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By Govett G. J S, Currie D. A, Cohen D. R

Analysis of mechanical size fractions of soils around the Paddington deposit (W.A.) and the Charters Towers Goldfields (Queensland) shows a bimodal gold distribution, with enrichment in the coarsest and finest fractions; this is probably a common feature of soils in arid terrains. To establish the true distribution of Au within the soil fractions, the effect of bulk Au content and percent weight variations in size fractions can be reduced by a normali- zing procedure. The greatest extent of lateral dispersion of Au recorded in the -125 ¦m fraction at Paddington and the -63 ¦m in the Charters Towers area as compared to the coarser fractions, and increas- ed levels of sample representivity in the finer fractions, favours their use in exploration. If orientation studies indicate the preferen- tial use of coarse or intermediate fractions, only wet sieving can quantitatively dis- aggregate the clays and remove finer contamina- ting material. The collection of extremely fine fractions such as the -63 ¦m is also accelerated by wet sieving. The additional costs of wet sieving may be offset by better interpretation of results through increased analytical sample representivity, anomaly contrast and continuity.

Jan 1, 1988

Subsidence data resulting from longwall mining in the northern part of the Newcastle Coalfield of New South Wales has been reviewed. Themain factors influencing subsidence variability in this area (apart from width/height ratio) are strong bridging strata, the effects of the first major goaf fall, mining direction and depth of cover. In 1987 the NSW Department of Mineral Resources produced a guide to subsidence prediction for the Newcastle Coalfield which is still widely used. The current study shows this guide to be no longer appropriate for this area. An alternative prediction curve, incorporating more recent data, is suggested.

Jan 1, 1998

By R L. Grogan

Regulators of deep-sea mining projects are becoming increasingly hesitant about the concept of adaptive management as a tool to facilitate compliance and continuous improvement. Adaptive management is a relevant and useful instrument to ensure that the mine plan is successfully implemented throughout the life of mine, in parallel with optimum environmental performance and compliance.CITATION:Grogan, R L, 2018. Adaptive management in deep sea mining – looking like you know what you’re doing when it’s never been done before, in Proceedings Life-of-Mine 2018, pp 20–22 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

This paper cites selected, prominent examples of current, major projects in Southern Africa in both the mining and civil fields. Differences and similarities in the life cycle of mining and civil projects are discussed. A closer relationship between the mining and civil fraternities is beginning to develop and should be encouraged because of the resultant exchange of experience and technology which benefits both disciplines. An attempt is made to assess future potential for new, major projects and trends in the implementation thereof.

Jan 1, 1999

By D Lalor, N Goodman

The increasing demand for batteries is resulting in the development of large-scale projects for the production of key battery metals such as nickel and vanadium. Several of these projects plan to extract the battery metals from the ore via chemical roasting, leaving large volumes of waste iron oxides after fuming and/or leaching of the battery metals. These iron oxide wastes can be smelted in a HIsmelt furnace using biochar as the reductant, to produce clean, green pig iron with net zero carbon emissions. This green pig iron can then be added to basic oxygen or electric arc steelmaking furnaces to produce green, net zero carbon, steel. This paper describes the flow sheets and the economics for potential projects producing green pig iron via HIsmelt using waste iron oxides from nickel and vanadium production plants.

