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By A Black, A de Jo, J Cavanagh, J Harding

Acidic and metal-rich waters have been discharging from Sullivan Mine, West Coast, New Zealand since the closure of the mine during the early- 1990s. This has resulted in a decrease in pH from a background of 4.5 to 2.8 and an increase in metallic elements in nearby Rapid Stream. In addition to the chemical effects on Rapid Stream, a study of freshwater macro-invertebrates revealed the absence of most biota downstream from the discharge. An attempt is being made to use the Sullivan Mine as a case study of problem and remediation analysis.

Jan 1, 2003

By Akerkar D. D, Dey M. L, Mathur S. B, Chowdhury S. K R

The extraction of gold and silver from chalcopyrite concentrates has been investigated. In view of the recent interest in non-cyanide leachants for gold and silver, one such alternative reagent, namely thiourea, has been employed in the present work. Precious metal leaching was attempted from received copper concentrates as well as pre-oxidised concentrates. Pre-oxidation of the concentrates was carried out by three different methods, namely roasting, pressure oxidation and biological oxidation. After pre-oxidation and leaching of the base metals, the leach residues were subjected to further leaching for precious metal extraction. The results obtained on the extraction of gold and silver from received concentrates as well as pre-oxidised concentrates are presented and the effectiveness of the three pre-oxidation routes employed is compared.

Jan 1, 1992

This paper deals briefly with three of the more controversial aspects of the geology of the Mount Isa ore deposits namely the geologic structures, the method of ore deposition and the origin of the ore.In the section on geologic structures, an outline is first given of the purely tectonic deformation advocated by the early authors. The current interpretation, which differs in the proposed order of events and causal forces, is then discussed. Other concepts, which attribute all or part of the deformation to sedimentary features or preconsolidation movement, are outlined ilnd commented on.The remaining two sections deal mainly with the better known lead-zinc orebodies. In the first of these a brief description and criticism is given of the early interpretation which was based on the deposition of successive waves of mineralisation which replacedindividual beds in the shales. The current ideas, which visualise emplacement of the ore between the beds rather than replacement of them, is then discussed. The final section develops the case for a sedimentary origin of the lead-zinc ores and broadly outlines the author's ideas concerning the evolution of the Mount Isa ore deposits.INTRODUCTIONAny consideration of the geology of Mount Isa must begin with the work of Blanchard and continue with that of Hall. Individually, or as co-authors, they published various papers on the geology of Mount Isa. Of these, the best known is their "Rock Deformation and Mineralisation at Mount Isa" (1941) which gave a comprehensive account of all aspects of Mount Isa geology.It is necessary to appreciate the limits set on geological knowledge of the mine and environs in 1941 by the extent of mine development and regional geologic studies. Underground, 7 level (897 ft.) was the lowest producing level. Development on 8 (1073 ft.) and 9 (1247 ft.) levels consisted only of exploratory drives and crosscuts in the vicinity of the Davidson Shaft. The tops of the 650 and 750...

Jan 1, 1961

Rio Tinto Iron Ore is currently working towards finalising comprehensive Native Title land access agreements, which cover all of the current eleven mines and infrastructure owned and operated by the company in Western Australia's Pilbara region. Critically, the agreements represent a mutual commitment to a long-term relationship and address many areas of concern by promoting indigenous enterprise, well-being and regional development opportunities. Our objectives in the process are to obtain the informed consent of the traditional owners for our Pilbara expansions while providing benefits to them in a way which provides lasting and substantial improvements to health, education, housing and real jobs in the mainstream economy.   To facilitate the agreement negotiations, Rio Tinto Iron Ore (RTIO) proceeded in 2005 to research and design a specific strategy around Aboriginal relations and local community engagement in the Pilbara. Wherever we operate, Rio Tinto follows a fairly simple formula in working with communities, which is comprehensively aligned to local context.   This presentation provides an overview of Rio Tinto Iron Ore's community engagement strategy in Western Australia's Pilbara region. It will also explore the establishment of regional standards on employment, business development and contracting that have been developed to ensure Indigenous people are engaged in the development of their region and are able to contribute to supporting the growth and development of mining in the area with the expectation that there is prosperity for all. This is an ABSTRACT ONLY no paper was prepared for this presentation.

