfer chutes.

Anyone interested in doing this course may contact the CMA or visit the website for dates and costs, and to download an application form. The course is generating high level interest. Numbers will be limited for practical purposes, so please do not delay if you are interested in registering for this course.

Jay Pillay, Chairman

Membership at January 2020 All members subscribe to the CMA Code of Ethics Acrow Limited Actom Afripp Projects Altra Industrial Motion South Africa (Pty) Ltd Bauer Bearings International Belt Brokers Belting Supply Services BMG Bonfiglioli Power Transmissions Bosworth Brelko Conveyor Products CedoTech cc Closeal Manufacturing Collisen Engineering ContiTech South Africa (Pty) Ltd Conveyor & Engineering Equipment Conveyor & Industrial Supplies (Pty) Ltd Conveyor Watch (Pty) Ltd CT Systems David Brown Gear Industries DRA Projects SA (Pty) Ltd

Dunlop Belting Products Dymot Engineering Company ELB Engineering Services Electromote (Pty) Ltd Fenner Conveyor Belting (South Africa) Flexco SA (Pty) Ltd FLSmidth Roymec Habasit South Africa (Pty) Ltd Hägglunds Drives South Africa Hatch Africa (Pty) Ltd HMA South Africa (Pty) Ltd Hosch - Fördertechnik (SA) International Belting & Marketing (Pty) Ltd Iptron Technology cc KevConBelt (Pty) Ltd Leoka Engineering Lorbrand Magnet Service Binder CC Martin Engineering Melco Conveyor Equipment Merlin consulting (Pty) Ltd Moret Mining

Nepean Conveyors OE Bearings Oriental Rubber Industries SA Osborn Engineered Products Pegasus Industrial Services cc Rema Tip Top South Africa Ringspann South Africa Rossi Gearmotors (Pty) Ltd Rula Bulk Materials Handling SENET SEW Eurodrive Shaft Engineering (Pty) Ltd SKF South Africa Tenova Takraf ThyssenKrupp Industrial Solutions South Africa (Pty) Ltd Timken South Africa (Pty) Ltd Transvaal Rubber Company Voith Turbo Weba South Africa (Pty) Ltd WorleyParsons RSA Zest Electric Motors

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COVER STORY

A Positive Approach With the failing of the country’s state-owned enterprises, a tough economy and slowdown in the mining and construction industries, owners and investors in the surface mining industry should take heart that the industry still holds many opportunities for those who remain committed.

S

o says surface mining industry association, ASPASA, director, Nico Pienaar, who believes that the difference between success and failure in the surface mining industry mostly relates to the attitude of the owners and employees of the company rather than the state of the economy, diminishing commodity prices or rising costs.

With members across the country, he says that as many companies are thriving as those who are failing. While they face the same odds as their peers, those who are thriving are most often the ones who have a positive outlook, participate in

Nico Pienaar of ASPASA

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Environmentally friendlier aggregates

Sustainable construction needs to start at the very foundation of all business projects with the sand and aggregates that constitute the largest part of just about every construction project.

This is an often-overlooked element of sustainable construction and requires that all materials used for ground stabilisation and concrete be manufactured with sand and stone that is procured through registered legal entities that adhere to all the relevant legislation relating to the environment.

All too often sand and stone is overlooked by green building practitioners, yet it constitutes the largest component of any construction work. By volume, sand and stone make up by far the biggest percentage of the dry mix of concrete and it is vitally important that a paper-trail be followed to ensure the materials are obtained from legal mining operations.

Sand and stone suppliers, as well as readymix or prefabricated concrete suppliers should be able to prove the supplying mine is operating with a valid mining licence from the Department of Mineral Resources and Energy (DMRE), has land-use rights from the local, provincial and national authorities, and complies with all relevant environmental protection requirements.

the association’s training and other initiatives, and those who constantly strive for ways of doing things differently in a changing economy.

Toughness required

“There are undeniable factors that can influence the success of a business, but a positive approach

Five years without loss of life

Surface mining operations under the umbrella of industry association, ASPASA, have upheld their proud achievement of zero fatalities on their premises for the fifth consecutive year.

Following the release of the Minister of Mineral Resources and Energy Gwede Mantashe’s 2019 industry health and safety performance statistics it became clear that continued efforts of the association’s members had yielded the best kind of reward.

“Planning, attention to detail, checking and rechecking of systems to ensure compliance has once again paid off for our members and we have recorded no fatalities once again. This underlines the serious nature in which ASPASA members view mine health and safety,” says Nico.

and never-say-die attitude can still go a long way towards steering a company in the right direction.

And, we have noticed that while some companies had been scared-off by negative reports, many of our members choose to take the lead from their own experiences and situations, rather than hinging their expectations on media reports or public sentiment.

“Based on these experiences I have compiled an informal list of traits that I have noticed sets many of the top performing mines apart from the struggling ones. On the following page I have listed the Top 10 actions that can be taken to make 2020 a great year.

Nico concludes, “Those who believe that the downturn is across-the-board and don’t look for business will not do very well and may even fail in future, however those who look for solutions and new markets are set to thrive. If you have given up or are overwhelmed by the bad news of the economy, then your opposition may already be lining up to buy your business on auction one day. Rather stay positive, keep doing the right things right and be part of the success story.”

ASPASA Nico Pienaar, Tel: (011) 791-3327 Email: nico@aspasa.co.za, www.aspasa.co.za

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COVER STORY

Top 10 list of actions that can be taken to make 2020 a great year.

1 2 3 4 5

Remain positive and adopt a can-do approach towards reaching company objectives Do not be influenced by negative sentiments, as they may not apply to your sector or even geographical area of operation Study and know your own market so that you do not have to rely on news and television to influence your decisions and determine your business confidence If you have the money to expand or invest in resources capitalise on the opportunity and grow your business Never neglect maintenance of your plant, equipment and fleet as you may need to act quickly to capitalise on opportunities

6 7

Never look for short cuts to save money. Rather look for opportunities to make more money.

Always maintain the highest possible levels of quality, as this is a long insurance policy to ensure customers keep using your product or services Nurture your employees and train them to look for positive opportunities. Never accept negativity and especially do not allow non-performing staff to blame poor performance on the state of the economy. Rather encourage them to seek opportunities in the place of negativity

8 9 10

Maintain a never-say-die approach even in the face of adversity

Plan to succeed independent of outside factors

Small mines get a big voice

The three main industry organisations representing smaller-scale mines in South Africa have formed a combined Leadership Forum to represent the interests of members at the highest levels through the Minerals Council.

The decision comes after a meeting held in Kimberley recently where representatives from ASPASA, the Claybrick Association and the South African Diamond Producers Organisation, known as CAS, committed to cooperate and combine the voices of the bodies members in order to better serve their common interests.

ASPASA director, Nico Pienaar, says that as serving members of the Minerals Council the newly formed Leadership Forum will allow the bodies to better address issues such as prohibitive legislation for large mines that is not always applicable to smaller mines, power shortages, insufficient rail infrastructure, diesel rebates, Royalty Act, illegal mining and a host of other issues. “The Minerals Council does not always grasp the problems smaller mines face and it is our intention to conduct surveys among our individual memberships in order to identify issues that need to be carefully documented and communicated to the council’s decision makers. “We have already identified a number of shared concerns that threaten the livelihoods of our members including illegal mining, criminal activities on mines, extortion carried out by 'Mafia-like' groups, impractical charter requirements and several others.

