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By J Koshy, M Ralph, P Foley

Mining in the state of Western Australia (WA) formally commenced in the 1840s, and over the ensuing 180 years has evolved to be the epicentre of the Australian mining industry and a significant contributor to the national economy. The lithology of WA is replete with mineralisation that hosts uranium and ‘critical minerals’ required for the global renewable energy sector. The state’s first uranium mine is under development, and high levels of activity are occurring in the state’s nascent critical minerals sector, with 168 WA-based companies pursuing rare earth-bearing minerals, 51 of which are actively drilling on their tenements. WA’s mineral deposits typically contain levels of the naturally occurring radionuclides (NORs) thorium-232 and uranium-238 that are elevated above the global crustal average. Workers are exposed to NORs during the mining and mineral extraction processes, and radiation doses that exceed applicable exposure standards may eventuate. The research traces the history of worker radiation doses from 1977 to 2020, finding the maximum dose was 163.4 mSv, more than eight times the current derived annual dose limit. Whilst 93.5 per cent of all workers received doses of less than 5.0 mSv per annum, the potential for elevated doses is ever-present as witnessed by 10.3 mSv reported in 2009/2010. The increase in activity coincides with a revision of the dose coefficients (DCs) associated with the intake of radionuclides. The research evaluates the revised DCs and forecasts doses from inhalation of radioactive dusts will nearly double, and lead to workers receiving doses exceeding 5 mSv for the first time since 2009/2010. The research finds that the current regulatory framework is fit-for-purpose. However, inter-agency relationships, and the capacity of the regulator to effectively regulate the current and future number of mining operations is questioned. The mining industry is vulnerable to capability and capacity constraints – but has failed to respond to issues in relation to competent radiation safety officers first raised by the Winn Inquiry (Winn, Mathews and Tough, 1984). Disconcertingly, monitoring of worker exposures to NORs reached a nadir in 2021, raising questions as to the veracity of worker doses reported to the regulatory agency. The research recommends personal dust sampling be prioritised.

Apr 16, 2024

By J Webb

The mining industry is relatively niche and complex compared to other global industries in its safety and operating environment. Whilst some of the technology required to decarbonise the mining industry will emerge from the mass market (eg batteries, energy storage solutions and renewable power generation) where exogeneous external investment and innovation will drive supply, bespoke applications such as material movement will be constrained by industry limitations. Underground load and haul equipment burns the majority portion of underground mine diesel, and typically 25 per cent of scope one and two emissions. Transitioning away from incumbent diesel engines offers a considerable health benefit to all mine workers, as well as decarbonisation achievements, and through trials there is emerging evidence of more productive equipment and realistic expectations of lower operating costs of fleet. However, new equipment and material movement systems that support these industry goals are currently approached with caution due to the pivotal role they play in delivering productivity goals, and the lack of experiential data and certainty to mitigate the supplier development risk during this technology transition period, where all resources are required to meet a booming industry. A group of mining companies and suppliers have the aligned aim to accelerate the understanding and availability of heavy haulage mobile equipment through collaboratively piloting equipment and working with suppliers and each other to aggregate market demand, encourage investment and resolve the mine design and technology choices through their involvement in the Electric Mine Consortium (EMC). This paper will outline the major challenges the industry must overcome in sourcing and adopting a zero-diesel particulate and zero-emission mine, drawn from cases and insights across ten EMC mining company members.

Mar 29, 2023

By Brady KT, Pattenden G

A laboratory size solvent extraction apparatus has been constructed, which incorp- orates three stages of countercurrent extraction, followed by two stages of counter- current stripping. The model uses a gravity flow system from one stage to another and air lift pumps to recirculate organic and aqueous phases. A novel pump/mixer system is used to transfer solutions from the mixer compartments to the settler compartments. The model has proven valuable in the teaching of solvent extraction principles.

Jan 1, 1984

The Skybolt is a new bolt concept, point anchored with resin in large diameter holes of specific sizes 38 mm and 45 mm. The new design achieves the optimum annular spacing required for mixing the resin anchor components which is essential for optimum resin bonding of the bolt to the surrounding rock. This paper explains the load transfer mechanisms between bolt/resin/rock, unique to this bolt concept. It compares the pull-out test results to those of paddle and expansion shell type bolts, and highlights the versatility of Skybolt over existing, currently used, rock support systems and the benefits mine operators can achieve when using the Skybolt.