Jun 1, 2010

By A Gerson, S Miller, R Smart, J Thomas

Environmental Geochemistry International (EGi) and the Ian Wark Research Institute (IWRI) collaborated in a three-year Australian Minerals Industry Research Association (AMIRA) research project (Project Number P387A) focussed on the prediction and kinetic control of acid mine drainage. As part of this project, single addition, and sequential net acid generation (NAG) testing was carried out on sulfide mineral samples. The test samples comprised a range of synthetic waste materials prepared using a quartz bulk and controlled quantities of the commonly occurring sulfide minerals; pyrite (FeS2), pyrrhotite (Fe7S8), arsenopyrite (AsFeS), chalcopyrite (CuFeS2), chalcocite (Cu2S), covellite (CuS), bornite (Cu5FeS4), galena (PbS) and sphalerite (ZnS). NAG test results clearly show that there are significant differences between the acid forming potential of sulfide minerals. The NAG test results for each mineral were compared with theoretical acidity values (NAPP*). The NAPP* calculation was based on stoichiometric oxidation reactions assumed for each of the sulfide minerals. Sequential NAG values for pyrite corresponds closely to predicted NAPP* values, confirming the assumption that pyrite oxidation occurs according to the stoichiometry assumed. For the pyrite sample with 5 wt per cent S, two NAG stages were sufficient for all of the sulfur to be released to solution. Since sulfides in waste materials will generally be dominated by pyrite, results also confirm the validity of including NAG testing for ARD evaluation of most waste rock. NAG testing confirms that of the sulfide minerals examined, only pyrite, pyrrhotite, arsenopyrite and chalcopyrite are acid producing, ie able to produce leachate with a pH less than 4.5. In the case of sphalerite, galena, bornite, chalcocite and covellite the pH of the final NAG solution was greater than 4.5. The significant differences between the acid forming potential of different sulfide minerals could lead to overestimation of acid producing potentials based on NAPP values calculated from total per cent S alone, ie assuming all S is present as pyrite. The oxidation of galena during the NAG test resulted in the consumption of acid. The examination of the galena surface by X-ray photoelectron spectroscopy (XPS) after oxidation in peroxide solution indicated the presence of polysulfide. The reaction of sulfide to polysulfide is acid consuming, thus explaining the net acid consuming behaviour of galena in the NAG test. This reaction pathway may provide a possible explanation for the lower than expected acid production observed for some of the other sulfide minerals examined.

Jan 1, 2003

By J D. Tolley

The shift towards clean energy technologies is having a significant impact on the mining industry, with the demand for minerals such as copper, nickel, cobalt, lithium, manganese, and graphite increasing exponentially. To meet the goals of the Paris Agreement, mineral requirements for clean energy technologies would need to quadruple by 2040, and to achieve net-zero globally by 2050, mineral inputs in 2040 would need to be six times more than today. The most significant driver of mineral demand is electric vehicles (EVs) and battery storage, with lithium seeing the fastest growth, and copper demand doubling over the same period due to the expansion of electricity networks globally. The demand for these minerals is expected to rise significantly as investments in clean energy technologies continue to grow in the future. As the world moves towards a decarbonised economy, the minerals industry is under increasing pressure to reduce its environmental and social impacts and meet the increased demand for minerals. Mining companies are facing additional challenges due to the depletion of near-surface mineral deposits globally, with more mines transitioning from open pits to underground. The transition to underground mining requires the right strategy to economically access deeper mineable inventories and to keep up with future clean energy technology demands to achieve net-zero globally by 2050. One key way to achieve this is through decarbonisation using ‘green’ mining technologies such as replacing current primary diesel mining fleets with battery electric vehicles (BEVs). However, these measures through electrification overlook the bigger opportunity to maximise the socio-economic returns from the mine while also reducing the overall carbon footprint. Corporate cut-off grade policy is one of the most significant influencers on the total environmental and social impacts of the mining industry. The purpose of a corporate cut-off grade policy is to implement strategies aligned with achieving all the mining companies’ corporate goals, with decarbonisation targets becoming a primary driver for mining companies. Table 1 shows the evolution of cut-off theory with the increasing number of dimensions and driving inputs per iteration.

