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This paper summarises the influence of slurry rheology on the grinding throughput of batch laboratory and continuous plant-scale mills operating in open and closed circuit configurations. The results of controlled changes in percent solids, particle size, slurry temperature, and viscosity control chemicals are demonstrated. An underlying rheological explanation of the above factors is offered which involves tying the specific rates of breakage that are occurring in the mill with the specific rheological character that the slurry is exhibiting at any given set of operating conditions. Some industrial scale operating guidelines are presented which have proven useful in increasing the net pro- duction capability of grinding circuits.

Jan 1, 1978

By P Hagan, S Campbell

A study was undertaken using various methodologies to determine the optimum loading and hauling configuration for different haul routes at Callide Mine, a coal mine located in central Queensland. The study involved development of an effective flat haul model that was used to estimate production rates in truck and shovel circuits that employ two excavators of differing capacities then Queuing Theory to construct a capacity constraint model for scheduling purposes to assist in truck allocation and finally a cost model to determine the most cost effective fleet configuration.The model was calibrated using haul road design and performance data of trucks and excavators currently in use at the mine. The study examined the effects of cycle time for different truck and excavator fleet configurations on production rate and costs.The study found haulage cost was directly related to cycle time while production rate reduced with cycle time. The study indicates the approach taken in combining a cost model with a capacity constraint model offers a simple and effective method of scheduling an optimum number of trucks in a haulage circuit.CITATION:Campbell, S and Hagan, P, 2012. Selection of an optimum truck and shovel fleet based on effective flat haul and capacity constraint modelling, in Proceedings Eighth Open Pit OperatorsÆ Conference , pp 19-26 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 18, 2012

Prior to 1972, Peko Mines Limited at Tennant Creek used a central mill at Peko, which consisted of a gravity circuit, flotation and cyanidation of tailings, to treat their gold ore from surrounding mines. The Warrego concentrator, 60km to the west, was built to handle the Warrego and Gecko copper orebodies, which were being developed concurrently with the concentrator construction The Warrego concentrator consisted of a flotation circuit, using autogenous grinding at 100 - 120 tph, compared to the more elaborate Peko circuit employing rod mill - ball mill grinding capable of treating only 18 - 26 tph. During development of the Warrego copper mine a gold rich ore pod was located, because of which the mining plans were adjusted to allow simultaneous, separate extraction of the copper and gold ores. However, the plans for the concentrator were not affected as the gold ore could be carted 60km to the Peko central mill for processing.

Jan 1, 1978

By G R. Ballantyne, M S. Powell

A comprehensive Australia-wide survey of comminution energy consumption at copper and gold mines was presented by the authors at the 11th AusIMM Mill Operators’ Conference 2012. The database has been extended to include major overseas mines and used to benchmark comminution energy consumption across the industry. The mines included in this study now represent 15 and 24 per cent of the total global gold and copper production respectively, and almost all Australian production. The comminution energy intensity per unit of saleable metal has been presented in a graphical form similar to a cost curve used in economics. The graphical method has been developed to assess the competitive advantage that can be achieved by reducing comminution energy intensity.This benchmarking tool has been applied to three published case studies to assess its applicability. The first case study indicated that a large reduction in size-specific energy (kWh/t -75 µm) was achievable by converting standard semi-autogenous and ball mill circuits to include high pressure grinding roll and stirred mills. The second case study investigated the metal-specific energy reduction historically achieved by Bougainville with the addition of a preconcentration screening plant. The final case study was conducted by Barrick Gold Corporation and involved incremental efficiency upgrades at three of its gold mines: Cortez, Cowal and Mara North. The application of the benchmarking tool to each of these case studies successfully demonstrated the scale and competitive advantage that was achieved by reducing energy intensity.CITATION:Ballantyne, G R and Powell, M S, 2014. Benchmarking comminution energy consumption for improved efficiency, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 95–100 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

Bendigo Mining operates a 600 000 t/a comminution, gravity, flotation and leaching processing plant for the recovery of gold from their Kangaroo Flat Operation, in the Bendigo goldfields. The free gold and gold bearing sulfi des present are typically coarse grained and hence are highly amenable to gravity recovery. Plant operating data is consistently showing that over 78 per cent of the feed gold is recovered in a circuit, consisting of inline pressure jigs, inline spinners followed by free gold tabling and intensive leaching of tabling tails. The circuit receives coarse crushed product from high pressure grinding rolls and the grinding mill discharge, which allows material to be re-circulated through the gravity process until the particles are small enough to enter the flotation circuit. A plant audit was completed on 26 November 2009 designed to give an indication of the overall operational characteristics of the gravity circuit including single pass efficiencies of associated equipment. The techniques, results and challenges of such a survey are discussed.

