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By E Yll÷, O HyvSrinen

Outokumpu has developed a new chloride leach process, called HydroCopper«, to treat copper concentrates. Chalcopyrite is quite refractory in leaching and in sulfate milieu an autoclave of high temperature and pressure is required. However, in the HydroCopper«-process copper sulfides can effectively be leached in atmospheric pressure using strong, aggressive chloride solution and copper (II) ions as oxidant. Copper is precipitated from the purified pregnant leach solution as copper (I) oxide, which is filtered and reduced by hydrogen gas to metallic copper powder, which is melted and cast into copper product. Sodium chloride formed in precipitation is decomposed in a chlor-alkali electrolyser, the products of which are circulated back to the process: sodium hydroxide to copper (I) oxide precipitation, chlorine gas to leaching and hydrogen gas to the reduction of copper (I) oxide. During 2003 - 2004 the performance of the HydroCopper«-process was confirmed in a demonstration plant processing one tonne of copper per day. It has been found to be applicable for different kinds of concentrates and can also tolerate a wide range of impurities. A significant advantage of the process is that gold can be leached as a chloro-complex and recovered with active carbon. HydroCopper« can economically recover copper from concentrates and process to a cast copper product. The best utilisation of the process is in most cases achieved when the plant is situated at the mine site. Higher recoveries are attained by the optimisation of the whole operation chain from the mine and the concentrator to the HydroCopper« plant.

Jan 1, 2005

By West RF, Pooley RH

An underground mine, a treatment plant and supporting facilities have been constructed at Lebong Tandai in Sumatra, Indonesia by PT Lusang Mining. Throughput is initially 50,000 tonnes per annum of ore with an inbuilt capability to expand to 100,000 tonnes per annum. Construction proceeded in parallel with design work on a tightly controlled critical path schedule. The very remote location of the mine, the difficult access and the fact that equipment was imported from many parts of the world presented a challenging project management problem. The transport system, which involves road, river and rail and support facilities on site had to be brought into full operation prior to the arrival of major equipment. Mine development involved the reopening of the old access drives and workings, refurbishing two shafts and the haulage system together with redevelopment of old stoping areas and the opening of new stoping areas. Ore production is now from three main areas using shrink and underhand stoping methods. Ore breaking and drive development is with conventional airleg mounted rockdrills and ANFO explosives. Exploration to locate and develop new reserves to replace ore mined is an ongoing activity.

Jan 1, 1986

By N McIntyre, R Trancoso, N Bulovic

Mining is essential for facilitating human development particularly as demand for critical minerals grows. However, over the mine life cycle, the environment is permanently changed. Once mining ceases, mine-affected land can leave significant legacy issues on the surrounding environment if not managed. Therefore, mine closure planning is critical. Mine closure occurs over large scales often with the aim of recreating resilient ecosystems over mined landscapes with mitigated negative impacts. The natural state of the landscape and the environmental risks over planning time-scales are largely driven by climate. Climate change is expected to impact different parts of the post-mining landscape, from stable landform design (soil erosion mitigation) to revegetation efforts and pit lake management. Consequently, mine closure plans may need to account for a non-stationary and uncertain future climate, that may be both different to the current climate and evolve during the mine life and post-closure. Here a new data-based approach is presented for incorporating climate change projections in mine closure planning, based on the recently released Coupled Model Intercomparison Project phase 6 (CMIP6) climate data used in the latest Intergovernmental Panel on Climate Change (IPCC) assessment report. The approach: (i) characterises closure-related attributes of the future climate, and (ii) identifies the amount (and direction) of change expected to occur, and its uncertainty, focusing on five metrics for demonstrative purposes and initially describing changes in erosive potential below. This provides information on the type of future environment (ie the changing baseline) that mine closure should plan towards, and identifies rehabilitation options that may be susceptible to increased risks from climate change.

