World Coal - April/May 2021

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ISSUE 2 2021 - VOLUME 30 NUMBER 2

ANSWERING MINING’S TOUGHEST QUESTIONS

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ISSUE 2 2021 03 Comment

CONTENTS 18

An Individual Approach Łukasz Gonsior, FAMUR Group, Poland, outlines an approach to client requirements in relation to highly customised gear products.

05 World News 08 The Future Of Coal Raj Shah, Coherent Market Insights, India, provides an insight into the future of the Indian coal industry.

23 The Magic Of Coal Preparation Plants In part one of a two-part article, Dr Andrew Vince, Elsa Consulting Group, Australia, demonstrates how coal preparation plants can obtain money for ‘nothing’ through incremental accounting, incremental ash equalisation, and near gravity capture.

28 Conveying The Need For Dust Suppressants Thomas Sloan, Quaker Houghton, USA, explores the importance of dust suppressants in the mining industry.

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Cleaner Conveyors Todd Swinderman, Martin Engineering, USA, details how to achieve a return on investment for the control of conveyor dust.

38 A Chain Reaction 14

It’s Next Level Armin Waibel, UWT Level Control, Germany, shines light on level measurement technology.

Franco Mazzucato, VAREYE, Switzerland, demonstrates how the concept of chain of custody can help satisfy all of the main requirements of coal producers.

45 Creating A Connected Mine James Trevelyan, Speedcast, UK, outlines how mining automation can help deliver business results.

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ISSUE 2 2021 - VOLUME 30 NUMBER 2

ON THE COVER With over 500 tool items, unique technologies, an individual approach to customer service and 28 years of experience in the market, Gorny Instrument Company offers high-tech rock-cutting and drilling tools for the mining industry. Visit www.gornygroup.com/worldcoal for more information.

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World Coal

MANAGING EDITOR James Little

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EDITOR LAURA DEAN

SENIOR EDITOR Callum O’Reilly

callum.oreilly@worldcoal.com DEPUTY EDITOR Will Owen

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jessica.casey@worldcoal.com SALES DIRECTOR Rod Hardy

rod.hardy@worldcoal.com SALES MANAGER Ryan Freeman

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COMMENT I

n February 2021, the UK government finally released a new roadmap out of the country’s third coronavirus-imposed lockdown, with all legal restrictions set to be lifted on 21 June 2021. The night the news was released, my phone and social media lit up with people’ rushed excitement to make grandiose celebratory plans. This, combined with the fact that many of my family members have now received their first vaccines, has inspired an intoxicating sense of hope. And while it is easy to get swept up in the sensation, it is important to remember there is a long road ahead, and this journey is subject to the data, rather than set in stone.

The UK coal mining industry is also currently experiencing a sense of uncertainty. On 18 February 2021, in the north east of England, what is thought to be the last shipment of coal from the region left the River Tyne. The 12 000 t load, which was extracted from Country Durham and sent to Belgium, raises questions over the future of the British coal mining industry, as the country works towards cutting its carbon footprint. In line with its carbon-cutting timetables, the government has stated that steel firms must stop burning coal by 2035, unless companies fit carbon capture and storage (CCS) technologies.

In the north west of England, however, all hope for the industry is not entirely lost. In October 2020, plans were announced to open the UK’s first new deep coal mine in 30 years in Cumbria. In January 2021, despite pressure from the country’s climate change advisors, the government announced that it would not intervene in the construction of the mine. This being said, according to West Cumbria Mining (WCM), recent “increased controversey” has led to doubt being shed on the project with the Secretary of State issuing a formal ‘calling-in’ of the planning decision.1 We will have to wait and see what the future of this project holds.

Elsewhere in the world, the coal industry is experiencing a resurgence. In India, coal made up 70 % of the country’s total electricity production, and although the country’s power generation did fall slightly in response to the pandemic, Rystad Energy expects coal power to come back with a vengeance, growing by 43%, and peaking at 1523 TWh in 2037.2 Similarly, in Queensland, Australia, the coal industry has been booming. The Queensland Exploration Council (QEC) Chair, Kim Wainwright, has stated that coal is now once again the region’s leading resource target in terms of exploration expenditure. In 4Q20, over half of the AUS$101 million Queensland mineral exploration expenditure was spent on coal, providing a clear insight into how valuable the coal industry is to the Queensland economy.

There certainly seems to be some hope on the horizon, both in terms of the coronavirus pandemic and the coal industry. But, as always at this point in time, all we can do is wait patiently to see how things play out. In the meantime, be sure to subscribe to all of World Coal’s social media channels, in order to ensure you are kept up to date with the all latest industry developments.

1.

2.

‘Statement from West Cumbria Mining’, West Cumbria Mining, (15 March 2021) ‘India’s Catch-22: Coal use set to boom as renewable wave can’t keep up with electrification growth,’ Rystad Energy, (16 February 2021)

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Online conference

3rd November 2021 With participation from:

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This virtual conference will focus on the latest developments, trends, and innovative technologies driving the figure of the Digital Mine.

Register for free at https://www.globalminingreview.com/digitalmine2021/

IN BRIEF USA America’s Power has issued a statement following the White House’s formal announcement of a new economy-wide target for the US to seek to reduce carbon emissions by 50 – 52% from 2005 levels by 2030.

RUSSIA The largest bulk carrier MINERAL YANG FAN (capesize) with 206 000 DWT has entered the Shakhtersk Coal Seaport. The length of the bulk carrier reaches 300 m, and the area of its upper deck is comparable to three football fields.

The width of the vessel is 50 m. Vessels of this class are capable of handling only specialised deep-sea terminals, so only a few of the Russian ports can accept them. The handling of vessels in the roadstead minimises the impact of coal on the port water area, and also reduces the environmental impact in the port area.

AUSTRALIA Johnson Winter & Slattery (JWS) has advised Peabody on its sale to MetRes of the Millennium coal mine, a metallurgical coal mine located near Moranbah, Queensland. MetRes is a 50/50 joint venture between Stanmore Coal and M Resources (a Matt Latimore company). Peabody will receive an upfront cash payment of AUS$1.25 million for the coal assets and a royalty on their coal sales capped at AUS$1.25 million for the asset transaction. Millennium and Mavis Downs are currently in a production halt after being placed in care and maintenance and lie adjacent to Stanmore Coal’s Isaac Plains complex in Queensland.

WORLD NEWS INDIA NALCO awarded Utkal E coal block mining lease

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he National Aluminium Company Ltd (NALCO), one of India’s leading producers of alumina and aluminium, has been granted the mining lease of the Utkal E coal block.

The lease has been granted by the Department of Steel & Mines, government of Odisha, through a notification issued on 12 April 2021. As per the notification, the mining lease of the Utkal E coal block is over an area of 523.73 ha. in villages Nandichhod, Gopinathpur Jungle, Kundajhari Jungle, Kosala and Korada under Chendipada Tahasil of Angul District. The initial capacity of the Utkal E coal block is 2 million tpy, with a total mineable reserve of approximately 70 million t.

NALCO previously executed the mining lease for the Utkal D Coal block in March 2021. With the granting of both the Utkal D and E coal blocks, the total mineable coal reserve of the company will be 175 million t, which will be pivotal in meeting the coal requirement of its Captive Power Plant at Angul, Odisha.

Initially NALCO will be able to produce 4 million tpy of coal from the operation of the Utkal D and E coal blocks. The lease for the Utkal D and E Coal block has been granted to NALCO for a period of 30 years.

USA DOE to invest US$6 million in products from coal waste

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he U.S. Department of Energy’s (DOE) Office of Fossil Energy (FE) has announced US$6 million in Federal funding for cost-shared research and development (R&D) projects under the funding opportunity announcement (FOA) DE-FOA-0002405, Advanced Coal Waste Processing: Production of Coal-Enhanced Filaments or Resins for Advanced Manufacturing and Research and Development of Coal-Derived Graphite.

The Advanced Coal Processing programme at NETL seeks to address the challenge of extracting the full economic value from coal waste, by supporting novel technologies to produce valuable products from coal waste-derived sources through laboratory and pilot-scale R&D. The use of coal waste in additive manufacturing and graphite production aligns with the goals of the Biden/Harris administration to expand and develop existing and new environmentally sound uses for coal waste, and to deploy these technologies in economically distressed power plant and coal communities.

While both coal from existing mines and coal wastes are acceptable feedstocks for these innovations, the use of coal wastes (e.g. tailings, ash, etc.) is preferred. This strategy encourages job creation as the nation transitions to clean energy and will help ensure that the cost of the energy transition is not disproportionately borne by these coal communities.

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DIARY DATES Mines and Money Online Roadshow 2021 06 – 18 May 2021 Online https://minesandmoney.com/online/ roadshow.php

Mines and METS 2021 07 – 09 June 2021 Online https://minesandmets.com

Coaltrans Asia 2021 19 – 21 September 2021 Bali/Online, Indonesia https://conferences.coaltrans.com/asia

MINExpo INTERNATIONAL 2021 13 – 15 September 2021 Las Vegas, Nevada, USA www.minexpo.com

IME 2021 26 – 29 October 2021 Kolkata, West Bengal, India www.miningexpoindia.com

The Digital Mine 2021 03 November 2021 VIRTUAL EVENT www.globalminingreview.com/ digitalmine2021

AIMEX 2021 16 – 18 November 2021 Sydney, New South Wales, Australia www.aimex.com.au

2021 Coal Association of Canada Conference 30 November – 02 December 2021 Vancouver, British Columbia, Canada www.coal.ca/news-events/events-calendar To stay informed about the status of industry events and any potential postponements or cancellations of events due to COVID-19, visit World Coal’s events page: www.worldcoal.com/events

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WORLD COAL ISSUE 2 2021

WORLD NEWS

AUSTRALIA Institute welcomes Australian government CCS funding announcement

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he Global CCS Institute has welcomed the Australian Federal government’s announcement of AUS$539.2 million in funding for new carbon capture and storage (CCS) and hydrogen projects, while stressing the need for long-term emissions reduction policy.

The announcement, which comes ahead of the climate summit hosted by US President, Joe Biden, has pledged AUS$275.5 million to accelerate four regional, clean hydrogen hubs and AUS$263.7 million to support the development of CCS projects and hubs.

Brad Page, Global CCS Institute CEO, highlighted the importance of funding for hydrogen hubs, saying coal or natural gas with CCS is currently the lowest cost, technically mature way to produce high volume, near zero carbon hydrogen.

JAPAN Nakoso IGCC plant completed

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consortium led by Mitsubishi Power, a subsidiary of Mitsubishi Heavy Industries (MHI) Group, has completed the construction of an integrated coal gasification combined cycle (IGCC) plant in Iwaki, Fukushima, Japan, that was followed by the formal handover to the customer, Nakoso IGCC Power GK. Operation of the new facility, which is a high-efficiency, clean commercial power plant incorporating advanced coal gasification technologies, started on 16 April 2021. Mitsubishi Power manufactured the core air-blown IGCC system, including the coal gasification furnace. The project called for the creation of the world’s largest IGCC configuration, roughly twice the scale of the Nakoso Unit 10 (former IGCC demonstration plant) completed earlier. This is the first domestically developed air-blown IGCC system of such large scale in commercial use.

