Global Mining Review October 2021 by PalladianPublications

OCTOBER 2021 VOLUME 4 ISSUE 7

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CONTENTS 03

Guest Comment

World News

The Myth And Reality Of The Mongolian Mining Industry

Claude Sharma, HARD-LINE, Canada, considers how automation is helping mines optimise their operations.

Maximising Sustainable Impacts Iliass Elfali, OCP Group, Morocco, outlines how to maximise the impact of sustainable mining programmes.

Integrated Systems: The Next Step To Zero Emissions Mining Solutions

The Mechanics Of Dynamic Ground Support

Chris Edge, Hallite Seals International, and Geoff McKenna, Komatsu Mining Corporation, discuss the importance of seals in mining roof supports.

Looking Into Space John Turnbull, SES Networks, Australia, explains how the mining industry is being transformed with multi-orbit satellite-driven broadband technology.

Keep Things Moving With Mobile Conveyors Paul Emerson, Terra Nova Technologies Inc., USA, discusses how flexibility and versatility can be added to an IPCC system using mobile conveyors.

Flotation Control Todd Loudin, Flowrox USA, outlines the benefits of rubber compounding pumps and valves in helping to combat abrasion.

Fighting Mine Fires

Seal Of The Longwall

Driving Energy And Process Efficiency Ormond O’Neill, Siemens AG, Germany, explores how using drives can maximise energy and process efficiency in mining applications.

Alan Bailes, Weber Mining & Tunnelling S.A.S, Australia, discusses recent advances in safety, using remote seals for the confinement of cavities in an Australian coal mine as an example.

As determination towards green initiatives grows within the mining industry, Elliott Duck, Mincon Inc., USA, outlines how companies can change the way manufacturers and mines think about operating efficiencies and equipment solutions. David Evans, DSI Underground Asia Pacific, provides insight into the importance of the mechanics and mechanical response of ground support in underground hard-rock mining.

Accessing Intelligent Data Thishen Naidoo, Emerson, Canada, explains how implementing modern control system architectures and communications can help mining companies improve efficiency and future-proof operations.

Ben Jones and Daan de Jonge, CRU Consulting, UK, provide an outlook for the Mongolian mining industry.

Breaking Through Remotely

Changing The Conversation On Mine Maintenance Costs Josh Swank, Philippi-Hagenbuch Inc., USA, describes a new way to address mining cost reduction, through proper equipment selection.

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Guest Comment IAN COLES Partner and Head of Mayer Brown’s Global Mining Group

MANAGING EDITOR James Little james.little@globalminingreview.com SENIOR EDITOR Callum O’Reilly callum.oreilly@globalminingreview.com DEPUTY EDITOR Will Owen will.owen@globalminingreview.com EDITORIAL ASSISTANT Jessica Casey jessica.casey@globalminingreview.com SALES DIRECTOR Rod Hardy rod.hardy@globalminingreview.com SALES MANAGER Ryan Freeman ryan.freeman@globalminingreview.com PRODUCTION Kyla Waller kyla.waller@globalminingreview.com ADMINISTRATION MANAGER Laura White laura.white@globalminingreview.com DIGITAL ADMINISTRATOR Lauren Fox lauren.fox@globalminingreview.com DIGITAL EVENTS COORDINATOR Louise Cameron louise.cameron@globalminingreview.com DIGITAL EDITORIAL ASSISTANT Bella Weetch bella.weetch@globalminingreview.com VIDEO CONTENT ASSISTANT Molly Bryant molly.bryant@globalminingreview.com GLOBAL MINING REVIEW (ISSN No: 2515-2777) is published bimonthly by Palladian Publications Ltd. Annual subscription (monthly) £50 UK including postage, £60 overseas (airmail). Claims for non-receipt must be made within four months of publication of the issue or they will not honoured without charge.

n 2010, the New York Times excited the mining world with highlights from the report of the US Geological Survey to the effect that the value of mineral wealth in Afghanistan was estimated to be almost US$1 trillion. That included 60 million t of copper, 2.2 billion t of iron ore, and 1.9 million t of various rare earth elements. Subsequent surveys have put the value at as much as US$3 trillion. The problem, of course, was that it was all, and largely continues to be, in the ground, and minerals in the ground in a country as challenging as Afghanistan have minimal value. Nevertheless, the report caught the eye of the Task Force for Business and Stability Operations (TFBSO), a body funded by the US Department of Defense, which experienced some success in Iraq in promoting economic development in a post-conflict environment. TFBSO worked for approximately five years in assisting the Afghan government to build technical, financial, and legal structures that would facilitate the development of a mining industry and encourage foreign investment in the same. What became of that initiative? Very little is the answer. Certainly, some capacity building in various government departments, the development of a system for competitive bidding in connection with the award of mining licenses, and, at one stage, the possible award of four licences to overseas investors. The TFBSO team oversaw the bidding for the Badakshan, Balkhab, Shaida, and Zarkashan licence blocks. Preferred bidders were selected and development contracts negotiated and agreed. Transparency following the process was somewhat limited, but what is certain is that it did not lead to the development of those projects. Beyond basic artisanal mining for gemstones, there has been the occasional muted success story. CENTAR Ltd, founded by Ian Hannam, was able to get a gold project underway; however, that was effectively taken over by local militants. Other potentially huge projects, such as Hajigak iron ore and Mes-Aynak copper, were never developed in any way. In the case of Mes-Aynak, this was largely a function of its location in a particularly challenging security environment. China has been an early starter there, having signed a contract to develop the project, but on terms and conditions which non-governmental organisations and other international observers felt could never support commercial development – China would have to return to the table. Illegal mining has also always been rampant. Perhaps former Afghanistan President, Ashraf Ghani, was correct when he said: “we are at risk of the curse of plenty, [the] curse of resources.” To many, these would appear to be crocodile tears. The historic absence of transparency in the conduct of the Afghan government has hardly endeared itself to potential foreign investors. Those investors have options, and Afghanistan has never presented itself as an option to be preferred. The recent political decision to exit Afghanistan and the resultant Taliban surge effectively puts paid to any significant investment from NATO block countries. What an irony that at the time that the US and Europe were publishing policies which detailed the threat to their economies from restricted access to strategic minerals, Afghanistan, nominally under NATO stewardship, was sitting on one of the world’s biggest hauls of rare earths, as well as potentially significant lithium deposits. So, what now? While it is still early days, geo-political analysis would suggest China, Russia, and India will play ball with a Taliban government. Even if NATO countries did want to be in the game, it is now unlikely they will be able to play on a level playing field with any of these countries. So, very little gained over the past decade, but all to play for over the next one. Groundhog Day – Afghanistan style. Palladian Publications Ltd, 15 South Street, Farnham, Surrey, GU9 7QU, UK t: +44 (0)1252 718999 // f: +44 (0)1252 718992 // w: www.globalminingreview.com

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WORLD NEWS ETHIOPIA Akobo Minerals complete Segele scoping study

fter 10 years of exploration work, culminating in a JORC compliant maiden resource estimate earlier this year, followed by the recent grant of a large scale gold mining license, Akobo Minerals has released its scoping study for the Segele deposit. The results are encouraging and exceed previous expectations. The scoping study indicates what the potential economics of mining the Segele deposit can look like. The study has been completed with contributions from respected geologists, engineers, and environmental, social, and governance practitioners (SRK Consulting, Sazani Associates, Goshawk Network Technologies and Borrego Sun). The result confirms that the mineralisation at Segele can be mined and processed with an estimated AISC of US$243/oz, while the total life of mine operational expenditure, excluding royalties, is estimated at US$137/oz. Total capital expenditure for setting up the mine plant to start production is estimated at US$8 million, equalling an average of US$153/oz for the current resource estimate of 52.410 oz. This average will go down as more resources are added over time. Akobo Minerals is planning to mine the gold mineralisation using methods such as shrinkage stoping or similar. These rocks will be brought to surface using an incline shaft that will take 11 months to build. At peak production, just under 6000 tpm of rock will be mined and this material will be passed into an industry standard crushing and gravity circuit, with cyanidation

where necessary. The company plans to purchase a plant capable of processing 20 tph, but initially operated at 10 tph to allow for expansion. The plant is expected to extract 90% of all gold in the mineralisation, but this will be confirmed by the ongoing metallurgical testwork. The scoping study has focused only on the mineralisation covered in the SRK mineral resource estimate, allowing for an anticipated mine life of 27 months. Ongoing exploration has identified additional mineralisation at depth, which leaves open the opportunity to extend the mine’s life. As with all anticipated underground mining operations, not all ore can be mined or exploited and as such, the scoping study estimates an extraction percentage 81%; the grade will be diluted by 5% and ore loss is expected to be 8%. These figures are in-line with or better than industry standards. A sustainable natural resources management plan is planned alongside mining. Such a plan may allow the company to contribute to the United Nations Sustainable Development Goals. The scoping study is the first phase in the process of developing a business plan for mining at Segele and has an accuracy of between 30 – 50%. Akobo Minerals has already begun a prefeasibility study, which typically has an accuracy of +/- 25%. The prefeasibility study will involve a resource upgrade, selection of mining method and detailed plant design. It also allows for the publication of cash flow models and ore reserves.

SPAIN Weir Minerals signs purchase contract for Highfield Resources’ Muga Mine

ighfield Resources has announced the signing of a purchase contract with Weir Minerals for important components of a process plant, in order to finalise the pre-construction activities at its flagship Muga Potash Mine. Following a recent AUS$18.1 million capital raise, the company is well funded to finalise the purchase contracts of the remaining long-lead items. With the signing of this purchase contract, 85% of the planned equipment needed for the plant has now been contracted. The remaining 15%, which includes cross-flow separators, dryers, thickeners and flotation columns, is expected to be formalised soon. The remaining equipment, mainly mining equipment, will be acquired prior

to start of operations. Completion of the procurement of the process plant equipment is key for allowing improvements in the detailed engineering design of the plant, with the design of the specific equipment used. In addition, it allows Highfield to cover the long lead manufacturing times of this type of equipment. Weir Minerals is providing both primary and secondary concentrate screens, which will be used for the granulometric separation in the initial phase of the crushing, grinding, and desliming processes. The hydrocyclones from Weir will be used to remove the fine particles from the slurry (known as desliming) prior to flotation. GLOBal mining review // October 2021

WORLD NEWS Diary Dates Iron Ore Conference 2021 08 – 10 November 2021 Perth, Australia & Virtual www.ausimm.com/ conferences-and-events/iron-ore Mining Indonesia 2021 17 – 20 November 2021 Jakarta, Indonesia www.mining-indonesia.com Mines and Money London 01 – 02 December 2021 London, UK https://minesandmoney.com/london International Mining and Resources Conference (IMARC) 31 January – 02 February 2022 Melbourne, Australia & Virtual https://imarcglobal.com/ MINEXCHANGE 2022 SME Annual Conference & Expo 27 February – 02 March 2022 Salt Lake City, USA www.smeannualconference.com Future of Mining Australia 2022 28 – 29 March 2022 Sydney, Australia https://australia.future-of-mining.com Euro Mine Expo 14 – 16 June 2022 Skellefteå, Sweden www.euromineexpo.com

To stay informed about the status of industry events and any potential cancellations of events due to COVID-19, visit Global Mining Review’s events page: www.globalminingreview.com/events

October 2021 // global mining review

COLOMBIA Nokia implements wireless 5G test for

AngloGold Ashanti Colombia

okia and AngloGold Ashanti Colombia, in collaboration with Epiroc, Sandvik, Tigo and OSC Top solutions, have conducted the first underground 5G mining trial in Jerico, Colombia. The successful trial proves it is possible to safely, sustainably, and efficiently deploy multiple mining use cases over a private 5G SA industrial-grade network in a challenging underground environment. It also demonstrates how government, service providers, and industry have come together to advance the digital transformation of the mining industry in Colombia and Latin America. Four mining use cases were tested as part of the trial, including mission-critical communications, connectivity and remote teleoperation of vehicles, mining machinery and systems, and inspection and monitoring with drones and high-definition cameras. Nokia deployed an industrial-grade 5G private wireless network, which provides ultra-wideband connectivity, with speed in excess of 1 Gbps and with scope for ultra-low latency. The network is powered by the latest Nokia AirScale 5G portfolio in the 3.5 GHz spectrum band with the support of Tigo Colombia, and has been deployed in the context of the 5G testing framework of the Ministry of ICT. The proof of concept includes AirScale radio bases and adaptive antennas with massive MIMO capability, all integrated into a 5G SA architecture with network partitioning capability, which allows independent virtual networks to be generated for each use case. The pilot was carried out in close collaboration with Epiroc and Sandvik, who are developers of vehicles and mining automation systems, with OSC Top solutions for the integration of services and solutions for drone inspection. According to a recent study by Nokia and OMDIA, 5G technology will generate a positive economic impact of US$11.4 billion in Colombia’s mining sector during 2021 – 2035.

BRAZIL Clariant opens Competence Center for Tailings

Treatment in Brazil

n order to support the mining industry’s efforts towards sustainability, Clariant has announced a new technical facility – the Competence Center for Tailings Treatment (CCTT) in Belo Horizonte, state of Minas Gerais, Brazil – exclusively dedicated to developing solutions for tailings management. The CCTT will develop mining chemicals and technologies to support the industry’s efforts from the heart of Brazil’s mining hub. The new lab is outfitted with state-of-the-art equipment and is home to a dedicated team of research and development experts. The new CCTT is a core pillar of Clariant’s Tailings Management Program, which comprises four complementary technology platforms: flotation, magnetic separation, dewatering, and rheology modification. Flotation chemicals for slimes, for instance, help mines recover valuable minerals that are currently going to waste, and flotation chemicals for secondary mining enable operators to reprocess old tailings. In addition, filter aids help operators dewater tailings better, leading to drier stacks, and faster throughput.

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WORLD NEWS GLOBAL IAMGOLD commits to net negative GHG emissions by 2050

AMGOLD Corp. has announced its commitment to achieve net negative greenhouse gas (GHG) emissions by no later than 2050. IAMGOLD’s commitment to net negative GHG emissions comprises two separate global targets. The first global target relates to reductions in Scope 1 (direct) and Scope 2 (indirect – energy) GHG emissions. IAMGOLD is committing to reduce its emissions profile to as close to zero as possible, by no later than 2050. Initial work will focus on defining specific options to address the company’s largest sources of emissions: heavy and light vehicle fleets and power generation and supply. IAMGOLD’s commitments will be updated in 2025 to incorporate targets for our Scope 3 (indirect - value chain) emissions. The second global target relates to GHG removals. Reversing the effects of climate change requires not only that emissions be reduced, but that substantial amounts of existing GHG also be removed from the atmosphere. As part of this target, IAMGOLD is committing to achieve net positive biodiversity, wherein the company will commit to creating more habitat than it disturbs.

IAMGOLD plans to achieve this global target through investments in nature-based solutions that further biodiversity objectives and act as carbon sinks. Investment opportunities will be pursued at the company’s operating sites, as well as regionally and globally, to ensure the maximum possible benefit for every dollar invested. By the end of 2022, IAMGOLD will complete an external verification of its emissions reporting, develop and announce medium-term targets on reductions and removals, and publish a high level roadmap on how the company intends to achieve its global target of net negative emissions, by no later than 2050. The roadmap will also include an estimated date by which the company expects to achieve net positive biodiversity. Work will advance through a dedicated steering committee with support from a range of external advisors. As part of its accountability and reporting framework, IAMGOLD will also be reporting in accordance with the Climate-Related Financial Disclosures (TCFD) guidelines. IAMGOLD expects to release its initial TCFD report in late 2022.

