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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

This paper discusses the prediction of subsidence over partial extraction systems in thick coal seams. A model based on empirical techniques using influence functions is developed to calculate the surface ground settlements above extraction panels. Independent of the influence function, two field parameters, the subsidence factor and the angle of draw (limit angle) are required to define the model. Both these parameters are best observed from critical or super critical subsidence areas. However in thick seams, extraction widths are typically sub critical and therefore it was necessary to refine an estimation process for sub critical conditions. Partial extraction systems in NZ are characterised by variability with respect to extraction thickness and depth. As extraction proceeds along a panel, conditions deteriorate once the critical span width is exceeded and therefore percentage extraction decreases. A further variable was introduced to the modelling which allows for varying extraction sequences. Two comparisons with field observations, one over a partial extraction panel, the other over abandoned workings, showed the method gave good agreement to measured subsidence values.

Jan 1, 2002

By K Fiedler, A Newell, P D. Munro

Test work is the foundation upon which the success of projects and subsequent operations is laid, reflected in Professor Arthur Taggart’s pithy observation: ‘Make your mistakes on the small scale and your profits on the larger scale’. Indeed, Professor AllanTrench has succinctly noted that ‘Get the metallurgical characteristics wrong and you don’t have a project’.With deposits becoming lower grade, more structurally and mineralogically complex, final products requiring lower levels of impurities and tailings management demanding more attention, test work now assumes even greater significance in the acceptance and successful execution of a project. This paper is the first in a series aiming to stimulate thought on the metallurgical test work process by getting back to the fundamental basics through exploring and providing some guidelines for the metallurgical testing world, noting preferred practices as well as precautions and mitigations. This covers the key characteristics of metallurgical test work programs, including what needs to be done, sample selection, quality control and associated drivers, and most importantly, selecting, assessing and managing test work facilities. CITATION:Newell, A, Munro, P D and Fiedler, K, 2018. Metallurgical test work – between a rock and a hard place, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 15–32 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By A Satyanaga, H Rahardjo, K G. Mercer

The soil-water characteristic curve (SWCC) is one of the most essential soil properties in unsaturated soil mechanics. The water flow and storage characteristics of an unsaturated soil are closely related to the amount of water contained in the pores and the negative pore-water pressure in the soil. These are both in turn, related to the particle-size distribution and the plasticity of the soil. The SWCC is obtained by laboratory testing which is difficult to perform, costly and time consuming. There is a significant advantage in establishing typical SWCC envelopes for different soil types from a geotechnical design and analysis viewpoint. This paper presents some of the research work undertaken by UWA and NTU to develop SWCC envelopes for soil types classified in terms of the ASTM D2487 Unified Soil Classification System (USCS). This was done by establishing a large database of soils from across the world, classifying them according to ASTM D2487 and undertaking SWCC testing for each soil. This paper presents the SWCC test results from a selection of three of the most common soil classifications encountered in geotechnical engineering practise.CITATION:Mercer, K G, Rahardjo, H and Satyanaga, A, 2018. The development of soil water characteristic curves for soil types classified according to the USCS, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 263–273 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

The extent to which man's activities are influencing the earth's climate is subject to considerable debate. Internationally however, this debate has been put aside somewhat by the Kyoto Protocol. This international agreement is the political response to the threat of Global warming, predicated on the precautionary principle.NZ is seeking to be a leader in the Kyoto Protocol. Given our unique GHG emission profile and the structure of our economy, and the major uncertainties in both the science of climate change and the Kyoto Protocol itself, this desire to lead is absolutely inappropriate in this instance. We face a different, and often more severe, set of challenges in an economy that prices C emissions than virtually all of our trading partners. Unfortunately, these differences have not been reflected in climate change policy development to date. This represents a major threat to New Zealand's economy, wealth and jobs, particularly in the sectors that have been the core drivers of our economy over the last 20 years or so - agriculture, energy, primary processing. We do not, and should not, seek to avoid the issue but we must protect our economy and move with or follow our trading partners and competitors, not lead them.