Compared to the Unit 10, power generation efficiency has been substantially enhanced, reaching 48%, which was enabled by the gas turbine’s having a higher combustion temperature.

In this case, the IGCC plant adopts a high-efficiency ‘combined cycle’ methodology. Coal is gasified in a gasification furnace at high temperature under high pressure; sulfur, ash and the like are separated out and removed; and the refined gas is used as fuel to drive a gas turbine. Compared to conventional coal-fired power plants, IGCC plants provide greater power generation efficiency and help to reduce carbon emissions. For these reasons, they respond to the needs of power providers in their efforts to make effective use of resources while simultaneously protecting the environment.

The IGCC plant construction project undertaken by Nakoso IGCC Power GK incorporates the hope and expectawtion that, by integrating the world’s most advanced thermal power generation technologies, the plant will contribute to creation of the local industrial infrastructure, and thereby to Fukushima’s recovery.

WORLD NEWS RUSSIA Eastern Mining Company present concept of ‘Green Coal Cluster’

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GK, one of the 10 largest coal mining companies in the Russian Federation, intends to create a ‘Green Coal Cluster’ in the Uglegorsk District of the Sakhalin Region.

The concept of the project was presented by the Chairman of the Board of Directors of VGK, Oleg Misevra, in the framework of the plenary session at the Open Day of the Sakhalin Region for investors. According to preliminary calculations, the implementation of the new concept will reduce the carbon footprint by 64 000 t of conventional carbon fuel and reduce carbon dioxide emissions by 176 000 tpy.

The Green Coal Cluster concept will include three innovative projects. One of them is already under construction: the longest main coal conveyor in the Russian Federation. The project combines modern technologies and advanced environmental standards. The facility under construction will: reduce the load on public roads; abandon the transportation of coal by cars, which will reduce emissions of exhaust gases into the atmosphere; and deliver coal in the most environmentally friendly way recognised throughout the world.

Another project is being implemented jointly with the

manufacturer of automotive equipment – the BelAZ plant.

The development of an electric dump truck with a carrying capacity of 220 t provides for the operation of a mining dump truck at the field, which uses an external source of energy from trolley lines. The use of such transport will lead to: a decrease in the consumption of fossil hydrocarbons; preservation of the climate; a decrease in harmful emissions at the place of operation of the equipment; an increase in the economic effects associated with the use of electricity; and an increase in the productivity of machines.

The most ambitious project within the Green Coal Cluster is the construction of a wind farm with a total capacity of 67.2 MW in the Sakhalin Region. The wind farm will include 16 wind turbines located in areas with high wind potential. In addition to the difficult terrain, the uniqueness of the project lies in the fact that the wind farm is being built according to the needs of the company to provide power supply to all production facilities. To date, two sites have been identified for the installation of wind turbines, where wind monitoring will be carried out until the end of 2021.

AUSTRALIA NSW IPC conditionally approves extension to Mangoola Mine

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ew South Wales’ Independent Planning Commission has approved, with conditions, an extension to an Upper Hunter coal mine.

Mangoola Coal Operations Pty Ltd, a subsidiary of Glencore Coal, sought approval to establish a new opencast mining area to the north of existing operations at its Mangoola Mine, 20 km west of Muswelbrook.

An additional 52 million t of run-of-mine coal would be extracted over approximately 8 years, with operations to cease at the site in December 2030 – a 13-month extension to the company’s existing development consent.

Supporters of the proposed mine extension cited the projected social and economic benefits to the local area, Upper Hunter region and to NSW, including job creation and retention. Those opposed to the project raised concerns about air quality, biodiversity, greenhouse gas emissions and climate change, impacts on water resources, noise impacts,

traffic and transport impacts, socio-economics, Aboriginal cultural heritage, and rehabilitation.

After considering all the evidence and community views, the commission has determined to approve the state significant development application, subject to 179 conditions – finding that “on balance and when weighed against the objects of the [Environmental Planning & Assessment] Act, ecologically sustainable development principles, the current policy frameworks and socio-economic benefits, the impacts associated with the project are acceptable and the project is in the public interest.”

The project will use existing infrastructure including the Mangoola Mine Coal Handling and Processing Plant, rail loop and mining fleet, and involve the development of a new haul road overpass, which would also traverse Wybong Road and Big Flat Creek, in order to connect the Northern Extension Area with the Mangoola Mine.

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WORLD COAL ISSUE 2 2021

Raj Shah, Coherent Market Insights, India, provides an insight into the future of the Indian coal industry.

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ndia is one of the top producers of coal worldwide, with estimated coal reserves of up to 319 billion t in 2018, according to Indian Bureau of Mines data in 2019, making it the fifth largest coal producing country in the world. Coal India Ltd (CIL), a public-sector company, is the major enterprise, contributing over 80% of the total national coal production.

The government of India currently owns 69.05% of stakes in CIL, while the remaining 30.95% is publicly owned. India is also the world’s second largest consumer of coal, with coal consumption reaching up to 942 million t in 2017. According to the International Energy Agency’s 2018 report on coal information, thermal coal accounted for 86% (806 million t), lignite (or brown coal) accounted for 5% (47 million t), and metallurgical coal accounted for 9% (89 million t) of India’s total coal consumption in 2017.

Power generation Coal mining and power generation are among the top major industries in India, together accounting

for approximately 1/10 of India’s industrial production. These industries directly employ approximately 500 000 people in the country, while simultaneously generating substantial employment in the transport sector as well. In the Indian power sector, the COVID-19 pandemic has increased the uncertainties in coal consumption estimates, due to the sudden reduction in commercial activities during the nationwide lockdown (until August 2020), which in turn has caused considerable decline in demand for electricity. Although, the residential sector in the country has seen an upsurge in demand for electricity, due to the prevalence of the majority of people working remotely and staying indoors.

Even before the pandemic, coal-based power plants struggled with the steady rise in demand for alternative energy sources, notably wind and solar power. India’s coal consumption is primarily dependent on the power sector, which is currently facing uncertainties in electricity demand – due to the economic slowdown in recent months and strong competition from low

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cost renewable substitutes.

According to PRS Legislative Research, an Indian non-profit organisation which conducts independent research, the total contribution of coal in power generation reduced Figure 1. Primary energy consumption of commercial fuels in 2018 (global average and in India). from an average of 72.5% to 65.6% between March and April 2020, amidst the rise in number of COVID-19 cases. There are a lot of factors responsible for this, including lower running cost of renewable power plants compared to coal-based thermal power plants. According to Power System Operation Corp. Ltd (POSOCO), a government owned enterprise under the Indian Ministry of Power, the plant load factor (PLF) of thermal power plants has declined considerably in the past decade, reducing from 77.5% in 2009 – 2010 to 56.4% in 2019 – 2020.1 A lower PLF suggests that coal-based plants in the Figure 2. India’s thermal coal production and consumption. country have been lying idle for long durations.

The declining utilisation of the total capacity, in addition to weakening demand, is expected to undermine the financial sustainability of thermal power plants even more in the coming years.

Coal production

Figure 3. Power consumption by consumer segment in 2018 – 2019. Sources: Central Electricity Authority; PRS.

Figure 4. India’s thermal imports by source. Source: IHS India coal data tables, June 2019.

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The Indian government is focusing on pushing self-reliance strategy in different industrial sectors following the COVID-19 pandemic, which also includes capacity expansion of Indian coal production. This is reflected by the government’s coal mining liberalisation initiative for the deregulation of the domestic coal market, which would significantly increase coal production in order to meet the expected demand growth. In June 2020, the Prime Minister of India, Narendra Modi, conducted the auction of various mining blocks for commercial purposes. This decision was part of the recent government campaign, Atmanirbhar Bharat Abhiyan, and was proposed through the Mineral Laws (Amendment) Ordinance, 2020. These 41 coal mines are located in different regions of the country including: Chhattisgarh (9), Odisha (9), Madhya Pradesh (11), Jharkhand (9), and Maharashtra (3). The resources also include two metallurgical coal reserves and two coal mines with both metallurgical and non-metallurgical reserves.

According to the Coal Ministry of India, the 41 coal mines, which are now open for auction, can hit a peak production of 225 million t by 2025 – 2026, which can potentially save subsequent foreign exchange for thermal coal imports. Despite having such high availability of coal reserves, coal is still among the top five commodities

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imported into India. Moreover, the country spent US$21.28 billion (Rs. 1.58 trillion crore) on importing approximately 247 million t of coal, of which 197 million t was of thermal grade, in 2019.

Nearly the entire requirement of metallurgical coal, which is a crucial raw material for steel producing industries, is imported as the availability of high-quality metallurgical coal is very limited in the country. These 41 coal assets will be auctioned off via a newly determined revenue share model, through which private players will be allowed to mine coal for commercial mining purposes, unlike before, where mines had stringent end-use restrictions – i.e. companies coud only produce coal for designated captive purposes and could not trade coal in the market. However, as of

now, foreign players have been shunned from participating in these coal mine auctions, contradictory to what the government expected.

Global investors are gradually recognising the climate impact, as well as the financial risks involved in stranded assets. A rise in the number of divestments made by global players in the thermal coal mining sector reflects this trend. For example, in June 2020, BHP Group Ltd, one of the global leaders in resources and mining business, sold its last Australian thermal coal mine, subsequent to the commitments made by the company in 2019 to progressively reduce its thermal coal mining business.

Instead, the highest number of bids were placed by major domestic companies such as Adani Group, an infrastructure conglomerate which is also India’s largest private sector Table 1. The details of state-wise geological resources of coal thermal power producer, which placed a (million t). Source: Indian Bureau of Mines, 2019 bid for 12 of the 19 mines initially put up State Proved Indicated Inferred Total for auction. This was followed by other major players, such as: Aditya Birla Group, Total 148 787 139 164 31 069 319 020 JMS Mining, Naveen Jindal Group and Vedanta Group, among others. However, Jharkhand 45 563 31 439 6150 83 152 this does not reduce the challenges for the government. During recent years, there has Odisha 37 391 34 165 7739 79 295 been a gradual decline in financial interests Chhattisgarh by corporates in the coal sector, due to rising 20 428 34 576 2202 57 206 concerns regarding coal’s environmental West Bengal 14 156 12 869 4643 31 667 and social consequences. Long term capitalisation of this business space is not Madhya Pradesh 11 958 12 154 3875 27 987 only challenging, considering the unfolding events towards a green economy, but also Telangana 10 475 8576 2651 21 702 poses a question relating to the value Maharashtra 7178 3074 2048 12 299 proposition and brand image of any entity involved in the coal industry.