Sep 18, 2023

By ZáWang, F Hungerford, T Ren

Operations in an underground drill site have to co-exist within the mineÆs ventilation and operational system. The space requirements of a drilling operation have to be adapted to the limitations provided in available site space, which is usually defined by standard mining operations and geotechnical influences. These limitations affect borehole design, equipment positioning in the site layout and possible interactions with mining equipment and services such as water and power supply.The ventilation requirements for drill sites and the means employed vary with depth of the site, space and likely presence of gas. All drilling operations provide a particular service for the mine and in each case, drilling must operate in a manner which controls all gas, water and cuttings returning from the borehole. The various standpiping systems employed have evolved under differing influences and must cater for conditions during and after the drilling operations.The influences that gas content, pressure and flow, rib stability, cleat direction, borehole length, potential water pressure and flow have on a mineÆs operation and ventilation systems have to be considered in the design of standpipe length, diameter and fittings. Past history has a strong influence on common practice while worst case effects of a possible in-hole event should be catered for.This paper describes the early drilling systems and their limitations in ventilation and gas management. The drill site dimensions and set-up are discussed in the context of roadway conditions, equipment layout, ventilation and logistics. The use of standpiping to control all returns from the borehole is illustrated by referring to likely scenarios in a drilling site to achieve the most effective sealed depth to accommodate the worst case possibility of intersecting high pressure gas or water during the drilling operation. Practices to allow gas drainage in the return airway of a panel are described.CITATION:Hungerford, F, Ren, T and Wang, Z, 2013. operational management of underground in-seam drilling sites, in Proceedings The Australian Mine Ventilation Conference , pp 43-48 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

Coeur d'Alene Mines is a precious metals producer which is dedi- cated to growth through it's exploration and acquisitions efforts. We foster and support these activities by providing our staff with long-term financial support, the encouragement to proceed with their projects and ideas, and a firm belief that we will be successful. Coeur's corporate headquarters are located in beautiful, historic Coeur d'Alene, Idaho. Our main mining operations are Rochester, locate near Lovelock, Nevada, Coeur Mine,located near Wallace, Idaho, and Thunder Mountain, located in central Idaho. Our Ken- sington Gold project is located about 45 miles north of Juneau in southeast Alaska. We have exploration offices located in Reno, Nevada, and Santiago, Chile. At this time, Coeurd'Alene Mines produces precious metals from mines located in the United States. Our Rochester open-pit opera- tion, which is 100 per cent owned and operated, is located in Nevada. Presently, this operation produces 5.5 to 6 million ounces of silver per year and 60-70,000 ounces of gold. We move 65,000 to 70,000 tons of rock per day of which about 23,000 tons is ore. The ore is crushed, stacked on permanent heaps and leached. The recovery is by Merrill-Crowe. Although the average grade is rela- tively low, 1.4 ounces per ton silver and 0.012 ounces per ton Au, the operation is very low cost. Our cost of production is less than $4.00 per silver equivalent ounce. Rochester is anunusual operation in that the crushed rock stacks without much compaction and the ores are easily leached. The final height on our heaps will be about 220', and overall recovery will be about 55 per cent of the silver and about 85 per cent of the gold. Reserves at Rochester are expanding and are now adequate for at least fifteen years of opera- Tion.

Jan 1, 1991

By B A. Wake, G G. Lowder, M J. White

The Tooloom gold field is located within the New England Fold Belt in the far northeast of New South Wales, approximately 130 km south southwest of Brisbane. Gold was first discovered at Tooloom in 1857. Within a few years up to 10 000 people were mining placer gold deposits in the Tooloom valley and a few tried their hand at mining hard rock occurrences as well. Mining of alluvial gold continued in a small way at Tooloom until very recently, but only in the last few years, since Malachite Resources acquired its interest at Tooloom (now 100 per cent), has the full potential of this large, reduced intrusion-related gold field been appreciated. By the mid 1870s, once the alluvials were largely worked out, most of the early miners had made the 270 km trek north to the newly discovered Gympie gold field and Tooloom slipped into obscurity. Such was this obscurity that the Tooloom gold field was not recorded on published Government geological maps until 2001, four years after Malachite became involved. The many hard rock prospects that Malachite has identified in recent years were largely or completely unknown. Tooloom is a good example of blinkered thinking when it comes to modern mineral exploration. The New England province in NSW has long been the æpoor relationÆ to the much better known and more highly favoured Lachlan Fold Belt in NSW. It has also suffered serious neglect compared with the Queensland part of the New England Fold Belt that hosts such major gold deposits as Mt Morgan (>7 Moz), Gympie (>3 Moz) and Cracow (>1 Moz). Tooloom is proof that prospective geology does not stop at state borders.