Jan 1, 2002

The Mt Todd Project is located 42 km northwest of Katherine in the Northern Territory. The identified mineral resource estimate for the Batman gold deposit is 66.7 million tonnes (Mt) grading 1.4 grams/tonne (g/t). Proved and Probable Ore Reserves total 42.3 Mt grading 1.5 g/t. Orebody definition and reserve estimation is based on extensive percussion and diamond drilling. Exhaustive bias analysis comparing grades produced from different drilling techniques has been undertaken. Similarly, detailed check assaying programs have been run to validate grade data produced by commercial laboratories used during the exploratory drilling phase. Significant biases were established from both studies and appropriate 'corrections' were made to drillhole databases prior to final resource and reserve estimation. 3D geostatistical modelling has been utilised for resource and reserve estimation, with specialist consultants contracted for this work. At all times, interpreted geological controls on mineralisation, provided by

Jan 1, 1994

By J Zhou, D M. Hunter, S M. Iveson, K P. Galvin

The REFLUX Classifier is used to perform particle separations on the basis of density utilising a set of parallel inclined channels positioned above a vertical fluidised section. In continuous mode, feed enters part way up the vertical section, while fluidisation water is introduced from below. Lower density particles are conveyed upwards and collected in an overflow stream, while high density particles segregate onto the inclined surfaces, settle to the base of the system and empty via an underflow stream. Pressure transducers are used to measure the suspension density in the vertical section. This suspension density is maintained by a pneumatically controlled underflow valve to maintain a target suspension density or ‘set point’.Previously, Galvin et al (2010) demonstrated the significant improvement achieved via a new laminar-shear separation mechanism, achieved by utilising closely spaced inclined channels in the REFLUX Classifier. For the separation of low-density coal particles from mineral matter, a channel spacing of 6 mm proved effective; however, for the separation of gangue minerals from much higher density minerals such as iron ore, the shear-induced lift needs to be even higher. In this paper, we examine the influence of two different channel widths on the continuous processing of an industrial iron ore feed in the REFLUX Classifier. It was found that when moving from 6.0 mm to 3.0 mm channels, the ability of the system to reject coarser gangue material and retain finer high density material across a particle size range from 0.125 to 1.0 mm was increased, resulting in a higher grade product.CITATION:Hunter, D M, Zhou, J, Iveson, S M and Galvin, K P, 2017. Influence of shear rate on separation of iron ore fines using the REFLUXTM Classifier, in Proceedings Iron Ore 2017, pp 205–210 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By P Bartsch

Uranium solvent extraction, USX has been applied commercially for recovery and concentration for over 50 years. Uranium in acidic liquor, which is prepared following ore leaching, solid/liquid separation and clarification, can be treated through a sequence of operations; extraction-scrubbing-stripping, to obtain purified liquor. USX has dominated the primary uranium industry as the preferred technological route to converter grade yellowcake. The practices of design and operation of USX facilities has found renewed interest as new mines are developed following decades of industry dormancy. This article seeks to outline principles of design and operation from the practitioner’s perspective. The discussion also reviews historical developments of USX applications and highlights recent innovations. This review is hoped to provide guidance for technical personnel who wish to learn more about good practices that leads to reliable USX performance.

Aug 8, 2011

By W J. Rankin, D R. Swinbourne

There are large tonnages of low-grade manganese ores in India fromwhich it is uneconomic to produce ferroalloys by conventionalsubmerged arc furnace smelting. A possible way to utilise these ores is to smelt them with carbon to produce pig iron and a manganese-rich slag, then to metallothermically reduce the molten slag to silicomanganese. Thermodynamic modelling of the metallothermic reduction stage using aluminium, silicon or aluminium-silicon alloy as the reductant at 1450¦C showed that an acceptable grade of silicomanganese could be produced. Manganese recoveries were predicted to be about 80 per cent. Heat balances indicated that silicothermic reduction may not produce enough heat to maintain reaction temperature. Small-scale laboratory experiments showed that the manganese grade of the alloys, and the manganese recoveries, were close to those predicted, but those for silicon were muchlower. Aluminothermic reduction produced the highest grade manganesealloy. The slag-metal equilibrium involving manganese, silicon and their oxides was investigated and it was found that equilibrium was not attained in any of the experiments, due probably to the very low rate of reactions involving silicon. This could be used to advantage in practice to achieve higher manganese levels in the alloys.