Andhra Pradesh 1149 432 1581 Instances where new coal plants are being built in the country are now even fewer, Bihar 161 813 392 1367 and those being built are ones which were Uttar Pradesh 884 178 1062 mainly planned approximately 5 – 10 years ago. According to the Institute for Energy Meghalaya 89 17 471 576 Economics and Financial Analysis (IEEFA) report, in 2012 – 2016, India commissioned Assam 465 57 3 525 approximately 20 GW of net new thermal Nagaland power capacity annually. But, between 9 402 410 2017 and 2020, this rate of adding net new Sikkim 58 43 101 capacity was reduced by 80% to an average of 4 GW annually. Furthermore, the quality of Arunachal Pradesh 31 40 19 90 coal produced in the country is very low when compared to the global standards.

The average energy content of the coal produced is 3000 – 4000 kcal, with up to 20 – 40% of ash content. This is in comparison to thequality of imported coal, which is 5000 – 6000 kcal with a lower ash content of up to 10%.

Figure 5. Total quantified energy subsidies, FY14 – FY19.

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In addition to this, many of the major coal-fired power plants in India are located in coastal regions, such as Mundra plant, which are not well connected by railway lines with the domestic Indian coal reserves, making the transportation of the domestically produced coal problematic.

The rise of renewable energy In spite of government initiatives, current market trends challenge the importance of a thermal power generation expansion for sustaining the energy security in the country. Instead, recent instances of foreign investments into the renewable energy sector in India suggests that the current government grants for fossil fuels will be spent on supporting the capacity expansion of the renewable energy industry at the domestic level.

For instance, in June 2019, ReNew Power, one of the leading independent renewable power producers in India, raised a funding of approximately US$435 million through dollar-denominated green bonds, together with an additional US$350 million debt funding from Overseas Private Investment Corp. Furthermore, in July 2020, ReNew Power also announced its plans to invest between US$200 million – US$280 million to set up a manufacturing facility for solar cells and modules in India with an initial manufacturing capacity of 2 GW.

Conclusion Although the coal sector is likely to always play an important role in the Indian economy for many years to come, rapid expansions in domestic coal mining now seems a risky development strategy, as the growth prospects in this sector are limited.

Therefore, a planning for a transition away from coal dependence should start as early as possible.

According to International Institute for Sustainable Development (IISD), subsidies provided to the fossil fuel (oil, gas, and coal) industry by the government of India accounted for approximately US$12.4 billion in 2019, relative to just US$1.5 billion for renewable energy. Out of this, coal subsidies accounted for approximately US$2.6 billion. The rising uncertainties in the investment risks of coal-based power generation, reducing PLF and the higher costs involved in the commissioning of new plants and the import of coal, emphasise the preliminary benefits of shifting government subsidies and public investments away from the coal sector and more towards clean and renewable alternatives, especially solar and wind power.

References 1.

‘Power sector at a glance, all India,’ Government of India Ministry of Power, https://powermin.nic.in/en/content/powersector-glance-all-india

SOME THINK THAT RAW MATERIALS TRANSPORT REQUIRES TRUCKING. WE THINK DIFFERENT. beumer.com

Armin Waibel, UWT Level Control, Germany, shines light on level measurement technology.

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n order to define the correct level measurement technology, it is essential to analyse the different process parameters of a particular application, such as material properties, process temperatures, pressure and connections, as well as the process atmosphere. The selection of the right level measurement technologies, their correct configuration, and smart positioning will save substantial costs and add up to a significant improvement in a plants’ economic efficiency over its lifecycle.

For challenging conditions and material A leading supplier of building materials in South Africa was looking to source a reliable continuous level measurement solution for a process hopper. The application revolved around a train tippler that tips the contents of the train truck with coal into the hopper below, which is then conveyed to the site. The measurement units have to meet high accuracy demands and cope in the challenging environment.

The mining sector in South Africa was once the primary driving force behind the history and development of Africa’s most advanced and richest economy. South African mining companies are key players in global industry and the country is the third largest coal exporter in the world.

The plant operator has been producing cement, aggregates, lime, ready mix, and fly ash since 1892 and now operates with 11 factories in South Africa, Botswana, the Democratic Republic of the Congo, Ethiopia, Rwanda, and Zimbabwe. With regards

to the modernisation of the facilities close to Cape Town, the operator was looking for equipment to provide innovative continuous level measurement.

Due to the nature of the application, the electromechanical lot system – which is popular in the cement manufacturing sector – was not the ideal solution here. Due to the fast running process flow and the dust intensive atmosphere, UWT engineers, together with the local partner Morton Controls CC, configured a radar free-radiating measurement detection system. The NivoRadar® NR 3000 was installed with a dust tube, which was fitted with an air purge to keep the dust off the lens. The radar was installed on a beam that was hanging over the bulk of the coal. The measuring distance was approximately 45 m (147 ft), with temperatures reaching up to 80˚C (176˚F), and process pressure reaching 0.8 bar (11.6 psi). The material density was approximately 800 g/l and the DK value ranges differed between 2.0 – 3.0 with a granular material characteristic. There are some vibrations within the application, low moisture and no electrostatic charge, but a very dusty atmosphere. After 2 weeks of successful testing, the choice of the right sensor solution was confirmed and several units were implemented into the plant application. The dusty environment was successfully overcome by the dust tube and airline connected to purge the lens. Accurate and repeatable reliable readings demonstrated the success of this solution applied to this difficult application.

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Figure 1. Continuous level measuremt solution for mining freight train coal with contact-free radar.

Figure 2. Installation of NivoRadar NR 3000 with aiming flange within the mining process.

The radar is certified for hazardous locations (Zone 20/21) and the stainless steel construction makes the continuous level measurement suitable for these kinds of application. The unit operates at a high frequency of 78 GHz and delivers a small beam angle of 4˚, which eliminates any signal interference at the flange but allows for optimum reflection of the bulk solids material.

Distances of up to 100 m (328 ft) can be measured, and the sensor can be used in very fine as well as rough-grained solids due to the high sensitivity range. The radar also offers a flat flange and aiming flange version.

Using the adjustable aiming flange, the radar was perfectly aligned since the probe could be fixed to the desired point, and the angle of the beam can be set to the desired point. Therefore, the installed radar sensor could be exactly placed over the trippler hopper and adjusted for continuous level detection of the material without delay and spurious echo, even within the limited space.

The non-contact technology sided cones did not influence the measuring results. The lens antenna is highly resistant to material deposits and offers a self-clean function for the sticky solids using an air flush connection. Even within applications where condensation occurs, the flushing connection provides functionally reliable measurements.

The device uses a two-wire technology and is kept simple, in order to operate via a local programmer with Quick Start Wizard and a plug-in display that allows programming and diagnostics onsite. The unshielded radar sensor has a completely dustproof design and provides reliable measurement results in high process temperatures up to 200˚C (392˚F).

More efficient silo management by visualisation of stock level The next consideration for the plant operator at this point of production was to connect the radar sensor to a complete system for level monitoring, in order to achieve improved transparency concerning silo management. The measurement system devices communicate directly with PLC control systems via an analogue ***4…20ma*** signal, or even a MODBUS RTU or Profibus digital protocol.

The level signals of the installed radar sensors on each silo could be bundled by the visualisation software NivoTec®, combined with a Wago WebController. The plant could securely access this information (password-protected), at any time of the day, via any internet browser over a predefined IP address using the visualisation software. It is possible to include any number of other measuring points in the visualisation system – without additional hardware costs. By utilising this level monitoring and visualisation, the plant operator established a complete system for fill level and trend display, data storage, and remote fill level information.

Historical digression Figure 3. Multifunctional FMCW radar level transmitter for continuous monitoring of solids and liquids with two-wire technology.

16

WORLD COAL ISSUE 2 2021

Coal mining has an interesting history to be told. One of the largest mining industries, mining for coal started out in the 18th century and boomed all the way to the 1950s.

Today, although maybe not as prevalent as some other

mined commodities, coal is still a valuable form of energy for opencast extraction.

Interestingly, the initial method for coal extraction was tunnelling into the earth, but this had to be stopped due to the perilous vapours that were emitted, for example: carbon monoxide, carbon dioxide, and hydrogen sulfite – deadly to say the least. The sensors now used in the coal mining process have helped with detecting these harmful vapours, and have thus helped progress the industry away from the traditional miner’s canary method.

What is the miner’s canary?

Very simply put, miners used to take a canary in a cage down into a mine with them. Canaries were known to be very sensitive to odourless vapours, such as carbon monoxide, and they would show effects of distress, rocking from side to side, before falling off their perches.

While not a very safe procedure for the animal, it was known to have saved many human lives.

After a time, the canary method of detection was stopped as it proved to be less effective than initially assumed.

The Pellistor was introduced as a replacement – a catalytic sensor able to detect a very wide range of toxic vapours and flammable gases.

Due to high maintenance costs and limitations – such as malfunction when exposed to chemicals made with chlorine, sulfur or halogen, as well as any metals containing silicon or lead – this method was also withdrawn after a time. The more modern and more effective method is the infrared LED–based gas sensor.

Conclusion: measurement technology offers critical support Level measurement technology is multifaceted and rarely stands still.

Exciting and challenging developments in different applications mean that the product range continuously has to grow and develop to meet these requirements. For continuous and point level measurement technology plant operators often need individually tailored solutions for their material manufacturing processes. Each process has specific requirements or demands for the sensors involved.

With particular attention to single steps during the manufacturing of the cement producing company in South Africa, the customised level measurement was a crucial component to supporting continued smooth running process flow – avoiding overfill protection, responding quickly when it comes to silo emptying, and providing transparency and control over content level within the vessels at any time.

With application-oriented product design of the installed radar sensor and paddle switch – supported by the level control visualisation system – a high degree of compatibility for the silos and vessels was given, so that they could be seamlessly integrated into the installations ensuring optimal silo management.

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18

Łukasz Gonsior, FAMUR Group, Poland, outlines an approach to client requirements in relation to highly customised gear products.

S

tarting with an analysis of customer requirements and progressing to the supervision of a deployed device, this article presents a life cycle assessment (LCA) path study of a bucket wheel drive gear mounted on a lignite excavator.

One of the product branches of the FAMUR Group is drive sets and gears used in industrial surface transport systems and equipment for mining in a broad sense. Apart from output transport technology, the company’s gears are used in the drives of running gears and boom rotation systems of lignite excavators, running gears, and conveyors installed on loaders and loader-reclaimers of loose materials.

Power transmission The market for power transmission products can be divided into standard products and products that are highly customised to meet the specific requirements of a particular application.

In the first case, applications generally do not require expert advice from the drive manufacturer. The interaction between the customer and the gear manufacturer is limited to confirming the correctness of a solution.

The second group of products is characterised by the presence of multiple product LCA phases and it requires: Design skills and experience, as well as access to commercial and proprietary design tools.

Research and development activities.

Optimised and reliable technological processes.

Experienced technical and production staff.

A specialised machine park.

Enforcement of a uniform quality control policy.

A consistent purchasing policy and proven supplier base.