Aug 2, 2023

By Y-B Kang, W-Y Cha, Y-M Cho

Molten slag used in the secondary refining process (RH process) for the production of Ultra-Low C (ULC) steel is typically composed of CaO-Al2O3-MgOsat.-FetO with minor constituents. FetO in the RH slag is the main source of reoxidation of the molten ULC steel in the ladle by 2Al + 3(FetO) = (Al2O3) + 3Fe, thereby serving as the source of the alumina inclusions. On the other hand, FetO also enhances the fluidity of the slag, thereby increasing inclusion absorption capacity. Optimum slag chemistry design is therefore required to produce clear ULC steel. The reoxidation kinetics was investigated in the present study by employing high-temperature experiments and developing the reaction rate model. Initial compositions of slag ((% CaO)0/(% Al2O3)0 and (% FetO)0)) and reaction temperature were varied and change of [% Al] in the molten steel was measured. The rate-controlling step was analysed. It was found that the rate-controlling step in some cases changed during the reoxidation: from a mass transport of Al in the molten steel to a mixed transport including Al2O3 in the molten slag. The experimental data validated the reaction rate model based on the elucidated reaction mechanism and FactSage thermodynamic database. The model suggested that high (% CaO)0/(% Al2O3)0 suppresses the reoxidation only when (% FetO)0 is low (5 or lower in the present study).

Jun 19, 2024

By Boontanjai C, Boyapati ER

Reagents used for batch flotation tests were Aeroxanthate-343 & 350, Dow Z-6, & reagent-4037 (from Benambra) as copper collectors; Na2SiO3 & Na2S2O3as gangue depressants; lime & HCl as pH regulators; and pine oil & MIBC (methyl isobutyl carbinol) as flotation frothers. A Denver Sub A flotation cell of capacity 250 gms was used for the batch flotation experiments. Atomic absorption spectrophotometer was used for copper assays and microscopy for selectivity and liberation studies. Melbourne tap water was used throughout the experiments. Unless otherwise stated, the following parameters apply to the flotation experiments: flotation impeller speed - 1300 rpm, pulp density during flotation- 22%, reagents addition - in 4 stages, total conditioning time for collectors - 8 minutes, total flotation time- 9 minutes. A variable quantity of copper mineral collector according to the test in question was added, then conditioned the pulp for 2 minutes. The froth was removed by hand, scraping the full length of the cell at constant depth every 10 seconds. No frother is required for this copper tailing flotation. Four concentrates were collected after addition of collector and conditioning at 2,4,6 and 9 minutes. The pulp volume was maintained at a constant level to yield a constant froth depth.

Jan 1, 1990

Seven papers have been reviewed and in this session. Broadly they can be grouped into three categories as follows: A Chemical Characterisation of Mine Waters Miller & Murray - Prediction of Time Dependent Factors in Acid Mine Drainage Jeffrey et. al. - Sulphide Oxidation in Pyritic Overburden; A Controlled Leach Column Study Sheridan et. al. - The Effect of Ore Type, Depth, and Leach Time on Cyanide Species in Column Tests using NaCN Leach Solutions B Mine Water Treatment Management Gilchrist & Hunt - The Recovery of Water from a Colloidally Stable Kimberlite Suspension Chapman, et. al. - Treatment and Utilisation of Hilton Mine Water