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LIFTING EQUIPMENT

Scrap Processing Division Opts for a Green Solution A local company is the first to use Sennebogen material handlers since the German-manufactured machines joined Babcock’s range of premium construction equipment available in southern Africa.

T

he Sennebogen 830E electric material handlers were custom built to Scaw Metals’ specifications and are being used to feed a shredding machine, as well as to offload trucks. They are also the first Sennebogen machines to be used in South Africa for rugged scrap processing applications. Scaw Metals Scrap Processing Division, based in Germiston, operates the largest scrap shredder in Africa as part of its processing facilities.

Operates the largest scrap shredder in Africa as part of its processing facilities Claude Delport, Babcock sales representative for Sennebogen, says that these robust material handlers are the ideal choice for this application due to their unique durability and performance, providing outstanding longevity in tough working environments.

Robust design

Sennebogen’s range of material handling equipment is one of the widest in the world, offering optimal and efficient solutions for any material handling task. Their simple, yet highly efficient

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technology coupled with robust design allows for minimal operator downtime. Claude says Babcock’s national footprint means technicians are close on hand with technical assistance and spare parts if required. “Our aftermarket support and service gives customers a distinct advantage as we provide around-the-clock local support that is quickly and easily accessed,” he adds.

The 830E material handlers delivered to Scaw in Germiston form part of Sennebogen’s E-Series, a new generation of environmentally friendly electrical units designed for demanding continuous use in material handling applications. Offering a diverse range of attachments, maximum operator comfort and optimised technology, these green efficient models combine high performance with zero fuel consumption and utmost safety. With the additional advantage of the elevating cab, operators have a clear view that assists with increased productivity on site.

Optimised

The 830E units come with a choice of either electric motor or Tier 4 emission standard diesel engines with optimised engine settings for reduced fuel

consumption and modern exhaust gas treatment for cleaner air.

“Scaw Metals chose an electric motor as it has the potential to reduce long-term operating costs by up to 50 percent. In addition, the emission-free, electro-hydraulic motor is environmentally friendly and features low-noise, vibration-free operation,” comments Claude.

The equipment’s high quality components and avoidance of over engineering guarantees a long product life and high value stability. Sophisticated motor technology, innovative ECO mode for auto idling, and no-load automatic stop function provides the optimal balance between increased performance and reduced consumption.

Other advantages of Sennebogen’s green efficient technology include: • A 90% reduction in soot particles and 50% reduction in nitrogen oxide and hydrocarbon emissions • Two robust slewing gears and extremely hardy cylinders for fast work cycles and reliability • Centrally accessible measuring and lubrication points and manageable technology save time and effort in everyday operation • High quality components and oils assist in achieving higher efficiency levels • High-tech cameras at the rear and sides keep the operator fully aware of his surrounds.

Babcock provides on-site service technicians and comprehensive technical support on all aspects of the operation and maintenance of the machines and, together with Sennebogen, guarantees the speedy, global supply of spare parts. Babcock’s technicians are trained at the Sennebogen Academy in Germany where a demonstration park, media technology and

training halls facilitate knowledge transfer at the highest technological level. Customers purchasing Sennebogen machines then receive handover and operator training from Babcock.

These material handlers are suitable for waste management, timber handling, steel mills and scrap handling, bulk material handling at ports and demolishing work, and are largely custom built to individual customer specifications and designed for high performance capacity.

No-load automatic stop function provides the optimal balance between increased performance and reduced consumption The machines are available with a selection of robust modular undercarriage solutions such as mobile, crawler, rail, gantry, or stationary units with options for pylon’s for added height; as well as various grabs and attachments.

Full service provider

The Sennebogen machinery available from Babcock includes a range of material handlers, duty cycle cranes for foundation work, dredging work, drop ball work and dragline applications, lattice boom crawler cranes for high stability heavy duty lifting, port cranes and mobile harbour cranes with a lifting capacity of 125 tonnes.

A family-owned company, Sennebogen was founded in 1952 and has since grown to become a full service provider and quality leader in crane technology and material handling. Its global footprint encompasses 120 sales partners and 300 service support centres worldwide.

Babcock Claude Delport Email: Claude.Delport@babcock.co.za

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“THE LINK FOR AFRICAN TRADING”

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TRANSNET FREIGHT RAIL

www.transnetfreightrail-tfr.net

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BELTCON 20

Pulley Designing Methodology in South Africa

T

he purpose of this paper is to recap on the current methodology used for designing conveyor pulleys in South Africa.

The content of the paper will discuss the deflection requirements and constraints imposed from using locking elements.

It will further elude to the additional deflection limits available by making use of the turbine end disk design.

The conclusion of the paper will be to table the recommended way forward for designing and evaluating pulley designs for the future.

The requirement for this paper came about as a result of fairly large conveyors being supplied to industry where the criteria for the overall allowable shaft deflection being set at 2 minutes at the end disc. Prior to this and to date the industry norm is 5 to 6 minutes.

The Beltcon 20 organising committee decided that it will be applicable to have this paper presented in an effort to advise the industry of the history and development of the pulley shaft design process in South Africa. The end goal is to place the industry in a position where they will be able to make an informed decision on the way forward in this regard.

The logical place then to start this review will be to present an overview of the presentations conducted, primarily at Beltcon, on this subject. The salient points will be highlighted and discussed.

Discussion

Papers were presented at Beltcon on the subject of pulley designs as early as Beltcon 1 held in 1981. The paper titled “The design of belt conveyor pulleys” was written by Bernard Lloyd and covered the general design theory of belt conveyor pulleys.

This was followed in 1983 with a paper titled “Belt conveyor pulley design – why failures?” by Terry King at Beltcon 2. In this paper he analysed and categorised pulley failures in the field. At Beltcon 3 in 1985, Terry again presented a paper this time titled “The function and mechanism of conveyor pulley drums” where he focussed on the pulley drum design.

This was followed by Simon Curry Gary Styger and Professor Rudolph Laubscher at Beltcon 16 in 2011 on the subject of “An investigation into the effect of manufacturing process on the fatigue performance of conveyor pulleys”, which was also the title of the paper.

At the same Beltcon the author presented a paper on pulley practicalities with reference to pulleys fitted with internal bearings.

Outside of Beltcon, Vinit Sethi and Lawrence Nordell wrote a paper titled “Modern pulley design techniques and failure analysis methods” in 2004. This paper was published on the “Ckit” website and a copy of the paper was given to the author by the late Max Schenck who was considered to be one of the leaders of pulley design in South Africa at that time.

Extracts of each of these papers will be discussed as relevant for the development of the design processes in South Africa.

Beltcon 1 Design of conveyor pulleys by Bernard Lloyd

This paper highlighted pulley design from the perspective that Jegkurt engineering were manufacturing pulleys and needed to base their designs on proven technology. To this end they reviewed design criteria from Germany, Australia and parts of the United States.

The principal approach which they took reviewed the design of the shaft, the end disk and the shell. Of these the end disk proved to be the element requiring the most attention.