Resources to perform load motion testing prior to the delivery of equipment to the customer.

19

Organised service teams that can take action in the locations where the equipment is operated.

Provision of access to original spare parts.

Case study: Lignite mine, Bulgaria An example demonstrating full competence on the side of standard, as well as highly customised

gear technology, is the delivery of gears for the KWK-2000 and KWK-400L lignite bucket-wheel excavators put into operation in 2019 at the Mini Marica Iztok EAD lignite mine (Figure 1).

The technical design and production of both excavators was carried out under the internal cooperation of FAMUR, FAMUR FAMAK and SKW Projekt, forming part of TDJ. Structural designs of new bucket-wheel drive gears and designs of worm-epicyclic gears used in the driving and rotating system were developed at FAMUR Institute – a company belonging to the FAMUR Group, specialising in the development and implementation of new equipment and technologies.

Designing the bucket-wheel drive gear Conceptual work began with the adoption of design assumptions in December 2016. The basic construction assumptions for the bucket-wheel drive gear of the KWK-2000 excavator were developed by SKW Projekt (Table 1). An additional requirement that influenced the final design of the gear was the need to support the bucket-wheel shaft on the bearings of the gearbox’s planetary carrier. This meant that the gear design, Figure 1. Construction site of the KWK-2000 excavator. particularly the gear body and planetary carrier, had Table 1. Basic construction assumptions for the FBWG 1000 bucket-wheel drive gear to transfer loads from the of the KWK-2000 excavator weight, as well as the mining forces of the bucket wheel, Parameters Value to the excavator arm.

Rated output (kW) 1000 The entire process of creating the structural Input shaft speed (rpm) 1000 design of the FBWG 1000 Overall gear ratio transmission 238 (approximately) gear included: The development of a Total weight (t) <38 conceptual design.

Bearing rating life (h) >50 000 Strength calculations.

Permissible longtitudinal inclination of the Bearing durability -17 – 12 gear (˚) calculations.

The development of a Forced lubrication system with dupicated pump system preliminary structural Lubrication method and drive independent of the design. kinematic gear train FEM strength analyses.

Modal analyses.

Oil filtration Duplex pressure filter CFD numerical thermal Maximum oil temperature (˚C) 80 analyses.

Ambient temperature (˚C) -25 – 45 The advanced The measurment of bearing modules of the software temperatures, oil temperature, packages used enabled pressures in the forced oil Diagnostic system enabling circulation system, oil flow rate, the optimisation of the oil flow indication and vibration stress distribution on acquisition, and monitoring the teeth (Figure 2). This Oil heating system for low ambient Electric heaters built into the was accomplished with temperature conditions gear oil compartment tooth line modification.

Permissible sound power level LWA according <104 The magnitude of the to EN ISO 9614-2 [db(A)] modification is assumed

20

WORLD COAL ISSUE 2 2021

with respect to the calculated shaft deflections and gear body deformations. Due to the demands concerning the sound power level, the geometry of the toothing was optimised on the level of both macro and micro-geometries. At the macro-geometry level, the contact ratio of gears, reference profiles, and tooth line angles are optimised.

On the other hand, at the micro-geometry level, modifications are made to the tooth head and foot. The introduction of these modifications was made possible thanks to the numerical analysis of the contact in the gears meshing while simulating full gear load.

The non-standard way of supporting the gear and its weight restrictions resulted in the necessity of conducting strength calculations as early as the conceptual design stage (Figure 3). One of the most important design decisions was to determine the plane in which the main body division of the angle-cylindrical part of the gearbox occurs.

Due to the large size of the components and the associated potential assembly problems, the concept of division by the gear axes was adopted.

In addition to strength calculations, analyses were conducted to verify the accuracy of the oil heating system used.

The calculations required the simulation of conditions replicating the minimum ambient temperature and typical wind conditions that occur at the premises of the gear recipient.

A separate scenario was created to simulate the dissipation of heat generated in the gears meshing and bearings via the casing walls.

Figure 2. Shaft deformation analysis and results of optimisation of stress distribution along the tooth line.

Figure 3. Stress distribution in the gear casing.

Gear production The production of the gears was conducted in a plant specialising in precise processing, located in Katowice, Poland, which was put into operation in 2010. In addition to the mechanical processing unit, there is also a heat treatment department (Figure 4).

The mechanical processing unit conducts processing processes, including: Milling.

Turning.

Drilling.

Surface and diameter grinding.

Precise toothing processing on milling machines and tooth grinders manufactured by Gleason.

An important part of the production process is quality control and the use of lean manufacturing. Critical parts are inspected using ZEISS coordinate measuring machines.

Figure 4. FAMUR heat treatment department.

Figure 5. FBWG 1000 gear unit on test stand during sound power level assessment.

ISSUE 2 2021 WORLD COAL

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with a frequency of 10 Hz. The equipment of the test stand enables the performance of a variety of tests. The closed cooling water circuit means it is possible to test cooling systems equipped with heat exchangers. The data acquisition system allows for the linking of the signals from the built-in sensors on the devices tested with the parameters of the test stand control system.

During the tests related to the sound power measurement, the drive motors are enclosed to eliminate unnecessary noise sources (Figure 5).

Installing on a target device

Figure 6. Service activities carried out by an employee of the FAMUR Group Service Center on the KWK-2000 rotation gear of the KWK-2000 excavator arm.

Gear testing The customer required the supplier to test the gear under load and check the sound power emission level. It was possible to conduct these tests thanks to a specialised test stand with continuous power of 1.8 MW and instantaneous power of 2.7 MW, owned by FAMUR Group.

The drives are controlled by a set of frequency converters with power return to the electricity distribution network, making it possible to control the rotational speed and load smoothly. One of the operating modes that can be set during testing is the impact mode. In this mode, the torque varies between ±30% of the preset torque

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One of the final stages of the life cycle is the delivery and installation of the gear on the target device (Figure 6). In the case of bucket-wheel lignite excavators, this task is particularly complicated and requires both experience and technical knowledge.

In addition to assembly and service activities, the FAMUR Group Service Center conducts activities in the field of remote diagnostics of the condition of machines. With this in mind, the FBWG 1000 gear was equipped with a diagnostic system that collects and transmits signals from sensors installed on the gear to the excavator control system. It also acquires and transfers the signals to the FAMUR RSIMS Predictive Maintenance system.

This enables the presentation of the operating parameters of the monitored devices, as well as the automation of processes associated with the detection of malfunctions, based on measurements of temperatures, vibrations, loads, and pressures in the forced lubrication installation.

Conclusion The experience gained from the design, production, testing, and, above all, supervised operation stages will pay off in future projects, where a high degree of adjustment of the design to the requirements and solutions used by the customer will be required.

In part one of a two-part article, Dr Andrew Vince, Elsa Consulting Group, Australia, demonstrates how coal preparation plants can obtain money for ‘nothing’ through incremental accounting, incremental ash equalisation, and near gravity capture.

O

nce dug, raw coal is typically processed in a coal preparation plant (CPP) to remove rocks and dirt in order to allow tight product coal quality specifications to be met to satisfy premium priced market demands. These relate to the proportion of ash, termed ash value, that is formed when the coal is combusted. It is an undesirable characteristic with specifications for metallurgical coal markets of around 10%, and typically higher (>20%) for non-metallurgical products.

The proportion that is recovered by a CPP is termed yield and is expressed as a percentage. Higher prices are associated with lower product ash values and lower yields, and lower prices are associated with higher product ash levels and higher yields.

The CPP is only one of the processes in the mine coal production chain which can involve underground and/or surface operations. In the surface mining context, typical operations involve overburden removal, mining, crushing, and coal preparation components.

The approximate coal production cost breakdown for typical surface and underground mines is believed to be such that approximately 85% of the cost is incurred prior to the CPP. In other words, only around 15% of the cost is incurred by the CPP. Given that without the CPP high priced coal product sales could seldom be achieved, such considerations dramatically magnify the economic importance of the CPP.

Incremental accounting concept If the CPP performs better than expected, there will be extra saleable coal, which can be considered incremental saleable coal. Therefore, more money is made simply by increasing yield from the same quantity of raw mined coal. The incremental saleable coal can also be considered to effectively incur rejects handling/disposal credits as less has to be dumped. The 15% incremental production cost only comprises costs relating to processing, reject, and product handling.

When the plant performs better than expected, extra product is generated, as if by magic, at very low incremental cost.

23

Table 1. Hypothetical mine cost structure

Cost Item

Breakdown (%) US$/product t

Overburden removal

65

19.50

Coal mining

20

6

Crushing and processing

15

4.50

Overall

100

30

Table 2. Hypothetical mine total and incremental

accounting outcomes

Basis Total

Incremental

Selling price (US$/t)

50

50

Cost (US$/t)

30

4.50

Profit margin (US$/t)

20

45.50

Typical CPP process

% profit margin

40

91

CPP processing separates product with metallurgical uses in iron and steel production that typically commands the highest prices. In particular, coal used to make coke is required to exhibit combinations of value in use properties that are quite rare, and the same is true of the coke so produced.

Some of the rare and valuable properties relate to the propensity of the coal to cake and coke when heated anaerobically in a coke oven, and occur if significant proportions of vitrinite maceral are present.

A typical older style CPP circuit processing coking coal is depicted in Figure 1, where an initial size separation at 0.5 mm is shown. Here, dense medium cyclone (DMC) technology is used to beneficiate the coarse fraction, and fine coal flotation (FCF) technology used to beneficiate the finer material. The total plant product (TPP) is generated by combining the coarse coal product (CCP) from the DMC, and the fine coal product (FCP) from FCF unit.

To properly analyse the performance of a CPP from a metallurgical context, it is necessary to consider imperfect operation of each equipment item. In this process, the raw coal passes through a screen which separates particles greater than 0.5 mm in size, and so generates coarse and fine streams. The coarse stream, assumed to be 75% of the raw coal feed, passes to a DMC unit that separates ostensively on particle density, with light material reporting to the overflow and the heavier rejects passing to underflow.

The fine stream, in this instance assumed to be 25% of the raw coal feed, passes to the FCF unit in which

Table 3. Hypothetical incremental revenue change for

1% point CPP yield change

Yield in CPP Feed (tph)

1000

1000

1000

Yield (%)

60

61

59

Product (tph)

600

610

590

Profit (US$/h)

12 000

12 455

11 800

Incremental profit change per 1% yield increase (US$/h)

455

-200

Annualised incremental profit (assume 90% availability) (US$)

3 587 220

-1 576 800

Figure 1. Schematic of a CPP circuit.

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To provide a hypothetical numerical example, based on the cost structure shown by Table 1, Table 2 provides a very simplified financial comparison of total and incremental accounting analyses.