Jan 1, 1992

By C Hertle

GHD-Black & Veatch (GHD-BV) have completed design and specification of the ash thickening plant at Tarong Power Station, including operation of a pilot plant. Construction of the plant is in progress and commissioning is planned for early-2004. The objective of the new plant is to convert the low concentration (lean phase) ash slurry currently generated by the power station into concentrated slurry which will then be pumped to the existing ash dam. Water recovered from the lean slurry will be returned to the power station for reuse. The drivers behind this project are to extend the life of the ash dam and to reduce water pumping costs. A maximum flow of 1000 litres per second is expected in the thickening plant. The process involves a screening phase, which removes large material that could cause blockages or equipment damage. A 50 metre diameter thickener then concentrates the screened lean ash slurry to 55 - 60 per cent w/w solids. In addition, the thickener plant will allow the harvesting of floating cenospheres (hollow, spherical ash particles) from the lean slurry. Cenospheres are currently collected from the surface of the ash dam and drained on a pad adjacent to the dam. The new system will use a surface skimmer to remove the cenospheres from the thickener and transfer them to settling ponds for further classification. The settling ponds simulate the detention on the existing ash dam, and allow entrained fine ash and slow settling cenospheres time to settle. As settling occurs in ponds, the slow settling cenospheres can be completely recovered whereas when they settle in the dam, the opportunity for recovery is lost. Cenospheres are a valuable by-product produced during the combustion process, and recycling of this material reduces the waste generated by the power station. Water recovered from the thickener drains to a three megalitre reservoir. Water is drawn from the reservoir for thickener plant service water and various other uses in the power station. The bulk of the water is used to sluice ash from the power station to the thickening plant. In the current configuration, surface water from the ash dam is reused but must be pumped several kilometres back up to the power station. The dam also holds an inventory of several thousand megalitres of water and has significant evaporative losses. Therefore the current raw water make up demand is substantial. In addition, some areas of the power station traditionally using raw water will be modified as part of this project to allow the use of recovered water, further reducing the raw water demand. The design incorporates many features of sustainable water management. By more effectively recovering water from the lean ash slurry, the amount of raw water make up required by the system will be significantly reduced. This method of water recovery provides a more sustainable and energy efficient ash-transport mechanism.

Jan 1, 2003

By S Shafiee, N Abbate

The evaluation of mining projects requires a methodology that will give flexibility and manage the existing uncertainty within the projects. The discount cash flow (DCF) and other traditional evaluation approaches, which are widely used in evaluating a significant number of mining projects, have simply assumed that the main variables remain constant in their evaluation; elements such as discounted rate, mine life, operating cost and production rate. The DCF ignores managementÆs flexibility to adapt and reforecast and revise decisions. Real options valuation (ROV) is one of the modern evaluation methodologies that provide a tool to adapt and revise mining projects under uncertainty and future variables movements. ROV brings more variables into the evaluation model compared to DCF and assumes them as uncertain and dependent. Finally, ROV provides a range of solutions that can assist in managing this flexibility.This paper endeavours to compare ROV and DCF for mining projects comprehensively and applies these two techniques in the model. The paper shows that ROV will be inclusive of extra value in mining projects due to variables not allowed for, or even ignored, when the DCF model alone is used. One of the significant advantages of the ROV method is being able to evaluate mining projects under different scenarios from the inception of the projects. Furthermore, ROV gives the ability to evaluate the mining project while allowing for abandonment, temporary suspension, or expanding the mining project. In other words, the ROV evaluation process creates an analytical environment, which allows for optimisation of the mining plan within the mining project, as well as the ability to change the capital structure dependant on existing circumstances over the life of the project. The ROV is a new evaluation method that can add value in mining project analysis and offers opportunities to amplify gains, or to mitigate losses. This paper also discusses some of the reluctance to use ROV instead of DCF in current project evaluation.CITATION:Shafiee, S and Abbate, N, 2012. Now, this is the time for mining companies to choose - Real option valuation or discount cash flow, in Proceedings Project Evaluation 2012 , pp 225-234 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