In essence the classification of the end disk as being thin or thick was problematic with the real issue being all the variations in pulley diameters relative to shaft diameters for ascertaining thick and

At Beltcon 6 in 1991, Allan Bell and Max Schenck presented a joint paper titled “Conveyor pulley standards, a possible solution”. Various pulley types and construction methods were reviewed from a standardisation perspective.

This was followed by the publishing of then SABS 1669 in 1996. South Africa now had a national standard for the design of conveyor pulleys. The same standard was later republished as SANS 1669 in 2005.

The drought on Beltcon papers was broken in 2007 (Beltcon 14) when Allan Lill discussed pulley design relative to using finite element analysis. His paper was titled “conveyor pulley design”.

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Figure 1 - Tee bottom end disk

BELTCON 20 when thin applications. Large pulley diameters with small shaft diameters will be thin and small shell diameters with large shaft diameters need to be thick. Deciding on the split between the two is the crux of the matter.

Reference is made to the T bottom, turbine and flat bottom end disk design.

Beltcon 2 Belt conveyor pulley design, why the failures by Terry King

On studying this paper, the sincerity of the writer comes to the forefront. The facts are presented with the main purpose being to inform and to advise on the way forward. The evidence of this becomes clear in the latter part of the paper.

Without boring the reader, he goes into the detail of failed pulleys being returned to their factory with the aim of refurbishing them. The failed pulleys were grouped according to failure modes as these were identified. From the grouping the design intent was captured and referenced accordingly.

What was of great interest was the fact that pulleys were being designed as having either shrink fit shaft to hub connections or bolted pressure elements for the similar. The statement made then was that the shrink fit was difficult to achieve while the locking element pressures could be “readily” achieved.

The recommendation then was that smaller pulleys could be made the press fit way and larger units using locking elements. A side note would be to question the relevance of this with modern day high accuracy numerically controlled type manufacturing equipment being used.

The focus needs to remain on the shaft deflection. In this paper the keyless friction type shaft connection was described as being the new generation of belt conveyor pulley. The author also makes reference to empirical formula for calculating and sizing the elements.

Shaft sizing;

“The shafts are sized both for the stresses at its point of entry to the hub and for its deflection.”

The following formula noted in the presentation is currently widely used and accepted in the South African context.

Drive torque is denoted by T The shaft bending moment is denoted by M Combined torsion moment is Te and the combined bending moment Me Thus, combined torsion moment Te2 = T2 + M2 And, combined bending moment Me = 0,5 (M + Te) Derived from this are: Torsion based shaft diameter is dr;

Bending based shaft diameter db:

Figure 2 - Turbine end disk

Fs and J s are taken as to be equal since the allowable direct principle stress F s is a fatigue case and the shear stress Js is not.

These principle stresses are considered to be 45 N/mm2 for EN3A (070M20) and 55 N/mm2 for EN8 (080M40) shafting.

The third shaft diameter will be determined from the “free” shaft deflection.

Deflection based diameter is dd; thus

Where: W = nett tension in kN without service factor. " = Bearing centre to hub distance in mm L = Hub spacing in mm E = Youngs modulus for shaft in N/mm2 " = Allowable deflection in radians

Figure 3 - Flat bottom end disk (semi-turbine)

It is noted that the value stated in the Beltcon paper is 0,001 radians for friction type shaft connections hubs which equates to 3,44 minutes. The identical paper published in Bulk Solids handling of April 1986 gives the same value as being 6 minutes for friction type shaft connections and 10 minutes for shrink fit hubs.

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BELTCON 20 The conclusion was that the hub was too stiff relative to the shell thickness and the stress point or area had moved to the weld area. These stresses in the weld area caused the shell to crack and then fail.

The best way to illustrate this is by means of Figure 5.

Thorough examining of the failure modes of the pulleys leads to the statement that there should be an allowable ratio between the shell diameter and the shaft diameter. In the conclusion of the paper the requirement for a standard was first to be noted.

The second conclusion was that pulley diameters less than three times the diameter of the shaft must be avoided.

Hindsight lets us make the statement Figure 4 – Various locking elements that this is so obvious. If the outside Type A locking element allows 0,05 degrees deflection = 3 minutes of arc. diameter of the boss on the end disk is Type B locking element allows 0.06 degrees deflection = 3,6 minutes of arc. too large there is no space for developType C locking element has no statement on the allowable deflection. ing and inputting the radii required for a turbine type construction thus placing it into the category of an ordinary rigid connection.

Beltcon 6 Conveyor pulley standards – a possible solution presented by Alan Bell and Max Schenck

Based on the work done by the presenters at Beltcon 6 “The design of pulleys and the requirement for developing a standard”, this presentation tabled the fundamentals of such a standard. Reference was made to most of the relevant specifications from the various mining houses at that point in time.

With reference to bearing centres a narrow and wide range of sizes was identified. These values were tabled accordingly.

In essence four types of pulleys were identified being the boss, turbine, L-bottom and T-bottom.

SABS 1669 1991 – Conveyor belt pulleys – Pulley types, construction and dimensions

When the national standard was published it signalled a new era in pulley design and manufacture in South Africa.

Significant to this paper is the statement in clause 4.7.2 regarding typical allowable deflections of the shaft at the hub.

Table 4 of SANS 1669 quantifies all the pulley types with the respective allowable deflection values. For the purpose of this paper specific reference is made to the definition of the shaft using a keyless locking element being 5 minutes.

Figure 5 – Failure at weld position

Beltcon 3 The function and Mechanism of conveyor pulley drums by Terry King

The author states that pulley shaft failures were adequately covered in the previous paper and that this paper focussed on the shell related failures.

For the purposes of our focus on pulley shaft deflection there are two specific aspects which need to be reviewed.

Of importance to note is that over the past two years since the last paper, weld crack failures were being noted on the shell local to where the pulley hub was welded to the shell.

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Clause 4.7.2 of the SANS specification covers the design of the shaft, shell and end disc and states that it will be in accordance with acceptable engineering practice and shall provide for a fatigue life as agreed between the manufacturer and the purchaser.

Beltcon 14 Conveyor pulley design presented by Allan Lill

This paper was presented on the basis that pulleys can be designed by making use of finite element analysis. The key finding of this paper is that the stresses evaluated in the weld area tend to be higher than what is anticipated by the pulley manufacturers. It was acknowledged that although this would indicate higher levels of failures it was not actually the case.

One of the recommendations was that pulleys should be

BELTCON 20

Figure 9 – L-bottom type pulley

Figure 6 showing rigid type design on right hand side

standardised and not redesigned on every project. This will allow the manufacturers to make use of the finite element analysis process by having less engineering input over a narrower spread of pulley sizes for it being standard.

Figure 10 – T-bottom type pulley

For purposes of this paper there is no reference made in this analysis indicating that shaft deflection could be considered to be a problem. All indications point to the welding and the stresses being developed local to these areas.

Beltcon 16 An investigation into the effect of the manufacturing process on the fatigue performance of conveyor pulleys by Gary Styger and Prof Rudolph Laubscher

Table 1 – Extract of table 4 from SANS 1669

The paper presented formed part of a thesis by Styger for his master’s degree. The research was conducted by assessing the stresses developed on the drum surface.