Jan 1, 2004

By J H. Wood, I Gray

This paper examines the occurrence of outbursts, coal bursts and rock bursts in underground mining. It then examines them from the viewpoint of the failure mechanism and velocity of particles. The presence of gas is extremely important as it can both act as the fluid pressure component of effective stress leading to failure, and as a substantial energy source in projecting material during a burst. For gas to drive a dynamic event it must be present as free gas held in voids within the rock or coal mass. This can pre-exist the burst event or be released from desorbing gas during it. The latter is typically part of a multi-stage outburst event which can reach very large proportions. Rock and coal bursts are driven by strain energy release and can vary in form. These tend to be single events associated with failure and strain energy release. It is also possible to conceptually have hybrid events where the failure of the mass and the energy release are due to both stress and expanding gas.

Nov 29, 2022

By I Gray

This paper examines the effects of the changes in stress that a coal may undergo as part of the drainage process. As a consequence of this, some coal seams will come to the situation that they have zero horizontal stress existing within them at the time of mining. The hypothesis of this paper is that this lack of horizontal confining stress means that on mining, the vertical stresses may be easily raised to a level where failure occurs. This failure may be accompanied by significant energy release from energy stored within the coal as well as that coming from the roof and floor. To determine the state of stress within the coal seam, the concept of the effective stress path that the coal passes through is examined and is found to be very dependent on the shrinkage of the coal with degassing, the Young’s modulus of the coal and its Poisson’s ratio. The Young’s modulus of the coal is important and has been found to be highly dependent on the state of stress within the coal. It may change by more than an order of magnitude.CITATION:Gray, I, 2014. The consequences for pillar stability of zero confining stress brought about by forced or natural drainage, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 331–336 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By the 1990's Australia could be the largest coal exporter in the world and one of the few industrialised countries potentially able to supply the shortfall in its domestic oil requirements by utilizing its oil shale and coal resources to manufacture synthetic oil. The major challenge to both industry and government in implementing the new role for Australia will be to ensure that their actions and policies enable the timely mobilization of resources needed to meet the potential demand for energy, both domestic and overseas. Australia's potential for coal production and exports and for the production of oil from shale and coal are discussed and the potential constraints to development Examined.

Jan 1, 1981

As world demand for various minerals increases the mining industry in its endeavour to satisfy this demand will, eventually,look to the extraction of orebodies which previously may have been uneconomical to mine. These orebodies may be of two types. Firstly, new low grade orebodies and secondly, remnant sections of previously mined orebodies. Some of the factors relative to remnant mining operations are discussed and the potent- ial of remnant mining in providing an important contribution to future world metal production is considered.

Jan 1, 1975

By Kershaw M. G

At the Risdon plant of the Electrolytic Zinc Company of Australasia Limited, impurities toxic to the electrolytic production of zinc metal, notably arsenic and antimony, have traditionally been coprecipitated when precipitating iron as ferric hydroxide. With the development of a new lead/zinc mine at Elura, New South Wales, it was anticipated that the concentration of impurities, particularly arsenic, in the zinc sulphide concentrates treated at Risdon would increase. This suggested that an increase in the capacity of the iron purification step in the Risdon plant would be required to cope with the higher input of these impurities.Laboratory investigations showed that the additional capacity would be achieved, either by a large increase in the amount of iron used as the "collector" in the process, or by a two-stage process. The latter approach was preferred as a increase in the amount of iron precipitated would lead to much higher operating costs and overloading of the existing equipment.In the two stage procedure, acidic iron bearing solution is added to solution feeding the first stage and most of the arsenic removed from solution when iron is precipitated from solution by neutralisation with limestone. Mter separation of the precipitated solids, acidic iron bearing solution is added to the solution, and remaining arsenic removed almost completely following neutralisation by limestone.This paper describes the laboratory and pilot plant results and the plant modifications required. Abrief account is also given of the operator training and acceptance in the use of the digital control facilities installed in the new plant.The new plant is working well and good solution purity is being maintained despite a substantial increase in the concentration of impurities in the raw materials.

Jan 1, 1990

Electromagnetic methods used in geo- physical prospecting for conductive ore bodies have proved successful in Canada,Sweden and other countries. In Australia however the depth of weathering generally exceeds 30 metres. This introduces a problem of highly conductive overburden and renders equipment useful elsewhere virtually ineffective. A discussion of several EM prospecting techniques is presented and a new system under development at James Cook University using V.L.F. transmissions capable of indicating changes in impedance (not only highly conducting media) is outlined.