Aug 2, 2023

By Baafi EY

Open cut mining in Australia is facing the greatest challenge in its history in attempting to compete not only with other operations internationally, but also with underground operations domestically. Most flat dip and shallow depth surface-mineable coal reserves have been depleted during the last two decades and new open cut operations must extract deeper coal deposits. As open cut coal mines move into deeper areas and the stripping ratios increase, the relative cost of overburden removal also increases. It therefore becomes even more important to design the mine around the optimum overburden removal scheme. The deeper mines are usually multi-seam operations with a more complex geology and with more geotechnical and hydrological problems. Deeper mines are subjected to greater problems requiring more detailed mine planning and design, such as selection of the optimum mining method and pit layout. In planning and design of such operations, the number of alternative methods which need to be considered is consequently greater.Dragline productivity and its stripping capabilities are directly affected by the selection of digging method, strip layout and pit geometry. Every mine has a unique combination of geological conditions. The operating methods that work well at one mine may not necessarily work at another site. Selection of an optimal stripping method, strip layout and pit geometry for a given dragline must be considered with respect to the geological conditions of the mine. With increasing geological complexity of Australian strip mines, it is becoming more important to use sophisticated techniques such as computerised mine planning methods to assist in optimising dragline operations.

Jan 1, 1998

By Mackenzie J. M W

The mechanism of clay slime flocculation in coal washing circuits is considered and it is concluded that polymer flocculants are most suitable. It was found that the addition of sea water with a polymer flocculant improved flocculation and settling, and it was also found that dilution of a flocculated pulp increased floc size and hence settling rate.In predicting plant consumption of reagent it was found that cylinder tests, or even pilot plant tests, could give erroneous results, particularly on flocculated pulps. Different flocculants may, however, be compared in cylinder tests.For filtration, flocculation with Separan plus sea water was much more beneficial than flocculation with Separan alone.INTRODUCTIONDuring the mining of coal, and its subsequent beneficiation by washing, large quantities of minus 10 mesh material are produced. This fine material, which consists of broken down shales and fine coal, causes difficulties in water clarification circuits, in refuse disposal, and in filtration of fine coal.These difficulties can be largely overcome by flocculation, and this paper discusses the mechanism of flocculation, the methods by which a selection of flocculant may be made from the large number available, and the limitation of the prediction of plant performance from laboratory tests. This work applies particularly to the washeries of The Broken Hill Proprietary Co. Ltd. (B.H.P.) and Australian Iron and Steel Ltd. (A.I. & S.) .

Jan 1, 1962

By Grantham DL

ABS'TRACT For a number of years research efforts have been directed towards improving the efficiency of sampling and analysing coal mine roadway dusts. In the past decade the practicality of rapid, on site analysis of the incombustible content of these dusts using a radioactive technique has been receiving close attention both in Australia and overseas. Accurate measurement of the total incombustibles present is only possible by time consuming chemical methods. As the densities of the solid incombustible materials are greater than that of coal, they absorb a higher proportion of incident low energy gamma radiation than does coal. The amount of such radiation "back scattered" from mine dust samples is therefore inversely related to their average densities, and hence to their incombustible contents. This phenomenon can be used as a measure of incombustible content by employing an appropriately designed and calibrated instrument.

Jan 1, 1981

By Moritz P

Thiourea has been recognised for a long time as an acid-stable complexant for gold. Generally, the use of thiourea has been shown to exhibit enhanced leaching kinetics compared to cyanide but suffers the disadvantage of excessive reagent consumption. Thiourea leaching is particularly com- patible with the extraction of gold from refractory ores. This is due to the need for an oxidative pretreatment to liberate the gold. Such pretreatments typically result in the production of an acidic residue. The application of novel thiourea leaching technologies to the extraction of gold from a bioleached pyrite concentrate was investigated. The interac- tion of leach variables with thiourea consumption and gold extraction was established. An economic assessment of thiourea leaching was compared with conventional cyanidation. The results indicated that gold leaching of the bioleached residue using thiourea compared very favourably with cyanidation.

Jan 1, 1991

Mine closure is a legitimate element of the mining cycle and like mine development involves technical planning, permitting, and finally construction. Closure begins with the mine's operational footprint and transforms the site so that it meets the explicit requirements of the owners and regulators. Implicitly, the closure will increasingly need to meet the requirements of other interested parties such as the local community, workforce, and future land users. Golden Cross is the first modern mine closure in New Zealand. It operated for 6 + years as a mid-size gold and silver mine winning ore from both underground and open pit sources, and processing via a carbon in leach circuit including a cyanide recovery stage prior to tailings disposal. The mine is situated in a sensitive high rainfall environment, and is complicated by the existence of a large ancient landslide underlying most of the tailings dam and waste rock embankment. The regulatory process for mine closure in New Zealand is not clearly understood by operators or regulators alike. The Golden Cross mine was permitted under the Mining Act 1971 and closed primarily under the Resource Management Act. This switch of legislation, the parallel reorganisation of many government departments, and change in societal expectations with respect to long term environmental stewardship during the life of the mine resulted in the requirements of closure being significantly different to the expectations at permitting.

