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By Schmidt LC

The method of supporting excavated roofs in underground coal mines by conventional roof bolting systems is challenged due to its shortcomings of being time-consuming and leading to possible unsafe installation. Though a few alternatives have been considered, the ultimate and most efficient bolting method has often been conceived as one using a self-drilling roof bolt, or a Rapid Face Bolting System (RFBS). The on-going Rapid Face Bolting Project undertaken by the University of Wollongong includes a special tubular bolt design.The tubular bolt designed for the RFBS is a "single-pass" bolt equipped with cutting tips used to drill a bolthole to accommodate the bolt. Different from that of the coring bit employed in geological site investigations, the principal design consideration for the tubular bolt is low cost associated with a small working life for the cutting tip.

Jan 1, 1991

Mineral exploration and development can have a significant impact on the environment and local communities, in some circumstances extending well beyond the mine site. Poor environmental performance and consequent social impacts by some companies have affected the reputation of the whole industry to the extent that the principal public concern about mining is its impact on the environment. This is consistent with public attitudes about other major natural resource sectors such as forestry and commercial fishing. Traditionally the community has relied on governments to set the benchmark for acceptable environmental and social performance through establishing and revising regulations governing the mining industry. This however assumes that regulations keep pace with community expectations. It also does not take into account those circumstances where governments can have conflicting roles as both watchdog and project partner. Government regulations and industry self-regulation are not in of themselves sufficient for the minerals sector to demonstrate that it has adequately addressed environmental and social issues associated with the sector. For the minerals sector to improve its reputation it must first improve its environmental and social performance. To do this requires the sector to operate to acceptable standards of environmental and social performance and for the sector to be able to credibly communicate this to its stakeholders such as investors, non-government organisations (NGOs), customers, staff, regulators and local communities. Independent third party certification of environmental and social performance (æcertificationÆ), already operational in forest and fisheries management, is proposed as a mechanism to enable the minerals sector to achieve this. World Wide Fund for Nature (WWF) and industry partners will be collaborating in a project to ascertain the applicability of æcertificationÆ to the minerals sector. A number of economic, social and environmental benefits are identified that could accrue should mining companies be able to differentiate themselves on the basis of environmental and social performance, an attribute evident in æcertificationÆ schemes. External audiences are seeking increasing levels of information and data on environmental and social performance of mining companies, be it local communities, investors, financial institutions or NGOs. Environmental and social reporting should be a key communications device that stakeholders can rely on as a reliable, credible source of information on environmental and social performance. WWFÆs contribution to the debate about environmental and social reporting has been to develop a process to assess the quality of environmental and social reports against reporting ingredients which WWF believe are important if a report is to be an accurate reflection of the reporting entitiesÆ environmental and social performance.

Jan 1, 2002

By J Nemcik, E Baafi, I Porter, G Spinks

Spray-on liners used in the mining industry for ground support and stabilisation applications are either cement based (æshotcreteÆ) or polymer based (æthin spray-on linersÆ). Some thin spray-on liners are a blend of both polymer and cement (eg Tekflex). A small number of thin spray-on liners (TSLs) have been trialled in Australia as potential replacements for steel mesh in roadways and other underground mining applications; however, they were found to cure slowly and the cured coatings became brittle after an extended time in place. The University of Wollongong in collaboration with the Australian coal mining industry has shown that a viable polymer-based alternative to steel mesh in underground roadway support applications can be developed to eliminate the use and handling of steel mesh. The work to date has: established the feasibility of developing polymeric alternatives to steel mesh in underground roadway support applications; identified the physical and material constraints to be endured by any new polymeric skin reinforcement system by measuring the mechanical properties of steel mesh; identified materials that can be spray applied; and demonstrated that polymer mechanical properties can be optimised to produce similar mechanical properties (elastic modulus, yield stress, elongation-at-break, etc) to steel mesh. The identified materials will: allow the face support cycle to be fully automated, or at least remotely operated and installed; remove personnel from the immediate face area; and substantially improve underground roadway development rates.