Aug 1, 2010

By J E. Everett, D Linden, P Maney

In response to the implementation of a new schedule for iron ore fines in the International Maritime OrganizationÆs (IMO) International Maritime Solid Bulk Cargoes (IMSBC) Code, improved measures for the management of moisture have been developed. In particular, prediction of cargo moisture allows management of iron ore fines within the supply?chain to facilitate the safe?shipping of iron ore fines.An ARIMA model, augmented to allow for shipment tonnage, has been developed to predict the moisture level from previous shipments of the same product. The model explains about 60 per cent of the moisture variance. It was found that inclusion of other available information, such as ore composition, train/rake assays and recent rainfall at port and mine, did not add to the predictive power of the model.CITATION:Everett, J E, Linden, D and Maney, P, 2013. Predicting iron ore fines shipment moisture, in Proceedings Iron Ore 2013 , pp 17-26 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

The Fosterville Goldmine in Victoria employs bacterial oxidation (BIOX« Process) to liberate gold from its flotation concentrate. Gold occurrence is primarily as submicron particles in pyrite and arsenopyrite and has been described as being in æsolid solutionÆ and therefore not amenable to direct cyanidation even with fine grinding. Once liberated by the oxidation process, the gold is then available for cyanide leaching. While the oxidation process is very effective, it has been found that a portion of the liberated gold can become suspended in the liquid phase in what appears to be a colloidal state. This liquid becomes a waste stream during washing of the oxidised solids and the suspended gold is therefore lost. This paper discusses investigations into the causes of the loss and also describes the successful use of quebracho tannin in reducing colloidal gold loss. Laboratory and subsequent plant trials, showed a gain of 2.6 per cent in overall gold recovery based on mill feed and waste stream data.

Jan 1, 2009

As a result of the rapid economic growth in Japan, environmental problems have become a national concern in the latter half of the In 1967, the Basic Lair for Environmental Pollution Control was enacted as a fundamental ::olicy in this field. This lair provided compre- hensive guidelines for the action to be taken pollution prevention. The biggest problem n air pollution of those days was that of the sulphur dioxide content of the atmosphere. Based upon the law, the smelters in Japan have struggled hard to solve this difficult problem. Consequently, the ambient SO2 level has been lowered gradually year by year. At present, the ambient SO2 level is nearly equal to that in the atmospheric background. Furthermore, the fixation ratio of sulphur in Japanese copper smelters has attained up to 99.5 per cent.

Jan 1, 1980

By M Castello, P Bouchard, M Sabsabi, A Blouin, B Nguegang Kamwa, M Constantin, K Fytas, M Laflamme, K Rifai, F Vidal

Canada’s Quebec province operates 26 metal mines, 19 of which are producing gold and generating over C$1.8 billion (US$1.3 billion) annually. In all those mines, numerous samples of rock are collected and analysed daily in laboratories in order to determine their gold content. However, laboratory results are generally available within 48 hours of sampling (depending on the number of samples received by the laboratory and the priority of the results), thus potentially slowing down mining activities. In an attempt to find a solution for delayed laboratory results, Laval University, in partnership with the National Research Council Canada (NRC), the National Institute for Scientific Research (INRS) and four mining companies (Agnico Eagle, Canadian Malartic, Hecla Québec and Iamgold) have launched the Laser-Induced Breakdown Spectroscopy (LIBS) project for in situ real-time mining sample analysis. This work aims to minimise the amount of LIBS point sampling necessary to be representative of a full scan of the analysed area. Eight sampling patterns are investigated. A statistical analysis of the data was performed by varying the pattern steps. Results show that two of the patterns, 1 and 5 (single diagonal crossing the stratification of the samples with opposite slopes) minimise the amount of point sampling while remaining representative. The most successful results are obtained from steps which are greater than 6. In terms of the type of material, pattern 5 and steps 9 are better for core sampling, while pattern 1 and steps 8 are better for rock sampling. The geological explanation for these results is the heterogeneous distribution of gold in the sample which seems to be more homogeneous in the rocks than in the core sample due to the small rock size. In terms of the mineralisation, pattern 5 is better for mixed sulfides and quartz veins, and steps 8 and 9 are better for quartz veins.CITATION:Nguegang Kamwa, B, Rifai, K, Laflamme, M, Constantin, M, Castello, M, Vidal, F, Bouchard, P, Fytas, K, Blouin, A and Sabsabi, M, 2017. Sampling strategy by statistical analyses of LIBS data in the context of a portable gold analyser, in Proceedings Tenth International Mining Geology Conference 2017, pp 221–232 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