By X Li, R Chu, X Deng

The hot-dip galvanising industry is the largest consumer of zinc, with over 40 per cent of the world’s total annual production of zinc used for galvanised steel. The dross generated in the hot-dip galvanising coating process is a valuable co-product, since it contains high quantities of recyclable metal. A new method to recover the metal from the industrial galvanising dross was proposed using supergravity separation. During the hot-dip galvanising process, the presence of zinc dross has a serious impact on the surface quality of the hot-dip galvanised sheet, forming zinc dross defects. To reduce the impact of zinc dross, the zinc dross on the surface of the zinc pool needs to be manually or mechanically removed at regular intervals. However, during the dross removal process, a large amount of metal zinc is inevitably carried out, resulting in low zinc utilisation rate and high zinc loss rate. This article proposes an efficient and low-cost technology for the recycling and utilisation of hotdip galvanised dross, which uses super-gravity technology to recover hot-dip galvanised dross online. The metal in the hot-dip galvanised dross returns to the zinc pot in situ, while a small part of the dross remains in the super-gravity equipment, which can reduce the amount of zinc dross by more than 60 per cent and achieve a reduction in zinc loss from 17 per cent to less than 7 per cent.

Jun 19, 2024

By J Manuel, A Trudu

Regulations on the emission of particulates from sinter plant stacks are becoming increasingly stringent and reducing these emissions by improving gas cleaning systems is a significant cost to the sinter plants. This paper describes an investigation into the emission of particulate matter from an iron ore sinter bed during the sintering of a Japanese Steel Mill (JSM) style ore blend in a 300 mm diameter pot grate test facility. Several techniques were trialled to determine a reliable method to sample the quantity of dust emitted and determine the mechanism of dust emission from the sinter bed. The nature of the dust was also examined using chemical and size analysis as well as optical and scanning electron microscopy. The paper discusses the techniques used to carry out the program as well as results on dust loading measured during sintering and the nature of the dust captured.

Jan 1, 2002

By J-T Zhu, Q-Y Tu, S-L Kong, L Wang, Y-P Cheng, H-Y Liu, Q-L Yang

China is the largest coal-producing country in the world, while the geological conditions of deep coal mining are extremely complicated with high ground stress, high gas pressure and low permeability, which results in the difficulty of gas drainage and aggravation of gas explosion and coal and gas outburst disasters. Co-extraction of coal and gas is an effective method to eliminate coalmine gas disasters and realise the safe exploitation of coal and efficient gas drainage at the same time. This concept is widely accepted by the main coal-producing countries around the world, while the concrete definition of co-extraction is vague and not unified, and there is little accurate theoretical support for co-extraction of coal and gas, which makes it hard to determine efficient gas drainage methods correspondingly according to the features of coal seams in a comprehensive and systematic way. Based on theoretical analysis, laboratory test and field observations, basic thoughts and specific definition of co-extraction of coal and gas were put forward after analysing the occurrence characteristics of coal seams in China. We obtained the mechanism of mining-enhanced permeability and established the corresponding theoretical model, which is the process of fracture network formation through opening recovery of the original fractures and new fractures produced by unloading damage. Based on the core idea of ‘mining-enhanced permeability’, engineering approaches of ‘unloading by boreholes drilling’ for the single coal seam and ‘unloading by protective seam mining’ for the coal seam group were proposed to realise safe and efficient co-extraction of coal and gas. Meanwhile, combined with engineering practice, we put forward the construction principle of coal exploitation and gas drainage system in different coal seam occurrence conditions. The above methods were applied successfully in the Tunlan coalmine in Shanxi Province and the Panyi coalmine in Anhui Province, which had established the ‘underground-surface united’ spatial gas drainage modes, and could ensure safe and efficient co-extraction of coal and gas in the outburst coalmines.CITATION:Cheng, Y-P, Wang, L, Liu, H-Y, Kong, S-L, Yang, Q-L, Zhu, J-T and Tu, Q-Y, 2015. Theory of safe and efficient co-extraction of coal and gas and its applications, in Proceedings The Australian Mine Ventilation Conference, pp 79–92 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