CANADA Agnico Eagle and Kirkland Lake Gold announce merger of equals

gnico Eagle Mines Ltd and Kirkland Lake Gold Ltd have announced that they have entered into an agreement (the merger agreement) to combine in a merger of equals (the merger), with the combined company to continue under the name ‘Agnico Eagle Mines Limited’. The merger will establish the new Agnico Eagle as the gold industry’s highest-quality senior producer, with the lowest unit costs, highest margins, most favourable risk profile, and industry-leading best practices in key areas of environmental, social and governance (ESG). Upon closing of the merger, the company is expected to have US$2.3 billion of available liquidity, a mineral reserve base of 48 million oz of gold (969 million t at 1.53 g/t), and an extensive pipeline of development and exploration projects to drive sustainable, low-risk growth. The merger will create a best-in-class gold mining company operating in one of the world’s leading gold regions, the Abitibi-Greenstone Belt of northeastern Ontario and northwestern Quebec, with superior financial and operating metrics. Consolidation within the Abitibi will also provide Agnico Eagle with significant value creation opportunities

8 October 2021

// global mining review

through synergies and other business improvement initiatives. Additionally, the company is established as the only gold producer in Nunavut and is well positioned internationally with profitable and prospective assets in Australia, Finland, and Mexico. The merger of Agnico Eagle and Kirkland Lake Gold combines each company’s strengths by bringing together two industry leaders in growing per share value in key metrics such as production, mineral reserves, cash flow, and net asset value. Both companies also share a strong commitment to returning capital to shareholders, with a total of US$1.6 billion being returned through dividend payments and share repurchases since the beginning of 2020. Under the merger agreement, which the Board of Directors of both companies have unanimously approved, the new Agnico Eagle will be led by a combined board and management team of experienced mining and business leaders, bringing together the proven cultures, strengths and capabilities of both companies. The transaction is expected to close in December 2021, or in the 1Q22.

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10 October 2021 // global mining review

Ben Jones and Daan de Jonge, CRU Consulting, UK, provide an outlook for the Mongolian mining industry.

he mining industry is key to the health of the Mongolian economy: revenues from the export of coal, copper, gold and iron ore, for example, amounted to approximately US$6.3 billion in 2019. The potential for further growth is staggering: CRU Consulting’s analysis shows that many of Mongolia’s coal assets are among the lowest cost producers globally. The country is also substantially under-explored, and holds vast polymetallic resources. However, while the mining industry has expanded significantly in the past decade – and further expansions are at various stages of development, including major ramp ups to operating assets at Tavan Tolgoi and Oyu Tolgoi – it has nonetheless generally failed to live up to some of the frothier

growth expectations of the early 2010s. In fact, there has been an absolute decline in exploration licenses since 2011. This reflects the practical barriers to successful investment in this frontier market. As investors such as Rio Tinto will no doubt attest, developing mining assets in Mongolia is not without its challenges. Developers are impacted by challenging technical conditions, including scarce water resources, fragile and under-developed infrastructure, and a deep scepticism among some sections of political and civil society about the merits of foreign investors in the industry. This article explores the myths and realities that stand over the Mongolian industry. It reports some of the key

global mining review // October 2021

findings from a recent in-depth study by CRU Consulting into the prospects for, and barriers to, future expansion of the mining industry in Mongolia, and discusses some of the major policy and investment decisions shaping industry and broader economic outcomes in the coming years.

A complex web of policy, institutional, and infrastructure related barriers continue to hamper investment The mining industry in Mongolia is likely to be shaped by a number of key barriers and impediments, which will be critical to address to ensure a secure future. From an institutional perspective, investors must grapple with a high level of state participation in the industry. Key strategic assets, such as Oyu Tolgoi and Tavan Tolgoi, are owned partly by the state mining company, Erdenes Mongol. Levels of transparency in this institution and the quality of overall governance more generally are low, and a clear dividend policy is lacking. These issues undermine the effectiveness of this organisation in developing and unlocking resource value. Policy instability and weak property rights have also been prevailing issues. Weary investors will point to the state’s appropriation of the Dornod Uranium deposit from Canadian-based Khan Resources between 2009 – 2011, or even current discussions regarding the prospects for revision to the financial agreement on Oyu Tolgoi, as reasons to consider investments extra risky. Inflation is an economy wide issue, but high transportation costs are a particular boon for exporters of bulk materials, such as iron ore and coal. An under-developed rail network and poor road surfaces mean

that transporting ores over long distances to offtakers in China, Russia, and beyond can be expensive. Many of the border points are particularly significant bottlenecks, with extensive traffic blocks a common sight in Gashuun Sukhait and Shivee Khuren. CRU Consulting’s analysis finds that transportation costs account for over three-quarters and half of delivered costs of iron ore and metallurgical coal respectively (10 – 40% higher than leading international competitors in the case of the former). This implies substantial upside to value creation in key industry segments in the event of network expansions and upgrades – in particular for South Gobi bulk exporters, such as those of metallurgical coal. Perhaps foremost among the productive constraints is the absence of sufficient water distribution infrastructure. With little rainfall, water scarcity is a nationwide issue: with an estimated 85 – 99% of water currently being extracted from non-renewable sources, this issue will only become worse over time if alternatives are not found. Such issues cannot be ignored by prospective mining investors and policy makers alike, and could represent a major constraint to future growth. Analysis by CRU Consulting suggests that the mining industry would ultimately exhaust local supply in some regions. As a result, without significant investment in a distribution network and more water efficient extraction processes, the industry has the potential to ‘crowd out’ water access in regions such as the South Gobi.

Strong growth is expected, but the upside to policy reform is huge

Business costs ($/tonne)

In spite of these barriers, CRU Consulting projects that continued macroeconomic development, population growth, and urbanisation in Mongolia (and internationally) will help foster the conditions for expanding 200 production and mineral revenues, 150 particularly in the short and medium terms, as expansions at Oyu Tolgoi 100 and Tavan Tolgoi take place. For 50 example, CRU Consulting projects in 0 the region of 70 – 85% growth in Met Coal Copper Iron Ore copper and metallurgical coal production by 2025, respectively Figure 1. Production growth by commodity 2020 – 2025 (2020 = 100). (compared to 2020 levels). There is further upside potential in Central & South America Australia Mongolia China North America Africa CIS 7,000 the event that some of the key barriers Oyu Tolgoi and obstacles discussed are 6,000 overcome. For example, Erdenet 5,000 CRU Consulting has explored the implications of constructing 4,000 additional railways, both in the 3,000 South Gobi and the northern corridor, on potential mine supply, investment, 2,000 and profitability. In the case of Tavan Tolgoi, it found that such 1,000 debottlenecking, as well as 0 optimisation of trucking routes, could 0 5,000 10,000 15,000 yield an approximate 15% uptick in Cumulative production, '000 tonnes Cu annual revenues, and an increase in sector margins more broadly approaching one-quarter. Figure 2. Copper mining business costs, 2020 (US$/t copper).

12 October 2021 // global mining review

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Balancing politics and economics are key to success Economic development in Mongolia is closely tied to key strategic assets, such as Oyu Tolgoi. The history of Oyu Tolgoi, with its landmark geology and drilling technologies, as well as its massive blow out in capital expenditures and acrimonious relationships among shareholders, is well known. However, as the equity partners prepare the next phase of investment in this asset, it will be critical to balance both the economic and political factors as part of efforts to enhance the assets’ long-term commercial future. In terms of economics, the scale of the resource clearly warrants further exploitation. Indeed, the future competitiveness of the asset critically depends on the development of a capital efficient mine expansion plan, in order to deliver stronger economies of scale and bring down the cash costs. Nonetheless, a large scale mine expansion plan based significantly around block caving is inherently risky from a technical perspective, and the shareholders will be naturally wary of further possible cost inflation. However, these important economic and commercial issues also need to be understood and communicated in a way which reflects the politics of this strategically critical national resource. There is a substantial weight of expectations from politicians, the Ministry of Finance and civil society that the asset makes a major contribution to the government’s coffers. The absence of any dividend to date has proven challenging to justify to many such stakeholders, and has, perhaps unsurprisingly, contributed to a reignited debate surrounding the fiscal and broader financing terms upon which the equity partnership rests. While it is in the interests of all parties that satisfactory value sharing arrangements can be agreed, any renegotiation of framework agreements also has the potential to damage investor confidence, which is a particularly acute issue with long lived assets in frontier jurisdictions. Such issues are confounded by the lack of high-quality independent analysis into how value is currently being shared, how that differs from established practices in other relevant mining jurisdictions, and what the implications might be of alternative fiscal and financing terms. Recent analysis undertaken by CRU Consulting, for example, finds that effective government take associated with the Mongolian fiscal regime is broadly in line with mainstream international practices: in a comparative analysis, it found that the effective tax burden on Oyu Tolgoi was ranked third out of the five countries studied. However, when exploring possible alternative tax policies and equity structures, it also found clear trade-offs between

government revenue, in the form of tax income and dividends, which are at the heart of the policy choices facing the Mongolian government. These trade-offs mean that the net effects of some potential changes to fiscal policy may be relatively limited. Using CRU Consulting’s detailed fiscal-mine model to explore the impacts of various potential alternative tax policy and financing terms for Oyu Tolgoi – the timing of the first dividend payment, for example, was found to be relatively insensitive to many of the potential reform options. While a combination of reforms to the tax and financing arrangements has the potential to influence cashflows further still, such deeper routed revisions have the potential to ensnare the negotiation processes and weaken long-term investment commitments. These conclusions may be challenging for some domestic stakeholders to the mining industry within Mongolia. Fundamentally, the highly capital-intensive nature of large scale mining operations implies a tendency for equity owners to both receive substantially backloaded profits and incur a high degree of revenue risk associated with inflation (and compounded by market volatility). This means that, under current equity arrangements (even in the event of substantial shift in financing terms or debt forgiveness), or under a shift to a more traditional tax policy led regime (encompassing loss carry forward rules), the prospects for substantial fiscal revenues during and for an extended period after any ramp up phase are relatively limited.

The future is bright, but a healthy dose of realism by investors is required

Mongolia’s natural resource endowment is undoubtedly rich. Export revenues have grown strongly over the past decade or more, but the industry has generally failed to live up to its promise. This reflects the complex web of policy, institutional, and infrastructure related barriers which potential investors must grapple with. CRU Consulting expects strong growth to continue in the years ahead, driven by expansions at Tavan Tolgoi and Oyu Tolgoi, but that debottlenecking infrastructure and water related constraints could have an important bearing in unlocking additional value. Much of the upcoming focus will be on the negotiations between the recently elected government and the shareholders in Oyu Tolgoi. In this context, it will be critical to balance both economic and political factors in securing an agreement regarding the long-term commercial future of this strategically critical asset. CRU Consulting’s analysis highlights the potential challenges associated with meeting political demands for large 2034: base case, scale, front-loaded revenue streams, 2032: 50% current fiscal given the capital intensive nature of shareholder debt terms & financing forgiveness agreement the mine expansion plan and the scale and structure of state participation. Finding an acceptable pathway forward could be 2033: revised 2035: 35% interest margin of Corporate Income tremendously valuable for both 5% Tax shareholders in the long term, and signal a bright future for the industry Figure 3. Oyu Tolgoi first dividend date by fiscal and financing scenarios. at large.

14 October 2021 // global mining review

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16 October 2021 // global mining review

Iliass Elfali, OCP Group, Morocco, outlines how to maximise the impact of sustainable mining programmes.

ining is resource-intensive and can be environmentally challenging if not counteracted appropriately, so mining companies must (at a minimum) operate sustainably within a circular economy in order to protect the planet. To create truly lasting value, however, a company’s sustainability programme cannot be insular – it is by adopting a holistic view of operations and investing in the technology, systems, and knowledge required to solve global challenges that each country, community, individual, and organisation can benefit. The phosphate rock mining industry can serve as a good example of how maximising the impact of sustainable mining programmes can reap rewards much further afield. As phosphorus is an essential element for the production of fertilizers, food supplements and food additives, both the health of the planet and global food security are at stake. That is why OCP Group, the responsible custodian of the world’s largest resources of phosphorus, according to the United States Geological Survey (USGS), has developed and implemented an industrial plan that places resource preservation at the centre of its operations and applies sustainable thinking to all its activities across the whole phosphorus value chain. OCP also undertakes activities which may seem superfluous, but which will amplify the positive impact of its existing actions. This includes investing in processes to enrich low-phosphorus-content deposits, as well as combating climate change through mine reclamation, simultaneously creating value for local communities through afforestation. This article explores in-depth illustrations of practices which phosphate rock mining companies – and the wider industry – could consider as ways to maximise the impact of their sustainable mining initiatives.

global mining review // October 2021

Recovery of low-phosphorus-content phosphate rock Resource preservation is important across the whole mining industry for the longevity of non-renewable minerals in a time of increasing demand. Companies should therefore be looking for ways to sustainably grow their existing deposits, whilst minimising their impact on the environment. Despite the USGS estimating that the world has many centuries of phosphorus resources left at current production rates, and Morocco being blessed with significant resources of high-phosphorus-content phosphate rock, OCP has developed an adapted reverse

Figure 1. The Beni Amir Washing Plant in Khouribga, part of the three-step beneficiation process to recover low-phosphorus-content phosphate rock.

flotation process to help the company maximise the recovery of low-phosphorus-content phosphate rock during the extraction phase. Beneficiation is a three-step process involving washing, flotation, and decantation. The phosphate rock is first measured and separated, with rock measuring more than 2.5 mm sent to the waste rock deposit. In the second step, the washed and sized rock, measuring between 0.125 mm and 2.5 mm (considered to be the final product), is stored. Rock measuring less than 0.04 mm is sent to the decantation basin, and rock measuring between 0.04 mm and 0.125 mm is sent to the flotation units for further treatment. Here, it undergoes attrition, desliming, ore conditioning and finally OCP's streamlined reverse flotation process, whereby flotation reagents are added to a single conditioner, enabling the recovery of both the carbonates and silicates (the floated product) at the same time. The non-floated product consists of the concentrated phosphate rock, and the floated product is sent to the decantation plant to join the rock measuring less than 0.04 mm, where both are mixed with anionic flocculants to increase the rock density and accelerate the decantation process. Water is then recovered from the thickeners for reuse in the washing units, as well as the remaining water recovered from the settling zones of the fine flocculated particles. OCP’s Youssoufia and Khouribga mines already benefit from beneficiation, and it is also being implemented at the Boucraa and Benguerir sites. As a result, 33% of Moroccan phosphate rock deposits considered to have very low phosphorus content have become economically viable and exploitable. As phosphorus provides a quarter of all the nutrients that plants need for their growth, and higher crop yields can also help prevent deforestation across the globe, this is vital for ongoing food security and the health of the planet for centuries to come.

Mine reclamation and rehabilitation

Figure 2. An argan tree being planted at a rehabilitated mine in Khouribga to provide a new source of income and opportunity for the local community.

18 October 2021 // global mining review

Local communities impacted by the presence of mining activities should be able to benefit from the operations and lead meaningful economic lives. Creating employment opportunities and investing in education and training is one means of giving back, but there are additional ways to create value for local residents. For example, OCP endeavours to leave mined areas more fertile than they were found, by recovering the soil through reclamation and afforestation activities. With an objective of reclaiming two times what is extracted every year, and 4.5 million trees planted and over 5000 ha. of land rehabilitated to date, this process is leading to major economic and social benefits for the local communities. At the beginning of OCP’s mining operations, the topsoil is removed, collected and stored, preserving its properties. Once mining operations are complete, OCP restores the topsoil and improves its quality by adding ameliorants before planting new tree species. One of the soil amendments tested is biochar – a charcoal rich in carbon, peat moss, compost and byproducts of OCP’s operations, such as phosphogypsum, which results from processing phosphate into phosphoric acid. As a result, the soil’s structure, water retention and microflora are all improved, and the amendments also provide stable carbon for the soil and prevent the leeching of nutrients.

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Reclamation has been used at OCP’s Khouribga mine to plant argan trees, a rare species valued highly worldwide, providing a new source of income and opportunity for the local community. The afforestation of arid and semi-arid former mining sites can also contribute to carbon capture in regions of the world that are not particularly fertile, by creating a carbon dioxide sink. It is not an easy process, which is why the company is investing in further developing its expertise in rehabilitating such marginal lands, identifying species which will be high-growth and high-value-add for the region, optimised irrigation techniques and ways to support orphan crops, which are those not sold internationally but vitally important for local diets.

Preserving water and sharing solutions The mining industry is a major user of water and reducing total water consumption requires an overhaul of operations and research and development (R&D) to devise new and innovative solutions. Investing in research and collaborating to share successes can not only help companies to become more water efficient, but also benefit communities across the world. Water is a precious resource across the globe, but particularly so in Morocco as a country that faces increasing water challenges. Recognising this wider problem, OCP has committed to preserve water resources during its operations

Figure 3. The desalination plant at Jorf Lasfar, part of OCP’s Water Program to help the group become more water efficient.

Figure 4. The Green Energy Park in Benguerir, developed jointly with IRESEN to help OCP achieve its ambitious clean energy goals.