Jan 1, 1974

By Luke K. A

Pressure on production at New Zealand China Clays has led to the development of a dewatering control loop for fine halloysite china clay. The development was based on the analysis of data from the automation of plate and frame filter presses. The analysis of the data has led to process changes, and the ability to quickly solve dewatering problems. As a result of control in the dewatering circuit press times have reduced on average 117% and output has increased proportionally.

Jan 1, 1989

As world demand for various minerals increases the mining industry in its endeavour to satisfy this demand will, eventually,look to the extraction of orebodies which previously may have been uneconomical to mine. These orebodies may be of two types. Firstly, new low grade orebodies and secondly, remnant sections of previously mined orebodies. Some of the factors relative to remnant mining operations are discussed and the potent- ial of remnant mining in providing an important contribution to future world metal production is considered.

Jan 1, 1975

A flow sheet has been developed to treat a high tonnage highly preg-robbing gold ore. The ore is low grade and fine grained with a high proportion of very fi ne free gold. The key components of the flow sheet include gravity, flotation, intensive cyanidation with direct electrowinning, and carbon-in-leach of the flotation concentrate. The circuit produces a low overall mass pull to concentrate allowing economic intensive treatment of large tonnage low-grade material. Efficient recovery of fine gravity gold using a Falcon concentrator in both the milling and flotation circuits, and subsequent intensive cyanidation in a Gekko InLine Leach Reactor (ILR) is critical to the process with over 70 per cent gold recovery expected in this circuit. Grind size control was also found to be important in controlling the activity of the preg-robbers in the carbon in leach circuit and also in the solid liquid separation performance. Tests at the large-scale demonstration plant have been conducted to demonstrate the effectiveness of this flow sheet. A large low-grade deposit is currently under development with the aim of developing a 10 Mt/a treatment plant with the subsequent addition of equivalent sized process lines in multiples of 10 Mt/a. The economic development of this orebody is critically dependant on understanding and exploiting the properties of the ore. In particular it is critical to minimise the effect of preg-robbers by recovering free gold with Falcon concentrators and InLine Leach Reactors. Recovery of the remaining gold by flotation into a small mass yield allows this fraction of gold to be treated by CIL leaching utilising high carbon levels. It is critical is to ensure operation at the optimal grind size to maximise liberation of the free gold and minimise pregrobber activity. The ore has been identified as preg-robbing with low recoveries obtained if treated using conventional cyanidation and carbon absorption. The mineralogy consists of predominantly fi ne grained free gold with minor sulfides including pyrite and arsenopyrite. With conventional cyanide leaching in the absence of carbon, gold recovery is less than 50 per cent. Direct cyanide leaching of the ore in the presence of activated carbon results in an improved but still uneconomic gold recovery. The gravity recoverable gold (GRG - as defined by Andre La Plante) content of the ore has been measured to be 70 per cent to 85 per cent in various tests with liberation grind size of approximately 106 ¦m. This indicates gold is predominantly free and suitable for recovery by batch centrifugal concentrators into a low mass yield. This property of the ore presents the opportunity to maximise the recovery of gold by separating it from the majority of the preg-robbers prior to leaching. Due to the very fine gold particle sizes and the necessity to maximise recovery of this fine fraction Falcon concentrators were selected for the duty, with their proven high recoveries at very fine gold sizes. The gravity recovery in the milling circuit is designed to be in the range 55 to 65 per cent. This has been achieved in the existing pilot plant using a Falcon operating on ball mill discharge within the mill recirculating load. Intensive leaching in an InLine Leach Reactor is essential to recover the gold from the gravity concentrates. Tabling is not a preferred option since recovery is lower than intensive cyanidation and any gold losses to table tails will report to CIL where recovery is reduced by the presence of preg-robbers. Furthermore, tabling recovery from the gravity concentrates is particularly poor due to the fine particle size of the free gold. ILR recoveries of 98 per cent were demonstrated in the pilot plant using an ILR100BA and leach conditions were investigated in the lab using pilot plant generated Falcon concentrate. Recovery of gold from the pregnant solution was achieved with direct electrowinning at pilot and efficiency and sizing parameters were determined at lab scale. To further increase free gold recovery Falcon concentrators will be installed in the flotation circuit. Location of the Falcons in the circuit is not finalised but installation on the rougher concentrate stream is favoured since it will allow multiple pass recovery. This is expected to recovery a further ten to 20 per cent of the gold, as indicated by lab tests on pilot plant generated material. The gravity concentrate from the flotation circuit will also be leached using InLine Leach Reactors. Initial intensive cyanidation tests carried out on lab generated flotation concentrates indicated higher recoveries than CIL can be obtained even though the concentrates contain significant levels of preg-robbing material. This can be explained by the high cyanide, high pH leaching conditions used in the ILR which alters the absorption equilibrium of the preg-robbers. Further optimisation of the leach conditions will be undertaken once more concentrate becomes available. Recovery of the remaining gold content is achieved by flotation into a small mass yield, however the preg-robbers are also recovered into this concentrate. Due to the presence of the preg-robbers gold leaching must be carried out in the presence of high levels of activated carbon in a CIL system. The recovery has been shown to be strongly dependant on the carbon loading and the concentrate particle size. The carbon competes against the preg-robbers for dissolved gold while excessive grinding increases the surface area and activity of the preg-robbers. This has been demonstrated in test work however the economic optimum leaching conditions and carbon loading have yet to be determined. The grind size is critical to the economics of the project, not only due to its effect on gold recovery but also due to its effect on the major operating and capital costs at both the front and back end of the process. It is critical to grind enough to obtain both gravity free gold and flotation liberation at low mass yields however over-grinding results in large increases in mill size and power at the front end and filtration or thickening costs at the tails. Because these unit operations treat essentially all the plant feed even small changes can result in major impacts on project economics. The viability of this project is greatly enhanced by the high recovery of gold into a small mass yield. In particular the production and intensive leaching of the free gold gravity concentrates will allow over 70 per cent of the gold to be recovered efficiently with minimal impact from preg-robbers. By using flotation the mass of the remaining fine preg-robber contaminated material, to be leached in CIL, is greatly reduced allowing this difficult material to be economically treated. This is an ABSTRACT ONLY. No paper was prepared for this presentation. 