It is very revealing that a profit margin of 40% more than doubles to 91% when considered on an incremental accounting basis. Additional yield therefore creates significant leverage, and every extra tonne of product generated by yield increase from the CPP has an equally significant incremental financial benefit. In the Table 3 example, a hypothetical CPP with a feed rate of 1000 tph is considered. It is initially able to achieve a 60% yield, but this is increased to 61% by CPP improvements. The net result is US$3.6 million additional annual profit. However, on the other hand, a decrease to 59% yield, reduces annual profit by US$1.5 million.

In summary, additional yield in the CPP achieves additional sales revenue at very low incremental cost. The corollary is that yield loss in the CPP is expensive to the mine.

WORLD COAL ISSUE 2 2021

hydrophobic (floatable) material is separated and reported as FCP. This is combined, at the mixing point, with the DMC product to make the TPP.

Incremental ash equalisation concept and near gravity capture Incremental ash is a concept that relates to the ash value distribution of particles that comprise a TPP. Due to this distribution, although the product may have a given overall ash value (e.g. 10%), it actually comprises a mixture of particles with a wide range of ash values.

It may contain individual particles that have a 5%, 6%, or 7% ash value mixed with particles that have higher ash values. In fact, it is conceivable that there is an individual particle with a 25% ash value in a shipment Figure 2. Coarse coal yield/ash washability curve. that is sold as having a 10% average ash value.

In an analogous way, the ash value of particles in the CCP and FCP streams also have distributions. If the Table 4. TPP yield from combing coarse and fine circuit products separating condition of the DMC is changed by a small amount to increase the overall product ash value, then Processing a small (incremental) increase in yield would result in an Circuit Split (%) Yield (%) Ash (%) associated ash value (incremental ash). A similar effect occurs in relation to the operating condition of the FCP Coarse 75 44.9 10 stream.

Fines 25 55 10 In this context, the incremental ash equalisation Total plant product 47.4 10 concept is that TPP yield will be maximised only when the incremental ash of the CCP and FCF streams are the same at the mixing point.

To summarise, maximum yield in the CPP is comprising the final products are equalised. The corollary achieved when the incremental ash values of all streams is that yield is lost in the CPP when they are not.

Independent and unbiased: supporting coal handling and preparation plants, mineral processing plants and allied processing industries through a cost effective, world class, Australia-based consultancy business model.

“Everything has the potential for improvement – Elsa helps you tap into the cost-effective solutions.”

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With more than 36 years processing experience, Dr Andrew Vince C. Eng., F.I.Chem.E. (Elsa Consulting Group) offers amazing realistically achievable, technological, and operational improvement solutions for new or existing processing operations.

Impact of mixing point If the desired TPP has a specification of, for example, 10% ash, then this can be met from 10% ash CCP material and 10% ash FCP material, as the combined TTP would have 10% ash after the mixing point in Figure 1.

For a 10% ash CCP, the data shown by Figure 2 indicates the yield would be 44.9%. For a 10% ash FCP Table 5. TPP yield from combing coarse and fine circuit products with closer incremental ash values

Processing Circuit

Split (%)

Yield (%)

Ash (%)

Coarse

75

44.9

10

Fines

25

55

6

47.4

8.8

Total plant product

with 55% yield, Table 4 shows that the TPP yield would be 47.4 % for a 10% TPP ash.

Approximately 25 years ago, tall column FCF machines were commercialised that were in some instances capable of achieving the same flotation yield, but with a 2 – 4% lower concentrate ash value.

Transposing that effect to the example in Figure 2 would result in a flotation yield of 55% and ash of 6%, for which the TPP yield remains the same (47.4%) but the ash becomes 8.8% (Table 5).

A detailed examination of the original CCP and FCP streams indicated that they had very different incremental ash values, and the effect of the new FCF technology was to enable the incremental ash values of the two streams to draw closer together.

To reattain the 10% TPP ash, it is necessary to increase the DMC separating relative density (RD).

Figures 3 and 4 demonstrate that this will have the effect of increasing the yield significantly. In fact, to achieve a TPP ash of 10%, it becomes necessary to increase the separating RD from 1.33 to 1.36 to give a CCP ash of 11.3%. The net effect on the overall process is summarised by Table 6, which indicates a TPP net yield increase of 7.8% points is achieved.

In summary, a reduction in operating parallel circuit incremental ash difference results in superior overall separations. The corollary is inferior CPP separations occur whenever incremental ash differences are increased.

Near gravity capture concept Figure 3. Expanded cumulative ash/RD curve showing revised DMC RD and ash values to maintain 10% TPP ash.

Figure 4. Cumulative yield/cumulative ash curve showing revised DMC RD and ash values necessary to maintain 10% TPP ash.

Table 6. Increased DMC product ash and yield required to maintain TPP ash

Processing Circuit

Split (%)

Yield (%)

Ash (%)

Coarse

75

55.2

11.3

Fines

25

55

6

55.2

10

Total plant product

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WORLD COAL ISSUE 2 2021

The near gravity capture concept relates to the amount of material present in the DMC feed that is within close vicinity to the separating RD. Here, this concept is used to address how the TPP yield is increased whilst still producing a 10% ash product, using the advantages of the low FCP ash provided by the tall FCF column. In order to do this, it is helpful to consider some example washability data.

For this example, Figure 4 depicts how the cumulative mass percentage yield increases with increasing product cumulative ash for the material fed to the DMC unit. This has been derived by examining the results of routine raw coal laboratory RD fractionations with ash analyses.

By looking at this data further, the mass percentage of near gravity material, within ±0.10 RD units of each fraction, can be discerned, and a plot is shown by Figure 5. It is clear that the near gravity level at 1.33 RD would be >65.9%. That is, at 1.33 RD there is a significant amount of material between the values 1.23 RD and 1.43 RD. This is important because it relates to the amount of material that is subject to misplacement to rejects by any inefficiencies in the DMC circuit when processing this raw coal.

Figure 6 is a washability histogram, which shows graphically the mass percentages in each RD fraction.

Taking a simplified approach of only considering washability data (i.e. assuming perfect separations),

the data shown by Figure 6 indicates that the revised separations occur at much lower near gravity levels.

To summarise, disproportionate but favourably large additional yield in the CPP is achieved by a small increase in DMC separating RD due to equalising incremental ash of parallel streams.

It is important to note that if the DMC separating point were at 1.75 RD, for example, a yield increase would also occur but its magnitude would be much diminished, due to the diminished amount of relevant near gravity material.

In summary, much larger yield increases in the CPP are achieved by a small increase in DMC separating RD, due to equalising incremental ash of parallel streams when there are large proportions of near gravity material present.

Figure 5. Mass percent of material between ±0.10 RD units of RD of consideration.

Conclusion Coal preparation plants incur small relative costs and yet enable high prices to be attained for saleable coal. They enable highly leveraged incremental accounting to be utilised, as well as affording significant yield increases via straightforward operational setting optimisation, which can include significant near gravity material capture. It truly is magical when incremental accounting, incremental ash equalisation, and near gravity capture are used to obtain money for ‘nothing’.

A major threat to this magic will be discussed in a subsequent article in World Coal.

Figure 6. Yield washability histogram.

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28

Thomas Sloan, Quaker Houghton, USA, explores the importance of dust suppressants in the mining industry.

T

he need for dust suppressants in the mining industry continues to increase due to health, safety, and regulatory reasons. Whether in a surface or underground mine, dust and other particulates are a constant safety concern for those working in the mining industry. These hazards can also cause a wide range of issues including respiratory illnesses, exposure to noxious gases, and operational risks. For underground mining operations, dust reduction activities tend to focus

on the mining process where the majority of the dust is generated.

However, there are also issues with the generation of dust during the transportation of the run of mine product to the surface. As the mined ore moves along the conveyer system, it is dried by the incoming air that is used to ventilate the working section. The conveying system transports material in the opposite direction to the incoming air, increasing the drying process and allowing the

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smaller dust particles to become airborne more easily, as a result of the increased air flow and speed of the system. A fugitive dust issue is thus created and needs to be addressed throughout the entire system.

of water can be made more effective by atomising the water used, as well as adding a surfactant to change the water’s chemical make-up.

The principle of surface tension can be seen when liquid spreads onto a surface. An example is water Dust control techniques spreading over an area of perfectly clean glass. The There are a variety of dust control techniques used degree of wetting is a balance between two forces to curb the amount of fugitive dust generated from a within the liquid. The liquid’s adhesive force (attraction mining operation. Water sprays are the most common to another substance) encourages it to spread onto the and effective method employed. They can be used glass while the liquid’s cohesive force (attraction to the for both dust suppression and re-directing air flow. same substance) tries to form into a ball. Surfactants With this in mind, they are installed to suppress dust (also known as wetting agents) have a direct effect on at all major dust sources, including: cutting, loading, these forces. Surfactants increase the adhesive force and material transportation sites. While operational and lower the cohesive force which allows the liquid to changes and mechanical means are standard for most easily spread. The effects any surfactant has on these operations, the use of chemical suppressants should forces can be measured by determining the surface be considered to compliment engineering controls. tension of the liquid.

There are various types of chemistries used to control Water typically maintains a surface tension dust dependent upon the application. Though there of approximately 72 dynes/cm, depending on its are several combinations of chemicals used to achieve temperature. By adding the appropriate amount of the desired results, all products primarily try to bind surfactant to the system, surface tension can be reduced dust particles together, create a seal over the dust, or below 45 dynes/cm, considered the point where increase the weight of the particles to the point that maximum wetting of dust occurs. When the surface they cannot become airborne. tension is reduced, it will allow the droplet to absorb many small particles of dust and wet them more easily.

Water spray This will increase the weight of the dust particles and For conveying applications, dust is generally controlled reduce their ability to become airborne. When enough with a water spray system that continuously wets small particles of dust stick together, they increase in the material throughout the transportation process. weight and fall to the ground. In a normal spray system, Though effective in most circumstances, increased the size of a water droplet can remain large and collide amounts of water can affect moisture specifications with or create a slipstream effect with smaller dust and the ability to transport the ore efficiently. The use particles, limiting its effectiveness. Reducing surface tension also has an atomising effect on water droplet size, effectively reducing overall circumference. The Table 1. Respirable dust weight and size of the dust particle are not able overcome the surface tension of the water droplet Prior to After Applications DUSTGRIP® JFP-95 DUSTGRIP® JFP-95 and, in some cases, the water droplet may increase the suspension process.

Continuous 0.221 miner operation 0.326 Shuttle car

0.317

0.169

Shuttle car

0.350

0.221

Scoop

0.372

0.152

Roof bolter

0.228

0.168

Table 2. Quartz

Prior to After Applications DUSTGRIP® JFP-95 DUSTGRIP® JFP-95 Continuous 5% miner operation 33.8%

30

Shuttle car

6.9%

4.3%

Shuttle car

22.9%

4.1%

Scoop

4.4%

4.1%

Roof bolter

14.2%

7.1%

WORLD COAL ISSUE 2 2021

Surfactants In practice, both liquid and solid forms of surfactants are commonly used, dependent upon available equipment and operation preference. Both forms have the same function and are applied via dilution in the water source that supplys the spray nozzles.