A conveyor pulley drum was set up such that the welds on the one side were stress relieved and the other side not. The pulley was then subjected to a load and the residual stresses determined and analysed accordingly.

Styger makes specific reference to the work done by King with a conclusion that more economical pulleys could be designed by making use of FEA. This statement implies that the design procedure followed by Terry King can be construed as being conservative.

The way forward

This is where the road ends regarding the development of the pulley design process from a Beltcon perspective.

Figure 7 – Boss type pulley

Figure 8 – Turbine type pulley

The next step must be to evaluate the recommendations from the locking element manufacturers.

None of the locking element suppliers makes direct reference to locking elements being on conveyor pulley applications in conjunction with turbine end disk designs. The reference made is equivalent to that when using a rigid end disk configuration. The allowable shaft deflection limit is set at 2 to 3 minutes of arc.

By inference they do not make any allowance for the profile of the end disk of the pulley. At the same time, it must be noted that they do not categorically state that this is the only profile that should be considered. The statement made by the locking element supplier is that this is what is considered to be a maximum requirement.

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BELTCON 20

This paper does not dispute this recommendation. The intent of this paper is to latch onto this recommendation and view it from the perspective that the flexibility of the pulley end disk will allow for the additional deflection which may be present in the system.

In the very first Beltcon paper on pulleys Bernard Lloyd makes reference to the fact that conveyor pulley end disks are flexible. At Beltcon 2 Terry King confirms this as well.

When Terry presented his next paper at Beltcon 3 he shares a very important finding with the industry. After studying a number of failed pulleys, he makes the statement in his conclusion that there should be a rule governing the ratio of shaft diameter relative to shell diameter. The value quoted is three to one. This conclusion needs to be examined further.

By implication the statement he makes is that there is a point where the radial distance between the outside diameter of the shaft and the inside diameter of the shell is insufficient for developing a thin disk conforming to a true turbine profile.

Simplistically one can look at the turbine type pulley again.

The focus must be shifted to the boss section of the pulley end disk. The outside diameters of the thickened section must satisfy the minimum calculated diameter for the locking element to be assembled and ensuring that there is sufficient material left to retain the magnitude of pressure being developed by the locking element during the tightening process.

By means of an example: A 450 mm diameter pulley requires a 150 mm diameter shaft to be fitted. The radial distance between the outside of the shaft and the outside of the shell is calculated as being 150 mm.

What can be done to remedy this? Essentially there are probably four possible ways to address this.

1. The outside diameter of the boss can be reviewed for adequacy. The pressure required to be exerted by the locking element can be reviewed and reduced to be functional for the application. The nett result is that the outside diameter of the centre boss can be reduced and if this is acceptable the process stops.

2. The use of a wider locking element or boss may also be considered. Being wider, the required locking pressure is readily achievable with a smaller boss outside diameter.

This improves the situation for developing the turbine profile in the end disk.

3. The third option will be to install a bigger shaft and opt for the option where the shaft diameter is enlarged in accordance with the smaller shaft deflection criteria of what would probably in the region of 2 minutes as per the constraint imposed by the locking element supplier.

In this configuration the smaller shell diameter is maintained while the shaft diameter is increased accordingly.

As per the example, the shell outside diameter remains at 450 and the shaft diameter increases from 150 mm to say 180 mm.

4. The final option will be to maintain the shaft diameter and increase the shell diameter to where the turbine profile could be readily developed. As per the example the shaft remains at 150 mm and the shell outside diameter could increase to say 600 mm.

The locking element will absorb say 25 mm of this distance while the actual hub distance could be in the region of 36 mm larger than the locking element. The 74 mm distance left will prove to be marginal for developing the turbine profile.

The shell thickness of the drum would be in the region of 15 mm. Similarly, the root radius will be similar from the shell to the end disk and from the end disk to the boss. This is 30 mm from the 74 mm leaving 44 mm for the turbine profile and thus making it inadequate for the application.

Figure 11 – Extract from locking element catalogue

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Figure 12 –Turbine type pulley

BELTCON 20

eter required for satisfying the belt construction requirement.

The second will be to ensure that a proper turbine end disk is developed in accordance with sound engineering principles ensuring that 5 to 6 minutes of overall shaft deflection is not an issue nor that the design is marginal.

Using the example from above, the required width of the locking element housing will be twice the length of the locking element. In this instance the locking element is 40 mm long resulting in the width of the boss being 80 mm. The required outside diameter of the boss is 272 resulting in the radial thickness of the boss being in the region of 61 mm with the shell being 15 mm thick. The minimum ratio should be a value of say 10 times shell thickness for determining height of the turbine profile element.

The radial thickness of the boss is 61 mm thick and the shell is 15 mm thick.

• The 15 thick shell dictates a 15 mm x 10 ratio = 150 mm turbine element height.

• The actual height is 149 mm as per figure 13.

• This distance should be adequate for developing a suitable turbine profile for the application.

Conclusions

The allowable deflection limit of 3 minutes is a requirement localised to the shaft and locking element. The inherent and allowable deflection component as a result of the turbine end disk profile of the pulley will allow the overall shaft deflection to be increased to the current and historic value of 5 to 6 minutes.

The transition from a rigid pulley end disk to a turbine profile disk has not been fully defined.

The accuracy of modern-day machining methods should be reviewed for ascertaining the relevance of shrink fitted shaft to hub connections in today’s operations.

Recommendations

Figure 13 – Shaft to shell ratios

There is far more to the last two paragraphs than initially meets the eye. There is merit in stating that there should be a minimum ratio between the pulley shaft diameter and the pulley shell diameter. What is apparent is that the 1985 logic for using a ratio of 3 is a very coarse value which should be reviewed and refined.

Common knowledge is that the outside diameter of the locking element boss can be readily determined. As indicated in the previous section, the turbine profile must be maintained in order to achieve flexibility for ensuring that the end disk will deflect and not be considered a rigid element.

The root of the profile local to the shell is dictated by the pulley shell thickness. A set of rules can be developed by the pulley manufacturers to address this issue. The thickness of the boss is determined by the width of the locking element.

Setting up a minimum ratio between the width of the locking element boss and the required shell thickness would then be very simplistic.

Once this rule is observed, it means that all pulleys will be checked for compliance to this requirement. This is likened to when pulley shafts are designed; three diameters are considered with the largest one being selected. Pulley shell diameters will be selected by making use of 2 parameters.

The pulley manufacturers must fully define and advise the industry on the transition requirements from a rigid end disk to a possible flexible turbine type profile end disk.To this end the CMA working group on pulleys must be tasked to investigate and research this matter in formalising and making the appropriate recommendations to the industry and the SABS technical committee responsible for the SANS 1669 national standard.

If repeatable shrink fitted shaft to hub connections are possible due to modern day high accuracy manufacturing processes and the economics of the process favourable, this application should be re-introduced as another option to industry.

This paper was first presented at the Beltcon Conference in 2019.

Copyright is vested with IMHC. www.beltcon.org.za Simon Curry Tel: (011) 608-4180 Email: scurry@flexco.com

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CONVEYING

From Leather to Intelligent Solutions The technology company Continental has played a key role in shaping the history of drive belts and, in turn, the development of the industry. Registration under the brand name Continental – including for drive belts – dates back to 1899.