Jan 1, 1988

By P Swart, A Fletcher, P D. Erskine

Glencore Coal Assets Australia (GCAA) operates five coalmines in Queensland and has rehabilitated thousands of hectares of mined land across these sites. Accordingly, GCAA seeks to continually improve rehabilitation outcomes over time and work towards progressive rehabilitation sign-off. The ultimate test of rehabilitation success is the attainment of an agreed land-use target, whether for biodiversity conservation or some type of agricultural production, and the ability of the rehabilitated landscape to resist degradation and retain desired functions (eg biodiversity protection or grazing productivity). However, success must be based on documented evidence that can demonstrate adequate progress towards rehabilitation targets and is assessed at appropriate intervals. To assist this task, a stepwise decision guide for the GCAA monitoring program was developed to ensure consistent monitoring data is collected across the range of sites. This presentation will discuss some of the processes that were followed to allow GCAA to identify appropriate metrics to assess rehabilitation success efficiently over thousands of hectares.CITATION:Erskine, P, Fletcher, A and Swart, P, 2016. Preparing for progressive mine rehabilitation sign-off in Queensland, in Proceedings Life-of-Mine 2016 Conference, pp 148–150 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By M Nehring, M Kizil, P Knights, A Mousavi, F Sotoudeh

A cut-off grade is used to distinguish an economically viable block of ore from non-economical ones in mining operations. In order to obtain a high Net Present Value (NPV), a strategic and precise determination of cut-off grades (mill feed/marginal, marginal/waste) is required. In recent years, the significant depletion of feed grades and increasing mining operating costs have affected the viability of new and existing mining operations. Hence, the introduction of a pre-concentration system to process ore before sending it the main processing plant has gained increasing attention for its potential improvements in resource exploitation processes, mineral processing, energy consumption and environmental impacts. The primary potential advantage of implementing a pre-concentration system is the improvement of resource utilisation and increased reserves as a result of a reduction in cut-off grade. The objective of this paper is to present a new cut-off grade method, which can be used in the presence of a pre-concentration system for underground metalliferous mining operations. The results of this study illustrate the potential economic benefits of using a pre-concertation system prior to a mineral processing operation as a result of the reduced cut-off grade and increased NPV.

Nov 10, 2020

By Morsky P, Kalapudas R, Natunen H, Virtanen M

The development of autogenous grinding modification in Outokumpu, known with the name 'Outogenius Comminution', was 'reversed'. At first the metallurgists studied and tested tens of years autogenous grinding in detail in full scale circuits at the concentrators of the company. After the final solution already had been found, also a pilot plant was built and now finally, research work is under way to develop a special laboratory method for testing the suitability of ores for 'Outogenius Comminution'.

Jan 1, 1993

By I Jabouri

There are many physical factors that can affect the self-heating rate of coal. The presence of seam gas has often been referred to as inhibiting coal self-heating due to the limited access of oxidation sites created by the presence of the gas adsorbed on the coal pores. Similarly, the presence of bed moisture in the coal also acts as an inhibitor of oxidation by blocking access of air into the pores. Gas drainage of a coal seam prior to mining removes both gas and moisture from the seam. Bulk coal self-heating tests in a two-metre column on both gassy, as-mined and gas-drained, dried high volatile bituminous coal show that removal of gas and moisture from the coal accelerates the rate of self-heating to thermal runaway from 8.5 days to 4.25 days, from a start temperature of 30¦C, with an airflow of 0.25 L/min. The corresponding gas evolution pattern for each of these situations is different. Therefore, it is necessary to take this change in coal condition into consideration when developing a spontaneous combustion management plan.