Equity finance provides the most suitable and frequently the only access to capital during the exploration and evaluation stages of resource projects when project risk is at its highest. Investors are prepared to provide equity funds in the knowledge that they are compensated for the higher risk they take on with higher potential returns or sufficient upside potential to justify the higher risk. The context of resource projects which determines the role of equity finance has changed considerably. Prior to the resurgence of the gold price and the development of new mining technology many resource projects were selectively mining orebodies by underground methods frequently with limited reserves proved up in advance of mining. The limited proved ore reserves base and the volatility of the gold price all contributed to a higher risk and higher return investment environment in which the use of equity finance was more appropriate and frequently the only option for capital raising. The financial risk of a resources project can be transferred to an underwriter who makes the commitment to distribute the financial risk between a number of investors. There is also the opportunity for financiers to use a mix of equity and debt finance to allow a company to proceed with the development stage where without such a mix the resource project would not proceed. By using a level of equity finance the project becomes robust enough in its ability to service the debt finance facility and the project proceeds with the equity participants receiving a suitable risk reward return. The liquidity from the establishment of a market for the company's securities enhances further capital raising and generally enables the company to satisfy its financial requirements on more favourable terms particularly during bull markets. The role of equity finance in the management of the financial risk during the exploration, evaluation, development and mining stages of resource projects is summarised in Table 1. In more detail the principal roles of equity finance and the ways in which equity finance impact on the risk management of resource projects will be considered in turn.

Jan 1, 1994

By I Ritchie, G Lane, C Morley, D Yataco

Marcobre SAC (Marcobre) is developing the Mina Justa project in Peru. The project has a lower grade oxide orebody overlaying the higher grade sulfide orebody. The oxide ore is treated by acid leaching; consumption of acid is high and is managed by vat leaching rather than the more conventional heap leaching process.The leaching process uses ore crushed to 100% passing 8 mm to optimise copper recovery. Acid consumption generally increases with a higher proportion of fines. Marcobre is investigating a three-stage crushing circuit with high pressure grinding rolls (HPGR) in the third stage, instead of the more conventional four-stage cone crushing circuit. The use of HPGR can result in higher fines production due to the higher compression forces in the crushing zone. This paper reports on the outcomes of the test work completed by Marcobre in 2016 and 2017 to manage fines production and compare the use of HPGR with conventional crushing on a high acid consuming ore.At moderate pressing forces, a HPGR crushing circuit appeared to produce similar size distributions to cone crushing. On average, both the copper recovery and the acid consumption in subsequent vat leaching were higher with HPGR crushing than with cone crushing.CITATION:Lane, G, Morley, C, Yataco, D and Ritchie, I, 2017. Are there differences in size distribution when comparing conventional crushing and HPGR?, in Proceedings MetPlant 2017, pp 60–72 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

By W Stange, N Hanson

An important aspect of the project evaluation process is the achievement of a clear and quantitative understanding of the primary drivers influencing project value and risk. A business scenario-based approach is required to ensure that the project meets value and risk hurdles over the short, medium and longer term. Adopting an optimising approach can aid significantly in the development of a project concept into a business that is optimal and sustainable in the longer term. Through the application of case studies, based on work performed with various mining organisations during the last five years, this paper will demonstrate how project value and robustness can be optimised. Experience has demonstrated that applying this approach results in significant value improvements and risk reduction û primarily by application of a rigorous, fact-based analysis and optimisation process that rapidly increases management team understanding and insight of key driver of value and risk.