Jan 1, 1999

Reliable predictions of the long-term water quality and water level fluctuations in a final void are vital if mine operators propose to decommission final voids in open cut mining operations. The catchments feeding final voids typically comprise a large proportion of coal placed or re-shaped spoil piles. Spoil piles from open cut coal mining operations have distinctive hydrological characteristics, which result in unique run-off behaviour. There is a need to understand the nature of spoil hydrology processes in order to predict the long-term hydrological behaviour and water quality responses of such systems. Preliminary estimates indicate that it may take 20 or more years for a void to flood. It is impractical for mine owners and operators to wait until long-term hydrological and water quality conditions have been established in a void, before reaching agreement with regulators about mine closure conditions. Reliable simulation of the long-term water quality and water level fluctuations in a void are therefore. The adoption of an agreed modelling approach and sharing of results from field data programs could result in the establishment of a database that could be used, with regulatory approval, for assigning parameter values, without the need for a specific data collection program for every individual void. Industry and regulators should agree on the model adopted for predicting post-closure behaviour of spoil/void systems. This will require reliable, robust methods for field data collection. This paper describes the field monitoring, data collection, model preparation and simulations undertaken over a three year period for Australian Coal Association Research Projects (ACARP) Project C7007. It presents the findings of that research, and provides comment on aspects of the project that were undertaken well and on aspects that could have been done better. Limited data is presented in this paper due to confidentiality arrangements with the relevant mine sites.

Jan 1, 2003

By Fuller P. G

The purpose and current practice of cable trusses in underground coal mines is briefly outlined and details of various cable truss designs are presented. The main part of the paper describes the in-situ performance of cable trusses installed as secondary supports in gateroads and recovery roads of longwall coalfaces. The performance analysis is based on the results of in-situ monitoring carried out at a number of sites at two underground coal mines within Australia. Truss performance has been assessed as load developed in relation to roof convergence, face position and time. Additionally, the influence of strata conditions, installation pattern/density, roadway layout and geometry have been taken into account. An analytical model has been developed to predict truss loads. The principal variables are listed and the basis of the model is described. Based upon behaviour observed in the field the model has been progressively upgraded and validated against measured performance. Guidelines on truss performance and factors which influence it are presented and the implications of these to the use of cable trusses is discussed. Possible methods for improving truss performance in certain strata conditions are outlined and some comments are made on the value of cable trussing compared to cable bolting in these Situations.

Jan 1, 1992

By Gomm SA

The Mount Tom Price Concentrator, which contains a heavy medium cyclone plant for beneficiation of the -6+0.5mm fraction of low grade iron ore, is described. Testwork was carried out on an opportune basis over a period exceeding twelve months, to evaluate the separation performance of the heavy medium cyclones. Plastic density tracers were used and ore samples were taken and analysed. The effect of operating medium specific gravity (S.G.) on the separation parameters, the iron grade of the sinks product, and the mass and iron recoveries were investigated. Also examined were the differences in perform- ance between particles of different size. The implications of the findings for plant oper- ation are discussed.

Jan 1, 1987

Byproduct coking is practised in three of the major Australian ironmaking centres, the Newcastle and Whyalla works of the Broken Hill Proprietary Co. Ltd. and the Port Kembla works of Australian Iron & Steel Pty. Ltd. Coking first commenced at Newcastle in 1915 and at Port Kembla in 1938. The installations established at these centres include coal cleaning facilities and com- plete byproduct streams. The Whyalla plant, because of its location is somewhat less extensive, having no coal cleaning plant and a comparatively restricted byproduct section. As new batteries have been built every opportunity has been taken to incorporate modern design features and improved operat- ing techniques. This has included the provision of equipment to reduce atmospheric and water pollution. A marked reduction of markets for byproducts has had serious repercussions on the profitability of this section of the Industry.