20 October 2021 // global mining review

– where it currently consumes 33% of its water during the mining process – and to use alternative and non-conventional sources, such as urban treated wastewater and desalinated water. Currently, 30% of the group’s water needs are covered by non-conventional water. Equally, 80% of the water used in the phosphate enrichment process is recycled for use in its operations. OCP’s targets are to reduce total water consumption by 15% by 2024, and to supply 100% of its water needs from non-conventional sources by 2030. One of OCP’s key developments is the slurry pipeline, which enables the company to bypass intermediary processing stages, such as dehydration of the phosphate rock at the mining operations and re-watering at processing sites. By transporting washed phosphate rock as pulp directly to the main processing platform, the pipeline saves up to 3 million m3/y of water at its full capacity. This is a very energy efficient solution, which utilises the difference in elevation between the mining and processing sites. When it comes to non-conventional alternatives, OCP is unique in the phosphate rock mining industry for using wastewater treatment with activated sludge technology to provide over 10 million m3/y of reusable water, primarily for industrial use. The wastewater undergoes three levels of treatment: Pretreatment, including screening – a process to remove oils and sand and primary sedimentation. Secondary treatment, which encourages bacteria to grow with a controlled supply of oxygen. Tertiary treatment, involving microfiltration to eliminate residual dirt and suspended solids, granular activated carbon filtration to remove organics and produce a high-quality effluent, and finally disinfection to kill bacteria, viruses and other potential pathogens, before the water is sent to OCP’s mines. The treatment plants also use renewable energy, as the sludge generated by the treatment produces biogas when processed, the recovery of which covers over 30% of the treatment plants’ electrical and thermal energy requirements. In addition, over 25 million m3/y of seawater is desalinated for the company’s industrial use through seawater reverse osmosis (SWRO) technology, which uses clean energy. Taking the constraints of seawater quality variation on the costal intake into account, the plant has been designed with an advanced pretreatment unit (which involves dissolved air flotation and ultrafiltration through membranes 0.03 microns thick), in order to ensure a high pretreated water quality and maximum availability. The water is then re-mineralised and distributed. As well as the on-site effluent treatment, the brine generated by the plant is diluted into the pumped cooling water and then reused in the hub’s processing units. Whilst this is all part of OCP’s Water Program, designed to help the group transform its processes, these solutions are transferrable. As a result, OCP participates in Morocco’s ministerial water committee responsible for defining the 2050 ‘National Water Plan’ and the Moroccan Coalition for Water (COALMA), a non-profit association and member of the World Water Council, which aims to strengthen the exchanges between the public and private sectors when it comes to the

management of water resources. OCP has also installed 35 000 m (linear) of water pipe in Fkih Bensaleh and at two treatment stations to provide 30 000 individuals in Morocco with water from OCP.

Carbon-free and efficient energy use through R&D Much like water consumption, the mining industry is a major user of energy, so meeting needs via clean energy and becoming carbon neutral are hugely important tasks. To truly go above and beyond, companies can also look for ways in which to invest in R&D, which will be positive for communities that may suffer from limited access to vital resources. For example, OCP has set ambitious energy goals, committing to meet all its electricity needs through clean energy by 2028 via wind, solar and cogeneration production, and achieve carbon neutrality by 2040. This is a significant undertaking, distinctive in the phosphate rock mining industry, and one which OCP has been investing in heavily since 2013. Currently, three of OCP’s mines – Benguerir, Youssoufia, and Boucraa – are supplied with almost 100% wind energy, whilst the Khouribga mine is supplied with 37%. Overall, 89% of OCP’s needs are met by clean energy. Diversifying OCP’s energy mix is being led in parallel with a wider Energy Efficiency Program, which also identifies optimisation opportunities that may provide benefits for communities around the world. Morocco is fortunate to have sunshine, which is why OCP is currently investing in solar energy studies and pursuing solar power patents. In conjunction with the Institut de Recherche en Energie Solaire et Energies Nouvelles (IRESEN), and with the support of the Moroccan Ministry of Energy, Mines, Water and Environment, OCP established the Green Energy Park (GEP) to develop new green energy solutions. Currently, OCP and the GEP are collaborating on the study and installation of two solar desalination systems for brackish water at Boucraa, which could present an alternative solution to cope with water stress in landlocked regions that have brackish underground water. Sharing the results of this study could have much wider global implications with industrial, agricultural, and domestic applications. The group is also planning to intertwine energy efficiency and mine rehabilitation efforts by utilising former mined land for solar farms.

Actions for mining companies OCP’s transition from a miner to a successful innovator with new models for fertilizers, solar power, water preservation, and more is a clear example of how a company’s commitment to maximising the positive impact of its activities can provide lasting value both for the organisation and to a wider extent. Whilst companies in the industry are looking at ways to implement sustainable activities to reduce their environmental footprint, they should also study the broader role they could play, whether that is through collaboration, sharing solutions, looking after local communities, or investing in vital R&D.

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22 October 2021 // global mining review

et-zero emission initiatives, lower carbon footprint action plans, and a push toward sustainability have become a necessity with regards to the future growth of the global mining industry. A strong focus on actioning these initiatives will be a key determining factor for the new competitive leaders of the industry, and the success of reaching its emissions goals. In the July/August issue of Global Mining Review, Philippe Baudry of RPMGlobal, said that sustainability for mines is now viewed as “an ethical norm and an important part of the businesses’ social license to operate, the challenge for the mining industry to move to a greener future is an opportunity to reset the industry’s reputation within the broader public.” This could also be extended to manufacturers and equipment suppliers, as they will ultimately determine the progress of these initiatives by developing efficient and sustainable technologies and tools to accomplish the work. This is an opportunity for manufacturers to step up their focus on efficient and green technologies, and, ultimately, solutions. Mincon is helping change the way manufacturers and mines think about these solutions through ‘integrated systems’.

global mining review // October 2021

What is an integrated system? The term developed from a reference to Mincon’s Drill Mast Attachments – drilling systems that integrate with a customer’s existing fleet of carrier machines, typically skid steers or excavators. It has since become a far more meaningful term for Mincon, as it has focused on developing new methods and processes within its own organisation, steering itself towards efficiency and sustainability. These methods and internal processes have become ‘integrated systems’ in terms of how they think and how they drive the development of

their products. As this grew, Mincon found that its customers also saw value in their focus on efficiency and sustainability, and began to adopt its ‘integrated systems’ thinking into how they made decisions on equipment solutions and service support contracts, recognising the importance of integrating the systems and processes that drive efficiency within their companies. The adoption of such thinking by mine operations and purchasing managers, as well as manufacturers within the mining industry, may well determine the speed at which sustainability goals are reached, and help to drive the development of new technologies sooner. This is where the loop is closed. Mines have the power to bring about this thinking within manufacturers.

Where it starts

Figure 1. Mining through hard rock requires power; efficiency is key to lowering emissions.

Integrating efficiency into solutions Mincon Group plc’s pursuit for more efficient drilling solutions is one of the key advantages for TDC-based supply and service contracts, where it continuously refines designs for its rigs, drill masts, down-the-hole (DTH), reverse circulation, and rotary drilling tools. Its determination for efficiency also extends to its customers as the company looks to build partnerships where it works closely to help the customers businesses grow and develop into effective and efficient challengers in their respective markets. It is a substantial undertaking and the company’s Technology Steering Group is continually working toward a stronger, greener future for the industry. The group comprises its most experienced and dedicated people across a variety of disciplines, from metallurgy and technical analysis, to product design and manufacturing. Mincon says this internal working group evaluates the latest materials technologies, drilling percussion concepts and manufacturing methods, in order to further develop both new and existing products. The company has also invested heavily in a dedicated research and development (R&D) facility. This introduces efficiency into its production, as the R&D facility can accommodate production of special parts for new products – reducing disruptions in the commercial production line. Mincon's R&D facility is the birthplace of a number of new technologies, including its hydraulic DTH system that is being commercialised in 2021.

24 October 2021 // global mining review

If mine operations make it a goal to support the growing and emerging manufacturers that focus heavily on efficiency and developing solutions for green initiatives, this could have a dramatic effect on the success of the industry’s goals for net-zero emissions by 2050, or even sooner. This effect has been clearly seen in the coffee industry, as consumers’ strong support of sustainable and ethically sourced coffee transformed supply chains and participation from growers. As consumers, mine operators and purchasing managers have the ability to drive change by supporting the manufacturers and suppliers that will help them develop sustainable and green efficiencies into their operations and equipment solutions now, and in years to come. Green-goal or efficiency focused partnerships are based on a united effort to gain feedback from every aspect of a mine’s operations, in order to build processes and solutions that contribute to the development of efficient and sustainable (economically viable/cost effective) solutions. This goes beyond the typical sale of a piece of equipment, and gets manufacturers more involved with the growth and development of innovative solutions (i.e. equipment, methods, and processes), in partnership with mines directly.

The total-drilling-cost model To increase overall project efficiency, many mines have actively pursued a new operating model where the equipment/service provider is bound by a service-level agreement to not only supply the equipment solutions, but also develop a continuous improvement plan to guarantee a specified level of productivity or face penalties. This total-drilling-cost (TDC) model, as an example, focuses on overall production rates and not just cost-per-metre drilled, which could remain the same for 50, 10 m-deep bores regardless of whether it takes one shift (or three) to complete them. Service providers entering into these TDC-based contracts are now evaluated on product life in addition to productivity over time – a more stringent performance requirement over cost-per-metre alone. An efficiency-based approach ultimately makes mines more successful in their operations and involves service providers and manufacturers more directly in their success, driving the development of new efficiencies. This is another proof-of-concept that shows the success of a mine’s operations requiring more than just equipment from a supplier. The TDC model has become an integrated system of efficiency for many mines.

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Building today’s solutions for the future Mincon Group plc’s pursuit of efficiency has now been embodied in its new Rock Drill range of products, which offer the drilling and mining industry a next step toward sustainable operations, by helping mines build efficient equipment

solutions into their green-action-plans. This is accomplished in several ways with the range of products, from the drill solutions options themselves down to the engineering and design methodologies used to develop them. The company’s unique approach could change the way manufacturers build equipment in the future.

The business-end of efficiency Drill Mast Attachments offer the business-end of the drilling rig without adding an additional diesel engine to the end user’s carbon footprint. These drilling solutions can be deployed quickly with lower manufacturing time, lower steel requirements, lower cost to the end user, and are easily integrated with existing or rented carrier machines, such as skid steers or excavators.

Efficient methodologies

Figure 2. Mining operations are expansive, integrated systems can significant reduce costs.

The engineering team that developed the Rock Drill range of products started out as drillers, and through this experience they developed a strong aversion to downtime from waiting for propriety parts or overly technical service requirements. This is where their unique approach has made a difference. The design methodology was to innovate simplicity into the product line. Simplicity meant that the drill rigs and drill mast attachments had to be built stronger for a longer service life. It also resulted in intuitive, easy-to-operate controls and minimal maintenance requirements from fewer wearing parts and less downtime. Instead of proprietary spare parts, reliable off-the-shelf components were used to reduce service downtime and lower maintenance costs and difficulty for end users. The results are drill solutions that last in operation well beyond standard industry service life, and that can be maintained cost effectively by the end user without having to depend on the manufacturer for service or support.

Developing future solutions

Figure 3. Efficient power can reduce drill size, cost, and lower maintenance requirements.

Figure 4. Innovations in technology drive drilling efficiencies, the SpiralFlush casing advancing system is a prime example of this.

26 October 2021 // global mining review

By extending the focus of their business into drilling rigs and mast attachment systems, Mincon has gained flexibility in their engineering and development processes. The company can now develop more efficient solutions across their product lines. Complete drilling systems that work cohesively as a single unit to offer more metres drilled per-litre of fuel, optimising drill unit functions for tooling technology efficiency.

Conclusion Mining has the foundation to build on, with examples of integrated systems working in the industry and others. The challenge for the mining industry to move to a green future is an opportunity for manufacturers, service suppliers, and mining operations to work together to push the boundaries of change and development as a team. When mining operations insist on this, it will drive manufacturers to develop the new methods, processes, and equipment solutions the industry needs to reach its sustainability goals. So what opportunities are there? Be the one who drives efficiency and the development of integrating more efficient systems. Start the conversation with manufacturers and service provides to see how they can help action new efficiencies. It is going to be the future of the mining industry. The leaders of that future will be those who start today.

David Evans, DSI Underground Asia Pacific, provides insight into the importance of the mechanics and mechanical response of ground support in underground hard-rock mining.

he ability for ground support elements to take the demands of sudden and severe service loads continues as an increasing requirement for geotechnical application within underground hard-rock mining. Large amounts of energy can suddenly release through the rock mass as stresses are redistributed and, at times, violent ground movement can occur. While the prevailing influences of geological stress fields may be mapped out, as well as local geotechnical considerations factored within mine design, there is an inherent degree of unpredictability in the way that stresses are released. Based upon the need to address such geotechnical demands, the mechanics of dynamic roof support remains an important area of continued study and research. While geotechnical design is the overarching discipline, the mechanics and mechanical

global mining review // October 2021

response of ground support elements are equally critical to understand and apply within this field.

Understanding mechanical energy Energy is, of course, a universal term applied across multiple scientific disciplines. Under a common definition, energy is simply the ability of an item to conduct work. As defined under international standards, the unit of measurement for energy is

Figure 1. Damage to underground workings from a rock burst event. Source: ACG/David Ortlepp.

the Joule – where one Joule is equal to the work conducted by one Newton of force acting over or through a distance of 1 m. Of course, multiple forms of energy exist: thermal, mechanical, electrical and chemical, to name a few examples. Energy will exchange and transform across interrelated systems – consider the transformation of energy within an internal combustion engine, from chemical and thermal to mechanical energy. In this sense, energy can be stored, released, and transformed (while noting that losses or inefficiencies will always occur under such transitions and transformations between systems). However, amidst this greater complexity, the unit of measurement for energy is held constant across all systems, under the simple definition of the Joule. Focusing specifically on the context of energy within a mechanical system, a basic scenario is the tensile testing of a steel specimen. Tensile testing is a common method that is used to determine the mechanical properties of different steel grades and to also assess the influence of geometric dimensions, as well as the elastic and plastic response through to failure. During testing, typically conducted under a constant rate of displacement or strain, tensile load is placed onto the steel sample. It will begin to elongate and the relationship between force and displacement is observed. This relationship is typically mapped out in a two-axis chart and, where all other test variables are held constant, it provides a relatively reliable outcome, particularly with standardised test specimens. Once the relationship between force and displacement has been charted, the energy of deformation taken by the test piece can be determined. Mathematically, energy is calculated as the integral of force with respect to displacement, as the system moves from a first position to a second position. From an easier perspective, this equates to the calculated area under the force vs displacement curve. Think again of the definition of the Joule – put simply, a force acting over a distance. When testing, work is cumulatively conducted as force acts through displacement – measured as two related variables – and the total work is the accumulation of the area under the test curve, measured in Joules. When measuring the dynamic energy of a roof bolt element, these same principles are applied, using force and displacement to calculate an energy value. However, the test method is greatly scaled up, to take the dimensions of the roof bolt element that is being assessed. Further to this, the rate of deformation of the test piece is significantly faster, by orders of magnitude, to simulate the speed of an underground rock burst event. Under more standard laboratory test procedures, loading is applied to a test piece over the order of minutes. However, in a dynamic test, the shock load is initiated in the order of 10 msec. and below. Again, the concept of energy transfer between systems applies – from stored energy within the rock mass to motion, and finally mechanical energy and work conducted by the ground support elements as they respond to the onset of load.

The growth of global research

Figure 2. Typical laboratory tensile test arrangement.

28 October 2021 // global mining review

The dynamic testing of ground support elements is a highly specialised field requiring the development of large scale test facilities, well beyond the capabilities of standard mechanical test laboratories. Research into the dynamic performance of ground support elements has been a growing field of work, particularly over the last 20 years. At the forefront of this effort,

a number of more pre-eminent facilities have been established in association with industry and academic institutes – of particular note are WASM (Australia), CANMET (Canada), and the Central Mining Institute (Poland). In addition to these more recognised institutes, other test facilities have evolved more recently, typically in association with operators and suppliers within the underground hard-rock industry. While this global growth in research capability is certainly of note, it is not within the intent or scope of this brief article to provide an overview of these facilities in detail.

Energy is a summary indicator only Figure 3. A quasi-static test curve (data from DSI Underground).