Aug 1, 2010

By K D. Tuckwell

The Treasurer, the Hon Wayne Swan, has nominated ‘maximising our advantages’ from ‘Mining Boom Mark II’ as the focus of the 2011/2012 Australian Budget. Australia therefore requires a bolder and better integrated economic reform agenda if it is to convert current strong demand for mineral commodities into lasting prosperity that benefits all Australians. Lasting prosperity, well past 2012, will only be achieved if Australia can effectively reverse a decade-long deterioration in the minerals industry productivity performance due largely to capacity constraints that inhibit growth. This requires improving the efficiency of energy networks, transport infrastructure, water markets, health and education services, access to skilled people and by streamlining costly, inefficient project approvals’ processes. The common thread that holds this economic fabric together is the importance of having the right people using the most appropriate technology within the correct policy framework.In December 2010, employment in the minerals sector stood at 187 200; 21 per cent higher than one year earlier, 15 per cent higher than the industry employment peak prior to the global financial crisis in 2008 and 14 per cent greater than anticipated by industry modelling published in 2008. Managers and professionals make up approximately 15 per cent of the total workforce, yet minerals-related higher education programs (mining engineering, metallurgy and geoscience) continue to be chronically underfunded, requiring direct industry subsidies of more than $25 M over the last decade. Also, the publicly-funded Vocational Education and Training (VET) sector continues to fail the industry in the delivery of quality training programs. Importantly, the industry is a key driver of economic activity in regional and remote Australia and is the largest source of private sector employment for Indigenous Australians who comprise up to a quarter of employees in certain locations.This presentation looks at what our industry and country need to achieve to ensure we have the right people for the challenges ahead. **This is an abstract only. No paper was provided for this abstract.**