A

nd it all began with a simple V-belt. The company has since developed and produced belts that deliver the necessary drive in almost every industry worldwide, from motorcycles to automotive and mechanical engineering, from agricultural machinery to elevators.

Whether small, large, with teeth, ribs or bumps, open-ended or continuous, the products and technologies have always set trends and opened up new opportunities for the market – and will continue to do so into the future.

Continental is constantly enhancing and refining its materials, products and production processes. “Our engineers are currently working on an intelligent drive belt featuring built-in sensors. Digitalization and networking are heralding the next era of drive belt technology,” says Claudia Holtkemper, head

of the Drive Belts business unit at Continental.

Quantum leaps in technology Let’s go back to the beginning. One hundred and fifty years ago, almost every factory had some kind of steam engine for powering weaving looms and spinning wheels. Energy was transferred by belts made from tough leather – a method that, at the time, was akin to an industrial revolution. But just a few years later at the dawn of the 20th century, Continental produced a V-belt made from a rubber compound with a connection lock. This set new technical standards for the transmission of rotary movements.

Its predecessor, the flat belt, could transmit only about one third of the force with the same width.

This represented a quantum leap in drive belt development, one that would be repeated in similar forms many times over. The demands placed on belts have grown continuously. They have to transfer more and more power, be as compact, robust and lightweight as possible, designed for use across all industries and, of course, they also have to work efficiently.

The Synchrochain Carbon drives the HyperPodX, which was created by students of the cooperative Engineering Physics course at the Emden/Leer University of Applied Sciences and the University of Oldenburg

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Continental took on these challenges as motivation for its pioneering achievements. As early as 1930, the company offered belts that were the ideal solution for applications in the agricultural sector thanks to their low weight, lengths of several metres and incredible flexibility. But the company wanted even more. It continued to enhance and refine materials and increase the precision of production processes and machines.

The first timing belts The fruits of the company’s endeavors were clear to see: “In the 1950s, we produced timing belts made from polyurethane. Thanks to its steel-cord tension cord, it was even more powerful and kept the belt tension at an even more constant level.

Unlike V-belts, its teeth were interlocking and very precise. This meant that our belts were once again in a higher performance class,” says Alexander Behmann, application engineer at Continental.

These properties opened up potential for higher rotary speeds and smaller installation spaces.

“Smaller installation spaces are seen in appliances such as vacuum cleaners, which nowadays are fitted with timing belts just 6 millimetres wide. To ensure that the belts are robust and durable despite their small dimensions, high-quality materials are vitally important,” says Alexander.

High performance drive for Hyperloops and industrial robots In the 1980s, material expertise had advanced to such an extent that V-belts could be manufactured without any need for a fabric coating. This made them even narrower, but also more powerful. The V-belts also featured a kind of interlocking system, giving them greater bending capacity.

Timing belts also underwent a similar development. With the Synchrobelt, the industrial supplier launched its first timing belt. It has an extremely wide range of applications – from printers and motors to all kinds of applications in the field of mechanical engineering.

The focus then was on improving materials and how they are combined, including fibre-reinforced compounds, EPDM, aramid tension cords and, later, carbon. “Today, Synchrochain Carbon is our strongest timing belt on the market,” says Alexander. This is because carbon hardly stretches, even under high tensile loads. It is frequently found nowadays in construction machinery, forestry and the energy sector.

And last but not least, Continental’s belts will provide valuable support in the field of Hyperloop technology, which experts consider to be a revolutionary approach to mobility. Students at the Emden/Leer

The positivelocking V-belt with open flank from 1982 was able to transfer considerably more load than its predecessors

Flat belts from Continental were already proving to be a reliable drive solution in agriculture in the 1950s

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CONVEYING

The V-belt with connecting lock already set technical standards for the transmission of rotary movements at the beginning of the 20th century

University of Applied Sciences and Oldenburg University used a Continental Synchrochain Carbon for a Hyperloop project. And with Synchroforce Carbon, the company also launched its first oil-resistant rubber timing belt.

When material expertise meets digitalization

The company’s portfolio now includes more than 18 000 dimensions and designs for a wide variety of industrial applications. Its latest achievement, a belt with integrated sensor technology for con-

dition monitoring in agricultural machinery, Also represents a step into the digital age. “Digitalization and automation are advancing in all areas of industry. Our mission is to support our customers on this path and offer them solutions that will help to make their business fit for the future. We will continue to work on this with our drive belt expertise,� Claudia concludes.

ContiTech Jochen Vennemann, Tel: +49 511 938-18024 Email: jochen.vennemann@contitech.de

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POWER TRANSMISSION

Refurbishment of Geared Units A convenient and cost-effective option for ageing African mines, some of them 50 to 60 years’ old, is to have their geared units professionally and costeffectively refurbished.

Norman Maleka

S

upplementing its refurbishment capability,

by SEW-Eurodrive (Pty) Ltd can also offer a drop-in gearbox replacement service. Geared units are particularly difficult to refurbish or modify on mines, as their large size means that production has to be halted temporarily in order to gain access.

This has a hugely negative impact on any mining operation’s bottom line. Thus, many mines hold out on replacing these essential high-capex items for as long as possible.

What makes the drop-in replacement service particularly attractive, in conjunction with refurbishment, is that the cost of repairing a worm gear unit usually exceeds its replacement cost SEW-Eurodrive is now able to replace historicallyinefficient worm gear units with the latest helical and helical bevel gearboxes, made from case-hardened steel for maximum durability.

The major advantage for mining clients, in particular, is that no modification to or adjustment of the original geared unit is required. “The drop-in replacement is based on a fabricated case that matches all critical dimensions of the existing gearbox exactly, and with improved mechanical and thermal ratings,” SEWEurodrive. National Sales and Marketing Manager Norman Maleka highlights.

While traditional worm gearboxes are only 60% to 70% efficient, helical or bevel helical units are up to 99% efficient. This is because the tooth profile, tooth pitch, and pressure angles, in addition to the precision case-hardened and fine-ground profiles, have been optimised to provide the highest torque possible, while maintaining maximum efficiency.

What makes the drop-in replacement service

particularly attractive, in conjunction with refurbishment, is that the cost of repairing a worm gear unit usually exceeds its replacement cost. Factors that need to be taken into account are the associated downtime when the unit is out of service, together with the total removal, repair, and replacement cost.

Drop in

An order can be placed for a drop-in replacement in advance, which enhances the cost-effectiveness of the solution. When an ageing drive is ready to be replaced, a modern drive can be assembled, delivered, and installed at the same time as the old drive is removed. “One must bear in mind that the drop-in replacement is a completely new unit, in addition to being the most efficient technology,” Norman elaborates.

Drop-in replacement units can cater for any competitor gearboxes, and are ideal for a range of industries, from cement and sugar mills to agriculture and milling, power generation, mining and conveying (materials handling), and water and wastewater treatment plants.

What’s more, the drop-in replacement service is ideal for these industries to take advantage of the latest technological developments from the drive engineering specialist, such as its X/M Series helical and helical bevel gearboxes. Some units are assembled in Nelspruit, translating into fast turnaround times and maximum stockholding.