Jan 1, 2007

By W Valery, A Jankovic

A growing demand within the minerals industry for sustainable development and the introduction of carbon taxes have resulted in a significant focus on improving the energy efficiency of comminution circuits. However, in this drive for improved energy efficiency the role of classification has been overlooked. Inefficient classification and large recirculating loads reduce circuit capacity, result in over-grinding and higher specific energy consumption.It is well understood that classification increases mill capacity; therefore, closed ball mill-cyclone circuits have become an industry standard. However, due to limitations in cyclone classification efficiency, the optimum recirculating load is limited to about 250 per cent. A simple relationship quantifying the effect of classification efficiency and recirculating load on grinding circuit capacity is presented in this paper. The possibility of improving the capacity of ball mill circuits by improving classification efficiency is discussed, considering the current practical limitations of classification equipment. Simulation tools were used to evaluate circuits with cyclones and with high frequency screens to identify opportunities to improve energy efficiency. The investigation also identified potential benefits to flotation recovery due to a reduction in over-grinding.CITATION:Jankovic, A and Valery, W, 2012. The impact of classification on the energy efficiency of grinding circuits - The hidden opportunity, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 65-70 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By L Eriksson, D Penn, J Appelgren

Atlas Copco, a leading supplier of equipment and services to the mining and construction industries, is consistently pursuing its strategy to offer the most productive and economical solutions by continuously offering new innovative products. These are, in most cases, developed and tested in close cooperation with demanding end users before being officially launched on the international market. The demands for higher productivity and improved overall economy have resulted in systems for automation of the drilling cycle and also tools for integrating the drilling equipment to the production control system used by the customer. In terms of improving the blasted material quality, the company has placed emphasis on accuracy in the drilling process and documenting what has been drilled. By applying state of the art technology to the common automation platform, developed for the surface drilling market, major steps in improving overall drilling productivity and blasting performance have been achieved. This paper will give some examples derived from the latest development of solutions for the companyÆs surface drilling products.CITATION:Appelgren, J, Eriksson, E and Penn, D, 2012. Rotary drilling automation increasing operator productivity and drilling quality, in Proceedings Eighth Open Pit OperatorsÆ Conference , pp 13-18 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 18, 2012

By A C. Robertson

Studies by Tennent, Isokangas Pty Ltd (TIP) have indicated that underground quarrying of backfill may be a cost competitive option for providing backfill for specialised situations in underground mining. Situations where suitable bulk fill material may not be available on the surface, and where the total cost of setting up a fill distribution system are prohibitive, could favour the mining of fill material underground adjacent to the stopes being mined. Considerations include environmental impact, scheduling, surface constraints and total costs. The examples quoted in this paper, and the case studies are based on the authorsÆ personal observations and experience.

Jan 1, 1998

By Ibaragi K

High grade ores were intersected in 1981 by a scout drill carried out by the Metal Mining Agency of Japan during a reconnaissance dril ling programme. The original aim of the hole was to explore a deep target where geophysical anczralies overlapped the abandoned old drifts (gravity- high, resistivity-low by airborne EM, and resistivity-low near the surface and high at depth by Schlumberger deep sounding). Subsequently, a follow-up drilling programm was commenced by the Sumitcrro Metal Mining Co Ltd, and all the 18 holes intersected high grade ores. The resources were then "guestimated" to contain ca.120 tonnes gold with an average grade of 80g/t Au between -40m and +120n a.s.l. The underground development was started in December 1982 and the first crosscut intersected the ore body at 100m level (a.s.l.) in July 1985.

Jan 1, 1987

By Sewell L. G, White H. S

OWING to two large falls of ground which resulted in serious accidents occurring towards the end of 1908, it became evident that the "open chamber" system then in use was unsuitable for the conditions existing in the Mount Morgan mine. It will be admitted that in all mining operations the first consideration is the economy of the system adopted, combined with its safety and ability to give the desired output. A sectional system with square sets has been introduced into the mine, in which due attention has been paid to these factors. In this paper a brief description of this system will be given. An outline of those previously used will be included, as it is necessary to understand the conditions which existed in the mine at the initiation of the sectional system. Outside the actual mining methods employed, various points that might prove of interest will be touched on.The square set system of mining has been in use throughout, the stopes in the gold ore in the upper levels of the mine since underground operations were started in Mount Morgan. In the oxidized zone the ore was of a friable nature, and in some cases rImning ground was encountered. In the lower levels the ground became heavier, and although the stopes were for the most part long, wide, high, and irregular, and not sectionalized, no difficulty was experienced in winning the ore, and no accident of a serious...