Jan 1, 1972

By J Cook, S Pike, D Pridmore

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The application of high-resolution seismic reflection to map structure and/or mineralisation in hard rock environments has progressed significantly in the last decade. Improvements in equipment, field practice, processing and understanding has seen the seismic reflection technique emerge as a cost-effective tool for high-resolution three-dimensional structural and lithology mapping to depths far greater and with superior accuracy than other more conventional geophysical techniques.This paper outlines results and preliminary interpretation of 2D and 3D seismic reflection surveys aimed at defining fault zones and locations for quartz load development in favourable host lithologies at the Cracow low-sulfidation epithermal gold system in Queensland, Australia.As this is possibly the first time that high-resolution seismic reflection data has been used to define the structurally-controlled location of low-sulfidation epithermal gold mineralisation, an important aspect of this work was the derisking or due diligence steps taken prior to commissioning the full 3D surveys at each site. This included full wave sonic logging, vertical seismic profiling and trial 2D lines. Interpretation of the 2D profiles and the drilling of interpreted structure provided the confidence to proceed with the full 3D survey.The advantage of collecting 3D data extends beyond ensuring that the received reflections are located correctly in 3D space. The final 3D data cube can potentially map the entire fault network, thus highlighting flexures and changes in orientation of the structures both vertically and along strike, which is an important aspect in the deposition of gold and for direct targeting.CITATION:Smith, R, Cook, J, Pike, S and Pridmore, D, 2015. Application of high-resolution seismic reflection surveys to exploration for blind vein systems at the Cracow low-sulfidation epithermal field, in Proceedings PACRIM 2015 Congress, pp 77–84 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By Zhang S

A probabilistic approach is proposed for updating open pit slope sta- bility based on successful performance. The suggested approach is developed within the framework of Bayesian probability theory. In seeking solutions to geomechanics problems consideration must be given to inher- ent variability of shear strength parameters and to the errors in the esti- mation of these parameters. The latter can be significant and may lead to consistent overestimation or underestimation of the values derived from site investigation and testing. Conventional deterministic methods of slope stability analysis do not allow systematic modelling of uncertainties in applied loads or in shear strength parameters. Within a probabilistic framework indicators of stability may be calculated, e.g., the reliability index and the probability of failure. Based on observation of slope per- formance at any given stage of a project, the mean or the standard devi- ation (or both) of a shear strength parameter may be updated. Consequently the indicators of stability can also be updated. The appli- cation of such an approach is demonstrated by an illustrative example.

Jan 1, 1989

Cominco Ltd's Polaris Mine in Canada's High Arctic has been successfully mining zinc ore in permafrost since 1981. Mining methods using frozen backfill have been the key to success. The mine is now producing about 60 per cent of the ore from pillars while maintaining high productivities. Annual ore production is just over one million tonnes providing more than 200 000 tonnes of zinc concentrate each year. Cominco Ltd has adapted management and operating practices to suit the harsh environment and the isolated site, and has shown that a profitable development can be carried out in the tough Arctic conditions, with minimum impact on the environment.

Jan 1, 1993

By Kukla G. T

A Seam deposit User oriented Mine Planning System (SUMPS) was developed by The Broken Hill Proprietary Company Limited (BHP) at its head office in Melbourne. It is one of the computer mine planning systems developed by the Corporate Data Processing (CDP) section of BHP. To date it has been employed in the feasibility study of four coal prospects for the BHP Group, including Gregory in central Queensland - Ham and Van Hoorn (1978). It was also used in detailed short term mine planning for Gregory. A recent application was in the feasibility study of Saxonvale, a multi seam coal deposit in New South Wales with seams up to 20 m thick. The other two applications of SUMPS were also on thick multi seam coal deposits. Development of programs for the underground sub-section of SUMPS is continuing. SUMPS was developed and implemented on mini computers with graphics and plotting peripherals. The company's philosophy towards computing is one of centralized development and project planning, with transfer of hardware and software to site once the mine becomes Operational.

Jan 1, 1980

The paper describes the studies conducted to date on the short term adsorption/desorption of gases in coal from the point of view of developing techniques to predict imminent outbursting conditions in coal mines. A number of different parameters such as'dP express, K' and AV 0/60 etc. which have been effectively used overseas were studied on samples of coal from Westcliff and Leichhardt Colliery. Results indicate that these do not seem to be valid indices for predicting an outbursting condition. Based upon desorption isotherms, a new index defined as "L" has been developed which shows promising results. This index is in a position to differentiate the changes in the structures of coal and its proness to outbursts. The "LZ value determinations and its usefulness opens a new field where it would be possible to determine outbursting conditions from existing drill cores obtained during exploration studies or from long holes drilled in advance from underground workings. The index is more or less independent of the time elapsed between the extraction of a sample and the conduct of the test. The test for "L" can be conducted'on site or in the laboratory. The test is simple, easy to carry out and the "L" value for a sample can be calculated in less than 20 minutes. It could be adapted as a routine test for monitoring outburst conditions in mines.

