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By P Radulovic, W Y. Lui

The Mount Isa Mines (MIM) copper concentrator at Mount Isa processes both chalcopyrite ore from the MIM underground mine and rotary holding furnace (RHF) slag from the MIM copper smelter. There have been numerous changes to the processing practices since commissioning this concentrator in 1973. Current management of the concentrator extends from grinding and flotation to concentrate handling (thickening and filtration) and tailings disposal (fill plants, tailings thickeners and process water systems).Predominant mill feed through the concentrator is chalcopyrite ore. RHF slag is processed when concentrator production exceeds mined ore production. The chalcopyrite circuit has two stages of grinding in parallel lines (Line 1 and Line 2). Each line has parallel preflotation and rougher banks, combining into a common scavenger/retreat circuit (including regrinding) and common cleaner circuit. RHF slag may be milled in parallel with chalcopyrite, utilising Line 2 flotation roughers and a Jameson cell cleaner. All final concentrate produced is combined and pumped to the concentrate handling plant. The concentrate is thickened, pre-fluxed and filtered in hyperbaric disc filters. Fluxing specification is set by the copper smelter, and filtered product transferred via conveyor belt to the smelter concentrate storage facility.Wet fill and paste fill plants utilise flotation final tailings as hydraulic or cemented hydraulic fill for stopes underground. Cement ratios and fill plant utilisation are varied depending on underground stope fill requirements. Tailings from the adjacent lead-zinc concentrator are also processed at wet fill. All tailings that are not utilised for backfill are pumped via wet fill to three parallel tailings thickeners. Thickener underflows are gravity fed to the tailings dams with thickener overflows recycled for site process water use. In addition to summarising historical operations, this paper will provide a detailed outline of more recent changes in the concentrator flotation circuit, equipment upgrades, reagent optimisation as well as product and process optimisation at the final concentrate handling and fill plants.CITATION:Lui, W Y and Radulovic, P, 2013. Mount Isa Mines copper concentrator - An insight into current and historical practice, in Proceedings MetPlant 2013 , pp 553-574 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By Fredley D. C

Georgius Agricola wrote in De Re Metallica in 1556 that a prudent a miner should not work in a region ruled by a tyrant-a person inimical to mining. In 1926, Associate Chief Sherman of the United States Forest Service in a speech stated, "It is the policy of the Forest Service to encourage the development of the mineral resources within the boundaries of the National Forests ... a man who fails to cultivate a friendly, helpful, cooperative spirit in his relations with those who are endeavoring to develop the mineral wealth of our mountains has no place in the Forest Service." Both statements are as true today as they were in 1556 and 1926. The challenge to the Forest Service and the mineral industry today is to maintain that cooperation in a world that has changed significantly since Agricola and Sherman. The United States Forest Service manages 77,000,000 hectares of land-mostly in the Western United States-an area equal in size to New South Wales. The vast majority-75 million hectares are National Forests, and 1.6 million hectares are National Grasslands. National Wilderness Areas account for 13 million hectares or rough- ly 17 per cent of the National Forest System. National Forest System lands (NFS) are some of the most visible, scenic and controversial lands in the country. They are also some of the most valuable for their mineral potential and production. The value of mineral produced exceeds US$4 billion per year. There are over 1200 producing mines, 15,000 oil and gas leases, and some of the largest lead, copper, silver, gold, platinum, molyb- denum, and coal deposits in the hemisphere. Every year the Forest Service approves nearly 5,000 mineral operations on the NFS. Much of the NFS (75 per cent) is open to location of mining claims pursuant to the 1872 Mining Law. And an equal amount of land is legally available for oil and gas leasing.