Despite the large areas of sedimentary basins in Western Australia, the coal resources are very meagre., This is a serious problem for the State, which-at present-lacks any other alternate source of fuel-for power production.. Located coal deposits are all poor in quality and mostly brown coals of little importance. The best..coal suitable for extraction is at Collie, where a black=sub- bituminous non-coking coal is mined. Most other coals recorded are low grade or lignite, with high ash'and moisture content and a low calorific value. Coal was first discovered in Western Australia in the bed of the Irwin River, 50-miles south-east of Geraldton, by the Gregory brothers, explorers, in the year 18+6,. but although investigated, it has never been developed. The most noteworthy discovery of coal was in the Collie River, 26 miles east of Bunbury, by Arthur Perrin in 1883. Production commenced in 1898 and ever since, Collie has continued to be the State's sole producing coalfield.

Jan 1, 1964

I The South Platform of the Gippsland Basin is an extensive area of shallow basement covered by a relatively-thin Late Mesozoic-Cainozoic section. Although the sporadic exploration to-date has not resulted in any hydrocarbon discoveries, the area is under-explored and its taste potential has not yet been fully evaluated. The best potential appears to be in areas underlain by the Golden Beach Megasequence where structures are mainly related to basement fault blocks.

Jan 1, 1992

By D M. Frantois-Bongarton

"A few situations are first reviewed where practical shortcuts lead to acceptable solutions where none seemed to be possible. These include: The solving of many complex sampling optimisation problems with the simple approach of the worst case policy (WCP). A simple approach to single-stage sampling problems will be mentioned at continuation. In the plants, minimising the impact of border effects in incorrect samplers, so that the resulting samples are approximately correct and acceptable in practice because the bias risk attached to them is controlled. Examples are given, as well as practical tools and a general methodology.Finally, some sources of undue conservatism are reviewed with general recommendations aiming at eliminating them.CITATION:Frantois-Bongarton, D M, 2012. Practical considerations and shortcuts in sampling, in Proceedings Sampling 2012, pp 171-174 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 21, 2012

By B Miles, D J. Williams, J Ahn, T A. Vangsness

The flooding of open strip coal mines in the Bowen Basin and Hunter Valley Coalfields of Eastern Australia has the potential to soften the spoil and floor materials to produce “mud”. This mud can act as a slip plane or weak zone when spoil is dumped into it, resulting in geotechnical instabilities. It is therefore important to understand the mechanisms and degree of degradation likely to occur within coal mine spoil of different qualities.To investigate this, five clay mineral-rich coal mine spoil samples were collected from the Bowen Basin, and each sample was subjected to wetting and drying cycles to simulate degradation that could be expected on wetting-up in situ, with their particle size distribution analysed both before and after degradation. These results were compared with the results of a modified slake durability test, in which the entire sample was tested.The paper presents the results of the accelerated degradation and modified slake durability tests on each of the five spoil samples. These results were related to the physical and geochemical characteristics of the samples, which highlighted their importance. The modified slake durability test may be used to rapidly simulate the expected in situ degradation of coal mine spoil on wetting-up, enabling susceptible spoil materials to readily be identified.CITATION:Vangsness, T A, Williams, D J, Ahn, J and Miles, B, 2018. Accelerated degradation and modified slake durability testing of clay mineral-rich coal mine spoil, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 83–96 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By D M. Frantois-Bongarton

Variograms can be powerful tools for the analysis and control of process streams and their sampling. Their uses and proper utilisation have been described somewhat unclearly to date, and their limitations and precautions of use are too rarely mentioned. The general meaning and properties of the variogram tool and its use in geostatistics are therefore reviewed in details to derive a critical view of its proper use for process control: what to expect from it and what it cannot deliver and which uses are illusory or potentially misleading. A summary of GyÆs seminal work accompanies this essay to put the concepts into historical perspective.CITATION:Frantois-Bongarton, D M, 2012. Review of variogram properties and remarks on its use in process control, in Proceedings Sampling 2012 , pp 175-180 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 21, 2012

The ASC has a dual role of business facilitator and law enforcer. Only certain types of expert report are of interest to the ASC. The powers of the old Companies Code and the Corporations law are compared. NCSC Policy Release 149 was dependent on the prescriptive powers given to the NCSC in the Companies Code. The Corporations Law does not give the ASC power to prescribe the contents of expert reports. The requirement now is for all necessary information. Research evidence is that some investors want simpler prospectuses while others need more detail. The ASC's examination of expert reports is after registration of primary documents. This leads to a necessity for experts to maintain adequate records.