While calculated energy provides an overall summary indicator of dynamic performance, it is important to understand the actual load bearing response of the dynamic roof bolt element – that is, assessing the detail and shape of the test curve. The variables of force and displacement remain significant: peak loads must be known, as well as the total displacement until rupture or final failure of the test element. Also of importance is the initial rate of loading – that is, how quickly the loads are generated as displacement occurs. A stiff load bearing response indicates that the element takes load and begins to contain energy very early in the dynamic event, shown as a steeper gradient on the test curve. A soft load bearing response indicates that the element is much slower to take initial load, but may provide greater elongation properties. Ideally, a dynamic system will offer both properties – a stiff initial load response, followed by good elongation values at a sustained load.

Typical performance values

Figure 4. The WASM dynamic test facility.

The selection and application of ground support elements, based on known performance parameters, is foundational within the field of geotechnical design. For underground hard-rock applications, primary bolting elements that bear peak loads within the range of 200 – 300 kN are commonly selected. In line with this load response, the desired dynamic displacement values are typically of the order of 150 – 200 mm. Within these ranges, as an approximation, corresponding energy values will be in the order of 30 kJ, up to more significant values exceeding 50 kJ. Displacements of 300 – 400 mm have been suggested at an extreme limit, although, at this level, surface support damage becomes a far more significant concern. Note that 20 kJ is commonly considered as the minimum recommended energy value for classification as a dynamic bolt. Of course, it is fully incumbent upon the geotechnical practitioner to determine the required ground support elements for their specific application – and all parameters should be considered, including: energy, force, and displacement. The final design of a dynamic ground support element should also meet the requirements of standard bolting applications.

Anchoring or slipping: generating the optimal response

Figure 5. A dynamic test curve (data from DSI Underground).

30 October 2021 // global mining review

Within the history of development, numerous dynamic bolt designs have emerged in an effort to best exploit the parameters of force and displacement. A primary consideration is the nature of anchoring within the ground at both the top and bottom of the bolt – and how anchoring ultimately relates to energy performance. The anchoring media is typically a polymeric resin or a cementitious grout – but this may be absent

where a mechanical expansion element is employed within the design to anchor the bolt. The anchoring method is critical to dynamic performance, and must be capable of transferring loads into the ground that exceed the mechanical strength of the bolt element. Essentially, the anchoring media must do the same work as the bolt in transmitting energy. The installed quality of the anchoring media is equally of significance and must be well mixed, cured, bonded, and repeatably installed for underground quality assurance. If the upper and lower bolt ends are firmly anchored to the ground, the bolt element will be immediately and directly loaded when ground movement occurs. In this instance, a stiff load response occurs and the bolt element subsequently performs mechanically. Other approaches have been to permit the bolt to partially slip through an anchoring media, at reduced mechanical loads, but seeking to achieve greater displacement values. In this instance, a softer response occurs and the bolting element is not loaded to its full mechanical performance. While displacement values may be increased, subsequent lower forces may detract from the total energy value. Where the steel element is firmly anchored and employed to do the work under mechanical deformation, the load bearing response typically has greater repeatability. However, where the anchoring media is partially employed to provide the dynamic response under slipping with the steel element, this introduces a further variable that influences performance results. An additional concern with slipping modes is the progressive loss of the overall bolting horizon within the geotechnical application, particularly where fault lines and wedged blocks may exist. A line of argument is to firmly anchor the bolt and let the steel element do the work.

industry, yet much remains to explore. A large number of variables reside within this experimental work – test methods, material grades, geometric sections, bolt class and design, debonding design, anchoring media, primary and secondary support needs, as well as surface support considerations – and all of these variables cast an influence over decision making within geotechnical practice. This complexity is further compounded by steel grade suitability and supply availability, under domestic and global considerations. When viewed within this broader context, but also understood at a more detailed level, it becomes clear that support for dynamic test work remains an imperative, to continue to build upon this body of knowledge that is increasingly essential for the safety and performance of the underground hard-rock industry.

Figure 6. The gradient indicates load bearing and energy response.

Deformation rates: Do mechanical properties actually vary? As research has progressed, it has become evident that the rate of deformation and the speed of the test event will alter the shape of the mechanical test curve and the overall energy response of the steel element. As described earlier, the formal mechanical properties of steel grades are determined under heavily standardised laboratory procedures, using dimensionally regulated steel samples and conducted at low loading rates. In vast contrast to this, dynamic loading events occur within the order of milliseconds – and the resultant mechanical properties differ from those of standardised test outcomes. For directly equivalent specimens, even for the same steel grade, the same section type and the same gauge length, high speed dynamic testing will repeatably witness a different energy outcome. Subsequently, for geotechnical designs within dynamic conditions, it is important to consider both the standardised mechanical properties derived from ‘quasi static’ laboratory tests, as well as the dynamic load bearing properties derived from high speed tests. It should be noted that the relationships within this aspect of the science are not perfectly known.

Figure 7. A cross sectioned sample of a resin anchored element following dynamic testing.

Continued research remains an imperative A significant history of productive research exists within the field of dynamic ground support and this is well attested across the

Figure 8. Overlayed test curves for two bolt elements of identical material type and free-length.

global mining review // October 2021

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Alan Bailes, Weber Mining & Tunnelling S.A.S, Australia, discusses recent advances in safety, using remote seals for the confinement of cavities in an Australian coal mine as an example.

ine fires are fought indirectly when access to the fire zone is impossible, as a result of: safety restrictions, blocked underground access, a limited supply of available firefighting materials, or a fire zone that is too large for available underground personnel. This approach involves sealing the mine or construction area off, using in-mine temporary seals as ventilation-control structures to isolate the fire area. These in-mine seals can be constructed from within the mine, or remotely through boreholes. Sealing the mine or isolating the fire or heating event area is designed to control or extinguish the fire by reducing the oxygen concentration in the mine atmosphere to a level that will not support combustion.

Rocsil® LS1 foam has a history of being used in underground coal mines around the world. The product is commonly used to provide confinement in open void areas (cavities) above longwall shields and roadways, improving safety for coal mine workers. The foam is an effective solution in recovering collapsed roadways and enabling longwalls to retreat more efficiently when experiencing poor mining conditions. For remote sealing, specially designed equipment effectively delivers the foam product into mine roadways or shafts without the need for labour to be deployed underground, or when exclusion zones are in place on the surface. Once the critical mine event is under control,

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the plug can be easily removed to facilitate safe re-entry into the mine. The remote Rocsil LS1 foam plug seal system is a current industry benchmark available to deal with underground explosions, heating, or fire events in a safe, cost-effective, and rapid way. Rocsil is pumped from the surface until it expands to the roof and ribs forming an airtight barrier (Figure 1). This article reviews the use of remote seals to control fires and heating events as current best practice in Australian coal mining, describing the current industry benchmark of foam seals. Rocsil HD20, a recent innovation delivering overpressure blast remote seals, is discussed, with case studies provided.

The benefits of remote seals The remote seals system provides a major advantage in removing mine workers from exposure to a high-risk situation. The remote sealing system allows for a Rocsil foam plug to be pumped from a place of safety, sealing the mine entry or roadway in the event of an emergency. These foam plugs can be installed to the specification required by the mine, now rated up to 50 psi. In the Australian coal mining industry, Weber Mining works with its selected applicator; Wilson Mining Services. Wilson specialises in engineering the delivery of resin injection systems and has a wealth of experience in using Rocsil to create remote seals. The companies also work together to ensure stringent quality controls ensure the foam conforms with Weber specifications. Ratio and density are maintained by advanced ratio/flow monitors and Wilson Mining’s team of chemical applicators. QC testing reports of the sampled product are then verified by the engineer, along with the camera footage,

to analyse and provide an ‘as built’ certificate for the rated seals. A Rocsil Foam Maxi standard pump with bulk IBC product packaging is used. This system improves pumping rates, reduces manual handling and has the added benefit of being a closed-circuit system, which reduces the likelihood of mine workers being exposed to chemicals. Using this system, product, equipment, and crews can quickly be mobilised to site. Preventative applications provide the most favourable option for clients with current Australian mining regulations requiring in-situ provision of remote sealing of mine operations. Using the Wilson system, this can be achieved by placing a mixing gun and two flexible hoses at an accessible point in the roof of selected roadways. The product can be applied from surface to seam using a high-volume delivery pump attached to the pre-installed hoses. The Rocsil product pods are connected in the event of a potential incident from a safe location. The Wilson Mining pre-installed remote emergency sealing system provides a significant time reduction in the event of a mine fire or explosion, allowing remote Rocsil Foam plug seals to be installed in pre-determined best suited locations, along with gas monitoring systems in fixed positions. The system is designed to mine site requirements and has been installed in many Australian coal mines as part of their emergency sealing plans. Advantages of the pre-installed remote Rocsil seal system include: Mine sealing plan designed and engineered for optimal outcome. Pre-determined safe installation locations. 70% faster installation than reactive drill and remote sealing methods. Pre-installed gas monitoring on inbye side of plug location. Hosing and remote heads pre-run and fixed in-situ. Rocsil quantities known and understood. Suitable for highwall portals entry, conveyor drifts, materials drifts, and shafts. Low cost solution for guaranteed sealing.

Rated surface to seam vent plugs

Figure 1. Diagram of a typical Rocsil surface to seam remote seal.

Rocsil LS1 is a proven solution to create ventilation plugs of various sizes in underground coal mines – preventing oxygen ingress into the goaf areas of a longwall, gases being released from the goaf, or installation of plug seals in roadways to prevent injury or damage from an overpressure event. It is an efficient product capable of expansion rates up to 35 times its original volume. Rocsil Foam LS1 has a fast reaction and curing time (1 – 1.5 minutes) and obtains an average density of 45 kg/m3. Engineering test work was performed on Rocsil Foam LS1 to design a mine rated plug seal which could be installed via the surface to seam (S2S) method. A maximum of a 30 psi rated plug seal was achieved.

Demand for a higher strength plug seal Figure 2. New South Wales case study application diagram.

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The Rocsil HD20 product was developed by Weber Mining in conjunction with Wilson Mining as a response to demand for

a higher strength plug seal. These high strength mine seals are typically utilised to protect against overpressure (blast) events in underground mines The Rocsil HD20 product was developed specifically to achieve a mine plug seal rated to a 50 psi overpressure loading. Following the product development and confirmation using FME analysis, the company was able to engineer a design to obtain a 50 psi rated plug seal using Rocsil HD20. The product gives a 60% increase in overpressure loading, compared to the 30 psi achieved previously including a safety factor of 1.1. Some key Rocsil HD20 product properties include: Slower set time of 2.5 minutes, allowing for increased permeation. Density of the foam increased to an average 60.6 kg/m3. Increased compressive strength to 97.3 kPa at 10% deformation. Using Rocsil HD20 often allows design parameters to be greatly reduced, saving infrastructure costs and negating the requirement for additional drilling to install boreholes.

Method The injection was executed via a 330 m borehole with a drill rig lowering the remote head and hoses to provide a goaf plug to seal off the area. The first 400 m3 of product pumped was Rocsil HD20. In order to ensure maximum penetration through the goaf floor, loose rock fill followed with 450 m3 of standard Rocsil LS1 to fill the void above and to close off the area path (Figure 3).

Results The results included the following: Continuous injection of 850 m3 was pumped in under 22 hours from start to finish. 44 250 kg of Rocsil applied in total: 24 000 kg of Rocsil HD20 and 20 250 kg of Rocsil LS1. The customer was satisfied with the injection outcome and the resulting seal (Figure 4).

Case study: Australian mine Australian mine S2S injection of underground roadway in an emergency situation.

Case study: New South Wales S2S injection in a longwall goaf behind a seal area required control of oxygen egressing into the area of concern.

Situation An Australian mine required an emergency remote Rocsil S2S application after a mine explosion event.

Situation An Australian mine required support with controlling oxygen egress through the rib around an installed seal in a goaf area (Figure 2).

Method Chemical applicators, equipment, and Rocsil HD20 product was deployed to the site within hours of the event. Engineering on the final seal installation of the roadways was developed with and agreed to by the mine and the regulator. A S2S injection was executed via a 380 m deep x 12 in. borehole, with a drill rig lowering the remote head into position in the roadways. The average plug size was 300 m3 of Rocsil HD20. 11 plugs were pumped to seal off all roadways into the longwall. The injection was guided by a camera, from adjustment holes drilled for the camera view. Over a number of weeks, the plugs were installed under direction from the mine and the regulator.

Results Figure 3. New South Wales case study, topside operations.

All plugs were installed successfully with approximately 190 000 kgs of Rocsil HD20 pumped to seal off the longwall. 50 psi plugs were achieved. Mine personnel have since worked through a full re-entry plan and are now back underground working on a start-up plan. The customer is satisfied with the injection outcome and the quick response time. The application of Rocsil and the latest innovation of Rocsil HD20 in creating remote seals represented a significant advance in mine safety.

References 1.

Figure 4. The end of the New South Wales project.

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ALSTON, N., SCHMITTER, J. L., ALCOTT, A., and FRY, R., ‘Recent case studies using the remote ROCSIL® FOAM plug system’, in AZIZ, N. and KININMONTH, B. (eds.), Proceedings of the 2020 Coal Operators' Conference, Mining Engineering, University of Wollongong, (2020). TREVITS, M.A. and MCCARTNEY, C., ‘Use of Rocsil® foam to remotely construct mine seals National Institute for Occupational Safety and Health (NIOSH)’, (2008).

Figure 1. Longwall shearer with seal-powered roof support legs.

Chris Edge, Hallite Seals International, and Geoff McKenna, Komatsu Mining Corporation, discuss the importance of seals in mining roof supports.

eals play a critical role in the functioning of the hydraulic cylinders that power mining roof supports. Their use in modern mining equipment means that roof supports can shoulder loads approaching 1800 t. To put this into perspective, imagine the combined weight of more than four jumbo jets stacked on top of each other. Each seal’s profile, design, and choice of materials contribute to mine safety, efficiency, and productivity. When miners face complex operating requirements, the sealing components in the equipment used to do the work must be equal to the task. Hallite Seals International and Komatsu Mining Corporation embarked on a collaborative partnership almost 50 years ago that continues to impact the industry today. The partnership started when Hallite provided Komatsu with a uniquely

innovative solution for their hydraulic cylinder hardware. Both companies have grown internationally and developed detailed portfolios of solutions for the mining industry throughout the years, and the partnership has remained strong. It is a relationship fuelled by sealing product innovation and a mutual commitment to solid equipment performance and customer satisfaction.

Seal-powered legs This article will focus on powered longwall mining operations (Figure 1). Specifically, it will discuss the location of critical seals and bearings, their function, and how an industry-leading engineering team is collaborating to continuously improve these products. Four seal profiles characterise the products and materials

global mining review // October 2021

best suited for longwall mining – piston seals, rod seals, static seals, and wipers (Figure 2). The 730 and 740 piston seals represent the inner and outer stage of the hydraulic cylinder leg. Both are assembled with proprietary bearings on each side. A combination of bearing rings of various widths are used depending on the application. The 730 is a double-acting piston seal in a four-part assembly designed for high shock loads and pressures (Figure 3), and the 740 is quite similar, but with a different back up arrangement. The 82 static seal and the 652 rod seal fit in the gland. Static seals function against mating surfaces with no relative motion between each other. Rod seals handle high-pressure, and they are designed with a polyurethane shell, an O-ring energiser, and a polyacetal anti-extrusion ring. Finally, the 842 wiper is installed at the end of the cylinder and supported by gland bearings. The wiper prevents the ingress of foreign particles and moisture into the cylinder. The 842 wiper is manufactured in Hythane® 371 high-performance polyurethane, and is proven for low compression set characteristics, wear and abrasion resistance, and fluid compatibility. The wiper is also known for a protective flap that directs both dirt and water away from the outside diameter, in order to prevent the water and slurry trap common with conventional wipers.

these changes. By the late 1990s, three significant seal issues had emerged that required the development of the advanced sealing solutions in use today. First, operators reported frayed bearing rings following service. Fraying caused metal-to-metal contact, and the fibres fell off the bearings and into the filters, creating valve problems. Second, as cylinders increased in size, extrusion gaps increased, resulting in piston seal damage. Third, wiper seals were ejected on advancing rams. Hydraulic fluid also changed over time from a mineral-based to synthetic solution, consisting of 2% oil to 98 parts water. Water-dominant fluids are much more aggressive than the fluids used previously, accelerating the ageing of the material. The three issues addressed above caused the following changes to come about:

Bearing rings The seal development teams worked together to innovate a solution for the bearing issues, and in 2000, the proprietary TGA material was introduced. Rigorous testing, up to 90 000 cycles, or the equivalent of 10 years of life in a mine, revealed that the bearings possessed yield properties capable of coping with higher pressure and side loads. There have been no reported bearing ring failures since the introduction of the TGA material, and on re-builds, the TGA presents little to no wear.