The process can be introduced in a mine wide water system to control dust in all areas of the mine, or locally to control one specific area.

In a conveying system, transfer points become a focal point for fugitive dust as the material is agitated during the process. This is the area at which the mined material becomes airborne itself when it transfers from one conveyer to the next.

At most 90˚ transfers, the mined material impacts a deflector plate that is used to direct the flow of material onto the centre of the next conveyer.

The physical movement of the material allows untreated dust particles to become airborne and create float dust. Though water sprays are used

continuously at these points, the function of the spray system is only intended to act as a ‘curtain’ to limit the flight of dust. The addition of a surfactant to the water system allows a curtain to be maintained, while also effectively wetting the material as it becomes airborne.

The combination readily produces a 50% reduction in measured fugitive dust, whether at a specific location or as measured by operators on specific pieces of equipment. Tables 1 and 2 present examples of how a coal mine in the US significantly reduced dust readings across all equipment and areas by adding a surfactant to their current controls.

Respirable dust rule

and specific operational changes can be enforced to protect workers from the elevated levels.

Tables 1 and 2 show results from samples taken following MSHA guidelines at an underground coal mine. Samples were taken both before and after the addition of DUSTGRIP® JFP-95, Quaker Houghton’s solid cartridge dust suppressant.

Conclusion The generation of dust is an unavoidable consequence of mining activity. Whether generated from mining processes or reoccurring issues from where dust accumulates, fugitive dust is a health and safety hazard that must be managed effectively. Careful consideration should be given to the use of engineering controls, mechanical means, and chemical aids available to reduce worker exposure and increase mine safety.

Current industry best practices include a combination of all these controls to increase the effectiveness of their counterparts.

On 1 August 2016, Phase III of the Mine Safety and Health Administration’s (MSHA) respirable dust rule went into effect. The concentration limits for respirable coal mine dust were lowered from 2 mg/m3 of dust of air to 1.5 mg/m3 at underground and surface coal mines The concentration limits for respirable coal mine dust were lowered from 1 mg/m3 to 0.5 mg/m3 for intake air at underground mines and for part 90 miners (coal miners who have evidence of the development of pneumoconiosis) Within the dust levels recorded, quartz must be 0.10 mg/m3 or less of the total make-up.

Lowering the concentration of respirable coal mine dust in the air that miners breathe is the most effective means of preventing diseases caused by excessive exposure to such dust. MSHA requires quarterly sampling be performed by qualified mine personnel at specific equipment and worker locations.

Personal Dust Monitors (PDMs) are used to collect coal dust readings while volumetric cassette pumps are utilised for quartz measurements.

The samples are measured portal to portal and can result in reduced dust standards if over the maximum 1.5 mg/m3 of coal dust and 0.10 mg/m3 C i n c i n n a t i D u a l S p r o c k e t Conveyor Cha hains ins are prov v en to be be t t e r tha an other quartz content. mining chains. Ton Tons s bett b et er, in fact. Te sts con confi fi r m ou r c h a i n s d e l i v e r 2 0 p e r c e n t If high levels of respirable m o r e s t r e n g t h . T h e r e s u l t i s g r e a t e r d u r a b i l i t y, m a x i m u m availabill ity and a coal mine dust or quartz t r o u b l e - f r e e s e r v i c e l i f e . T h a t ’s how we del i ver the l o west cost pe r t on. are found, a reduced total For 90 years, Cincinnati has proven to be THE STRONGEST LINK. respirable coal dust standard

C ontact us a t 1 •5 1 3 •7 2 8 •4 0 4 0 o r v is it c in m in e .c o m t o le a r n m o re a b o u t C in c in n a t i Min e Ma c h iner y products .

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Todd Swinderman, Martin Engineering, USA, details how to achieve a return on investment for the control of conveyor dust.

M

ost conveyors handling bulk materials have some amount of material loss from spillage, leakage, dust and carryback emissions, collectively called fugitive materials. The root causes are often obvious, but rarely addressed.

Rather, the standard approach is to treat the symptoms. The consequences of failing to control fugitive materials include: unplanned downtime, excessive cleaning costs, regulatory actions, poor public relations, and safety incidents. Addressing the issues with workable long-term solutions improves availability, housekeeping and safety, ultimately enhancing the company’s cash flow.

Perhaps the most insidious of all forms of fugitive material is dust. Some of the issues are obvious – accumulations on floors and structures, premature bearing failures, and even explosion risk – but some are less noticeable, such as the long term physical and mental health issues caused by respirable and nuisance dust. A particle is considered respirable if it is 10 µm or smaller, which can penetrate into the gas exchange regions of the lungs and cause serious lung diseases.

Nuisance dust is generally understood as inhalable particles from 10 – 100 µm that are known to irritate the airways and cause inflammation, which can affect breathing and lead to chronic conditions, such as chronic obstructive pulmonary disease (COPD). It is estimated that for every accidental death in industry, there are 20 deaths due to the long-term effects of dust exposure.

These deaths are not as sudden, but are just as traumatic, and often do not show up as fatalities in the company injury statistics because a worker can be on disability for years before passing.

Reducing visible dust emissions (usually defined as ≥40 µm) from conveyors is typically a primary goal, partly because it attracts the attention of workers, neighbours, and inspectors. The Occupational Safety and Health Administration (OSHA) provides a list of hazardous dusts in 29 CFR 1910.1000 Z and recommends wet or vacuum cleaning, while prohibiting the use of compressed air, dry sweeping, or brushing in most situations (see 1910.1053[h]). For dust management, OSHA requires engineering controls, such as enclosures and dust collectors, be considered first. If not practical or effective,

work practices or respirators are needed to limit exposure. Quite often the use of respirators is seen as an acceptable alternative, but a closer evaluation will show respirators reduce productivity by as much as 19%, and prolonged use can affect cognitive and sensory abilities significantly.

These decreases in productivity alone can justify improvements to conveyor dust containment to reduce emissions.

Skirtboards The skirtboard enclosure is essentially a low-efficiency settling chamber. The basic concept is that a dust particle will settle out of a laminar air stream based on the speed of the air flow, Vair, and the terminal velocity, Vt, of the dust particle (Figure 1).

There are many rules of thumb, along with traditional and industry-based practices for skirtboard sizing and dust curtain placement, in an attempt to contain the dust in the skirtboard enclosure. Most of these practices are without proof of performance other than having always being done that way.

Current practice for conveyor skirtboard enclosures is to design for Vair ≤ 1.0 m/sec. by increasing the height (H) of the enclosure. Two common rules of thumb for the enclosure length are two times belt width, or 0.6 m for every 1 m/sec. in belt speed. It is interesting to note that if H is increased, the distance (L) that the average dust particle must travel also increases. A detailed design study of air flow and particulate settling was performed using SolidWorks 2019 Flow Simulation software.

A ‘standard conveyor’ was established as the baseline for the study (Figure 2). The standard conveyor is a 1200 mm wide belt with a 35˚ trough angle, travelling at 2 m/sec. A generic material was used to produce the baseline data, with a bulk density of 1442 kg/m3 and a nominal 50 mm minus particle size distribution with a 20˚ surcharge. The discharge chute was sized based on the rule of thumb: material volume equal to or less than 40% of the chute cross section. A drop height of 3 m, an open area of 0.9 m2, an average particle size of 25 mm, and bulk flow of 1680 tph were used to calculate the induced air volume.

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Several variables were investigated to simplify the analysis. The complete conveyor with discharge and receiving belts was modelled and, while there were significant regions of recirculation in the upper discharge section, the air flow in the chute was reasonably consistent. The chute was thus simplified

Figure 1. Theoretical dust particle settling distance ‘L’ in skirtboard enclosure.

to that shown in Figure 3, with the air volume and dust particles injected into the last 2 m of the chute.

The combination of variables studied are given in Table 1. Both external and internal analyses were conducted, with complete moving discharge and receiving conveyors (Figure 4). The bulk material surface was set to absorb particles and the walls set to reflect particles. The effectiveness of the enclosure variations was determined by counting the number of each size of particles that escaped the end of the enclosure compared to the number injected.

The results of the external analysis indicated that escaped dust particles increased in speed, as the air current is affected by travelling around the belt and the discharge pulley. This phenomenon is known as the Magnus Effect and emphasises the need for effective belt cleaning as close to the discharge as possible. A space of 1 mm between the bottom of the skirtboard and the belt was used to simulate leakage.

Curtain designs

Figure 2. Model of complete standard conveyor receiving and discharge for external analysis.

Figure 3. The standard conveyor used for baseline internal analysis.

Several experienced maintenance technicians were surveyed and their preferred curtain arrangements modelled. In addition, multiple curtain designs and placement schemes were studied, including staggered, slit, curved, angled, with and without slits, with holes, and no curtains.

Several unconventional skirtboard enclosures were modelled in an attempt to create recirculation in the enclosure and improve dust settling (Figure 5).

The optimum design for the standard conveyor was determined to be a conventional enclosure with a height of 600 mm a length of 3.6 m and three dust curtains placed in defined locations (Figure 6).

Worn exit curtains were also modelled, and as the spacing above the load increased, the dust settling performance deteriorated. The use of a single curtain right at the exit proved problematic in all cases, acting to speed up the exit air flow even further when close to the belt and re-entraining dust in the exiting air stream, while being ineffective in creating recirculation within the enclosure. When the curtain placed at the exit was worn too much, it was as if there was no curtain at all. A curtain placed right at the exit and adjusted close to the load creates another fugitive material problem, sometimes called the popcorn effect, where the curtain causes spillage by knocking material off the belt.

Results Particle density

Figure 4. Typical external analysis results – dust particle trajectories.

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WORLD COAL ISSUE 2 2021

Solid density had little effect on the settling of nuisance dust particles from 100 - 25 μm. In every case, 100% of the 100 and 40 μm particles settled almost immediately. As the bulk density increased, there was a moderate reduction in respirable dust emissions.

Discharge chute and tailbox The junction between the discharge chute and the skirtboards was found to be an important design detail for creating recirculation. Making the width of the discharge chute narrower than the width of the skirtboard helps to fold the air flow going into the first curtain, and that encourages distribution of the air flow toward the top of the enclosure, rather than along the surface of the material. The retrofit and mitered junctions were significantly more effective than a simple butt connection and Figure 5. Example of one of the unconventional chute designs analysed.

300 mm height, as shown in the standard conveyor Figure 3.

The tail box had little effect on dust emissions out of the exit end of the skirtboards.

In most configurations, the height of the tail box was set at 300 mm. The tail box length was set at 600 mm to match the typical 600 mm idler spacing used in the load zone by most conveyor manufacturers and engineers

Length of skirtboard It was found that for most situations, a 3600 mm long skirtboard produced the best results.

Increasing the length to 4800 mm and height to 900 mm had some marginal effect, but may not be worth the extra investment.

Figure 6. Typical recirculation air flow results with three curtains.