Nov 22, 2011

By P R. Botha

Mining has played a significant role in human development and without the mining sector, society would not enjoy a large number of the benefits that it does today. However, mining has also carried with it some important lessons, which remain the source of ongoing learning. One of these lessons is the poor closure or abandonment of mines, worldwide. This has in many cases resulted in large tracts of unproductive land, representing a source of environmental pollution and a safety hazard to the community. Frequently associated with this is a legacy of mining communities having fallen into economic and social decline, beyond mine closure.Due to this legacy, governments, society and the mining sector pay far greater attention to mine closure planning today, than was done in the past. Typically closure planning has focused on the engineering aspects of a mine, namely decommissioning of the workings and plant; dismantling of unusable infrastructure; and rehabilitation of disturbed land. These are important aspects of closure but a more holistic, long-term approach is required which encompasses environmental and social aspects and aims to leave a positive legacy behind.In planning for a mine closure scenario with a lasting positive legacy, it is critical that the broader receiving environments (social, economic, physical and biological) within which a mine is located, define and drive the closure plan and the mine planning as a whole. This ensures that the broader environment influences mine closure, as opposed to looking at how a closed mine will impact on the environment. The ultimate aim is to first understand the broader environment and then to fit the closure of a mine into it. The earlier this approach is followed in the life of a mine, the greater the operational time frame available, and hence a better chance is presented for planning and managing a mine towards the desired, tested and agreed post closure scenario. Within this broad context, there is tremendous scope to achieve successful mine closure. However, it is critical to note that mine closure is not the sole responsibility of the mining companies, and neither is it possible for said mining companies to achieve mining closure alone. This concerted effort requires a multi-stakeholder approach in which partnerships are created and risks, responsibilities and opportunities are shared and managed. To achieve sustainable closure, a multi-stakeholder approach based on an initial forward-looking closure vision is required. This approach provides an early basis for consideration of alternative land uses and economic options from which specific actions to achieve the preferred option can be defined. The Anglo American plc Mine Closure Toolbox has been formulated and developed around this concept. The Toolbox aims to expand mine closure planning - from financial provisioning for rehabilitation and physical closure, to planning for sustainability beyond mine closure and leaving behind a positive legacy.This paper focuses on the business case for mine closure planning and provides an overview of the Anglo American plc (AAplc) Mine Closure Toolbox.CITATION:Botha, P R, 2012. The business case for mine closure planning and an overview of Anglo AmericanÆs mine closure toolbox approach, in Proceedings Life-of-Mine 2012 , pp 7-10 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By J Q. Shi, M Karakus, Y Liu

Predicting the spatial distribution of rock mass properties in cave mining is a critical challenge. In this study, we introduce a novel machine learning-based model to advance our comprehension of rock behaviour. This model specifically focuses on the spatial distribution of rock mass and mechanical properties, a crucial aspect of our understanding of rock mechanics. Our model is inspired by the recognition that neighbouring information serves as crucial prior knowledge for predicting the spatial distribution of these properties, wherein closer neighbours are likely to exhibit similar characteristics. To effectively capture and model these neighbour relationships, we design a neural network-based model to map the spatial locations within the data set into a new highdimensional space. Within this transformed space, we utilise Euclidean distance to identify N neighbours. Leveraging these neighbours, we introduce a straightforward yet highly effective approach—label propagation—to construct a graph that illustrates neighbour relationships. This graph not only facilitates the prediction of the spatial distribution of rock mass properties but also offers a measure of uncertainty for these predictions. We validate the proposed method using a real rock data set and showcase its efficacy in capturing intricate relationships and distributions within rock properties, enabling precise predictions across diverse spatial scales. Our results underscore the potential of machine learning-based approaches to revolutionise the field of rock mechanics, providing valuable insights applicable to geotechnical engineering, mining, and other sectors where an accurate understanding of rock properties is paramount. This model has direct practical implications, offering a new tool for geotechnical engineers and mining professionals to enhance their understanding and prediction of rock properties, thereby improving safety and efficiency in their operations.

Sep 1, 2024