Familiar ground

Another advantage is that the client is already familiar with the older unit, which means that specialised technicians or support is not required for the drop-in replacement. The latest X/M Series has been designed to deliver better power and torque. The footprint, shaft centre distance and centre height and the input/output shaft diameter remain the same. Thus the installation process is exactly the same as with the older unit.

SEW-Eurodrive (Pty) Ltd Tel: (011) 248-7000 Email: info@sew.co.za www.sew-eurodrive.co.za

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STOCKYARD

Stacking up Efficiencies Thyssenkrupp is an industry pioneer and world leader in the manufacture of stackers, drum reclaimers and other stockyard machines. Moving with the Industry 4.0 tide, the global engineering specialist has introduced new technology that improves stacker efficiency and performance.

T

heir stackers are responsible for stockpiling an extensive range of materials at mines, quarries and ports across the African continent. The company recently delivered a locally designed and manufactured 2000tph, 100m long (including the tripper), 300t stacker to a coal mine operating in South Africa’s Waterberg region.

that provide analytical process controls for stockyard blending and homogenisation as well as scientific control of mineralogy of stockpiles,” shares Jacques.

Through online analysis, the presence and amount of a large number of different elements can be determined, eliminating the need for taking samples to the laboratory thus saving time and costs.

“We have invested substantially in our stacker design to ultimately provide cost and time saving benefits to our customThe ers across Sub-Sahara Africa,” availability notes Jacques Steyn, General Manager: Materials Handling of this massive at thyssenkrupp Industrial Soamount of data lutions Africa. The company allows for a completely locally designs and builds automated stockyard stackers with capacities system which results in from 50 to 20 000tph, in better planning and boom lengths from 10m to consequently a more 65m and in an assortment efficient plant of shapes and sizes such as fixed, travelling, luffing, slewing as well as a combination of the aforementioned.

Using this information as input, this stacker and stockyard management system achieves an optimal blend of mineral stockpiles and subsequently ensures a constant mineralogy feed to process plants.

“There are customised stacker solutions to customer specifications. Local design, manufacture and customisation illustrates our commitment to providing customers with best-in-class products in the shortest turnaround time.”

A pivotal role

Jacques observes that stackers play a pivotal role in continuous stacking processes with stacking critical for efficient reclaiming and homogenous blending. “The basic operation of these machines and the mechanics of stacking and reclaiming have not changed significantly over the past 5 decades.

However, with the advent of the digital age, manual control systems have given way to automation and most modern stackers are fully or semi-automated.”

Machines are now controlled from remote on- and off-site offices. Changes are also seen in the way in which information is fed to and from the equipment. Automation of the entire process provides stockyard managers with vital information such as knowing exactly where the stackers and/or reclaimers are, how they move, what quality and quantity of material they are processing as well as the grade of material that is being conveyed.

The availability of this massive amount of data allows for a completely automated stockyard system which results in better planning and consequently a more efficient plant.

Scientific control

“We have designed and developed online analysers

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Stackers are normally designed for the life of mine but Jacques points to the importance of general maintenance to ensure that the machine remains in good working order to maximise its life cycle.

“If these machines are properly maintained, they

will continue working for 40 years plus.” To assist customers in safeguarding the health of their stackers, thyssenkrupp offers best-in-class service which includes a structural inspection and analysis, an aspect often overlooked by customers who tend to focus on servicing easy-to-replace mechanical, hydraulic and electrical components.

Jacques warns that failure of a stacker’s main structural component can result in protracted downtime and exorbitant repair or replacement costs, making regular inspections crucial.

Digitisation space

In today’s global economy, improved productivity, production, efficiencies and safety are critical to operational survival of a mine or plant. Carbon emission management is another factor that no longer can be ignored.

“Automation certainly ticks all these boxes. Operations are often daunted by the initial capex involved in automating equipment but research shows that over the life of a mine or plant, automation maximises factors that contribute to profitability and minimises factors that drive up Opex, presenting

a solid argument for investing in this technology.

Operations are often “These technological addaunted by the ditions to our stackers initial capex involved in place us firmly in the digitalisation space automating equipment but and bring these maresearch shows that over the life chines into the modern of a mine or plant, automation age. There can be no maximises factors that contribute doubt that stackers to profitability and minimises will continue to play a factors that drive up Opex, fundamental role in the future of modern mechapresenting a solid argument nised and autonomous for investing in this bulk materials handling, technology making a valuable contributing to an operation’s sustainability,” Jacques concludes.

thyssenkrupp Industrial Solutions (South Africa) Kgothatso Ntsie Tel: (011) 236-1000 Email: kgothatso.ntsie@thyssenkrupp.com

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STORAGE SOLUTIONS

Solid Fertilizer Products Dry bulk fertilizer products, whether they be within fertilizer factories or at shipping or receiving points, are mainly stored in stockpiles. Employing a pile instead of a high silo is an economical solution for large volumes. In most circumstances, the stockpiles are covered in order to protect both the environment, as the product is prevented from being blown around, and the product itself as it is shielded from being affected by adverse weather conditions.

I

n most instances where a fertilizer product boasts both a consistent composition and quality from an upstream chemical process, the piles also often function as buffer storage. The piles are thus employed to balance time and volume between production and shipping or to balance reception during interim storage and onward transport to users.

This gentle treatment of a material, together with the minimization of dust, also applies in principle to all equipment within the fertilizer handling value chain In other instances where there is very little or no consistency, specifically when mined ores of varying qualities and/or characteristics arrive at a chemical plant and require homogenization prior to a chemical process, piles can also be employed as a blending bed. This is often the case for large fertilizer storages, especially those with high throughputs for either stacking, reclaiming or both, and are usually equipped with fully automated stockyard machines.

Stockyard machine expertise

Tenova Takraf is a global OEM for mining and bulk

Portal reclaimer for phosphates in Saudi Arabia

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handling equipment with a history dating back almost 300 years. The company boasts a successful 50 year plus track record of supplying stockyard machines to the global fertilizer industry, with its first scraper reclaimer (for a potash factory) being supplied in 1966.

Since then, the company has designed, manufactured, supplied and successfully commissioned around 400 scraper reclaimers across various commodities with a large majority being employed in the effective handling of potash, urea, phosphates and sulphur.

Tenova Takraf's approach to this vast array of global projects is “flexibility�. This means they treat the specific requirements of each project in a unique manner, ranging from the supply of a single machine to various machine packages and/or delivery of a complete bulk conveyor system including storage bin machines, conveyor belts and loading & unloading equipment.

Such complete handling systems leverage an extended and well established material handling portfolio covering stockyard / disposal facilities, loading / un-loading equipment, conveying, port facilities and in-plant handling equipment.

Stacking and reclaiming

In most instances, a storage facility is fed material through a network of conveyors that efficiently carry the product to be stored. In order to achieve an optimal pile width within the storage area, the stacking of material is carried out via overhead tripper cars. Having supplied machines with capacities of up to 4 000t/h, Tenova Takraf boasts significant experience in the supply of these underroof tripper cars.