Jan 1, 1998

By A Woodley, G Keir

The mining industry faces concurrent pressures of reducing water use, energy consumption and greenhouse gas (GHG) emissions in coming years. However, the interactions between water and energy use, as well as GHG emissions have largely been neglected in modelling studies to date. In addition, investigations tend to focus on the unit operation scale, with little consideration of whole-of-site or regional scale effects.This paper presents an application of a hierarchical systems model (HSM) developed to represent water, energy and GHG emissions fluxes at scales ranging from the unit operation, to the site level, to the regional level. The model allows for the linkages between water use, energy use and GHG emissions to be examined in a flexible and intuitive way, so that mine sites can predict energy and emissions impacts of water use reduction schemes and vice versa. This paper examines whether this approach can also be applied to the regional scale with multiple mine sites.The model is used to conduct a case study of several coal mines in the Bowen Basin, Australia, to compare the utility of centralised and decentralised mine water treatment schemes. The case study takes into account geographical factors (such as water pumping distances and elevations), economic factors (such as capital and operating cost curves for desalination treatment plants) and regional factors (such as regionally varying climates and associated variance in mine water volumes and quality).The case study results indicate that treatment of saline mine water incurs a trade-off between water and energy use in all cases. However, significant cost differences between centralised and decentralised schemes can be observed in a simple economic analysis. Further research will examine the possibility for deriving model up-scaling algorithms to reduce computational requirements.CITATION:Keir, G and Woodley, A, 2013. Regional trade-offs between mine water and energy use - a water treatment case study, in Proceedings Water in Mining 2013 , pp 21-28 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

Removal of Thiocyanate from Solutions by Precipitation

Sep 13, 2010

The optimal production of the metals needed by society is best achieved by a close synergy between concentrate production and smelting. For over 75 years commencing in 1923, such a close relationship was enjoyed between the Sullivan Mine in Kimberley, British Columbia and the Trail zinc-lead complex. An effective program of continual change and improvement at the Sullivan concentrator was achieved through a strong entrepreneurial spirit. This spirit was in part maintained through a favourable location in south-eastern British Columbia that resulted in a dynamic local community that has survived the closure of the mine. Innovations to be reviewed include feed forward reagent control, the use of column flotation to zinc and lead cleaning and the application of ultrafine grinding coupled with concentrate dewatering using hyperbaric filter technology.

Jan 1, 2005

By K M. Cook, D Clark

Fatality prevention and zero harm are key focus areas for resource companies. However, they remain an ongoing challenge for high hazard industries, including the mining sector. As one example the latest International Council on Mining and Metals (ICMM) Safety Performance Report shows that, while there is generally a declining fatality trend since the organisation commenced publishing data in 2012, there were still 33 fatalities across member companies in 2022 (ICMM, 2023b). Every fatal incident brings significant pain and suffering to the colleagues, friends and family of those involved, however the failures and causal factors leading to each incident are frequently very familiar to people working in the industry, particularly those tasked with managing risk and safety. In the words of Dame Judith Hackitt, Grenfell Tower Fire Investigator, ‘there are no new accidents – just different people making the same mistakes because they haven’t learned’ (Hackitt, 2022). The recurring themes in terms of the nature of fatal hazards and their associated causes across the mining sector show that, despite improvements evidenced by the favourable declining fatality trends over the long-term (in general and outside of catastrophic multiple fatality events), changes are required to achieve fatality elimination and the aspiration of zero harm. This extended abstract and the accompanying presentation apply a mining frame of reference to the idea that there are no new accidents, examining how this applies within the industry and why the lessons from past failures are not always well understood or applied to prevent the reoccurrence of material unwanted events. Many contemporary mining and resources organisations have extensive internal incident history data and a wide variety of information on fatality incidents is publicly available, including the annual ICMM Safety Performance Report. This extended abstract and the accompanying presentation explore how this existing data can be used effectively to learn from the past and proposes practical ideas regarding strategies for successful knowledge transfer to the workforce as a key component of preventing history repeating and improving safety performance across the industry. As noted by ICMM, ‘sharing lessons from failure is vital to improving health and safety, but it’s not enough’ (ICMM, 2023a).