Jan 1, 2005

By F Soleimani

Coal and gas outburst is a common hazard in coalmines and due to the complexity of its nature, efficaciously predicting the possibility of its occurrence is intricate. The mechanical and gas flow properties of coal, in situ and mining-induced stresses and geological structure are involved in outburst occurrence, whereas suggested thresholds for its prediction do not consider them all. Numerical modelling is known as an effective method that can not only consider couple the effect of different physics but also analyse the effect of associated parameters. In this paper, a coupled fluid flow and geomechanics model has been developed in COMSOL Multiphysics to simulate outbursts by considering the effect of gas pressure and composition, damage mechanics on related coal properties, and progressive excavation and mining-induced stress. For the proposed fully coupled outburst model, the effect of pore pressure and sorption are applied to the stress while the influence of stress changes and damage are considered in updating coal porosity and permeability in each time step. In addition, to study the effect of mining-induced stress, the excavation process is simulated by changing the material properties over time according to the schedule of heading development. Then, outburst initiation is analysed from the energy point of view by using the concept of energy conservation law. The simulation results are used in calculating energy sources of the outburst initiation, also, the effect of particle size and ejection velocity are studied, and the significance of particle size effect on the energy analysis and deformed coal on outburst initiation is discussed.

Oct 12, 2022

By B Abbasi

It is well known that most roof falls in coal mines typically occur at and around intersections. Room-and-pillar and longwall coal mining systems typically develop 3-way and 4-way intersections. This research develops an improved scientific understanding of stress distribution and associated instability behaviour around 3-way and 4-way coal mine intersections through 3-D numerical modelling and limited field observations. Numerical analyses were performed for an Illinois longwall coal mine to identify factors that influence intersection stability. The stability of immediate roof, floor strata, and coal ribs at and around intersections are considered with pre-mining regional horizontal stress. Non-linear failure analyses used the Hoek-Brown failure criterion for rock mass. Progressive failure zones in and around intersections were developed. For a typical 4-way intersection, pillar corners across the intersection fail first and lead to progressive failure of the immediate roof and floor layers. The mechanism of failure is similar for a 3-way intersection but the shape and extension of failed zones differ. For the 3-way intersection, the effect of off-set distance was analysed. It was found that minimum off-set distance of about 10 m (centre to centre distance between two 3-way intersections) was required to minimize interaction between two intersections. A simple instrumentation program monitor ground movements around intersections. These data were used to design the intersection geometry that is now being practiced by the mine. CITATION:Abbasi, B and Chugh, Y P, 2018. Instability analysis in three-way and four-way coal mine intersections, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 345–359 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By N Belluz, L Johnson, N Wiwoho, P Manning

The Kucing Liar skarn deposit is located in the Ertsberg mining district, which also contains other skarn deposits and the Grasberg porphyry copper û gold deposit. The Ertsberg district is located in the province of Irian Jaya, IndonesiaÆs easternmost province. Mining development began in the Ertsberg district in 1972 with the mining of the Ertsberg deposit. Daily production in the district now averages about 230 000 tonnes of ore, with the bulk of the ore coming from the Grasberg open pit and the balance from underground mining of skarn deposits. During 1998, 45 218 additional metres of drilling were conducted to delineate and understand the Kucing Liar orebody. The deposit was first intersected in drill holes in 1994 and then was intersected in underground workings located about 1000 metres from the discovery drill hole in 1995. Initially, the two intersections were thought to be different orebodies but are now realised to be different parts of the same orebody. The Kucing Liar deposit consists of magnetite û copper û gold replacement and skarn mineralisation in favorable Tertiary and Cretaceous units. The deposit is approximately 2000 metres in length and averages about 200 to 250 metres in thickness. The width varies from 400 to 600 metres. Drilling in 1998 was directed towards delineating the deposit on its NW and SE ends and to determine its down dip extension. Reserves for the deposit at the end of 1998 stand at 320 million tonnes at 1.4 per cent copper, 1.4 g/t gold, and 5.3 g/t silver. Many important questions remain to be answered concerning the relationship of the Kucing Liar orebody to the major faults in the district and to the Grasberg intrusive complex which contains the Grasberg orebody. Continued exciting developments are anticipated as work to understand the deposit by drilling and geologic study continues.