Continued improvements The aforementioned setup is what characterised a mine in Australia. Over the years, with working pressures and extreme side loads gradually increasing, the maximum diameter for roof support legs adapted to suit

Piston seals The piston seals featured a profile focused on reducing stress to solve failures. Performance improved from 11 000 – 30 000 cycles – the equivalent of 1 – 3 years of life in a mine. However, the seal development team knew they could do more, so continued to design a 60 000 cycle solution. This achievement required redesigned back-up rings tested up to 60 000 cycles, then up to 90 000, and finally up to 100 000 cycles – where mechanical failure with the seal package outlasted the mechanical parts. The anti-extrusion rings were coloured yellow to help the customer identify the new seals.

Wiper seals

Figure 1. Seals and bearing ring types used in roof support leg cylinders. Typical gland and piston sealing configuration.

Figure 2. 730 piston seal with support rings.

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Extreme pressures forced the wipers out of the hydraulic cylinder assembly. The development team initially thought that adding more material to the seal would address the issue, but that did not work. They also believed that increasing the fill of the seal would better capture it in the gland wiper seal groove. This increased the surface contact and caused a rocking motion during cycling that forced the seal out of this groove. The team eventually solved the issue by reducing the material in the heel, which decreased the contact on the rod. This solution removed the rocking motion, and a stiffer material provided a sharper stronger lip. The material created more of a scraper with the wiper lip, and the new seal was coloured green for identification.

Case study: Australian coal mine Because of its size and challenging load conditions, a mine in Austrailia required roof supports rated up to 1750 t. When the mining equipment was first delivered in 2007, this load bearing requirement was significantly higher than any other Komatsu-powered roof support in operation. The specification called for a cylinder leg design with a minimum 480 mm bore. At the time, this presented a significant leap in technology for the companies in both the physical size of the leg cylinders and the test life expectancy of a minimum 90 000 cycles. It was the largest longwall mining leg cylinder bore with the longest test life expectancy produced for its time. Since the team had established best design practices for piston, gland, wiper and bearing ring materials, this historical programme allowed them to demonstrate the products’ performance in an unprecedented field application. The sealing package was successfully installed, the products performed as tested, and they continue to be used on site today.

Forward momentum The companies are now developing alternative seals for bespoke design hydraulic spool valves used in powered roof support applications. Prototype samples of the initial design will be evaluated and tested at the Komatsu facility in Manchester, UK. As the specialist provider of seals used in Komatsu longwall hydraulic cylinders and various custom-built hydraulic control valves, the team at Hallite are focused on continuous improvements in performance

and reliability. Testing rigs at both the seal manufacturer’s facilities and its equipment manufacturing partner’s facilities ensure thorough checks and evaluation of all roof support seal components before they are put into service. The seals range from less than 10 mm dia. up to large piston seals of 480 mm dia. All are compatible with water-based fluids and a working pressure of 350 bar (5000 psi) up to 1000 bar (15 000 psi). The underground longwall mining environment aggressively impacts all equipment, where unplanned downtime can be detrimental, so product reliability is essential to managing costs.

Conclusion Improvements in the quality of seals used in hydraulic cylinders and valves, such as those used in armoured face conveyors and shearer ranging arms, are advancing. For example, in order to reduce high shock loads in a shearer ranging arm’s cylinders, Komatsu and Hallite engineers worked together to design a solution. The result was a seal package applied across the range that increased the ranging arm life and reliability. As Komatsu expands its footprint in China for reliable cylinder and valve designs fitted with reliable seals, the partnership with Hallite will continue to play an essential role in providing established powered roof support equipment suppliers with the solutions they require. When collaborations, such as the one between Hallite and Komatsu, come together, the findings benefit not only customers of the companies, but promote a better understanding of industry challenges.

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40 October 2021 // global mining review

Claude Sharma, HARD-LINE, Canada, considers how automation is helping mines optimise their operations.

here are more ways now than ever before to extract valuable minerals from surface and underground mining operations, and that trend will rise even further as the digital transformation continues to become more sophisticated. While each producer does not follow the same mold, it is natural that more mines are integrating autonomous and semi-autonomous solutions. The switch to autonomous and/or a gradual incorporation of modern technology could be tricky, trying and expensive, but is nevertheless inevitable. Advancements in this field are meant to meet operational demands at accelerated rates, meaning higher efficiencies and profits. What must be considered is how many of these new developments promote a much higher standard in safety – protecting workers first, as well as operational assets. HARD-LINE has identified this problem, and its modern and expanding fleet of innovation caters to the changing direction of the autonomous mining ecosystem.

Varying options A system with automated functions implemented underground at one site could be a perfect fit, depending on the plans of that operation. However, all sites are different and, therefore, so are the needs. Some operations have gone fully (or mostly) autonomous, others are in the blended stages of old and new technology, and then there are those that have yet to adapt; however, an upgrade might not always be necessary. HARD-LINE’s TeleOp packages can match the requirements of any operation, regardless of project type. In the simplest terms, TeleOp allows the tele-remote operation of all types of heavy machinery from a control station in a safe area on the surface or underground, regardless of distance.

Early development: Kirkland Lake Gold, Macassa Mine, Canada Operating in Canada and Australia, Kirkland Lake Gold Ltd is a senior gold producer with a target production of 1.3 – 1.4 million oz in 2021. This year, the Macassa Mine, located in Kirkland Lake, Ontario, enhanced its TeleOp base system (two control stations above ground) by adding TeleOp Assist, which equips vehicles with 3D LiDAR technology to help keep machines from colliding into walls (Figure 1). The TeleOp system allows for tele-remote operations during shift changes, taking advantage of downtime between blast cycles which increases profitability and production, something that was noted by the mine’s underground general electrical foreman. With TeleOp Assist adding intelligent steering assistance and collision detection modes to the application, vehicles and assets experience less damage while production is maintained or increased. Assist has other time-saving advantages – such as its cruise control feature that allows operators to set a fixed throttle position to help reduce operator fatigue – which aid better prioritisation

of time critical operations, such as loading. Another benefit is the takeover command. When it is time for the operator to take full control, it can be done seamlessly as there is no need to stop, or even slow down, when transitioning between modes, whether it is TeleOp Assist or TeleOp Auto.

Taking it to the next level: Pucobre Copper mine, Chile Based in Chile, Pucobre specialises in the exploitation of medium-sized copper deposits. A recent partnership has seen an underground mine in Copiapó use semi-autonomous and assist technology from HARD-LINE for the first time (Figure 2). In this case, TeleOp Auto, a system that allows control of load, haul, dump units (LHDs), as well as trucks in the future, from a control room located outside the mine. TeleOp Assist was also implemented. A study during the original trial, using semi-autonomous LHD and assist technology, has helped Pucobre make the decision to implement a new design in the mine that will increase productivity. The TeleOp Auto tool facilitates safer operations, while optimising the mining process. This tele-remote application is also intended to be used on heavy machinery for drilling and haulage purposes.

Case study: Underground gold mine, USA At an underground gold mine in Nevada, US, HARD-LINE’s TeleOp Auto system was trialled on a haul truck. The purpose was to minimise operating costs and maximise efficiencies by implementing TeleOp Auto on machinery the mine already owns, and to bring additional value to an existing ramp design. The system would allow the truck to manoeuvre on the mine’s 4.5 km ramp during shift changes, while an operator above ground monitors the autonomous operation. A driverless vehicle was operated autonomously 4500 m up the ramp, from an underground area to the mine’s surface portal. The operator took control of the truck once it reached surface parking near the entrance. The application is a step towards an around-the-clock operation that is safe and efficient. The mine’s underground ramp was the ideal environment to apply this type of autonomous technology. It is the sole access to the underground working area and the primary pathway for transporting material. Moving material during downtimes proved beneficial as the mine typically losses up to two hours of potential production time each shift during shift changes and blast cycles. This method increased machine utilisation by up to 20% per day when used during downtimes.

Case study: Underground gold mine, Canada As mine sites explore new avenues of digital transformation, bundling and combining automation packages broadens the optimisation process in any mine.

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At a prolific mining district in Red Lake, Ontario, an underground gold mine experienced gains in productivity safely while using TeleOp Multi. The multi system allowed several vehicles and types to be controlled from one TeleOp station. For this project, the mine increased development rates with several operational improvements, including: multiple TeleOp control stations (remotely operated from the surface), six LHDs, a rock-breaker, and locomotive. The underground locomotive transports ore and waste on a dedicated tramming level. In this case, according to mine management, there were not nearly as many windows of downtime which improved

Figure 1. HARD-LINE technician installing 3D LiDAR technology on a load, haul, dump unit (LHD) for TeleOp Assist.

Figure 2. TeleOp Auto increases productivity at Pucobre mine in Chile.

productivity, including mucking rates, material handling rates, and even development and overall stope cycle rates, because the material can move much faster. At the time, approximately 20% of the mine’s muck was being moved using HARD-LINE’s technology. Each TeleOp system is powered by TeleAi, which also allows for the control and monitoring of auxiliary devices and sensors with centralised management, reporting, and diagnostics.

Breaking through autonomously Rock-breakers are integral machines at many mine sites all over the world. While their movements may seem straightforward, the manoeuvrability of rock-breakers can be complex, especially when the autonomous element is involved. Autonomous rock-breakers not only provide the advantages of remote control, such as increasing production, removing operators from dangerous environments, and cutting operating costs; but also producing solutions for limited visibility, poor depth perception, and high latency. Furthermore, it does not require a highly trained operator to manoeuvre a rock-breaker efficiently and safely. At MinEXPO 2021 in Las Vegas, Nevada, HARD-LINE unveiled its breakthrough in autonomous rock-breaker technology, known as Auto Rockbreaker, for the first time (Figure 3). A few of its features include: target extraction, obstruction detection, and autonomous manoeuvrability – achieved by utilising state-of-the-art artificial intelligence (AI) and computer vision techniques. The new version of the TeleOp station provides rock-breaker users with a wide array of features, which include touch screen for easy control, buttons for quick deploy and parking, 3D view for better situation awareness using LiDAR and cameras, and easy target selection from candidate targets provided by AI. Moreover, it offers easier control features, such as automatic head levelling and a new way to control the rock-breaker called intuitive control. The on-board smart control system provides low latency and safety features that automatically handle failure situations. HARD-LINE’s release of Auto Rockbreaker is a step forward toward improving its fully autonomous suite of mining machinery.

Conclusion

Figure 3. Auto Rockbreaker’s user interface on HARD-LINE’s TeleOp System.

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The benefits of optimising a mine with automation are easy to understand. Whether it is a single innovative formula or multiple solutions working in unison, mines are adjusting as technology advances. Automating mines and vehicles not only contributes to much safer working conditions for employees and a better bottom line for businesses, but it shows the industry is moving forward as more companies in all mining fields embrace change.

Thishen Naidoo, Emerson, Canada, explains how implementing modern control system architectures and communications can help mining companies improve efficiency and future-proof operations.

n the wake of the COVID-19 pandemic, the world of work continues to undergo crucial transformations. The shift can be considered somewhat seamless for certain sectors, such as technology workers. Traditional industries such as mining, on the other hand, operate massive and distributed assets, and are slower to move due to requirements for on-site workers.

However, even here, the industry is working to gain productivity. Mining companies have had to evaluate the sustainability of their current operating models, and this has necessitated a renewed focus on automation, along with the evaluation of remote operations technologies to improve adaptation during

global mining review // October 2021

challenging times. Better data connectivity and analysis lead immediately to improved operational uptime and asset utilisation. These technologies also pave the way for the adoption of autonomous mining methods, which will surely accelerate for operations everywhere. Intelligent data access depends on several fundamentals, including: Reliable methods of connecting with field-located source data. Low-latency preprocessing at the edge to streamline data flows. Analytical and asset management systems taking advantage of the previous two points to provide the right intelligence at the right time.

processing and asset data. The scale and capabilities of ROCs vary. In Australia, for example, several companies have adopted the ROC model, consolidating several streams of real-time data from different sites to improve daily decisions. An ROC naturally makes sense for widely distributed sites, but it demands computing devices, networking, and certain infrastructure support. Furthermore, it is not enough to simply capture and transmit vast amounts of data if it is not available in context. Data is only powerful and actionable when matched with a good predictive maintenance strategy to avoid stoppages, with analysis to optimise equipment and systems. These users need solid and scalable methods of transferring high data volumes from mine sites to the ROC, where staff can analyse this data to maximise machine uptime and asset utilisation.

Whether mining operators are installing new projects or upgrading existing assets, there are many automation technology options which can be implemented to provide intelligent data access to improve the availability and maintainability of production systems.

Architecting for success

Tackling remote challenges Many production facilities are large and distributed over wide geographic areas. Mining operators contend with both these issues, as well as a general lack of power and communication infrastructure. Operations and maintenance personnel usually work out of a central location, making it difficult but important to detect remote operational issues, and to address them efficiently. Deploying personnel at the right time, with the necessary skill sets and supplies, is a top priority to prevent or resolve issues. At older sites, the staff may have been largely on the move, looking for trouble and communicating by radio back to a main location. Applying newer technologies enables mining operations to establish a much more capable remote operating centre (ROC). This is not a new concept in itself, but what is new is the vastly improved visibility and insights made possible by access to

Industrial automation technologies have traditionally been used for direct control and are designed to withstand the harsh environments common to mining sites. In recent years, advances in computational and communication capabilities have enabled these automation elements to play a much larger – and, in fact, preferred – role when it comes to accessing data. An ROC needs to consolidate several streams of real-time data generated at various sites – including direct operational data – along with equipment condition monitoring signals, such as: motor temperatures, vibrations, and energy consumption. By using this and other inputs, with all values gathered in appropriate context with each other, a mining organisation can optimise production and coordinate logistics, supply chains, and maintenance activities. Much of the success and overall productivity gains from the ROC model is contingent on the integrity of plant hardware, sensors, and instrumentation which feed data back to the ROC to be processed and analysed. In addition to the real-time data streams, it is important to gather diagnostic and integrity information from thousands of field devices, so that each one can be proactively maintained to preserve overall productivity.

Figure 1. A mining site's automation architecture can deliver high availability and comprehensive data communications when it is architected with modern programmable logic controllers (PLCs) and edge controllers, such as Emerson’s PACSystems RX3i and CPx400 series. This architecture uses PROFIBUS fieldbus rings for field signal connectivity, and OPC UA over Ethernet for communications with upstream computing assets.

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A comprehensive automation solution architecture must address user needs at three distinct levels (Figure 1): Input/output (I/O), fieldbus, and HART connectivity to field devices. Edge computing and communication capability. Process and asset analytics and management functionality. Structuring an architecture in this way meets several control and data acquisition needs. Edge-located controllers can be installed as simplex units, one per equipment train, so that each train can operate independently and in parallel with others, in order to reduce any single points of failure. Where there are single points of failure associated with a controller, users can choose modern programmable logic controllers (PLCs) or edge controllers offering easy-to-implement ‘check box’ redundancy. Fieldbus installations are often susceptible to physical damage, due to their location and routing, so it is recommended for users to choose protocols capable of operating in a self-healing ring configuration. Designing an architecture in this manner maximises availability, while reducing the overall project hardware cost and the future need to carry spares.

At the field, the edge, and the ROC Traditional I/O is sufficient for basic signals, but many instruments are available in fieldbus or HART-capable configurations for transmitting extended information. Fieldbus devices natively send and receive many values instead of just one process signal, while HART is an industry-standard protocol for sending and receiving digital information over analogue 4-20mA signal wiring. These approaches can supply more advanced information, but only if the supervisory controller is capable of accessing or passing-through this data. HART passthrough is attractive in many cases, especially for retrofits but also in new installations, because the HART information can be used by supervisory systems and handheld maintenance communicators with no extra

controller configuration involved. This technology leverages standard or existing two-conductor shielded wiring, enabling a smart instrument to interact directly with the controller, so that users can proactively configure and manage the field device. However, to avoid more complex installations, it is important that controllers and I/O modules are designed to provide HART passthrough to supervisory systems. Before it was possible or cost-effective to deploy computing hardware at the edge, the only choice was to transfer large amounts of data to central computing resources, using signaling and networking burdened by the task. Modern PLCs, and an even newer category of edge controllers, are much better at communications and computations (Figure 2).