Jan 1, 1980

Bendigo is AustraliaÆs second-most productive goldfield, having produced some 22 million ounces of gold between 1851 and 1954. Bendigo Mining Limited (BML), the sole lease-holder of the Bendigo Goldfield, is developing a mine that is planned to produce ore from beneath the historical workings for at least the next 25 years. The high-grade Bendigo reefs occur in the proximity of the chevron anticlines, which characterise the goldfield. Typically the reefs display relatively small cross-sectional areas and large (subhorizontal) strike dimensions. They occur in clusters due to interrelated structural controls. Most of the gold occurs as visible grains and laminae, and as such grade estimation is not amenable to ænormalÆ sampling and estimation techniques. The initial phases of exploration and development of the mine focused on understanding and resolving these sampling and estimation issues. In 2005, BML reviewed and updated the March 2004 Feasibility Study, refining the life of mine development strategy. The strategy fundamentally aims to exploit the 11 million ounce Inferred Resource and additional exploration potential by developing the current Kangaroo Flat Mine to produce ore at an initial rate of 450 000 t/yr in 2006/07, expanding to 600 000 t/yr by 2009/10; and developing the Eaglehawk Mine to produce 1 Mt/yr by 2011/12. Ore will be processed initially at the Kangaroo Flat site, and from 2011/12 also at the Eaglehawk Mine 1 Mt/yr processing plant. The two mines will connect underground in 2009. Total ore treatment capacity will be 1.6 Mt/yr, producing 600 000 oz/yr from a head grade of 12.7 g/t gold. The project is planned to operate for 25 years, processing 33.6 Mt of ore producing 13.7 Moz of gold. To achieve this production rate, the exploration and ore delineation programs will require up to 16 diamond drill rigs producing over 200 km of core per year. At the same time, approximately 8 km of on-reef development must be monitored and typically 18 stopes managed concurrently. The processing plants will be located in geographically constrained areas, which will limit the ability for selective stockpiling and campaign treatment.

Jan 1, 2006

Aspiring to be excellent makes you a good leader as it shows a capability for strategic thought, defining and implementing a vision, making a job easier, more efficient and effective. Every great business leader can generate additional revenue or cost savings for their company. Becoming excellent requires the desire and action to follow it through. There are many established methods of excellence: benchmarking, target setting, supply chain and market analysis, employee suggestions and knowledge sharing forums. In BHP Billiton, practices benchmarking is a key tool in generating improvements for functional areas such as processing, mine operations and mine planning. Practices Benchmarking involves organisational and technical questions that allow the site to self-assess their maturity and generate a prioritised improvement path. Not only does it benchmark and identify gaps, but the approach also facilitates networking, education and team building. For new leaders it is important to remember that you are not alone. Chances are your problem has been solved before. Networks û internal, external, formal and informal can get you started and often save you time and effort. Any leader can achieve success in excellence through a proper process of problem formulation, data and analysis. Again, using key players can make the process more effective. It is important to remember that the people side of the solution is the key to success and that monitoring will ensure the solution will work. In the words of BHP BillitionÆs CEO, Chip Goodyear: Excellence is a mind set. ItÆs something that comes when people get rewarded forthinking outside the box and applying their skill and knowledge. It happens, not in$50 million chunks, but in hundred thousand and million and $2 million chunks.When you get 35 000 people thinking that way, then youÆve really got somethinggoing.

Jan 1, 2005

By Rose CW

Typical rehabilitation programmes for spoil piles and waste dumps in open cut coal mines involve the spreading of topsoil to assist vegetation growth. In the early years of rehabilitation before a protective vegetation cover has been established, this topsoil is susceptible to erosion during rainfall events. Since the long term success of rehabil- itation procedures is sensitive to adequate topsoil maintenance and since, on many mine sites, topsoil is a scarce resource, erosion losses of topsoil (particularly once fert- ilised) can severely restrict rehabilitation Measures.

Jan 1, 1983