Jan 1, 1991

By U Rehm

The biggest hard rock double-shield tunnel boring machine (TBM) in the world, with a diameter of 12.4 m, is currently excavating the North-South Bypass, which includes a crossing under the Brisbane River, Brisbane, Australia, to relieve the often congested road traffic in the city centre. Ten years ago a 10.7 m Mixshield giant helped to handle the Olympic Games in Sydney linking the airport with the city centre for an improved transportation of fascinated visitors. In Shanghai, currently the biggest TBM in the world with 15.43 m diameter presents excellent performance rates; and in Paris a convertible Mixshield could be quickly changed from earth pressure balanced (EPB) to slurry type in order to handle the very heterogeneous ground conditions. In Madrid a 15.2 m EPB giant finished its tunnel job four months ahead of schedule. Large-scale TBMs have proved their economic and innovative potential to create the current and future underground architecture of mega-cities. TBM technology has made further large innovative steps in the last decade. State-of-the-art is a TBM for very heterogeneous ground conditions comprising hard and soft rock with additional high groundwater pressure. The machine concept is adapted to the various ground conditions and allows for a quick and flexible application. Ground treatment by means of additives developed to a helpful tool in this connection. To meet the special challenges of urban tunnel projects of nowadays it is of very high importance, beside applying highest developed technology of TBM, to have a comprehensive technical support during the project phase and to develop positive relationships between all participants of the project which last longer than only for one project.

Jan 1, 2008

By Pollard D. M

The effects of pH, temperature and the form of zinc used on the kinetics of cementation of cadmium from process liquors were investigated. Batch tests were conducted in stirred beakers, and the cementation reaction was found to be first order controlled. The rate controlling step was thought to be the diffusion of zinc ions from the zinc surface to the bulk solution. The pH was found to have a significant effect when using Prime Western zinc or zinc dust. High reaction rates were favoured at low pH levels and a minimum rate was observed at a pH level of approximately 5 to 5.5. The pH was found to have little effect when using high grade and cathode zinc. The reaction rates increased significantly with increasing temperature; a reaction temperature of 55¦C resulted in almost complete removal of zinc from solution. Effective cementation rates were only acheived with cathode zinc after pickling in acid. The nature and specification of zinc used determined the cementation rate of cadmium, resulting in the following order: 1. Zinc dust 2. Prime Western zinc at pH 3 3. High Grade zinc at pH 3 4. Pickled cathode zinc 5. Prime Western zinc at pH 3 6. High Grade zinc at pH 3 7. Cathode zinc "as received".

Jan 1, 1989

Lithocaps are potentially voluminous zones of advanced argillic and associated argillic alteration located above the subvolcanic intrusive environment. They constitute exploration objectives for epithermal and porphyry-type deposits. High-sulphidation epithermal deposits may be sought within lithocaps, whereas low-sulphidation deposits may exist on their edges. Porphyry Cu-Au/Au deposits may be accessible beneath lithocaps if systems are telescoped sufficiently. Oxidation of the basal, pyritic parts of lithocaps may promote supergene sulphide enrichment under appropriate tectonic and climatic conditions.

Jan 1, 1995

The genesis of the Bulong Laterite Ni/Co deposit spans some 60 per cent of earth history: from development of the parent rocks in the Archaean to lateritic weathering in the Cainozoic. In a man's term, the discovery and evaluation history of the deposits has also been protracted and, at any given time, the perceived value of the deposits has depended upon the available technology and world markets.

Jan 1, 1996

By Giannini LM, Carras S

A fundamental problem in mine planning is that of determining the "optimum pit limit" of a mine. This optimum pit limit yields information which is considered essential in the evaluation of the economic potential of a mineral deposit, and in the formulation of long -, intermediate -, and short-range mine plans. Since the mid 1960's a number of mathematical techniques based on the "block model" have been proposed for solving this problem. When applied to large ore-bodies the implementation of these techniques, especially the more elaborate ones, poses considerable computational problems. In this paper we report on our work, done jointly with Systems Research Institute of Australia (SRIA), in devising strategies for overcoming these Problems.