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Edge controllers natively work with operational technology (OT) protocols, such as PROFIBUS and HART, which are required to access field devices, as well as with information technology (IT) protocols, such as OPC UA and MQTT, required for connecting to higher-level resources. These controllers provide high-performance access to field signals, and they can be used to pre-process the low-latency field-sourced data as needed, minimising the required upstream data volume. Once the data is transmitted to ROC computing assets, and perhaps on to cloud resources, is when end users can really begin to obtain value (Figure 3). Supervisory control and data acquisition (SCADA) systems, or other dedicated analytical

software, can be used to baseline and track operational performance, providing a tool for engineers and operators to optimise control functions. Like many large processing industries, mining operations use many instruments, valves, pumps, and motor controls. With the right instrumentation and edge computing, all these devices can transmit valuable machine health monitoring information to a supervisory asset management system (AMS). With HART instruments, HART-enabled I/O modules, and HART-capable controllers and supervisory software, this source data flows directly to the AMS software. Users can ensure instrument calibrations are up to date, confirm instruments and valves are healthy (not plugged or wearing), and proactively identify issues so they can order replacements and plan shutdowns.

Future-ready

Figure 2. Emerson PACSystems RX3i CPE330 PLCs and CPL410 edge controllers are readily implemented as redundant pairs, and provide deterministic control in conjunction with secure data processing.

By implementing modern control technologies, either as new projects or retrofits, mining companies will gain immediate benefits, while future-proofing operations. Deploying complementary field instruments, communication protocols, and controllers in this manner is necessary to enable process optimisation and asset management efforts most effectively. Today, these methods allow mining companies to establish one or more centralised ROCs, so their experts can efficiently work on, or be deployed to, operations anywhere. Experts located anywhere in the world can be leveraged to work closely with local personnel, supporting many remote sites and supplementing onsite maintenance expertise. Moving forward, mining companies can scale-up and add assets at one site, or they can consolidate information from a fleet of assets across many sites to gain insights. Soon, even more advanced capabilities, such as augmented reality, will also be a commonplace part of remote access and connectivity, enabled by automation systems available today.

Figure 3. Redundant architectures and communications reliably transport mining operational data to the remote operating centre (ROC) and the cloud, where it can be visualised and analysed to maximise uptime, asset utilisation, and efficiency.

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Ormond O'Neill, Siemens AG, Germany, explores how using drives can maximise energy and process efficiency in mining applications.

hile most of the talk and focus in many process industries these days is on digitalisation and the positive affects it can have on efficiency, cost reductions and the environment, it is very important to remember that the real workhorse and the backbone of most industries remains the industrial hardware. In mining, crushers, mills, hoists, conveyors, pumps, and more are needed to mine, mill, and transport the ore. In turn, these

heavy mechanical devices need motors, drives, gear boxes, transformers, switchgear, and automation equipment to operate and perform their tasks. The mills, including motors, gears and drives, are often the most important, expensive, and highest energy-consuming equipment in a mine, so it is important that the miner selects sustainable and energy-efficient devices that are best suited to the grinding requirements.

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Advantages of a drive Modern milling, conveying, and hoisting applications rely on drives to operate and control their motors, in order to optimise the mining process and to minimise their carbon footprint. There are four main mill types used for first and second stage grinding, namely semi-autogenous grinding (SAG) mills, autogenous grinding (AG) mills, high pressure grinding rolls (HPGR), and ball mills. The first stage of the grinding circuit traditionally uses SAG or AG mills, though in specific applications these can be replaced by HPGRs. The second stage involves ball mills. The AG mills, SAG mills, and HPGRs are usually variable speed applications, while ball mill applications, which were traditionally fixed speed, now tend to be variable speed as well. In the case of horizontal mills, the first step to determine which drive is best for the application is to define in which power and speed (torque) range the mill should operate. This determines whether a single-pinion, dual-pinion, or, for the highest power ranges, a so-called ‘gearless mill drive’ (GMD or ring-motor) system is best suited. Due to wear and tear issues, the low power factor, the inability to optimise the grinding process, high transient torques during start up and high-inrush currents causing network instability, wound rotor induction motors (WRIM)

with resistance starters (e.g. LRS) are becoming a thing of the past. The advantages of using a variable frequency drive (VFD) simply far outweigh the only real advantage of the WRIM/resistance starter solution, namely the relatively low capital cost of the equipment. The 24/7 operation of a mill means the CAPEX gains made can be wiped out in just one single day of additional maintenance downtime. The use of a drive introduces variable speed control to applications, leads to a far more optimised process operation, ensures an ideal speed control, and minimises transient effects on weak networks. In the case of horizontal mills, using a drive extends the lifetime of mill liners, ensures a smooth starting and stopping of the mill, reduces mechanical wear and tear of the gears, simplifies inching and creeping, and allows for the implementation of features such as automatic frozen charge detection (FCD). Choosing the right drive depends on the application and whether high-speed (1000/1200 rpm) or low-speed motors (typically 180 rpm) are being used. This, in turn, often depends on the end-user’s trust in the availability and the reliability of the gearbox. High speed motors are driven using a drive and a gearbox between motor and pinion in either a single or dual-pinion configuration. Low-speed motors, on the other hand, use drives with pinions directly coupled to the motor, i.e. without gearboxes. Applications above approximately 18 MW are usually realised using GMDs. HPGR applications always use gearboxes in combination with drives and high-speed motors. The use of drives with load share control reduces roller wear and tear and optimises the grinding process.

Selecting the best motor High speed solutions involve a gearbox in combination with an induction motor. These are cheaper from a CAPEX perspective and the individual parts are lighter/smaller than in low-speed configurations. However, the necessity of Figure 1. Power levels for the various mill drive solutions. requiring a gearbox means Indirect driven pinion- HIGH speed Direct driven pinion- LOW speed they are generally Dual or single pinion drive systems Dual or single pinion drive systems less efficient (up to SCIM or SM + VFD SCIM + VFD Low Speed High Speed 1.5% energy loss in the gearbox), involve more mechanical parts, are more prone to wear and tear, and Typical motor speed: 160-200rpm Typical motor speed: 1000-1200rpm require more Main equipment needed maintenance. In Main equipment needed Girth gear · · Girth gear Pinion addition, a small · · Pinion · Coupling auxiliary drive to · Torque limiting coupling (TLC) Gear box (ratio approx. 5) · · Synchronous/Induction motor Aux. drive mounted at gear box execute the · · (Excitation unit for SM) · Coupling maintenance · Drive Induction motor · · Insulation transformer modes of the mill · Drive · Insulation transformer is usually only required at the main gearbox. Figure 2. Standard mill configurations depend on the mill type and the required speed.

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Low speed solutions involve drives (VFD), in combination with synchronous motors (SM) or squirrel cage induction motors (SCIMs), directly coupled to the pinion via a torque limiting coupling. The use of low-speed synchronous motors is historically driven, due to the previous lack of existence of medium voltage (MV) drives and because the physical restriction of the induction motor construction, which means low-speed induction motors with 30 – 48 poles have a very low power factor of 0.6 or less to the mains. However, today the use of a MV drive in combination with a 6 – 12 pole induction motor means a power factor to the line of 0.95 can be reached. This, combined with the fact that modern drives can operate motors at any frequency – rated frequencies far below 50/60 Hz have become normal – means that a drive operating at a frequency range of approximately 15 – 24 Hz covers the typical speed range of 150 – 240 rpm used in horizontal grinding mills. There are a number of advantages in using an induction motor instead of a synchronous motor, the most important being the simplicity of the rotor. An induction motor simply consists of a very robust squirrel cage rotor. No brushes, slip rings or excitation circuits involving transformers, rectifiers, or additional rotor windings are required. With the exception of regular lubrication of the bearings, modern SCIMs are maintenance-free and designed for at least 30 years of operation. In addition to higher CAPEX, the other main disadvantage of low-speed motors is the need for a large auxiliary drive for inching and creeping purposes, if not executed by the main motor, as no gearbox exists. The need of a torque limiting coupling is recommended for such solutions.

What drive is best? Having established the importance and advantages of using a drive, it is now necessary to select the right one. There are a variety of different variable frequency drive technologies available, and while the power and speed rating of the motor are often the most important factor when choosing a drive, other issues – such as: voltage ratings, driving (two quadrant) or regenerative (four quadrant) capabilities, start-up torque requirements, variable or constant torque operation, the ambient conditions of the application, and the cooling method (air/water) – also play a deciding role. Mill applications are constant-torque applications where the size of the motor and drive is mainly determined by the start-up requirements. The drives normally need to be designed for 150% overload at start-up. Drives can be broken down into four main categories, namely 3(5)-level voltage source inverter (VSI) drives, multi-level VSI drives, cyclo-converter drives, and load commutating inverters (LCI). The VSI drives are based on IGBT and IGCT semi-conductors with DC capacitors, while cyclo-converters use pure thyristor-based technology. These three drive types are suitable for grinding applications. The fourth drive type, LCI, with a reactor in the DC-bus, is not suitable for mill applications as it is physically not able to provide the high overload required to start up a mill. 3(5)-level VSIs are mainly 12 and 24 pulse drives. The IGBT variants come in both air and water-cooled designs,

can operate both as two and four quadrant drives (in milling applications generally two quadrant drives are sufficient), operate in power ranges of up to approximately 6 MW per mill drive, and are generally cheaper than their IGCT counterparts. As with all the other drive variations, it is possible to obtain higher power levels by using parallel drive connections. The main disadvantage of the IGBT technology is the required derating at low frequencies and, of particular importance in mining applications, the high derating at very high altitudes. The IGCT variant only comes as a water-cooled device, but has the advantage that it can operate in higher power ranges of up to approximately 8 MW per mill drive, and is also suitable for use in very low frequency applications. However, this drive also has a high derating at very high altitudes. Multi-level VSIs, on the other hand, can operate as up to 36 pulse standard devices, resulting in very low harmonics to the mains, as well as to the motor windings. They come in both air and water-cooled designs, can operate both as two and four quadrant drives, and in power ranges of up to approximately 8 MW per mill drive in the air-cooled variant. A wide output voltage range between 3 – 11 kV is possible, and since both the voltage and current output is almost sinusoidal, very little heat is generated in the motor, meaning motors with standard insulation (DOL motors) can be used and no derating of the motor is required for drives operation. Similar to the 3(5)-level VSIs, the main disadvantages are the derating at low frequencies and the high derating at very high altitudes. The resulting power factor to the mains of a VSI drive is usually in the range of 0.95/0.96. The third category, the cyclo-converter, is an extremely simple and robust drive that comes in both air and water-cooled variants and, thanks to its thyristor technology, requires very little maintenance, while offering an extremely high level of reliability. It can be used up to very high-power ratings, with approximately 9 MW with one mill drive for air-cooled operation. The main disadvantage of the cyclo-converter is its poor power factor of approximately 0.8, and the fact that it creates more harmonics in the power supply network. This means the cyclo-converter requires power factor correction and harmonic filters in the power supply network, which leads to additional expense and the requirement for additional outdoor space. This may not

Figure 3. A copper milling application using two 6.5 MW low-speed induction motors with a cyclo-converter.

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necessarily be a big disadvantage if the power factor compensation and harmonic filter for the cyclo-converter is considered when planning the power factor compensation and harmonic filter installation for the whole mine. Furthermore, the cyclo-converter itself is cheaper than the other drives and requires 50% or more less indoor space than other drives, so this compensates somewhat for the disadvantage and costs for harmonic filters. This, together with the fact that it is the most robust drive and best solution for high altitudes, due to its very low derating and its high efficiency at both low-speed and low-frequency operation, means the cyclo-converter perfectly fulfils the requirements for low-speed mill drives in the mining industry.

Mill technology controller In pinion mill drive configurations it makes sense to install a mill technology controller (PLC) with the specific purpose of enhancing the functionality of the mills. One such feature is the frozen charge detection (FCD). By the PLC examining the start-up torque of the motor and automatically recognising the existence of a frozen or baked charge before it falls from the top of the mill, potential damage to the mill shell and the bearings can be avoided. In the case of a dual-pinion configuration, the PLC eliminates unwanted counter-torque effects and ensures accurate load sharing between the motors, thus significantly reducing the mechanical stress on the equipment, prolonging the life of the assets, and increasing the mill’s availability and reliability. Additional functions, such as mill stopping with balancing, creeping mode for maintenance and inching mode for positioning the mill in case of liner exchange, can also be integrated into the PLC.

Similarly, in HPGR applications the use of a technology PLC not only minimises the roller wear but, by controlling the load sharing of the motors, optimises the grinding throughput.

Digitalisation Each customer must decide for themselves where their priorities lie, but every modern drive system should benefit from the huge strides being made in digitalisation. Under the umbrella of asset health analytics (AHA), the correct use of sensors can provide detailed information to a cloud-based condition monitoring system, providing better system transparency, early fault detection, and reduced maintenance requirements and costs. AHA draws data from sensors to monitor – among other things – the power supply; the drive; the motor and motor bearings; the gearbox; the pinion; the equipment mechanics, such as the bearings and the brakes system; the e-house; and the external water-cooling system. This data can be displayed in various dashboards for immediate visualisation and information, but also stored/archived over long periods of operation for further analysis. This long-term data archiving of the equipment (mill, conveyor, etc.) operational modes and measurement data is an effective means to document the equipment history. Furthermore, it allows the system to recognise long-term changes in an asset’s general condition during its operational lifetime, and uses this information to make specific recommendations for conducting maintenance tasks in time to avoid unexpected equipment failures or performance losses. This, in turn, leads to improved reliability and performance by contributing to a better overall understanding of the equipment’s operation, as well as facilitating the continuous development of solution design improvements as part of the product lifecycle. Such data analysis can be done on site by in-house experts or, via remote access to the site by motor, drives and gearbox experts, often in the form of service contracts. These service contracts generally involve regular reports of the status of the individual mine’s assets and allow potential anomalies to be recognised long before any damage can occur.

Make the right choice

Figure 4. Typical system configuration for Mill Drive Technology functionality.

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Mining companies have their work cut out for them as they face declining ore grades, safety concerns, environmental protection regulations, decarbonisation, and volatile prices. Cutting-edge solutions for mills, conveyors, pumps, and hoists combining variable frequency drives with the right motor and digital technologies are the way forward, in order to ensure efficient, eco-friendly solutions. The right hardware and software combination will determine the future success of many mining applications. This is of particular importance for grinding applications, due to the size, costs, energy-consumption and importance of the mills, the key components in many mining processes.

John Turnbull, SES Networks, Australia, explains how the mining industry is being transformed with multi-orbit satellite-driven broadband technology.

ining, a traditionally land-based industry, is beginning to look very different. Advanced satellite technology, previously financially viable only for military organisations with deep pockets, has become increasingly democratised. With the cost of deploying satellites decreasing over the years due to technological advancements, more mining companies now have access to their capabilities to

transform yesterday’s mines into fully connected intelligent mining ecosystems. The mining industry is not entirely new to satellite technology. Satellites provide mining companies with aerial imagery and geophysics for exploration, and remote mines have traditionally invested in very small aperture terminal (VSAT) systems to transmit and receive data, voice, and video signals via a satellite

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network over long operational life cycles. However, legacy VSAT systems lack the bandwidth and flexibility to support modern mining operational requirements. Because of past telecommunication and network investments focused on analogue voice and narrowband data connections, many mining companies now find they have limited connectivity between mining sites, resulting in information and operational technology (IT/OT) systems and processes that exist in separated silos. Together with disparate, ageing excavation and transport equipment, this has perpetuated a highly inefficient ‘pit-to-port’ manual production path.

Advancements in mining operations Sustaining mining lifecycles and profits for years in a constantly changing market requires fully connected and more intelligently automated systems. A multi-orbit satellite system is one of the most cost-effective ways to achieve the performance and availability necessary for these connected next-generation solutions. Forward-thinking mining companies, such as Guyana Goldfields, Newcrest Mining and Ivanhoe Mines, among others, are using IP and Ethernet services delivered over SES Networks’ multi-orbit satellite technology to expand mine productivity, improve safety, and drive positive business outcomes. Such next-generation multi-orbit satellite systems combine low-latency medium earth orbit (MEO), geostationary earth orbit (GEO) wide-beam, and geostationary earth orbit high-throughput satellites (GEO HTS) to provide mining companies with high-performance broadband connectivity in even the most remote locations.