Jan 1, 2008

By G H. Luttrell

The use of secondary desliming cyclones ahead of froth flotation cells to reject ultrafine (-45 ¦m) particles has become a popular option in the United States for preparing fine coal feeds for froth flotation circuits. In light of this popularity, several experimental studies have been performed at industrial plant sites to develop a better understanding of the impacts of ultrafine desliming on froth cell performance and, ultimately, overall plant performance. These studies included an evaluation of various circuit configurations incorporating different flotation technologies (conventional machines and column cells) as well as different dewatering systems (disc filters, screen-bowl centrifuges, and thermal dryers). The data obtained from these studies indicate that deslime circuits offer several important benefits including lower product ash, reduced product moisture, better froth handling characteristics, and lower capital and operating costs. In addition, case studies conducted as part of this investigation have been used to develop generic guidelines for how deslime circuits may be successfully applied to improve the overall profitability of fine coal flotation circuits for both the metallurgical and steam coal markets.

Jan 1, 2005

Stope filling practice on the Great Boulder Mine was described in -a paper published in Aus.I.M.M., Proceedings No. 137, in 1945. When the paper was presented the process had emerged from the experimental stage, most of the initial operating difficulties had been overcome, and it had been established that this method of filling was suitable for the working of ore bodies in the Kalgoorlie field: Since 1945, it has fulfilled its early promise, -and during 1947, the tonnage of fill placed was sufficient to cover current operating requirements as called for by the mine ore breaking programme. The object of this paper is to outline current operations. In so doing it will refer' to some ground covered by the previous paper, but will omit details of the initial experimental work. It will include, however, a description of further experimental work on the use of hydraulic filling for worked-out shrinkage stopes, arid will provide more accurate data on costs than were available previously.ESTIMATE OF TONNAGE OF FILL REQUIRED.Early in 1946, the mine ore reserves were analysed in order to estimate the relative tonnages to be mined per four-weekly period by shrinkage stope methods -and by cut and fill stope methods respectively. This analysis was extended beyond the blocks already prepared for stoping, and inclqded the majority of the major ore blocks in the mine ore reserves. It gave the following results:-For a mill tonnage of 28,000 tons per period, 6,933 tons were required from cut and fill stopes, and a possible future maximum programme of 35,000 tons per period would require...

Jan 1, 1948

By Macaulay J

The recovery of gold from cyanide liquors is frequently effected by using activated carbon. Process economics however require non destructive methods of gold extraction from the carbon so that it may be recycled.Stripping at atmospheric pressure usingthe method of Zadra et al(l) suffers from the disadvantage of unfavourable kinetics with strip times of the order of 48-72 hours. Subsequent research has led to development of processes which strip the gold more rapidly namely: A.A.R.L. process, (2,3) organic solvent (4,5,6) and pressure stripping (7,8)This paper reports on a development of the pressure stripping technique in which stripping and electrowinning are carried out at elevated temperature and pressure.

Jan 1, 1984

The high maintenance of load-haul-dumps (LHDs) and front end loaders in hard rock affects mine planning with reduced availability and productivity. Intensive study of maintenance costs and availability of machines related to machine age and life provide the basis for planning from available operational alternatives.Derived programmes and experiences have led to the beginnings of unmanned operation and automation through reduction of manual diesel units and spreading electrification and use of radio. But electrification has obvious layout limitations. This approach to the present has resulted in better utilisation, costs and safety and the computerised monitoring and control provides continuous awareness of machine and work conditions with the promise of future improvements.

Jan 1, 1991

The sole reason for a mine to exist is to extract the finite mineral resource. Accurate grade control is critical to the economics of any mine. If grade control is not optimised, then no matter how good the downstream processes are, the full potential of the operation will not be realised. The detailed implementation of grade control varies but typically consists of sampling and assaying to determine the location of the ore zones. A lot of time, money and effort are spent defining the location of the ore as accurately as possible à but then it is blown up! The effect that blasting has on grade control is rarely adequately accounted for when the rock is excavated because there has never been an accurate and practical method for measuring blast movement. This paper draws on over six years of research into measuring and understanding blast movement, which started at the Julius Kruttschnitt Mineral Research Centre (JKMRC) of the University of Queensland. The research has made a unique contribution to open pit blasting by helping to develop a practical tool for measuring blast movement, which was then used to improve the understanding of three-dimensional blast movement dynamics. However, these achievements would be of largely academic interest without taking the final step of using this technology and knowledge to account for blast movement by translating the ore polygons in response to the measured movement vectors. This paper provides an overview of blast movement but focuses on one site where blast movement was measured during three separate periods, with significantly different orientation of the mineralisation on each occasion. The theoretical ore loss varied from nine per cent to 24 per cent. The differences are primarily due to the orientation of the ore polygons relative to the direction of movement. The optimum grade control solution is a combination of accurately accounting for blast movement and designing appropriate blasts.