Jan 1, 1986

By Still RF

Sintering of lead and zinc concentrates is practised by Sulphide Corporation Pty. Limited to provide both desuiphurised lump sinter feed, for simultaneous reduction to zinc and lead in the Imperial Smelting Process blast furnace, and sulphur dioxide gas for sulphuric acid manufacture. From November, 1969 a 20 percent increase in production rate has been obtained through improvements in operating technique. A gradual increase in bed permeability was achieved by modifications to the feed mix conditioning equipment and by improving moisture control. However advantage could not be taken of the higher permeability to increase sulphur elimination because the hardness of the lump sinter decreased. Higher throughput, better quality sinter and more stable sintering conditions were however made possible by simultaneously: 1. reducing segregation and compaction in the sinter bed, by narrowing the discharge opening of the main layer feed hopper, 2. reducing the sizing of sinter returns to give a closer size spectrum of particles in the feed mix, and 3. increasing the sulphide sulphur content of the feed mix to give higher bed Temperatures.

Jan 1, 1972

By Smith DM Jr

Silver deposits, in which silver forms at least fifty percent of the value of the ore, are abundant and large on the east side of the Pacific and are absent in the western Pacific. To determine if this uneven distribution is related to features of consuming plate tectonic boundaries which dominate the metallogeny of the Pacific Rim, the variation of Ag/Au in porphyry copper deposits was used to estimate the relative silver content of magma generated in subduction zones. Porphyry copper provinces with high Ag/Au occur in regions of the eastern Pacific where silver deposits are abundant, suggesting that the distribution of silver deposits is controlled by the relative abun- dance of silver in subducted ocean crust. Ocean crust being subducted in the eastern Pacific is mostly less than 50 million years old in contrast to most ocean crust in the western Pacific which is much older. Enrich- ment of silver in young ocean crust at spread- ing centers may reflect metallogenetic evolution over geologic time. Silver may be transported to the surface in volcanic rocks, and deposits are common where felsic varieties are abundant. The high ,solubility of silver in natural waters provides a natural storage mechanism for silver weath- ered from these rocks and ultimately circulated in near-surface hydrothermal systems where many silver deposits form. The regional distribution of silver deposits is not influenced by discoverability, vertical metal zoning, or regional tectonic style. The effect of igneous differentiation is unclear.

Jan 1, 1987

In looking towards 2000, it is more than appropriate that we look back on the history of diamond drilling to give us a better understanding of where we have come from and see the significant advances that have been made.

Jan 1, 1992

By Hayashida O, Numata Y

Ultraviolet and infrared spectroscopic analyses and the extended lluckel molecular orbital method were applied to determine the electronic and binding states of 2-mercaptobenzothiazole and the adsorption system of 2-mercaptobenzothiazole on pyrite. 2-mercaptobenzothiazole exists rather in thione form than in thiol forru and the two adsorption peaks in solution were assigned to both 7t--?rt* transitions. 2-mercaptobenzothiazole chemically adsorbs on pyrite mainly due to forming the bond between iron (pyrite) and sulphur (2-mercaptobenzothiazole).

Jan 1, 1993

This paper summarises the results of a study carried out for the Sustainable Minerals Institute, University of Queensland, aimed at identifying the major water-related issues facing the minerals industry internationally and the research required to support the development of practicable solutions. An overview is given of the sources and uses of the worldÆs water resources and of the regional and global sustainability of water supply and management. Agriculture is the worldÆs major user of water; it wastes more water than the minerals industry uses. Water reform and its potential impact on the minerals industry are discussed with particular reference to Australia and South Africa. The sources, uses and management of water on mine and processing sites are outlined. Particular attention is paid to the importance of groundwater as a source of often saline water that can be used in mineral processing and for other purposes. Aquifer storage and recovery has the potential to help conserve water resources. Generally, the major uses of water on mining and processing sites are for mineral processing and refining and for the associated tailings disposal. Water consumption for these purposes may be reduced by recycling process water, using saline water, paying close attention to water management, thickening tailings and using techniques such as dry stacking and paste. A change in the minerals processing paradigm in respect of water use could come through research into new, improved and less costly dry processing techniques. The treatment of mine and processing water will be required increasingly before water is reused, stored, discharged or sold, and before sites are decommissioned. Research and development are required to reduce costs and develop new treatment methods. Mine closure and decommissioning raise a number of long-term water issues requiring continuing generic and site-specific research and development.