Apr 16, 2024

By A Stasi, B Brice

Water is a limited and precious resource in Australia. Because of the increasing demand for water from all sectors of the economy and the variability in supply, efficient management of water resources is of vital importance. The national water reform agenda has provided a strong impetus to all states and territories to progressively move towards more efficient and sustainable water management. The Queensland Water Act 2000 is the legislative framework for providing water for the environment and for planning for the security of supply to water users. The comprehensive water planning process prescribed in the Act results in new tradeable water allocations that are separate from land. These water allocations are well specified and can be traded on a permanent or temporary basis. Trading of water allows it to move to its highest value use, thereby encouraging the most efficient distribution of this limited resource. In addition to transferring ownership of water allocations, it is also possible to change the attributes of the allocation, such as the location from which water may be taken. Changes to water allocations are subject to approval from the resource manager. Pre-testing allows for certain changes to be approved very quickly, making the trading process more streamlined and cost effective. Temporary trades, or seasonal water assignments, currently account for the majority of water trades in Queensland. However, permanent trading activity is expanding steadily as old water entitlements are converted to tradeable water allocations and as the market matures. The permanent trading market provides significant opportunities to the mining sector. It allows mining companies to buy water allocations at market prices without compromising environmental outcomes or causing third party impacts.

Jan 1, 2006

Reason Analysis of Impurity Containing and Technology Discussion of Quality Improvement for Low-Quality Iron Concentrate

Sep 13, 2010

By M Ogle

"Booster fans are relatively rare in Australian coal mines. However, as mines become progressivelydeeper it is likely that such fans will be increasingly adopted as a method to sustain or improve the ventilation of underground workings. The reasons why booster fans may be an att ractive alternative include: increased cost of sinking additional ventilation shafts with greater seam depths; environmental objections to shaft sinking projects; and increasing urbanisation and surface constraints limiting availability of potential ventilation shaft sites. As Tahmoor Colliery movedinto its northern lease the ventilation constraints became the limiting factor on production. Thelimitations of the old workings meant that the existing ventilation system would be inadequateto sustain the required production. Extensive ventilation modelling was carried out to evaluatevarious potential solutions and the recommended option was the installation of a booster fanor fans, to gain underground access to an already approved shaft site in the northern lease.Proposals were sought from recognised fan manufacturers and various alternative arrangements were tendered. Ultimately the choice was between one large centrifugal fan and a set (three or four) of smaller æauxiliary-likeÆ fans in parallel. The successful tender was for a single centrifugal, an arrangement very similar to the booster fans that have been operating eff ectively at Westcliff Colliery for a number of years. This paper describes the current ventilation network, evaluation of the ventilation options, the fan selection process, and the project status to date."

Jun 1, 2012

By H Han, X Wang, T Li, D Duan

"In this paper, the reduction and separation behaviour of iron and slag in carbon composite iron ore pellets has been investigated experimentally using an electric resistance furnace simulating a rotary hearth furnace process. The factors that affect the formation of iron nuggets, such as temperature, holding time, molecular ratio of C/O and basicity, are discussed. Results show that the reduction of iron ore, carburisation of reduced iron and the composition and quantity of slag are very important for producing iron nuggets. Through optimisation of process parameters, iron nuggets can be formed below 1300¦C when holding time is 20 minutes, C/O is 0.7 and basicity less than 0.5. This study provides a theoretical and technical basis for iron nugget production.CITATION:Duan, D, Han, H, Wang, X and Li, T, 2013. Iron nugget production technology in rotary hearth furnace process at lower temperature, in Proceedings Iron Ore 2013, pp 363-368 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 12, 2013

By A Jewbali, R Perry, R Inglis, L Allen

"The use of conditional simulation to characterise mine plan uncertainty is increasing for the assessment of risk in mining projects. While the development of grade uncertainty profiles is relatively straightforward and can be validated using standard geostatistical techniques, the addition of geological uncertainty to evaluate total risk remains problematic. Some of the problems associated with geological uncertainty methods include the clustering of data in favourable geologic units, difficulty in training image definition and the inability to address change of support issues for categorical variables. Despite these obstacles, the importance of geological uncertainty as a contributor to total uncertainty has prompted Newmont to explore and evaluate the use of various techniques (and combinations of techniques) on different deposit types.Two orogenic deposits of different geological complexity were selected for the study: Subika, a shear zone-hosted deposit, and Merian, a deposit containing gold mineralisation associated with quartz vein zones and stockwork within which are found higher-grade quartz breccia zones. Newmont trialled various categorical simulation approaches to determine the applicability of these methods for each deposit type and the effect of parameter choice on the width of the uncertainty interval. Some of the techniques that were trialled include multiple point statistics methods, sequential indicator simulation using local probabilities as well as variations of these methodologies.The goals of this study included: gaining an understanding of which techniques may work best in which deposit types gaining an understanding of the intricacies of each method gaining an understanding of the effect that each method has on total uncertainty analysis.This paper presents a comparison of the various techniques and makes recommendations for their use in uncertainty analysis.CITATION:Jewbali, A, Perry, R, Allen, L and Inglis, R, 2014. Applicability of categorical simulation methods for assessment of mine plan risk, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014, pp 85–98 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 24, 2014