Jan 1, 2009

By R Pie, J Crusius, P Whittle, J J. McNee

The Main Zone and Waterline pit lakes at the Equity Silver Mine near Houston, BC (Canada) are the sites of an ongoing three-year government- and industry-funded research program. In order to assess the feasibility of various bio-remediation strategies, field-scale manipulations were conducted using enclosed mesocosms (limnocorrals). Two manipulation strategies were tested: addition of algal nutrients (phosphate and nitrate) to Main Zone Pit surface waters; and addition of algal nutrients (surface waters) and dissolved organic carbon (deep waters) to the Waterline Pit. Nutrient addition was conducted in order to stimulate algal production and enhance metal scavenging by biogenic particles, while dissolved organic carbon (ethanol) was added to increase oxygen demand and foster the development of sulfate reduction in pit bottom waters. Fertilisation resulted in rapid growth of natural phytoplankton populations in the surface waters of both pits. In the Main Zone Pit, the stimulation of algal growth resulted in the pronounced removal of both dissolved and total metals (Zn and Cu) from surface waters, with higher rates of metal removal being observed at higher nutrient additions. Metal removal could be attributed to the scavenging of dissolved metals by biogenic particles and subsequent particle settling. A similar pattern of removal from surface waters was observed in Waterline Pit (Zn and Cd). The addition of ethanol to deep waters in Waterline Pit was effective in promoting sulfate reduction in the lower layer. The development of reducing conditions resulted in near-quantitative removal of dissolved Zn and Cd, presumably as secondary metal sulfides. Iron, As and Ni profiles in Waterline Pit exhibited no evidence of removal from either surface waters or bottom waters. Collectively, the results demonstrate that the passive forms of bioremediation tested in these pit lakes may be effective for whole pit-lake remediation.

Jan 1, 2003

By M Maulen, K van Olden, T Elkington

A large open pit is planned at the site of an existing underground mine. Strategic planning work has been undertaken to investigate the project value associated with an expansion of underground operations in conjunction with the proposed pit. Previous analysis determined that any depletion of the available pit resource that changes the optimum pushback sequence has a significant negative impact on overall project value. Therefore, to investigate the viability of an underground expansion requires a system to identify the stope resource that would add value to a combined operation if mined ahead of the pit. The key solution to this problem was to generate a resource model variable that defines the blocks, which have greater discounted value if mined by stoping rather than by the open pit. A key assumption was that the open pit is the main driver of overall project value. From the identified potential underground resource, series of mineable stope shells were generated at a range of cut-offs. This stope reserve data formed the input to a mixed integer program based software tool that was developed and used to optimise the underground mining plan, at conceptual level, for various project configurations. A dynamic programming tool was then applied to evaluate the optimum value of a combined open pit and underground operation. The overall objective of this project was to determine the strategic plan that yields the optimum value for a combined undergroundûopen pit operation. The results provided a clear focus and direction for more detailed design and planning.

Jan 1, 2009

INCREASE OF CATASTROPHE FREQUENCY AND SEVERITYIn the last couple of decades the frequency of natural catastrophes has increased dramatically. This realization results from the statistical analysis of the comprehensive loss data that we have been collecting constantly over the last 30 years and have evaluated in connec-tion with the preparation of our "World Map of Natural Hazards", which is now in its second edition (Munich Re, 1988). Each month brings data on between 30 and 50 new loss events. Fortunately, however, only a few of these have to be added to the list of major natural catastrophes, that is only those involv-ing damage that considerably exceeds what the country or region concerned can handle itself so that substantial na-tional or international aid is required. That is generally the case if the number of dead runs into the hundreds or thousands, if tens or hundreds of thousands of people are rendered home-less and if the total economic loss is in the region of US$ 100 million. These major catastrophes, about which we have fairly comprehensive data even in the case of those that occurred farther back in the past, numbered only 14 in the 1960s but 70 in the 1980s; they there-fore increased over a period of 30 years by a factor of 5. The trend is also very clear when we consider the total economic loss, which - adjusted for in-flation - increased during the same period from an average of US$ 3.7 bil-lion per year to US$ 11.4 billion, i.e. by a factor of 3.1. The insured losses, finally, increased by as much as a fac-tor of 4.8.