Jan 1, 1994

By Rayner J. G, Leckie J. F, Moorehead C. F

The Coronation Hill gold-platinum-palladium prospect is located in the valley of the South Alligator River (latitude 13'35'S, longitude 132'36'E), about 80 kilometres east of Pine Creek in the Northern Territory. Coronation Hill was one of thirteen sites in the South Alligator Valley at which uranium was mined between 1955 and 1964 after initial discovery by the Bureau of Mineral Resources in 1953. Most of the mines were operated by United Uranium No Liability. The Sleisbeck mine 25 kilometres south of Coronation Hill was operated by North Australian Uranium Corporation and the group of mines at Rockhole about 20 kilometres to the north-west of Coronation Hill was operated by South Alligator Uranium No Liability. The uranium mine at Coronation Hill produced about 26000 tonnes of ore averaging 2.6 kg/t U308 with an estimated average gold grade of 10.4 g/ gold. Gold was commonly associated with the uranium mineralisation and was recovered at the gravity treatment plant at El Sherana. Gold was also recovered in 1986 by Pacific Gold Mines Limited by treating the tailings from the Moline and Rockhole uranium leach plants at a CIP plant at Moline. With the completion of uranium contracts in 1964 mining in the South Alligator Valley ceased. Exploration for uranium continued in the area during the 1960s and 1970s with no success. The Coronation Hill Joint Venture (BHP Gold Mines Limited 45 per cent, Pioneer Minerals (Gold) Pry Ltd 45 per cent, Notgold Limited 10 per cent)carried out the first exploration specifically targetted at gold in 1984 with the drilling of five vertical drill holes which indicated high potential for a substantial gold resource at Coronation Hill with no associated uranium. The Joint Venture has sub- sequently drilled about 25000 metres of diamond drill holes at Coronation Hill alone. Analytical results from 1985 drilling established that platinum and palladium were associated with gold. An indicated resource of 3.49Mt at 5.12g/t Au, 0.21g/t Pt and 0.56g/t Pd has been calculated using a lg/t Au cut off.

Jan 1, 1991

By Servant S

In the mine of this study, cemented hydraulic backfill is placed under the form of a slurry at a percentage of solid by weight varying from 50 to 65 per cent. This slurry settles and cures in the stope. During this process an important amount of water must be drained from the scope. Field observations in the case studied here show that the geometry of the drains system has a significant impact on the drainage of the stopes. The mode of filling produces a backfill showing an evident stratification typical of a sedimentation process. In situ observations on this material show that this stratification translates into a very strong heterogeneity in the physical properties of the cemented backfill. This heterogeneity should affect the hydraulic conductivity of the backfill in the scope. In order to study this aspect, finite element simulations were performed. This paper presents the results of these simulations, where the impact of this stratification on hydraulic conductivity is related to the performance of the backfill drainage system for various geometry. This preliminary study is aimed at providing a better understanding of the role of the drains in the dewatering process of the backfilled stope in the case of this Mine.

Jan 1, 1998

By J P. Jona, S R. Poulson, C H. Gammons

Spatial and temporal trends in water chemistry in the acidic (pH ~2.6) Berkeley Pit lake, Butte, Montana, can be explained by a newly developed iron-cycling model. Key elements of this model include: subaqueous oxidation of pyrite and other metal sulfide minerals by dissolved ferric iron, producing Fe2+ as a by-product; re-oxidation of Fe2+ to Fe3+ in the epilimnion, assisted by A ferrooxidans; precipitation of secondary ferric minerals (schwertmannite, jarosite) in the epilimnion; and replenishment of the Fe3+ concentration of the hypolimnion by seasonal lake turnover and gravitational settling and re-dissolution of ferric precipitates. Pyrite oxidation rates were approximated by using published rate laws and information on the Fe3+ concentrations (~5 mmol) of the Berkeley Pit as a function of depth. The results indicate that subaqueous pyrite oxidation may be releasing as little as 6 + 106 or as much as 600 + 106 moles of H+ each year to the lake; the large range reflects uncertainty in calculation of the specific surface area of pyrite in the flooded pit. This helps to explain the observation that the pH and metal concentrations of the Berkeley Pit have not improved with time since mine flooding began in 1983. Vertical cycling of ferric iron in the pit lake permits pyrite oxidation to continue in deep water, even in the absence of dissolved oxygen. This hypothesis is supported by preliminary stable-isotope data.