Investing for long-term competitive advantage Mining companies want to improve profitability, productivity, safety, and resource management. Yet, they also operate in a volatile environment where commodity

prices constantly fluctuate, price declines can quickly impact profit margins, and where there is always pressure to cut costs. However, cost-cutting without investing in smart technology or converged broadband-connected systems, while boosting the bottom line short-term, would only leave mining companies competitively disadvantaged in the long run. Budget cuts can cause productivity slowdowns and closures that further compound financial woes. Cost-cutting alone, without productivity and efficiency boosting technology in mind, can lead mining companies to reduce operational capacity and output and underutilise skilled mining personnel – resulting in them becoming less competitive over the long-term.

The broadband advantage Fortunately, the transformation to broadband connected mining does not require heavy infrastructure investment or major upgrades to IT/OT systems. By deploying and linking new Industrial Internet of Things (IIoT) capable sensors and programmable logic controllers (PLCs) embedded in trucks, conveyor belts, excavation tools and equipment to cloud-based IIoT platforms, mining companies can remotely monitor, control, and manage mining assets and all aspects of their operations across far-flung locations. Moreover, connected mining operations benefit from telemetry and ‘big data’ intelligence that provide operators and commodities traders with a consistent flow of aggregated, real-time data, from which they can proactively derive insights to act more quickly in response to market changes. Additionally, low-latency, fibre-equivalent broadband connectivity with differentiated quality of service (QoS) capabilities ensures high performance, application-aware access to internet, cloud and private network content and business applications – as well as enhanced mobile 3G and 4G/LTE device performance – at mines anywhere. Mining operators can quickly and easily connect to cloud and edge applications, sensors, and remotely controlled mining vehicles, robots, and equipment to gain true process and operations efficiency. Transforming legacy mines into flexible, future-proof smart mines will simplify mining operations, so that on-site and remotely located personnel can focus on improving metrics and pit-to-port productivity and yield, not managing complex communication and IT/OT systems.

Improvements in efficiency, safety, and uptime

Figure 1. Modern mining equipment is being filled with sensors that deliver millions of data points every day.

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At the same time, broadband connected mining equipment and systems improve safety, productivity, and efficiency for mining operators. Mining vehicles, such as excavators, trucks and bulldozers, can be remotely controlled via hand-held devices used on site to operate unmanned

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equipment in dangerous blast zones, underground mines, or on unstable ground. Video, sensor data, and control software delivered over a broadband connection can give operators real-time control of vehicles and equipment from a more protected environment. Fully connected mines also enable operators to facilitate and troubleshoot operations at multiple sites, using autonomous controls for mining vehicles and their critical functions, such as: ignition, steering, transmission, acceleration, and braking. Production-specific functions, such as blade control, dump bed control, excavator bucket and boom operation, can also be controlled without the need for on-site operator intervention.

Ivanhoe Mines

Case studies

Looking ahead: the future of mining

New technology is critical to the future of mining, with digital technologies promising lower operational costs and better utilisation of existing assets. Capabilities such as real-time data visualisation, analytics, automation, and virtual/augmented reality point towards improved safety, efficiency, and profitability.

Ivanhoe Mines partnered with SES Networks at its Kamoa-Kakula Copper Project in the Democratic Republic of Congo. It needed a turnkey network solution that would bring fibre-like connectivity at its greenfield site and support the latest communications applications. Using managed services and fibre-like connectivity powered by SES’s MEO satellite fleet, on-site operators could access videoconferencing to connect with subject matter experts at headquarters; utilise cloud-based applications to view and upload critical data, thus optimising workflows and data visibility; and achieve improvements in overall productivity and safety.

In the future, mining operations will be fully broadband-connected and automated. Mining solutions will enable automated mining via high-throughput hybrid MEO/GEO satellite systems that provide ubiquitous internet and private network connectivity at throughput rates of more than 2 GB/sec. Low-latency MEO satellites will connect IoT sensors Newcrest Mining for real-time data capture, enable the use of wearable As a forward-thinking mine operator, Newcrest Mining technology to monitor miner well-being and safety, and wanted to bring digital solutions to its mining sites – such facilitate the operation of autonomous equipment and as sensors, machine-to-machine protocols, real-time drones that stream real-time video feeds from voice, video, and data applications – which were all vital inspections and monitoring. GEO satellites, in the throughout its operations. It faced increasing pressure for meantime, will ensure business continuity. broadband to drive its business-critical applications. This is a future that is already fast approaching. After both microwave and submarine fibre optic cables Multi-orbit satellites already cover 99.9% of the Earth were deemed unviable for its remote location, Newcrest and can ensure future-ready hybrid networking did an overhaul to replace its VSAT links. The brownfield solutions by integrating GEO and MEO satellites, in mine now runs on SES’s fibre-equivalent MEO order to deliver fully connected intelligent mining connectivity, which quickly turned the situation around ecosystems and ground-breaking cloud connectivity. by accommodating different operational technologies, This integrated approach promises connectivity that supporting Newcrest’s SAP system and Office 365 surpasses the limitations posed by terrestrial applications, as well as offering future-proofing for infrastructure, reaching new markets and under-served emerging digital solutions. areas. The adaptability of GEO-MEO-Cloud constellations also allows for easier 5G rollout. An effective global 5G network needs to be built on an ecosystem of interconnected networks and infrastructures, utilising complementary technologies that comprise both terrestrial and satellite infrastructures. Multi-faceted, hybrid satellite service offerings deliver a path for mobile network operators to expand their reach, and thus deliver on the prospect of stable, universal 5G coverage and services worldwide. By 2025, as many as 1100 satellites could be launched each year, up from 386 launched in 2018. As satellite costs continue to fall, more companies will be able to reap the benefits. With more mining companies looking into space, the future of mining Figure 2. It has become crucial for mining companies to improve their abilities operations is right on track to be fully broadband-connected and automated. to analyse real-time information.

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Paul Emerson, Terra Nova Technologies Inc., USA, discusses how flexibility and versatility can be added to an IPCC system using mobile conveyors.

hilst in-pit crushing and conveying (IPCC) systems have the logical advantages of conveyor haulage when considering the environment, safety, water usage, carbon footprint, dust abatement and the life of mine OPEX, there are also some practical complexities when considering IPCC as an alternative to traditional truck haulage, particularly in deep opencast mines at large capacities. This discussion explores some of the issues, concerns and perceptions related to IPCC systems, as well as the potential to overcome these issues by utilising Super Portable® mobile conveyors, which are integral to the IPCC system.

IPCC challenges One of the main challenges for the successful deployment of an IPCC system in deep opencast mines is the mobility and

flexibility of the system when compared to truck haulage. These mines are dynamic, and mining faces are continuously moving in multiple dimensions, due to advance rate sensitivity, sequencing phase geometry, and selectivity. The flexibility of the trucks provides inherent shovel efficiency and the ability to adapt to the mine dynamics. Generally, the largest OPEX component in a mine is the truck haulage cost from the pit, which is where an IPCC system can add value through reduced OPEX. The traditional approach to IPCC in opencast mines has remained relatively unchanged for several decades, relying primarily on truck haulage followed by primary size reduction on ROM material and conveyance. To add to the difficulties, most mine plans are designed around traditional approaches at early study stages, before crushing and conveying is properly considered.

Figure 1. Terra Nova Technologies Super Portable® fully mobile ramp conveyors at a 7000 tph copper operation in the US.

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This usually results in the IPCC system being ‘shoehorned’ into a mine plan previously designed for trucks and shovels. The feed to the IPCC system in the pit also presents challenges. In many mines, the most OPEX effective system would usually be to utilise trucks, with a short haul in the pit as a means of interfacing between shovels and primary crushing/sizing, followed by out-of-pit conveyance. This scenario maintains high shovel efficiency, reduces truck fleet size, and eliminates the costly haul from the pit to the surface plant or waste pile. The issue with this scenario is that there are no practically feasible or proven, truly mobile in-pit truck fed crushing stations available, and for this reason ‘semi-mobile’ stations are limited to really being ‘relocatable’ at best, with a low frequency of moves and high cost of relocation. This does not suit the dynamic progression of most mines. Mobile direct shovel fed solutions are typically limited to mineral sizers, which usually restricts their use to overburden removal. That said, with mines going deeper and strip ratios increasing, the focus on overburden removal for an IPCC system should probably be the primary focus for most mines, in order to reduce the high OPEX of hauling the overburden/waste materials from the pit. This scenario has the advantage that there are a number of successful shovel-fed sizer stations, which have the ability to maintain some of the shovel efficiencies associated with loading trucks, and that eliminate double handling. The effectiveness of these stations is generally restricted by the mobility of traditional bench conveyors and the high cost and practicality of relocating, extending, reducing, or shifting these conveyors.

Versatility of mobile conveyors In 2015, BHP Billiton conducted a study for their Mass Mining Methods (MMM) investigation at Escondida, Chile, where the fully mobile conveyors were eventually selected as the means to practically link fully mobile sizer stations to the out-of-pit conveyors. The highly manoeuvrable and efficient way in which the self-propelled conveyors, equipped with on-board diesel generators, can be added or removed, in a simple ‘plug-and-play’ manner, allowed for the sizing stations to follow the shovels in an effective way, maximising shovel and conveying availabilities and efficiencies in the pit. In a similar manner, fully mobile conveyors were supplied to a mine in the US to increase its mining efficiency, by linking the mobile loading/screening unit to a stationary but portable slurry station, in order to maintain the efficiency of the material handling equipment that feeds the sizing rig.

Inherant system redundancy One concern of in-pit conveyances, when compared with truck haulage, is the redundancy of the haul trucks. This consideration is often debated in IPCC system studies, with regards to the availability of a conveying system compared with trucks. Typically, the argument is that if one conveyor shuts down, then the entire IPCC system is down. On the other hand, if one truck goes down, the system can still operate, albeit at a reduced capacity. This is where Super Portable fully mobile conveyors can overcome this valid concern, in that if any one of the chain of mobile conveyors has an unscheduled breakdown, it is simply removed and replaced in a similar fashion to trucks. Under normal operating conditions, a mobile conveyor is added in for advancing or removed in a retreat mode. Similar 10 000 tph systems, operating in large copper heap leach systems, have proven to have high reliability and usually a few spare machines are also kept on hand to replace operating units in the event of an unexpected breakdown. This type of fully mobile conveyor adds the flexibility and versatility to follow a mobile shovel-fed station and interface with the out-of-pit conveying. Usually, there would be dual mobile sizer stations in a large opencast mine, which provide additional redundancy when combined with a modular mobile conveying system.

Flexibility of mobile conveyors Figure 2. Terra Nova Technologies Super Portable mobile conveyor.

Figure 3. Graphical representation of the mobile conveyors considered in an IPCC system.

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Another factor to consider when analysing trucks in comparison to conveying for an IPCC system is the flexibility of trucks within the mine pit. Unlike other conveying options, fully mobile conveyors are self-propelled and can be relocated when required. Another benefit of the fully mobile conveyor is that the equipment was originally designed for multi-lift stacking systems, with a variation that is referred to as a ramp conveyor. These ramp conveyors typically operate up 20% grades and have sufficient power for the conveyor and crawlers to account for inclination during operation and relocation. At the other end of an IPCC overburden/waste rock disposal system, a Super Portable fully mobile stacking system can be deployed. The stacking system comprises a string of fully mobile conveyors, arranged head-to-tail,

feeding a horizontal feed conveyor, arranged at 90˚ to the string. The horizontal feed conveyor feeds a fully skirted horizontal conveyor, which subsequently feeds a telescoping radial stacker/spreader that discharges material to the area being stacked. The fully mobile, self-propelled equipment is capable of retreat or advance stacking and the horizontal conveyor and radial stacker index in advance or retreat modes in unison, without interrupting material feed. Once retreated or advanced by the effective length of the horizontal conveyor, the system encounters a brief shut down, in order to add or subtract a fully mobile conveyor, which is then repositioned between stacking areas in rotation, in order to share the workload evenly. When not in use, inspections, scheduled repairs, modifications, cleaning, and preventive maintenance are performed. Each fully mobile conveyor has a complete electrical system – housing its own diesel generator, programmable logic controller (PLC), and drive system – and can be relocated independently.

well as using a system engineering approach, increases the likelihood of not only sustaining, but evolving a whole new opencast mining method using this technology. This approach, when combined with the versatility of fully mobile conveyors, can provide further added benefits, such as utilising the same mobile stacking equipment to stack filtered tailings, co-mixed with waste rock and stacking rock containment abutments, in order to overcome geotechnical issues for dry tailings disposal.

Availability and reliability As part of the aforementioned MMM study, BHP benchmarked the performance of a 10 000 tph heap leach stacking system at a large copper mine in Chile, in order to investigate the system’s reliability, availability, and suitability for use in waste rock at high capacities. The conclusion was that there was a very high reliability rate associated with individual fully mobile conveyors – approximately 99.95% net availability with regards to unplanned breakdowns/failures. It was noted that there was high system utilisation with up to 27 multiple units in series at approximately 6800 operating hours/year, and the single system achieved >90% availability. It was further calculated that upward of 95% availability could be achieved with the addition of a spare horizontal conveyor, horizontal feed conveyor, and radial stacker – effectively providing a redundant stacking with only three additional pieces of equipment. The stacking system nameplate capacities were achieved/exceeded and conveying waste rock at higher capacities was deemed viable. It was noted that for automatic reconfigurations to take fully mobile conveyors into and out of line, a relatively short time of between 35 and 45 minutes was generally achieved. The system required only a minimal amount of support equipment for the operation, inclusive of spillage and floor preparation, and there was a low annual cost of mobile equipment specific, non-conveyor component spare parts.

Figure 4. Graphical representation of the mobile stacking system in retreat stack mode.

Figure 5. Mobile stacking system with 27 units in series at 10 000 tph at a copper mine in Chile.

Conclusion A plug-and-play fully mobile approach allows IPCC systems to link mobile sizing stations to out-of-pit conveyors, and negotiate pit ramps, multiple benches, and feed waste stacking systems in advance or retreat. These high capacity, self-propelled, highly mobile, and manoeuvrable conveyors can drive up benches or over stacked material with relatively low ground bearing pressures, requiring minimal dozer support during operation and the ability to negotiate difficult topography in complex valley fill situations with a high degree of redundancy. Good collaboration between a mine operator and an original equipment manufacturer, as

Figure 6. ‘Plug-and-play’ fully mobile conveyors at a 7000 tph copper heap leach operation in the US.

global mining review // October 2021

Todd Loudin, Flowrox USA, outlines the benefits of rubber compounding pumps and valves in helping to combat abrasion.

here are many different types of flotation in mining and minerals, including: column cells, which are tall round tanks that use compressed air to create air bubbles via spargers or cavitation tubes, and tank cells, which perform a slightly different flotation method and are often found on the outlet of the hydrocyclones. In both cases, level control is performed by a control valve that maintains the proper level in the column to optimise the overflow of a froth of precious metals. In column flotation, the valve controls the discharge of waste and is generally a very abrasive environment. In both situations, the control valve performs a very vital function and must be capable to survive the environment for long periods of time before maintenance. A control valve that requires frequent repairs is less than ideal. In some cases, the entire column or cell may need to be emptied for valve repair. In flotation cells, often a very simple control valve is utilised. This valve is a dart valve which is simply a plug that fits into the bottom of the flotation cell with a

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regulated opening to control the flow. This type of valve requires a box in which the valve is housed within. This metal enclosure adds significant cost to the cell overall pricing.

The correct valve for flotation control Most major flotation column manufacturers have recognised that pinch valves provide accurate control, but more importantly survive for long periods of time in abrasive environments. In flotation cell technologies, many manufacturers have eliminated the extra metal structure on the outside of the flotation cell to house dart valves and have begun to utilise pinch valves to control cell flow from cell to cell. When sizing the pinch control valve, special attention must be given to the head losses created by inlet and exit velocities and any losses through bends or elbows. Given the low driving head within a cell technology, these losses can result in improper valve sizing. A common mistake is to select a valve size that is too small for the intended flow rate. Some pinch valve companies have developed special

sizing software that takes into account these piping losses and ensures the correct selection of the valve. Pinch valves inherently have very high Cv values, which allow for very high flow rates. Often, a single pinch valve can manage flow rates that would require two dart valves to perform the same flow rate.