Jan 1, 1911

By T Goldsmith

The mining industry is cyclical, but those are more than normal business cycles. In the early 2000s the industry saw the start of China as a game changer for the mining industry which lead to catch phrases like ‘stronger for longer’ and even ‘stronger forever’. Enter the global financial crises and the more recent slow-down in the Chinese economy and confidence that the future is bright has dimmed! This paper looks at the long-term forces that are likely to impact the global mining sector and explain why the industry has an excellent future. However, the industry is not without its many challenges and while demand may be in a prolonged step change, the ability to generate profits will depend on the fitness of each asset and company.The author also discusses the hated terms of ‘boom’ and ‘bust’ and considers how the industry can reduce them, but normally exacerbates them. The ability of the junior sector to raise funds being a primary example and one that remains closed to all but the very best exploration assets. There is also consideration of Australia’s position as a mining country in the future world.CITATION:Goldsmith, T, 2014. The future of the global mining sector, in Proceedings Ninth International Mining Geology Conference 2014 , pp 15–20 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

Our modern cities are almost incapable of sustaining themselves without subsurface infrastructure, which is not identifiable at first glance. This very soon becomes evident when the chaotic conditions prevailing in some cases in the multi-million cities on the African, Asian and South American continents are taken into consideration. This does not simply apply to the hopelessly congested streets in the downtown areas. If anything, it is shown here too that a subsurface infrastructure represents an important prerequisite for public health right up to banishing the danger of disease. Even during the 1990s, this has been clearly underlined through examples of cholera and plague epidemics in parts of Central and South America as well as on the Indian subcontinent. The overriding significance of an inner urban subsurface infrastructure in order to create decent conditions in the major built-up areas was once again emphasised not all that long ago at the United Nations HABITAT-II Conference in Istanbul, Turkey, in June 1996. More than 15 000 delegates from all over the world mulled over and discussed the prerequisites for humane living conditions in human settlements taking the varying climatic, topographical and cultural marginal conditions in different regions of the globe into account. Apart from the built-up areas themselves, the utilisation of underground space is experiencing high and ever increasing significance in less densely populated regions. Attractive and fast transport links between industrial centres call for high- performance transport arteries for the economic, speedy and unhampered carriage of people and goods. Important impulses for the economic power of a region or nation are provided by transport development and links. As a consequence, tunnels for roads and railways are being built or planned to a great degree for crossing mountain ranges, rivers and straits.

Jan 1, 1999

By G Gopinath, R Balachander, H S. Venkatesh

This paper describes in detail the controlled blasting adopted and the measurements undertaken for the successful excavation of large twin tunnels under a shallow cover for a six-lane highway project in India. The tunnels are D-shaped, each 15 m in diameter, and the cover between the tunnels and the existing railway track was about 14 m. These twin tunnel tubes were characterised by two separate three-lane carriageways for each direction of traffic, and were planned with about 25 m of reinforced cement concrete (RCC) portals at the entrance and exit of the tunnels. The major challenge of the project was the blasting of tunnels in rock below an operating railway line. As the tunnels approached the area below the railway line, the ground vibrations were monitored vertically above the blasting faces and on the railway track sleepers. Vibration intensities between those generated from tunnel blasting and those from the movement of the trains were compared, and it was found that the vibrations from blasting were lower than those from the moving trains. Though the permissible level of ground vibration based on the Indian Standard (IS) code happens to be 70 mm/s, the maximum charge per delay was calculated restricting this limit to 50 mm/s. This ensured that the vibrations in the vicinity of the railway tracks never exceeded the prescribed limit of 70 mm/s. The surface ground settlement before and after the blasts were also measured using an optical levelling instrument, which confirmed that there was no significant impact on the surface movements due to blasting. Extensometer readings inside the tunnels showed that there was no deformation in the tunnel. These twin tunnels are now operational and are providing faster connectivity with safety.CITATION:Gopinath, G, Venkatesh, H S and Balachander, R, 2015. Controlled blasting for twin tunnels with a shallow cover under an operating railway line, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 801–808 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015