Jan 1, 2003

By Miller M. J, Bauer J. C

The continuous copper drossing process operated at Port Pine since 1962 has had limited copper removal capacity as determined by a maximum tolerable Cu/S ratio in feed and the level of sulphur in blast furnace bullion. Recent process development has been to overcome these limitations to meet increased copper throughput requirements. A sulphur addition system was developed and installed in August 1987. The system has capacity to increase sulphur input by over 150%, meeting the increased copper capacity requirement and also allowing independence from the upstream process for sulphur supply. Developments in process understanding have been applied within the limitations of the existing furnace design with a 10% increase in the maximum tolerable Cu/S ratio.

Jan 1, 1989

This paper will be a discussion of the geological exploration and drilling carried out on the Mt Davy Block, Greymouth Coalfield. A brief summary of the geology of the Greymouth Coalfield will be given to put the Mt Davy Block into perspective.

Jan 1, 1979

By Zingano A, Costa J. F

Brazilian amethyst production is mostly obtained from underground mines in the southernmost part of the country, involving approximately 6000 miners and generating an income of US$ 20 million per year. Amethyst-bearing geodes are hosted by Cretaceous continental flood basalts of the Serra Geral Formation. The economic zone occurs in the massive (colonnade) intermediary section of the Sao Gabriel Basalto. The tunnels and stopes follow the occurrence of geodes leading to an erratic and complex layout. A ground control survey revealed excessive roof convergence. Topographic results show excessive roof deformation and some roof falls have already been reported. To understand the ground conditions, prevent roof falls and better define the pillar dimensions detailed geomechanical mapping was carried out using the scanline method. Uniaxial compressive strength tests provided complementary information for rock mass classification. Results of the geomechanical classification were used to modify the mining layout taking into account the roof and pillar geomechanical characteristics. Retreat pillar mining minimised ground instability.

Jan 1, 1997

By M L. Muller, A R. O’Donnell

The Mount Isa Mines (MIM) Copper Concentrator has an extensive history of reagent trials, with different reagents coming in and out of favour over the years. The research and use of carbon depressants is particularly prevalent, as carbonaceous pyrite is a major source of concentrate dilution. Years of research led to the use of naphthalene sulphonate due to its excellent carbon depression properties. However, due to rising reagent costs carbon depression ceased in the late 1990s. This led to the loss of knowledge about the use and value of naphthalene sulphonate. Cyanide is used at the Copper Concentrator for the sole purpose of pyrite depression and over the years multiple projects have been devoted to finding alternatives to it. In 2012 the neighbouring MIM Lead-Zinc Concentrator replaced cyanide with naphthalene sulphonate which resulted in cost savings and the elimination of a hazardous reagent. In 2013, plant trials were conducted at the Copper Concentrator in hopes to replicate the outcomes obtained at the Lead-Zinc Concentrator. The results of the trials conducted at the Copper Concentrator showed that naphthalene sulphonate could not replace cyanide and this work was set aside to pursue more promising projects. Further research conducted in 2014 found that mineralogy and a better understanding of the depressing mechanism of naphthalene sulphonate held the key to improved pyrite depression at the Copper Concentrator. The findings showed that Mount Isa copper ore contains two forms of pyrite; euhedral pyrite (cubic pyrite) and framboidal pyrite (carbon rimmed spheres of pyrite), both of which require different reagents to sufficiently depress them. Naphthalene sulphonate was found to be an excellent carbon depressant, suitable for depressing graphite and framboidal pyrite, whilst cyanide specifically targets euhedral pyrite.In 2015 laboratory test work was conducted to examine the use of naphthalene sulphonate in conjunction with cyanide to selectively target both forms of pyrite. This work led to a full plant trial, the results of which showed a significant increase in plant performance, with higher copper concentrate grades and recoveries being achieved. This paper aims to focus on the benefits and importance of understanding past work and linking a detailed knowledge of feed mineralogy to reagent selection for improved plant outcomes.CITATION:O’Donnell, A R and Muller, M L, 2018. Selectively targeting hydrophobic gangue minerals at the Mount Isa Mines Copper Concentrator, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 413–421 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By Berglin IK