For the recovery of product from a pile, scraper reclaimers are the preferred (and dominant) equipment of choice for operators and planners alike.

Some of the advantages of these machines include: • Proven robustness and reliability • High efficiency and low operating costs • Simple and steady working movements allowing for full automation • Gentle treatment of material and almost dustfree handling of fertilizer products

Indoor areas

As a result of general market developments and increasing fertilizer logistic requirements, the global demand for storage volumes and handling capacities is increasing. This growing demand has resulted in large pile widths, sometimes even exceeding 60m.

For such indoor applications, the portal reclaimer, which boasts separate main and auxiliary reclaiming booms, is the preferred solution, as it requires a minimum amount of space due to its shape. This results in the maximum covered storage space for the product stack.

Depending on bulk products’ densities, the company

is able to supply portal reclaimers with handling capacities of up 6 000t/h and with rail-spans that can exceed 60m.

Special features

As previously mentioned, scraper reclaimers are, due to their method of operation, very gentle in their treatment of material and thus operate with minimal dust creation. This makes them ideally suited to fertilizer material that often comes in granulated form.

This gentle treatment of a material, together with the minimization of dust, also applies in principle to all equipment within the fertilizer handling value chain including boom stackers and/or overhead tripper cars. These machines, which generally employ cone shell stacking for the minimisation of dust, can also be equipped with lowering booms or special chutes in order to further improve handling and dust minimisation.

Nevertheless, depending on the characteristics of the fertilizer product and the customers’ unique requirements, Tenova Takraf is able to equip their scraper reclaimers and stockyard machines with special features such as: • Stainless steel design for blades and chutes • “De-lumpers” arranged within the discharge chutes for the breaking up (“de-lumping”) of caked bulk material • Hoses on hose reels for fresh air supply to operator cabins • Life-time lubricated outboard roller chains • ATEX-certified components in case of inflammable / explosive bulk material such as sulphur.

Overhead tripper car for a urea storage facility in USA

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STORAGE SOLUTIONS

Bulk storage arrangement

In addition to the globally popular solution of employing portal reclaimers in combination with overhead tripper cars for indoor fertilizer storage facilities, other alternative solutions can potentially be employed or even be better suited in certain specific instances.

Spending the time to properly evaluate all options and making an informed decision based on all

factors including the overall space situation, storage shed design and structure and/or on individual mass flows, may mean that the following machine solutions might be an even more suitable choice: • A stacker with tripper-car travelling on ground along the pile • A combined stacker / reclaimer • A circular storage arrangement.

The images above provide a view of some typical portal reclaimers across various fertilizer types. A: Portal reclaimer for urea in USA, B: Portal reclaimer for sulphur in Kuwait, C: Portal reclaimer for potash in Russia

Stacker installed within a sulphur storage facility in Kuwait with discharge being conducted via a portal reclaimer

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In addition, the requirement for homogenization may bear significant influence on equipment selection.

Nowadays, very light building structures even for large shed dimensions are available and quite commonplace. Often, these light building structures do not allow for any under-roof installation of incoming conveyors with a travelling tripper car.

In such cases, an alternative approach in combination with such a light building structure might employ an on-ground travelling stacker. In such instances where all equipment is installed at ground level, access to equipment for maintenance is significantly safer and more efficient as an additional benefit.

If space at the site is limited, then a circular buffer storage facility may turn out to be the most effective space-saving solution. Bulk material is stored against a retention wall, with both stacker

and reclaimer mounted on a central column.

In circular buffer storage solutions, the feeding of the pile is conducted via a boom stacker employing the cone shell stacking method. Reclaiming is accomplished via a cantilever reclaimer, which conveys material into a central chute located below the central column.

From this central column, material is then fed, via a feeder, to the outgoing conveyor.

In operations where material logistics can be managed in such a manner so as to avoid simultaneous stacking and reclaiming operations, a combined

If space at the site is limited, then a circular buffer storage facility may turn out to be the most effective space-saving solution

Circular buffer storage for 360° endless slewing operations with lowering stacker and cantilever reclaimer in India

Combined stacker / scraper reclaimer with drag-trough discharge employed in a covered bulk storage area in China

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STORAGE SOLUTIONS stacker / scraper reclaimer can also be an effective costsaving solution.

In this instance, stacker and scraper booms are mounted on the same chassis resulting in substantial cost savings not only for the equipment itself but also in reduced rail lengths and fewer conveyors being required.

Homogenization / blending

In instances where fertilizer originates from mined ores and/or where variations exceeding the acceptable product range can be expected, material consistency can then be at risk. In order to protect against such consistency issues, the stockpile may, in addition to its buffer function, also be given the additional task of homogenization / blending.

Blending beds generally operate in an adjusted combination of chevron-stacking and front-reclaiming. The stockpile is built up according to the so-called “chevron method” in a longitudinal stockpile, or the so-called “chevcone method” in a circular stockpile. In both methods however, stacking is required to achieve a sufficient number of material layers.

Reclaiming is then conducted via a bridge-type reclaimer, which takes material from the front side of the stockpile.

In this manner, reclaiming achieves a perfect mixture of material, depending on the number of layers and the incoming deviation and/or distribution.

Tenova Takraf Ralf Katzke Tel.: +49 (0)341 24 23 5 00 Email: takraf.sales@tenova.com, www.takraf.com

Stacker and bridge-type reclaimer in circular blending bed in India

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Your boutique business destination Surrounded by lush gardens in the hub of Johannesburg’s northern suburbs, The Peartree in Craighall Park caters for groups of fifteen through to 100 guests in three well-appointed and equipped business suites.

Breakfast meetings, working lunches, indoor or outdoor dining, half-day and full-day packages including all welcome refreshments, teas and lunches are offered in Standard, Gold and Platinum packages.

Secure parking, Wi-fi, lockable space, all underpinned by highly qualified and helpful staff dedicated to ensuring your event is a success, make The Peartree a destination of choice.

www.thepeartree.co.za e-mail: info@thepeartree.co.za Tel: 011 781 1401 41 St. Albans Ave, Craighall Park

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MARKET FORUM

Bottlenecks at depth Bottlenecks were preventing one of the world’s deepest gold mines from achieving its targeted throughput 2 850 metres below surface. Weba Chute Systems designed and manufactured the solution.

A short slew conveyor was at the centre of the South African mine’s challenge, providing the only source of ore from that level. Frequent stoppages from belt cuts on this conveyor, often from large rocks stuck in the bottom of the existing chute, meant costly downtime and disrupted material flow to the plant.

The solution, according to, Dewald Tintinger, technical manager at Weba Chute Systems, was to design a completely new chute solution that would remove the need for the slew conveyor arrangement.

“The chute we designed has a bypass leg that drops waste material directly into the bypass, while allowing an inline channel of reef onto the conveyor belt,” Dewald says. The custom-designed chute was able to replace the mechanical moving component, which also improved the safety of the working area.

Growing the market The growing popularity of Products’ expanded offering has led the company to boost its service and repair facilities.

Andrew Frank, operations manager at Mato Products, highlights the recent completion of the new spray-painting booth, which has doubled the firm’s capacity to finish refurbished items.

Well known as a leader in conveyor belt lacing, the Multotec subsidiary also offers a range of belt cleaning solutions.