Jan 1, 1990

By A Melkumyan, M Balamurali

Geological domains describe the mineralisation state and stratigraphic location of different geological regions of mines. They play a very important role at the geological modelling stage as weight percentage of chemical elements information within each geological domain is assumed to be correlated while information coming from different geological domains is considered uncorrelated. Having correct domain assignments to both the chemical assays and the 3D space of modelling is critical for building a reliable geological model of the mine.As standard practice significant effort is invested into the interpretation of the deposit and identification of the geological domains for the chemical assays and the 3D geological space. Despite these efforts, there are some chemical assays with ambiguous geological domain where the exploration assay domain and the block domain do not match. Incorrectly including a sample in the wrong domain can cause a large change in the predicted weight percentage of chemical elements estimation for that block. Therefore, the major challenge of grouping the spatially correlating weight percentage of chemical elements is how to determine which of these domains best fits these misclassified samples.This work proposes machine learning based autonomous technique for identifying to which geological domain (the exploration assay domain or the block domain) the misclassified sample belongs. The proposed methodology is based on Gaussian Process (GP) classification. The GP machine learning approach consists of training and inference stages. At the training stage the GP automatically learns the properties of different geological domains using the chemical assays with unambiguous domain assignment. Then, at the inference stage the GP makes predictions for the geological domains of the assays with ambiguous initial domain assignment.We tested the proposed technique by conducting a case study for an iron ore deposit located in Western Australia. The results demonstrate that the application of the proposed GP technique removes statistically significant deviations in the assay values in many regions: mineralised ore region, unmineralised region, highly weathered region and intrusive material that is highly variable. In this case study the proposed methodology autonomously identified the geological domains for more than 50 per cent of samples which are initially ambiguously classified. For the majority of the assays the GP predicted domain agrees with the geological domain assigned by the exploration assay.CITATION:Balamurali, M and Melkumyan, A, 2014. Automated identification of geological domains for exploration assays with ambiguous initial domain assignment in an iron ore deposit, in Proceedings Ninth International Mining Geology Conference 2014 , pp 99–106 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By S Mitra, D O’Dea, N Barrett, T Honeyands, E Copland

This work describes a novel mapping technique that allows the direct overlay of calculated local phase equilibria on micrographs of the physical system. The technique demonstrated integrates FactSage™, ver 8.2 (by Thermfact Ltd. and GTT-Technologies) phase equilibria calculations with mapped compositions determined by Scanning Electron Microscope – Energy Dispersive X-ray Spectroscopy (SEM-EDS) to visually express calculated properties while preserving the spatial information of the sample. The developed methodology is used to analyse interrupted blast furnace softening and melting tests containing mixed burdens of lump and sinter. Tests are interrupted at 1300C and cooled to room temperature for analysis. Phases present at room temperature are analysed to infer the liquid fraction and phases present at high temperature. Analysis of the interface regions between the dissimilar burdens allows insights to be gained into the interaction mechanism. During the transition from solid to liquid, migration and interaction of liquid oxide across the interfaces of the dissimilar burdens has been observed and demonstrated to impact softening and melting performance. Specifically, interaction of the oxides generated by lump (primarily FeO, SiO2 and Al2O3) and sinter (primarily FeO, CaO, SiO2, Al2O3 and MgO) are analysed, and the occurrence of a range of new mineral phases such as merwinite, melilite, olivine and bredigite observed.

Jun 19, 2024

Increasing use has been made of engineer ing geology and hydrogeology in the development of the infrastructure for mining projects. The Geological Survey of the Department of Mines, the Department of Main Roads, the Irrigation and Water Supply Commission and private consulting organisations and mining companies, employ spec- ialist staff to carry out engineering geological and/or hydrogeological investigations. Such in- vestigations have been of assistance in recent mining developments in northern Queensland, in- cluding those in the Cloncurry - Mount lsa, Weipa, Greenvale and northern Borten Basin areas.

Jan 1, 1974

By R Bresca, A McCallum, J Scealy

The Endeavor Mine, located to the north of Cobar, New South Wales, was purchased by CBH Resources Pty Ltd in September 2003. The operation has been producing lead and zinc concentrate continuously for over twenty-three years. In 2004, a water management program was instigated to improve the raw water use efficiency of the mining operation. The water management program involved the establishment of a Water Management Committee, a review and quantification of water use across the site, investigation and implementation of efficient water use practices, and workforce awareness training. The program has seen the amount of water used per tonne of ore milled reduced from an average of 1.08 kL/t in the March 2004 quarter, to 0.68 kL/t in the March 2005 quarter. This paper outlines the Endeavor Mine water management program and may serve as a model for other operations that are planning to improve their water use efficiency.