Since 1962, ferro alloy production in Australia has been concentrated at Bell Bay, Tasmania with a major expansion occurring in 1976. This concentration was based originally on the perceived requirements of the expanding Australian steel industry, but recent stagnation within this industry has seen Temco become progressively more export oriented.In 1984, approval was given for a $47 million uprating of facilities which will allow for the introduction of the latest technology to ensure high quality, low cost production in a highly competitive export market.

Jan 1, 1985

By D M. Silva, J C. Alves

According to the literature, material transportation represents 50 per cent of the operating costs for an open pit mine. In this context, this paper proposes a multistage approach for dynamic truck dispatching in real open pit mine environments, implemented in the commercial package SmartMine®, marketed by Devex SA. The first stage of this approach defines the optimal number of trucks that maximises the tonnage production by means of a robust linear programming model, which considers the operational constraints of a real mining process. The second stage uses a dynamic dispatching heuristic joining computational simulation and multicriterion optimisation techniques for decision making for truck dispatching. Another relevant contribution of this work is the publication of realistic instances collected from a dispatching system managing an iron mine, containing information about the hauling and loading fleet, the equipment situation when the working shift starts, cycle times, the time line of special occurrences (such as equipment stoppages and loading equipment reallocation in order to satisfy the mine planning) and the tonnage produced. These instances were generated with the purpose of submitting the method to the test of a real situation that considers the uncertainties existing in the process studied. The proposed approach was validated by means of a discrete event simulation model applied to the previously designated instances. Using this multistage approach as a mechanism for dispatch decision making, it is shown that the haulage fleet productivity increased when compared with the real values reported from the instances. These results are important because they show that the proposed approach generates efficient dispatch decisions for trucks operating in a real environment, reducing operating costs, increasing production and making the mine more competitive.

Sep 26, 2011

Up to 80 per cent of the copper in a bornite ore can be quickly leached with percolating acidified ferric sulphate solutions. The upper limit for rapid copper extraction is set by the conversion of bornite to slowly dissolving chalcopyrite. The dissolution occurs in two stages: a rapid linear initial stage, followed by a slow, non-linear stage. The initial step is largely controlled by the rate of oxidant supply (Fe2(S04)3); temperature is not an important variable during the initial reaction. The second leaching stage is controlled by chemical and physical factors and is temperature dependent. The initial copper leaching rates are insensitive to both the concentration of the ferrous sulphate reaction product, and the sulphuric acid concentration.

Jan 1, 1973

By T Peters

The Kibali Gold Mine is currently comprised of several open pits, a 3.5 Mtpa underground mine and a 7.5 Mtpa processing plant. Development of the underground operation commenced in December 2012, with initial access established through twin surface declines, followed by the commencement of a blind sink 8 m diameter rock hoist shaft in March 2013. Stope production started in December 2014 with ore and waste trucked to surface. The 755 m deep blind shaft sink was completed in August 2015 together with the cutting and equipping of three main station levels. Two of these levels provide access for the establishment of the underground materials handling system as well as the main dewatering system for the mine. This paper covers the process of determining the optimal location of the Kibali hoisting shaft relative to project-specific critical factors, and then focuses on the design and implementation journey associated with the off-shaft development that essentially encompasses the Material Handling System (MHS) for the mine. The journey starts from the findings of the previous owners Feasibility Study (FS), a subsequent Optimised FS, followed by detailed engineering through to implementation. It was identified during implementation that a significant change in the designed off-shaft layout was required following detailed underground geotechnical and hydrogeological investigations. In addition, the paper provides details on the MHS performance since commissioning to steady state, and on key learnings relating to the overall project process.

Mar 29, 2023