“To keep up with market demand, we have expanded our spray booth significantly in terms of size and throughput capability,” says Andrew. “It can now accommodate components up to a length of 2,2 metres and provide a more productive environment for operators.”

This now allows for all repair and finishing work, even on the longer diagonal belt cleaners, to be spray-painted in-house, he adds. Importantly, this improves turnaround time, quality control and cost to customer.

Mato Products Tel: (011) 923-6000 Email: marketing@multotec.co.za www.multotec.com

The solution, which also involved 70 metres of conveyor belt extension, required the new chute to bifurcate the flow of material from the stopes into a reef stream and a waste stream.

“We achieved that by installing a chute section mounted on a trolley frame, actuated to split the material flow as required,” Dewald explains.

Another benefit was that the area no longer needed regular cleaning. Previously, four shifts of cleaners, comprising four workers each, were required to service the area around the slew conveyor and remove spillage.

Weba Chute Systems & Solutions, Tel: (011) 827-9372 Email: weba@webachutes.com, www.webachutes.com

The new spray booth is equipped with the latest filtration technology and complies with the highest standard of health and safety

Cost and installation time analysis When diesel engine service and repair company, Diesel Power International Services subsidiary based in Namibia, needed advice on what cranes and hoists could be applied effectively to their newly designed work space, that would house their assembly lines and diesel engine stripping facilities, they called in Konecranes from Cape Town to assist. Installation and delivery times were tight, but the innovative solution that resulted from a Cost and Installation Time Analysis conducted by Konecranes sealed the turnkey deal.

“The project was for a semi-free-standing gantry with 1 x 3.5 ton single Girder Crane and 2 x 500kg Column Mount Jib Cranes and hoists” says Markus Labuschagne, Konecranes’s Regional Branch Manager who is based in Cape Town.

repaired and serviced.

Markus concludes, “As a result of our cost and installation time analysis it was our recommendation that the alternate cranes we had identified as suitable for their project, would cover a greater area than the equipment originally specified, and would offer greater benefits to the client, in addition to the fact that we were able to deliver the equipment to the customer in Namibia within their stated timeframe.”

Konecranes Markus Labuschagne, Tel: (011) 898-3500 Email: markus.labuschagne@konecranes.com www.konecranes.co.za

“The equipment specifications that the customer had originally requested - one 3.5ton jib crane and two 500kg jib cranes - would have worked out at a higher costing and not enhanced the layout of the proposed floor area. Additionally, our cranes have enabled the customer to place items on the new mezzanine level in the production plant” he says.

The 3.5 ton crane will be used for the lifting, stripping and assembly of truck diesel engines while the 2 x 500kg column mount jibs will be used for serving two work stations where smaller components and parts are BULK HANDLING TODAY

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MARKET FORUM

Belt feeder FLSmidth has launched their new Hybrid Apron Belt (HAB) Feeder for run-of-mine and stockyard applications. A modular, hybrid, belt-overapron feeder, the feeder delivers the strength of an apron feeder with the spillage control of a conveyor system.

It is a robust, power-efficient and high-tonnage hybrid belt-over-apron feeder that offers combined advantages of both apron and belt technologies.

It provides a cost-effective solution for feeding abrasive materials, such as mineral sands, iron ore and bauxite, in mid-tier ROM applications and stockyard management operations.

The low-profile loading deck easily accommodates different types of loading methods, including direct truck tipping, side tipping, front-end loading, dozing and ROM bypass tips, in order to prevent double handling. The feeder’s modular design allows for transportation within a standard-size container, simplifying freight solutions to remote locations around the world. Modularity also allows for specific discharge heights, depending on the required application.

The HAB Feeder design incorporates a number of safety features, including a start-up alarm that is located behind the wing walls, an emergency stop on either side of the feeder, and an emergency bar at the feeder opening.

According to FLSmidth’s Manager of Capital Equipment, PC

Kruger, “This feeder is specifically designed to feed abrasive materials at an adjustable rate onto conveyor belts and sizers. Because it is entirely modular, it can be installed with minimal site preparation, anywhere near a stockpile. It is semi-mobile for simple onsite relocation or repositioning.

Moving the feeder is as easy as dragging or pushing it with standard stockyard equipment.”

FLSmidth PC Kruger, Tel: 076-812-7610 Email: pc.kruger@flsmidth.com, www.flsmidth.com

Greater versatility The Potain Hup 40-30 self-erecting crane boasts a range of innovative design and technology features which, according to Louw Smit, sales director at Crane & Hoist Equipment SA, will enable greater versatility on construction and other project sites.

“One of the major advantages of the Potain Hup 40-30 unit is that, with its 40 metre jib, it offers different configurations making it unique to this category of self-erecting cranes,” Louw explains. “The crane can easily be adapted for a range of job site applications increasing efficiency and versatility.”

The crane has a maximum capacity of 4t, can lift 1t at its jib end of 40 metre and features a telescopic mast for a range of working heights. This design boosts the height under hook attainable by the crane to 25.6 metres in its “low position,”

and 30 metres when extended to its greatest height. The logistics are also improved, as no extra mast is required to install the crane.

Further versatility is delivered with the crane’s luffing jib that offers three positions: horizontal, 10° and 20°. These options give the crane a height under hook range of 20 to 40 metres.

Louw explains that shortening or extending the jib is a swift and straightforward operation, with the Hup 40-30 offering convenient configurations for both short and long jib lengths.

Crane & Hoist Equipment SA (Pty) Ltd Tel: 083-413-7524 Email: info@che-sa.co.za www.che-sa.co.za

The Potain Hup 40-30 has a high-performance slewing radius that allows it to be positioned closer to buildings

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High security welded mesh

Pallisade

Gates

Gate Automation

Razor wire and more ....

What is High Security Weld Mesh HIGH Security Weld Mesh is wire fused and welded at a Horizontal distance of 76.2mm and a vertical distance of 12.7mm also known as 35B/3510 where 3 denotes 3”(distance between vertical wires), 5 denotes 0.5” (distance between horizontal wires), and B or 10 denotes gauge of wire

Salient Features • Difficult to Climb: The spaces between the Horizontal wires are too narrow for fingers to have grip • Impregnable: Extremely difficult to cut with a hand cutter as the beak of a wire cutter will not be able to penetrate the horizontal wires • Excellent Replacement option to Solid Wall as: 1. More economical than a solid wall 2. Faster to install than a solid wall 3. CCTV Camera has a clear view • Further upgrade possible with electric security system • Anti-corrosive & low maintenance

Standards

• Manufactured according to BS EN 10016-2 • Wire Sizes in accordance with BS EN 10218-2 • Tolerance on Mesh Size in accordance wiht EN 10223-7 • Tolerance on Panel Size in accordance with EN 10223-4 • Welding Strength in accordance with BS EN 1461 • Zinc Coating in accordance with EN 10245-1 • Anti Corrosion in accordance with BS En 3900 E4/F4

Tensile Strength • Wire has a tensile strenght of min 550 MPA

MARK: 083 454 6488

Email: mark@palifence.co.za

www.palifence.co.za BULK HANDLING TODAY

Jan/Feb 2020

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BULK HANDLING TODAY

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