By E Westthorp, J Phillips

The detection of ethylene in mined-out ‘goaf’ areas of underground coalmines is an industry standard indicator of accelerated oxidation where the coal temperature has exceeded 100°C. If uncontrolled, this naturally occurring process can lead to spontaneous combustion and catastrophic mine explosions, such as the Moura No 2 mine explosion. Spontaneous combustion trigger action response plans (TARPs) typically use the detection of ethylene as a trigger for definite change requiring immediate reaction, which can include the withdrawal of coalmine workers.Following the completion of sealing of longwall goaves at Crinum North Mine, ethylene was often detected in trace quantities. These trace quantities were below 1 ppm and detected via the bag sampling regime, with the use of a gas chromatograph. Any ethylene detected in these instances was not associated with increased quantities of carbon monoxide to conclusively indicate a heating within the sealed area.Ethylene was only detected in a newly sealed goaf and would not remain present for a period following the sealing. As part of the longwall recovery process, the predominant roof support mechanism during the recovery was the use of timber cribs. It was decided to investigate the possibility of this timber generating ethylene.Preliminary tests were completed by placing timber specimens from several species of Australian native hardwoods in gas bags in air. Over time, some of the samples showed significant levels of ethylene within the bags.CITATION:Westthorp, E and Phillips, J, 2017. Findings from preliminary testing to determine alternative sources of ethylene within sealed areas of underground coalmines, in Proceedings Australian Mine Vent Conference 2017, pp 203–206 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

A Loss of Strength of Gold Sulfide Concentrate Before Grinding and Cyanidation Using Magnetic Impulse Treatment Gold recovery from sulfide concentrates is going with cyanidation usually. The fine grinding to 95 per cent -0.020 mm is required for refractory concentrates, in which gold encapsulated by sulfides. According energy consumption is 10 and more kW h/ton. At this paper we suggested to use magnetic-impulse treatment with small energy consumption 0.1-0.2 kW h/ton for loss of sulfide strength before grinding and cyanidation. The object of studies was the gold-pyrite flotation concentrate which was produced from ores at the Kumtor Mine, Kyrgyzstan. The concentrate composition, physic-mechanical properties and loss of strength mechanism were studied there. The tested concentrate assayed, per cent: 62.5 pyrite, 10 feldspar, 10 mica, 5 quarts, 5 carbonates, 4 haematite and another. Haematite has intimate intergrowth with pyrite ? partially with quarts. The magnetic susceptibility of haematite and less pyrite causes in these grains and mineral complex the effect of magneticstriction. As a result numbers of deformations are increased and minerals and gold are also exposed. Lateral and longitudinal strains in the minerals by magneticstriction were calculated in this work. By quantitative analysis of pyrite mono fractions were showed next micro impurities: alumina, arsenic, nickel and others elements. These micro impurities are generated a charged dislocation, cracks and micro cracks. The inter-granular links at a boundary of haematite-pyrite, pyrite-quarts, haematite-quarts have disintegrated. The dislocation is depended from mineral modulus elasticity. It was determined an indicator of mineral electro-mechanic sensitivity which characterises a conversion of electro-magnetic energy to mechanic energy. Pyrite has most dielectric constant and electro-mechanic sensitivity as haematite and quarts. The dislocations in pyrite are account for clacks and a loss of mineral strength. Size analysis of the flotation concentrate after magnetic-impulse treatment is shown the increasing the content of thin fractions by comparison no treated concentrate. Magnetic-impulse treatment has increased the effect of the next fine grinding too. The electronic microscopy has confirmed a loss of strength of gold sulfide concentrate. The gold recovery by cyanidation increased too after preliminary magnetic-impulse treatment of concentrate by laboratory tests. The magnetic-impulse concentrate studies at the Kumtor plant have showed that a recovery gold increase in the processing of cyanidation. The consumption of energy also reduced.

Sep 13, 2010