Jan 1, 1999

We are all no doubt aware that with today's high costs it is more important than ever to get the maximum possible return on capital invested in the mining industry. Screening is an important and often costly process in the size classification of industrial minerals and for this reason alone it is essential for both managers and operators to fully understand what type of screening equipment is best suited for a particular application and why. The advent of elastic materials such as rubber and polyurethane have added a new dimension to the process of screening. It is important to understand why the physical properties of these materials can be of benefit in the screening process, and recognise which type of screening applications best take advantage of these orooerties.

Jan 1, 1984

By G Bournival, Y Saavedra Moreno, S Ata

Flotation frothers are heteropolar molecules that are preferentially adsorbed at the bubble interface to enhance the flotation performance by promoting the formation of small and stable bubbles. Frothers have different characteristics that can be used to classify them. A classification framework has been recently presented by Saavedra Moreno et al (2022) to classify non-ionic frothers by conducting a principal component analysis (PCA) and a hierarchical clustering analysis (HCA). However, for the purpose of the present research, only five frother characteristics, including molecular weight (MW), hydrophile–lipophile balance (HLB), critical coalescence concentration (CCC), the minimum Sauter mean diameter (DL), and foam stability index (DFI) were used in the PCA and HCA. All those characteristics were evaluated for a two-phase system in the absence of particles. Realising the important role that particles play in froth stability and behaviour, the effect of hydrophobic particles on the presented frother classification framework was investigated in this study. Four frothers with different characteristics, methyl isobutyl carbinol (MIBC), 1-pentanol, tri (propylene glycol) (TPG), and tri (propylene glycol) methyl ether (TPM), were chosen. The experiments were carried out in the presence and absence of silica particles esterified with 1-pentanol. It was evident that the results for 1-pentanol, TPM, MIBC, and TPG in the three-phase system agreed well with the frother classification presented for the two-phase system as frothers were clustered in the same groups. The findings from this research support the use of the frother classification system presented in two-phase system to select a specific frother for a particular application without the necessity of conducting laborious experiments in a three-phase system.

Aug 24, 2022

Most compact bucket wheel excavators in use are in the small to medium range. Large compact bucket wheel excavators compete directly with con- ventional longer boom excavators which have operational advantages over the large compact. There are, however, situations where the large com- pact excavator is viable. In the development of these large compacts there are a number of technical features to be addressed. In addition the SECV now propose to expand the concept to a large compact bucket wheel excavator with a bridge and loading unit for their Loy Yang Open Cut.

Jan 1, 1989

By J Zhou, T D. McGrath, K P. Galvin, C P. Lowes, J J. Eksteen

Pre-concentration of low grade ores can improve the economic and environmental sustainability of an operation significantly, with opportunities for implementation ranging from run-of-mine to mill discharge depending on ore specific characteristics. For a gravity separation, where the performance is fundamentally constrained by mineral liberation, these feeds often represent a very difficult separation given the dominance of the relatively coarse gangue and fine liberation sizes. Thus, building knowledge of the feed through characterisation of the density distribution is critical to assessing amenability before progressing towards lab/pilot-scale test work and full-scale operation. The traditional approach to determining the density distribution typically involved sink/float testing, however, recent developments in hydrodynamic fractionation using inclined channels now offers a more cost-effective alternative with minimal health and environmental risk. A non-hazardous dense liquid, namely an aqueous solution of lithium heteropolytungstates (LST), is supplied as fluidisation to a REFLUXTM Classifier, consisting of a vertical section below a system of inclined channels, operating in semi-batch configuration. Fractionation is achieved by increasing the flow rate incrementally and collecting the particles to form a series of flow fractions. The purpose of this paper is to present this new method in the form of a case study, aimed at assessing the amenability of a low grade gold-bearing sulfide ore to pre-concentration. The robustness in the method is demonstrated through comparison with sink/float data, examining the density distribution and the liberation-limited product grade and recovery achievable. These data are then used as a benchmark to assess water-based continuous gravity separations conducted on the feed using a laboratory-scale REFLUXTM Classifier. This data set is used as the basis for process modelling and empirical validation for the recently established partition surface of the separator.

Nov 10, 2020