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An enclosure height beyond 600 mm for the standard conveyor with a single exit curtain did reduce nuisance emissions, but tended to increase respirable dust discharge. This is due to the average settling path being greater with the higher enclosure.

Air flow As would be expected, the average air velocity through the skirtboards was directly proportional to the induced air flow and cross-sectional area.

Average velocities in the skirtboards due to induced air ranged from 0.8 – 2.8 m/sec. Belt speed had a minor effect on the average velocities. The maximum air velocities were almost always found where the air flowed under the skirtboard curtains.

These high air speeds kept the respirable dust suspended, so reducing induced air into the chute was also shown to be important to improving performance.

Curtains The best results were obtained with three or more curtains (Figure 7). The design of the slits in the curtains is important to allow air to pass through, allowing the airflow paths to fill the entire chamber and not just flow at high speeds under the curtains.

It was found that the individual flaps should be approximately 50 mm wide, with slits at least 5 mm wide and the curtains extending the full width of the enclosure.

Preferred embodiments

Figure 7. Summary of results – percent of dust particles exiting the enclosures.

The best value for the cost of the skirtboard enclosure and its effectiveness is judged as skirtboards 600 mm high and 3600 mm long, with three full width slit curtains using either the retrofit or mitered discharge chute-to-skirtboard connection (Figures 8 and 9).

Table 1. Variables used in the particle study

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Parameter

Standard conveyor Experiment variables

Belt speed (m/sec.)

2

2–8

Belt width

1200

600, 1200, and 1800

Bulk material solid density (kg/m3)

1500

750, 1500, and 3000

Air flow (m3/sec.)

0.5

0.25, 0.5, and 0.75

Curtain placements

1 at exit

1 to 6 curtains, at various spacings

Curtain clearance (mm)

50

0 – 150 above load

Skirtboard height (mm)

300

300, 600, and 900

Skirtboard length (mm)

2400

2400, 3600, and 4800

Wall roughness (mm)

1

0 – 100

Chute to skirtboard

Standard inline

Miltered, full width, and 90˚

Tail box length: 600 mm

300 high

300, 600, and 900 high

Dust particle dia. (μm)

All configurations modelled with 100, 50, 40, 25, 10, and 1 μm dust particles

WORLD COAL ISSUE 2 2021

Design recommendations Design recommendations include: Discharge chute width across skirtboards 200 mm < width between skirtboards.

Skirtboard outside width based on horizontal dimension of free belt edge for sealing and belt wander edge allowance ≥ 115 mm per side (FoundationsTM method).

Skirtboard height ≥ 600 mm.

Inlet to skirtboards air volume flow ≤ 0.50 m3/sec.

Length of skirtboards for material loading turbulence ≥ 1000 mm when required.

Length of skirtboards for dust settlement ≥ 3600 mm, plus extra allowance for loading turbulence if necessary.

Skirtboard dust curtains: Entrance (1st) curtain 300 mm past end of extra allowance for material turbulence and distributing air flow.

2nd (middle) curtain centred between entrance and exit curtains.

Exit (3rd) curtain 300 mm from end of skirtboards.

Curtain clearance above the bulk material: 25 mm preferred, 50 mm max.

Curtain flaps: approximately 50 mm wide strips separated by slots ≥ 5mm.

Conclusion While some improvement is seen with increased skirtboard height and length, it is doubtful that it can be economically justified on the reduction of respirable dust alone. A return on investment for control of nuisance dust for new and retrofit designs can be based on reducing cleaning labour, increased equipment life, and/or elimination of dust collection. If the improvements reduce the TWA of respirable dust emissions to the point where engineering or administrative controls can be less stringent, then a financial case could also be made based on improvements in labour productivity.

Figure 8. Recommended mitered skirtboard enclosure for new construction.

References 1.

2.

3.

JOHNSON, A.T., ‘Respirator masks protect health but impact performance: a review,’ Journal of Biological Engineering, Vol. 10, No. 4 (2016), https://jbioleng. biomedcentral.com/articles/10.1186/s13036-016-0025-4 [Accessed 1/14/21].

SWINDERMAN, T., 'Foundations, The Practical Resource for Cleaner, Safer, More Productive Dust & Material Control', Martin Engineering, 4th edition, (2009).

'Foundations for Conveyor Safety, The Global Best Practices Resource for Safer Bulk Material Handling', Martin Engineering, 1st edition, (2016).

Figure 9. Recommended skirtboard enclosure for retrofit or angle transfer.

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Franco Mazzucato, VAREYE, Switzerland, demonstrates how the concept of chain of custody can help satisfy all of the main requirements of coal producers.

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C

orporate responsibility is a wide concept, encompassing the social responsibility of companies, as well as environmental friendliness, trade fairness, and much more. A novel stream adding to that is the concept of chain of custody (CoC), as more and more end-users get passionate about knowing that the products that they purchase derive from sustainable sources.

Several systems for the certification of CoCs have developed over the last few years and offer an array of services, sometimes based on the data security level provided by blockchain technology.

This article analyses the features of the VAREYE CoC and operational control system, using a case study to reference the short journey of coal from the mine through some transportation, warehousing, and transformation processes required to ship anthracite in different grades ready for shipment to specific end-customers globally.

Background The anthracite production process considered for this article is relatively simple; the raw coal

is ‘simply’ extracted, by various means, from the ground and either deposited on huge fields for further shipment or directly sent, often via conveyor belts, to the subsequent process stage – a refinery.

Some processes to remove impurities can include: washing with water; removal of ashes, ground, stones, and sulfur; crushing and pulverisation; screening from coarse to fines; agglomeration; and blending.

Although the full story is slightly more complicated, it is enough to help understand the position at each stage of the coal journey.

A certified chain of custody for coal A coal producer looking for a system to prove to their customers the true origin of the coal that they were selling also needed a flexible system to match, from the operating standpoint, exactly the kind of processes carried out within the perimeter of the mine. This was in addition to the refinery and tools to optimise the output from their facility, producing several millions of tonnes of coal per year. They decided to test and adopt the VAREYE system.

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The supplier as the first link in the value chain Several ‘end-users’ are far more interested in the CoC of the products that they purchase than the suppliers are. In all cases, even if the end-user is the direct customer of the system, the first act is to create a ‘supplier’ within their CoC. After the creation of the supplier within the system, all subsequent supply chain interactions are fully in the hands of the participants to the CoC, who in turn and in a controlled manner, will be the custodian of the raw materials and of the manufactured (semi) finished products.

The original raw material supplier steps in The supplier has to generate a supply in supply lots (i.e. on a daily basis, equivalent to some thousands of tons of raw coal per day); this act generates one quick read code (QRC) per day associated to the actually extracted quantity of raw coal.

The supplier’s task, once the initial set-up is complete, only consists of:

Figure 1. Guaranteeing the full traceability of the origin of coal.

Defining the material to supply: a one-off activity.

Creating the transporting company and the next user of the coal in the system (in this case the next user is internal – the refinery, and just transportations over conveyor belts are used).

Defining an actual supply lot for that day’s raw coal production.

Assigning that lot to the transportation via conveyor belt.

Every time that a new user is created, an automatic email is sent to the email address provided by the supplier. The concept of CoC fully applies here: the supplier, the very first custodian, knows perfectly well to whom the material must be delivered and who is going to carry out the transportation, so the next two custodians in the CoC have been easily identified.

Generating QRCs The step of creating an actual supply for the raw coal lot generates a master QRC: every subsequent QRC generated along the CoC will be linked to this one via a series of unchangeable links, all mastered by the web-based system, and this constitutes the guarantee about the solidity and the continuity of the CoC. Also, assigning the lot for transportation to a logistics provider generates a QRC that will be readable exclusively by the transporting entity (the ‘custodian’ dedicated to that transportation, i.e. the captain of a vessel or a truck driver) and by the receiver.

If transportation occurs via trucks, the truck driver will need to install a dedicated application on their mobile phone, by simply inserting their telephone number and nothing else. As the logistics provider knows all needed transportation details, the information provided is enough to identify, without margin of doubt, the custodian for the trip.

Once the application is installed, the truck driver must scan the QRC provided by the supplier for that lot. The application will record the geolocation of the scanning, the timestamp, and will consider the driver as the new custodian of the raw coal lot.

Geolocation and security

Figure 2. Tracking each transportation step individually.

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WORLD COAL ISSUE 2 2021

Some companies need to know where their lot is at any moment during the trip, or want to ensure that the journey does not cross unwanted borders (i.e. in the case of sanctioned countries). Although several expensive systems exist to accomplish this task, such as container shipments, VAREYE has implemented a premium feature in its smartphone application to allow for GPS tracking of the smartphone position during the journey from the port of loading to the port of discharge, assuming that the custodian must be present during the trip as the responsible person for the lot.

Reaching the transformer – the refinery In this case, the raw material reached the receiving refinery via conveyor belt, while a sub-lot of the original lot was sent to an internal warehouse for raw materials: the corresponding QRCs can be coupled later to a single code without losing the CoC properties. The receiver’s user at the refinery can acknowledge receipt of the lot by accessing the web database or by scanning the corresponding QRC directly from the smartphone application. This would trigger the following two actions: The quantity received by the refinery’s user is deducted from the original quantity of the full lot.

The refinery’s user is the new custodian of the in-taken volume.

Transforming the raw coal The QRC is then moved to the ‘production’ area of the system. This environment, available to transformers, keeps track of the transformation of a raw material (input) into a product (output), in terms of mass balance.

Joining QRCs from several sources is possible, thus preserving the full quality of the CoC and keeping full operating control of the transformed quantities of raw materials. This is especially relevant to cases in which the alignment of volumes across multiple storage places and production is a cause of book-keeping concerns, because the mass balance control is guaranteed.

The recipe to convert raw coal When processes run very regularly and in a predictable way, the transformer can use a standard

recipe for the transformation of raw coal into several types of anthracite. When processes are unstable for any reason, the transformation can be carried out on the basis of actual weights in effect obtained during the transformation of each single lot, including the formation of solid and liquid waste and other losses.

Moreover, the actual process needs the addition of water to facilitate the segregation of coal; water (or any other material) can be added as a non-CoC material to the raw coal, thus fully preserving the CoC of the products obtained at the refinery and fully reflecting the mass balance requirements for the CoC.

Operational tools The refinery needed some improvements in the operational control during the separation phase.

The addition of water causes a mass imbalance that has to be corrected manually per each lot on the basis of hygroscopic measurements from the laboratory, in order to report back the adjusted weight of anthracite products in respect to the original humidity content of the raw coal. Dedicated tables are embedded into the system, where actual data can be input on a day-by-day basis and calculations are carried out automatically.

As information is stored for a contractually agreed timeframe within VAREYE, the customer can use the historic data base to measure the performance of the separation processes over time, and to analyse it in search of opportunities to improve and optimise.

Unshipped finished products, rejects, residues Products that are not directly shipped to customers can be stored within an internal warehouse for shipment in the future, or for future blending with different semi-finished products to conform to customers’ requirements, or, being defective, for recycling back into the production process.