Jan 1, 2003

By C Dowding, C Aimone-Martin, P Abeel

This paper presents measurement and analysis of the dynamic response of a five-storey building to very high frequency excitation (>100 Hz) from blasting vibrations originating from a contiguous excavation of rock. Velocity response measurements in the rock and on the structure were employed to calculate the time-correlated dynamic displacement response of the building to blasting. Time-correlated structure response measurements are needed to advance the understanding of the response of urban structures to high-frequency excitation. Current regulations and understanding are based upon measurements of the response of one- to two-storey residential structures by 10 to 40 Hz excitation. The extension of these observations to taller structures when excited by high-frequency excitation needs to be investigated further.Measurements show that the amplification patterns at the ground level and top of the structure match or are lower than that observed by the US Bureau of Mines (Siskind et al, 1980) for the shorter residential structures. They decrease with increasing peak particle velocity. From the measurements, the global transverse shear strains found by differentiating ground floor and top displacements were calculated to be 12 µstrains. Time-correlated bottom and top of structure displacements show that building response may be more reflective of wave propagation up the structure than whole-structure inter-storey drift.In addition, a 3D model was used to compare computed displacements and strains to measured results. Modelled responses varied considerably, both in magnitude and location of the maximum strain. No conclusion can be made regarding the best 3D model to employ to simulate building response. More data such as motions measured at many points in the structure are needed. Maximum inter-storey transverse shear strains calculated with the model were found through the acceleration excitation and were less than 12 µstrains for 37 mm/s rock motion excitation. The inter-storey transverse shear strains calculated with rock displacement input were less than that found with the acceleration excitation.CITATION:Dowding, C, Aimone-Martin, C and Abeel, P, 2015. Measured and modelled response of a multistory, urban structure to high-frequency blasting excitation, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 211–220 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

Can mining promote sustainable development? What is sustainable development? Is sustainable development good for corporate sustainability? Does it work in practice? If so, is it good for business? This paper does not seek to provide definitive answers to these issues. Rather, it is presented in the interests of sharing information and contributing to the pool of collective experience. The discussion will draw on the experience of Placer Dome in Papua New Guinea (PNG). Sustainable development means development that is maintained at a steady level without exhausting natural resources or causing ecological disturbance. The term æsustainable developmentÆ is often linked to the concept of ecological equilibrium, development that is self-replenishing. While its essential meaning remains the same, in practice, and for todayÆs complex and industrial world, different people will interpret sustainable development in different ways. Given the dynamics of development and the competing social, political and economic interests, sustainable development must be seen from a much broader perspective. This is the point that this paper will attempt to make. Mining, an activity that uses non-renewable resources, can promote sustainable development. The 1987 Brundtland Report (also known as the Report of the World Commission on Environment and Development), defines sustainable development in a broader manner - as development that meets the needs of the present world without compromising the ability of future generations to meet their own needs (Elkington, 1997). This definition calls for inter-generational equity in the development and use of resources by many organisations, including multinational corporations. Corporate sustainability, on the other hand, is about developing strategies that guide a corporation to stay alive and, more importantly, to stay ahead of its competitors. It is basically about survival in a competitive social and commercial environment. In a corporate world, profitability is survival. In this context, corporate profitability, the main ingredient of corporate sustainability, is important for sustainable development. Without profits, corporations will find it difficult to practice sustainable development or indeed any development. Sustainable development can integrate mining activities with the rest of the community, add value and, in the long-term, profits to the bottom-line. Ultimately, sustainability will force corporations to adopt strategies based on a longer time scale to survive. In the mining sector, corporate sustainability depends on a close relationship with all stakeholders, particularly landowners for whom sustainable development is critically important. Increasingly, there is an acceptance of the view that success is not achieved simply through competition in price, cost and technology but, more importantly, through creating social infrastructure which support community ethics, norms and values essential for trust and partnership. Needless to say, mining companies that engage in appropriate community-based development in support of inter-generational justice recognise the true value of sustainability. This is sometimes called the æhuman sustainability approachÆ which underlines the critical significance of trust in relationships with stakeholders and continuous improvement of corporate capabilities directed towards the future (Dunphy and Griffiths, 1998). In the long-term, such development will enhance corporate public image and acceptability. In practice, both concepts can be built on the principles of economic viability, environmental quality and social justice -what, in todayÆs parlance, is increasingly becoming known as the ætriple-bottom-lineÆ approach to business (Elkington, 1997). Underpinning this approach is a process of continuing dialogue and co-operation between governments, non-government organisations (NGOs) and business.

Jan 1, 1999