Tailings management For many years, pinch valves have been the desired valve for tailings control and isolation. In a tailings circuit, the solids may be extremely high: this could even be as much as 70 – 80% solids. Not many valves will survive in these high solids. Heavy duty slurry knife gate valves have also been utilised in these heavy slurries. Knife gate valves can (and do) survive in these environments, and have some benefits. A slurry knife gate valve typically has a discharge cavity that allows solids or built-up material to be discharged out of the bottom of the valve on each closure. Knife gate valves offer the advantage over pinch valves of having a very short face-to-face and much lighter weight, especially in large diameters. Pinch valves have been utilised quite a lot in spigot valves for tailings distribution to the tailings dam. The reason pinch valves are better than knife gates for longevity is that the rubber sleeve in the pinch valve has a straight through flow when in the open position – they are literally an extension of the pipeline. in addition, pinch valves have self-cleaning properties when scale builds up on the inner surface of the rubber sleeve: as the valve starts to close, the rubber is flexed. This starts to flake and break scale build up on the rubber sleeve. As the valve closes further, the fluid velocity increases and blasts away the remaining scale. Pinch valves have no pockets or cavities for material accumulation that is found in almost every other type of valve available. In high solids slurries, pinch valves are by far the most trouble-free valve available. That is providing the rubber sleeve is well engineered and manufactured out of high-quality rubber and is well compounded. However, it should be noted that, unfortunately, not all pinch valves are well made.

Thickener underflow pumping Slurry centrifugal pumps are quite frequently utilised for thickener underflow pumping. These centrifugal pumps often

have rubber linings throughout the pump and a rubber coated impeller to protect against the extreme abrasion. Over the past 10 – 15 years, peristaltic pumps have started to be the pump of choice for thickener underflow. The reasons the peristaltic pump has become more popular is due to both survivability improvements and the fact that this type of pump provides more accurate control of the thickener. Thickened slurry may include 60 – 70% solids before it is sent to filtration. When slurry percent solids increase, the mean time between failures (MTBF) of a centrifugal pump decreases sharply. A peristaltic pump can survive even 80% solids pumping. Peristaltic pumps are positive displacement devices. With each revolution of the peristaltic pump, a fixed volume of slurry is delivered into the piping. For this reason, the peristaltic pump can be very precisely controlled simply speed up or slowing down the rotation. Centrifugal pumps (when run at low speeds) typically come off their pump curves and become erratic and hard to control. One other reason peristaltic pumps are growing in this application is that they are relatively trouble free and very easy to repair. The most common failure is the rubber hose and it can be replaced fairly rapidly and at a much lower cost than repairing a centrifugal slurry pump. Peristaltic pumps do have limitations. The largest limitation is their maximum flow rates. A 4 in. (100 mm) peristaltic pump will have a maximum flow rate of approximately 440 gal./min. Centrifugal pumps are made in much larger sizes than peristaltic pumps and can produce several thousands of gallons per minute. So, peristaltic pumps may be literally too small for very large thickeners in many mining operations. But the peristaltic, when and where it can be used for thickener underflow, is often a superior form of pumping, especially when solids percentages go above 50% solids.

Peristaltic pump differing operating principles Peristaltic pumps were first manufactured in the 1930s. When rubber became more reliable, it paved the way for the peristaltic pump. There are three different designs that have varying degrees of pump functionality and performance. The first design, and probably the least desirable, is a shoe style peristaltic pump. This design typically has two fixed metal

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hose to keep the pumps doused to try to reduce the heat. In addition, this style of pump is filled approximately halfway with a casing full of Two fixed shoes grind against glycerin to dissipate the heat rubber hose, creating two compressions for every 360 degree that the pump generates. Lubricant Dill Line is very revolution. high. This large amount of glycerin adds significantly to the operating expense of the pumps. The second type of peristaltic pump is one that Figure 1. A shoe design peristaltic pumps generates significant heat and damage to the rubber utilises two or more rollers hose. The pump also requires massive amounts of glycerin to dissipate the heat generated by the to compress the rubber metal shoes rubbing against the rubber hose. hose. The rolling design does not generate the heat found in shoe design peristaltic pumps. Generally, there are two factors that determine how long the rubber hoses last. The first is how many times the rubber hose is compressed; and the second major factor is the introduction of heat to the rubber hose. Since this design does not create immense heat like found in shoe designs, then the hose MTBF is better than shoe designs. Moreover, this type of pump requires either a very small amount of glycerin, or even none at all. The final design is an eccentric single roller design, which was first introduced to Figure 2. Eccentric single rolling peristaltic pumps on thickener underflow at a the market approximately 15 years ago. Mexican mining operation. This design also does not generate heat from the rolling action. The biggest benefit of this design is that there is only one compression per revolution. The eccentric single roller design compresses half the number of times of both of the other two designs. Thus, this design will result in a hose life a minimum of two times longer than a Cam shaft with roller multiple roller design, and a hose life two to five times longer that rolls over the hose. than shoe designs. The savings in operating costs on an annual basis with this design can be as much as several hundreds of thousands of dollars if there are numerous Lowest glycerin fill level. peristaltic pumps utilised. Piping scheme convoluted. Not conducive to convenient piping arrangement.

In-line piping arrangement.

Figure 3. Eccentric single rolling designed peristaltic pumps compress the rubber hose only once per every 360˚ revolution, resulting in far superior hose life and lowest operating cost.

shoes that compress the rubber hose as the pump rotates in a 360˚ fashion. These metal shoes rub against the rubber hose and generate drag, friction, and heat. This style of pump needs to operate at very low revolutions per minute to prevent significant heat generation. If this style of pump is run at higher revolutions per minute, the pump assembly and rubber hose get very hot. These types of pumps have been implemented in mining operations where the mine uses a fire

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Conclusion Mining is one of the harshest types of processing on the planet, where pumps and valves in this environment are subject to extremely abrasive mediums. There are two schools of thought on how to survive in abrasive flow streams. One is to make materials harder with special coatings such as satellite and others. The other school of thought is to utilise soft elastic rubber to combat abrasion. In many cases, the rubber option will be the least costly, but still highly effective. Rubber compounding has advanced significantly over the past several decades: even in acidic mediums mixed with minerals, there are rubber compounds capable to handle both the acids and abrasion. Three different rubber compounds ideal for such circumstances are EPDM, viton, and hydrogenated nitrile rubber.

Josh Swank, Philippi-Hagenbuch Inc., USA, describes a new way to address mining cost reduction, through proper equipment selection.

very mine plays its own game of give and take when it comes to reducing expenses. And with the beating that mining equipment – especially truck bodies – face day in and day out, finding ways to balance longevity and productivity can create a challenge. Navigating this decision can leave many mine managers turning to different rules of thumb to help them prioritise between operational productivity and equipment durability. For addressing cost, one popular approach promotes a heavy-duty, more durable truck body to provide years of low-maintenance operation. However, these heavy-duty units also tend to be heavy in weight, reducing the amount of material that can be hauled, as well as heavy in price. These durable bodies tend to outlast the original purchasing manager and leave new management questioning the ‘heavy duty’ approach. In contrast, another school of thought places emphasis on increased hauling capacity and higher productivity from a lighter weight ‘throwaway’ body. These units are lower in price but often wear out quickly, leading to downtime and the need for repairs or replacements. Even those seeking some middle ground end up without a viable option in an

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off-the-shelf truck body that does not maximise the mine’s potential. The only option that provides a unique, sustainable solution to the productivity dilemma is a custom-designed truck body, manufactured to meet the specific challenges of the individual mine. This article outlines not only the truck body features that can lead a mine toward an efficient operation, but also a new way to think about reaching a mine’s full potential.

Look at the mine Before a mine manager starts researching truck body features, they need to take a long, hard look at their mine. Is a humid environment causing issues with carryback?

Are trucks hauling corrosive materials? Do materials need to exit slowly while dumping the bed? These basic questions lay the groundwork for any equipment decisions. Working with a custom equipment manufacturer adds the benefit of the manufacturer working in tandem with the mine, in order to analyse specific requirements, while also offering an objective and experienced eye to encourage consideration of often overlooked details. Finding this synergy and expert insight requires the understanding of what a true custom manufacturer offers. The inclusion of add-ons, such as sideboards and floor liners, is not an indication of a custom manufacturer. Many important options to maximise effectiveness in the mine go far beyond these add-ons to include the truck body’s design, material make-up, and much more. A truly tailored answer to a mine’s durability-productivity problem will address these numerous elements, all the while ensuring that good bones lie underneath any custom solution. And with the instability of steel prices and availability, there is little time and material to waste on not getting a design right the first time. With the groundwork in place, a mining manager can move on to considering the features that will ensure they are getting a functional, efficient, and durable truck body.

Body basics

Figure 1. High sides and a poor baffling design can cause round water tanks to be unstable. Square tanks, such as this one from Philippi-Hagenbuch, address these issues. The squared off corners and a more sophisticated baffling system can prevent water from surging between compartments and offer easier maintenance access through doors in the baffling, rather than cutouts.

Figure 2. Customising individual truck bodies to the mine’s specifications increases loading safety and greatly reduces the potential for loading damage, by ensuring width is correctly paired with the loading tool.

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No matter the skill level, sometimes operators cannot help but damage ill-fitting off-the-shelf truck bodies when the loading tool comes into contact with the truck body while filling. Whether the truck body is too small, is mismatched with the loading tools or does not have the proper height, repeated damage during loading can quickly destroy a body and cause expensive maintenance and repair issues elsewhere on the truck. Customising individual truck bodies to the mine’s specifications increases loading safety and greatly reduces the potential for loading damage, by ensuring width is correctly paired with the loading tool. This provides the lowest possible loading height and allows the shovel bucket to get closer to the truck body floor, nearly eliminating the chances that loading equipment will damage the truck’s sides, while simultaneously reducing the whole-body vibration associated with mass dumping. Additionally, choosing a wide body option offers well-balanced weight distribution across all the tyres, which reduces the potential for uneven tyre wear and extends the truck components and body’s life. With heavy use and high reliability required in mining applications, maintenance is inevitable. Simple design considerations in the body can either speed the process up and decrease issues, or lead to delays and additional challenges to address. For example, adding four free-floating lifting eyes into the floor of the body, rather than the sides, should be considered. This enables fast and easy removal or installation of a body for maintenance without the risk of bowing, a common issue with lifting points incorporated on the sides. As body sides age, traditional lifting points integrated into the body sides, such as pivots and holes, can become fatigued and create

a risk of a potential safety situation when removing or installing a body down the road. Bolsters and frame rails provide maximum reinforcement to the sides and floors of bodies. Traditional bodies simply butt-weld bolsters to frame rails, making them vulnerable to wear and tear. Look for custom bodies with intersecting bolsters and frame rails as these offer superior support that will not buckle under the immense stress of materials, keeping the payload at maximum capacity. Ensuring a truck body has these general design features will help to make sure mines get a body with good bones that can be infinitely customised and refurbished to find the sweet spot for handling daily abuse, while maintaining productivity. And in the volatile steel market, partnering with a custom manufacturer ensures the best steel is used throughout, and that parts and materials are available and made in-house. Additionally, checking off all these boxes provides mines with a solid base to expand on with other truck body options that can further streamline operations, such as rear eject bodies.

Rear eject offers an upgrade Rear eject bodies provide an efficient, low-maintenance alternative to end-dump trucks for smaller, niche areas within the mine. As the name implies, rear eject bodies use an ejector blade to discharge material. Without moving or raising the truck bed, the blade pushes material toward the rear of the truck. This simplifies the dumping process and enhances efficiency since operators do not have to wait for the bed to lower before driving away. Mines can further enhance their level of productivity by keeping an eye out for a few rear eject features that prioritise simplicity and decrease costly downtime. When selecting a rear eject body, mining operations should keep in mind that less is more. Rear eject bodies, constructed with a single hydraulic cylinder, minimise maintenance costs and maximise uptime by operating both the ejector blade and the rear tailgate mechanism at the same time. Selecting a body with ejector guides integrated into the inside of the truck bed provides smooth operation and decreases overall maintenance requirements, by eliminating rollers that typically break or bind. With the guides and track within the bed, there are no external rails that loader operators can hit, which can disable a unit until costly repairs are made. Some rear eject bodies feature designs tailored specifically to reduce carryback. Naturally, the unique sweeping action of the ejector blade reduces the tendence for carryback even with materials prone to sticking to the sides or floor of the truck bed. But certain conditions – such as a humid, sticky environment – pose even greater challenges. In these instances, true custom manufacturers can work with mines to add exotic steel liners to the ejector blade to deter sticking and further ensure no carryback. Integrating a rear eject body into a mine has its obvious benefits for dumping, but these bodies can also be fitted with add-on attachments that further increase

Figure 3. As the name implies, rear eject bodies use an ejector blade to discharge material. Without moving or raising the truck bed, the blade pushes material toward the rear of the truck. This simplifies the dumping process and enhances efficiency since operators do not have to wait for the bed to lower before driving away.

the flexibility and utility value of the specialty body in the mine.

Spreading and stemming become an option By safely controlling the dumping rate, when paired with a material spreading attachment, rear eject trucks can increase efficiency for tasks where materials need to be evenly and precisely distributed. They are ideal for applications such as haul road maintenance or certain drying applications, including spreading salt, diatomaceous earth, or lime onto leach beds. These attachments are available from custom equipment manufacturers and are designed to integrate seamlessly with the rear eject bodies. Spreading attachments can handle a wide range of material – from very fine to 2 in.-minus-sized material – and spread width can be adjusted from approximately 5 – 60 ft or more (1.2 – 18.2 m). In addition to hauling and road maintenance, it can also help to spread grit for traction on icy roads in the winter. Stemming is another time-consuming task where an attachment can revolutionise productivity and increase rear eject versatility. Many operations rely on side-dump buckets or loaders to fill blastholes with stemming material after the explosives are packed in the bottom. Opting for a rear eject body with a stemming attachment, however, can greatly improve efficiency. Consider this: using a single 3-t loader, operators might only be able to fill two holes per load before travelling back to aggregate piles to get more material. Depending on how close the stockpile is, this can result in cycle times of 15 minutes or more. With each blast averaging 100 or more holes, filling the blastholes with stemming material often takes two to four crew members several days, creating a significant drain on productivity. Alternatively, producers running a rear eject body with a stemming attachment on a 40-t articulated truck,

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for example, would be able to streamline the process and increase efficiency by 200% or more compared to traditional methods. Custom rear eject bodies are compatible with stemming attachments that incorporate into the rear eject body, offering an adjustable arm that can be easily positioned over the stemming hole to precisely deposit material in less time and with minimal labour. The ejector blade pushes material to a cross auger, which loads the articulating stemming arm and conveyor. The ejector blade speed, in-cab controls, stemming conveyor, and operator controls at the stemming arm all precisely control the flow of material for even distribution. Finding more cost savings with support solutions does not stop here. A mine’s water tank selection also provides an excellent opportunity for improvement.

Do not forget water tanks Though they may seem basic, water tanks are crucial for dust suppression, firefighting, and more. Traditional round water tanks limit productivity and increase costs. Round tanks suffer from designs with high sides, which results in a poor centre of gravity that can lead to tipping. Instability is worsened by a baffling system that incorporates open maintenance access cutouts leading to poor water compartmentalisation and excessive water churn. The safety concerns and instability operators feel in these

water trucks result in reservations to completely fill the tank, reducing efficiency and requiring more trips to refill. To combat this, look for a square tank that addresses these issues from the ground up. The squared off corners and a more sophisticated baffling system can prevent water from surging between compartments and offer easier maintenance access through doors in the baffling, rather than cutouts. Not rounding off the sides also allows for a higher storage capacity, so drivers can be more efficient with their trips.

Lasting solutions Every mining manager wants their mine to operate at its full potential – and that usually rides on the back of a haul truck. However, designing an operation around one of the industry philosophies that pits durability and productivity against one another rarely offers a sustainable solution. By laying the groundwork and incorporating the assistance and endless options available from a fully custom manufacturer, mining managers can include their wants and needs into their unique operation. A close, personal relationship with a custom manufacturer can not only equip managers with more knowledge about the solutions available for their unique operation, but it can set up a mine for years of future success, while others waste time and money bouncing between off-the-shelf options.

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Global Mining Review October 2021

Articles inside

Changing The Conversation On Mine Maintenance Costs

Flotation Control

Keep Things Moving With Mobile Conveyors

Looking Into Space

Driving Energy And Process Efficiency

Accessing Intelligent Data

Maximising Sustainable Impacts

Seal Of The Longwall

Breaking Through Remotely

World News

Fighting Mine Fires

The Mechanics Of Dynamic Ground Support

The Myth And Reality Of The Mongolian Mining Industry

Integrated Systems: The Next Step To Zero Emissions Mining Solutions