The CoC mechanism also applies to by-products, i.e. for the management of solid waste, which is subject to controls due to its potentially harmful nature. The supplier can demonstrate not only how much solid waste is produced from each lot in a firmly measured quantity, but also how it is shipped and received by the end-user; this constitutes a relevant advantage facing inspections by controlling environmental authorities.

Mixing final products and shipping

Figure 3. Personalise tracking while maintaining full control of the CoC via mass balance.

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WORLD COAL ISSUE 2 2021

Occasionally, types of anthracite are blended to obtain a final product exactly matching the characteristics required by customers. In order to maintain a full CoC traceability, this feature is also incorporated into the system.

Each lot of product ready for shipment is entitled to its own QRC, still linked in the CoC with the

The end of the journey

original master QRC from the mine. Again, the refinery knows exactly who is going to transport each anthracite type, and where it is going to go.

Those constitute the next links in the CoC.

The end-users can take custody of the incoming QRCs via the application or the web-based interface; only after the QRCs acquisition and weight confirmation can the end-users download a CoC certificate for each single lot received via truck, ship, or train. The certificate is automatically generated

by VAREYE when there is no detected interruption in the CoC.

Shipping by train The system is also able to cope with types of logistics where no actual custodian can be identified; for those means of transportation, the custody of the product is maintained by the shipping entity until it reaches the next user, because, for example, a national railway system might be unwilling to take custody under a CoC scheme for any material. The concept of a CoC is fully maintained anyway, as long as the QRC is in the hands of the refinery and until it reaches destination.

Conclusion A CoC system, similar to the one analysed in this article, is able to satisfy all of the main requirements provided by a coal producing customer. In particular, it generates a solid CoC certificate based on the mass balance of input and output materials and helps maintain full traceability of the streams of products deriving from the raw coal, as well as granting online access to transformation parameters of raw coal into anthracite and tracking shipments in break bulk mode.

This system might therefore constitute a solid alternative to some of the more expensive and more complicated systems that are available today on the market, thus contributing to and reinforcing the sustainability image of companies adopting it.

Shipment tracking Each transport has its own QRC that can be read by the logistics provider and, upon arrival, by the end-user. Additional features include the splitting of shipments among several logistic providers, by maintaining the traceability of each single QRC and the tracking of each shipment, designed in principle for trucks and ship, by using the geolocation feature available on all smartphones.

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James Trevelyan, Speedcast, UK, outlines how mining automation can help deliver business results.

I

n 2019, Internet of Things (IoT) specialist Charles Towers-Clark wrote that “mining is now at a critical junction in which it will either adopt new technologies or be left behind.”1 He noted that second tier operators, more agile than the giants of the industry, are already acting on opportunities to use emerging technologies to enter markets they have been largely blocked out of.

The giants have apparently been paying attention, with Grand View Research reporting that the global mining automation market was worth US$3.6 billion in 2017 and will grow at 7.3% compound annual growth rate (CAGR) through 2025.2 At the beginning of 2019, Rio Tinto announced the launch of the world’s first autonomous long-distance railway network

45

to transport iron ore to the company’s ports in the Pilbara Region of Western Australia. In southern Mali, Resolute Mining uses automated vehicles and drill equipment to extract 300 000 oz/y of gold from the Syama Complex.

On the hunt The established leaders of the business are now moving into automation for reasons other than just ‘being left behind.’ Coal is the largest revenue-generating material mined today, but its dominant share is levelling off as natural gas and renewables continue to grow. With volume growth increasingly unable to boost revenue and profits, investments that improve operations and productivity look more appealing by the year. According to McKinsey & Co., worldwide mining operations are approximately 28% less productive today than they were a decade ago.3 In a March 2020 interview, the CEO of Resolute Mining, John Welborn, cited several benefits that automation delivers.4 The first is safety; the company’s policy manual forbids manual interaction with automated equipment onsite to keep people out of harm’s way. Robotic systems, which never need to rest, also enhance productivity delivering an approximate 30% gain in operational efficiency.

He cited a third benefit that may surprise people: simplifying the operation using robotics allowed the company to train native Malians to do the work, rather than rely on expatriate miners with training and experience in drill operations.

Putting automation to work The range of automated systems in use today is broad. Automated drills scan the coal face and prepare it for blasting with far greater precision and speed. Automated vehicles haul material, navigating confined space and rough roads using GPS and signals from wireless beacons on the ground. Asset trackers mark the location of hundreds of millions of dollars of equipment and can trigger alerts in the event of theft or misuse. More sophisticated versions transmit telematics data from engines to predict maintenance needs and increase uptime.

Video surveillance cameras feed data analytics that can automatically identify and flag human errors that may endanger people and operations, from missing hard hats to unsafe handling of explosives.

Drones capture video feeds of mining waste, which can be rendered into 3D models of piles to assess their safety and stability.

The most advanced companies are developing ‘digital twins’ of their operations. Using data from construction and operation, they create a digital replica that uses real time data from the field. As additions and changes to the facility are proposed, the digital twin can test the decision’s accuracy before installation. By eliminating errors, the

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WORLD COAL ISSUE 2 2021

technology can save millions of dollars on field implementation.

When carefully implemented, each of these technologies can generate a reduction in risk, cost savings, or productivity improvement that offers a material improvement in business results.

The connected mine It is a vast array of new solutions – and it rests on something in short supply at mine sites: reliable, affordable, high-capacity communications. To achieve breakthroughs in safety, productivity and profitability, data must flow at high volume with no interruptions or degradation of service. While miners focus on pulling raw materials from the ground, managers rely on the system’s ability to draw massive amounts of data from those same processes.

The design of communications infrastructure – and the management of operating networks – has become critical to the safe and profitable operation of a coal mine. The remoteness of mining sites requires the integration of multiple communication technologies into a high-performance whole. Key elements in connectivity for the connected mine include:

Mine site communications Wi-Fi is essential for communications, in order to enable every computer, tablet, and mobile phone on the site to access daily operations. That accessibility is balanced by short range and lower power, however, which is particularly problematic for underground mines. To overcome this, private long-term evolution (LTE) technology is becoming increasingly popular for its long-range ability to penetrate walls and barriers, high bandwidth, and reliability. Nokia has introduced a digital automation cloud that uses LTE to interconnect every aspect of operations and enable the full range of automation and IoT applications.

Backhaul access terminals These are multi-mode terminals that support multiple satellite bands, microwave links, cellular service and optical fibre, and connect seamlessly with mine site networks. Terminal software manages the logistics of making and breaking connections, from virtual SIM cards to least-cost routing.

Backhaul network Satellite can offer the most cost-effective way to reach remote mine sites. Depending on the location, a productive mine may also be able to integrate optical fibre as the primary path and retain satellite as a backup. Providing the backhaul requires a network of satellites, teleports, fibre and high-performance cellular base stations in strategic locations, as well as high-capacity peering with wired and mobile networks, in order to ensure connectivity to the rest of the world.

Intelligent management Managing all this connectivity requires major intelligence in the network to identify available transmission routes and automatically switch service between them to achieve the best performance at the lowest cost. At the highest levels, using technologies like software-defined wide area networks (SD-WANs), to automatically analyse and manage traffic among routes is best to offer very different kinds of performance, providing customers with predictable quality of service and better utilisation of the available bandwidth. In addition to managing the network, a management platform should provide end-to-end visibility into remote sites and applications, ensure robust cybersecurity, offer direct connection to cloud services, and permit companies to run their propriety applications securely within the network.

Successful mines have a long life, but often follow a predictable pattern. Well-designed communications should adapt to the changing requirements on the ground throughout that lifetime to cost-effectively support current needs.

During prospect and exploration, the primary need will tend to be a transportable VSAT terminal supporting an ‘office in a box,’ with local Wi-Fi, cybersecurity, IPPBX, and optimised file synchronisation. In development, sites require

automated network management for the fixed VSAT, BGAN, and LTE systems that support IoT, asset tracking, video surveillance, and crew welfare. During extraction, the priority is on ensuring high performance for IoT, autonomous vehicle and tracking systems, as well as mine site communications by Wi-Fi, private LTE, and two-way radio.

Automation solutions deliver results Creating the connected mine as a platform for automation is obviously a big investment. What kinds of problems is it able to solve?

A major manufacturer of industrial compressors depends on connected mine technology to backhaul sensor data from the field to company headquarters, where data analytics predict and schedule maintenance to minimise downtime and costs. When a single pump failure at a mine site can cost hundreds of thousands of dollars per day in lost production, payback comes fast.

For a large mining company, an automation solution provides real-time monitoring of employees and man down capabilities, as well as geofencing that triggers alerts when assets leave a set location and telematics that feed predictive maintenance applications. Real-time analysis of the video feed from surveillance cameras also alerts any human

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error that may endanger people and operations, from missing hard-hats to unsafe handling of explosives.

Altogether, the connected mine system identifies bottlenecks in operations, increases uptime, reduces theft and improves safety, in addition to contributing to the continuity of operations and crew morale.

Asset tracking technology at a major resources operation tracks the location and movement of tens of thousands of customer assets. A small, battery-powered sensor attached to equipment periodically sends GPS coordinates and CANBUS telematic readings, which are integrated into customer applications. Improved maintenance efficiency based on actual run times has reduced downtime by 30 – 50%, while location data has increased operational efficiency and reduced capital expense.

A mining company operating across multiple regions in the Middle East, Africa, and Asia set a goal of centralising operations management at a single control centre, which could gain a 360˚ view of the assets and their production. Achieving that goal required a large scale automation deployment at the sites and extremely reliable data connectivity. Connected mine technology was crucial to delivering high quality of service by optimising the utilisation of hundreds of circuits. By doing this, the company reduced its production costs by 30%.

Conclusion Creating a connected mine and implementing automation projects on its foundation is a team sport. Like most major infrastructure projects, it requires systems design and integration, technology products, procurement and logistics, onsite installation, testing, training, maintenance, and technical support. Experience shows the value, however, of appointing one experienced organisation as the prime contractor and making it accountable for all projects in its area of expertise.

References 1.

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TOWERS-CLARK, C., ‘The Mining Industry Could Strike Gold With Automation,’ Forbes Magazine, www.forbes.com/sites/ charlestowersclark/2019/10/31/the-mining-industry-could-strikegold-with-automation/ ‘Mining Automation Market Size, Share & Trends Analysis Report’, Grand View Research, www.grandviewresearch.com/industryanalysis/mining-automation-market LALA, A., MOYO, M., REHBACH, S., and SELLSCHOP, R., ‘Productivity in mining operations: reversing the downward trend,’ McKinsey & Company, www.mckinsey.com/industries/metalsand-mining/our-insights/productivity-in-mining-operationsreversing-the-downward-trend NOONE, G, ‘What does the future hold for automation in the mining industry?’, NS Energy, www.nsenergybusiness.com/ features/automation-mining-industry-future/

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