Jan 1, 2006

By T D. H McGrath, O Baker, W P. Staunton, C Ypelaan

"The carbon-in-pulp process has been used extensively in the gold industry since the late 1970s to recovery leached gold from solution. Despite more than 30 years of experience in operating carbon circuits, average gold solution loss has remained at an average of 0.02–0.03 ppm (mg/L), higher than the ‘best practice’ target of 0.01 ppm.Process modelling, such as SIMCIL developed by the Curtin Gold Technology Group (GTG), can provide information on optimum set points; however, manual control of the circuit limits the potential benefits.An automated carbon measurement device, the Scout Carbon Meter, has been developed to allow for automation of carbon concentration measurement, and automated control of the carbon transfer pumps. This paper describes the results from the evaluation of the first two prototypes of the meter.Citation:Staunton, W P, McGrath, T D H, Ypelaan, C, Baker, O and Eksteen, J J, 2016. Optimising Carbon Management - Increasing Gold Recovery and Decreasing Costs with the Carbon Scout, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 225–228 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By C Ausa, Nyunt Htay, A, L Deiparine

The main tectonic elements in Myanmar are a late Mesozoic and Cenozoic magmatic arc system in the west, repeated in northern Myanmar by more than 300 km of dextral movement on the Sagaing Fault, and the back-arc continental region affected by early and late Mesozoic orogenies, in the east. Historically most lode gold production has been from latest Cretaceous high-grade mesothermal veins and derived placers in the Wuntho and Tagaung-Myitkyina segments of the magmatic arc. Placer deposits in the Ayerwaddy River north of Myitkyina are currently worked by more than 100-bucket dredges. South of Wuntho, the magmatic arc and Pegu Yoma fold belt host epithermal gold with associated As, Sb and Zn in mid-Tertiary marine sediments. MyanmarÆs most productive lode gold deposit, the Kyaukpahto mine, lies within a north-trending district east of the magmatic arc and north of Mandalay. Here mineralisation and associated jasperoidal silica occur in Eocene sandstones and Permian and Triassic carbonates. Possibly this district continues southeastwards, across the Sagaing Fault, as sediment-hosted Sb Au and locally skarn Au mineralisation within a 1100 km long fold-thrust belt. Also present in the back-arc region are sandstone-hosted Au Cu in a Palaeozoic slate belt, and gold and stratabound gold-base metal mineralisation in the medial metamorphic belt. While untested targets remain in the magmatic arc, particularly for high sulphidation Au, the best potential is clearly within the back-arc slate and fold-thrust belts in the western part of the Shan Plateau and in northeastern-most Myanmar.

Jan 1, 1999

Passive systems for the treatment of acid mine drainage (AMD) are typically more economic in the long term than active systems. Various flow charts for treatment selection have been prepared by scientists in the USA, however, they have typically not included a variable important at New Zealand AMD sites on the West Coast: topography and available land area. Very steep topography, dense and often protected vegetation (and animals such as snails), and a high-rainfall climate result in AMD with very high flow rates in locations with very limited space for remediation. Flow charts specific to New Zealand have been prepared which accommodate topography and available land area. Parameters necessary to use the flow charts are iron and aluminium concentrations, pH, ferrous to ferric iron ratio, dissolved oxygen concentration, topography and available land area. Prior to full scale construction, is it recommended that flow rates be quantified, small-scale trials be conducted, and cost, effectiveness, limitations, and risk of failure be reviewed for various options. One full-scale remediation system has been installed in New Zealand based on this methodology and another is planned. The performance of these systems, as well as future systems to be installed, will be used to validate these treatment system flow charts.

Jan 1, 2007

By M Akhtar, E Jak, M Shevchenko

This article presents an overview of the experimental phase equilibria studies of S-containing systems (Ni-Sn-S, Cu-Sb-S, and Cu-Sn-S) and As-containing systems (Fe-Sb-As and Fe-Sn-As). These systems improve the prediction capabilities of FactSage in a 20-component ‘Cu2O’-PbO-ZnOFeO- Fe2O3-CaO-SiO2-S-(Al2O3-MgO-CrO-Cr2O3-Na2O)-(As, Sn, Sb, Bi, Ag, Au, Ni, Co) system for complex pyrometallurgical operations during both refining and recycling. Experiments involved equilibration at predetermined temperatures (300–1200°C) with or without preheating, followed by rapid quenching in a brine. Quenched samples were then directly measured using an electron probe microanalyser. For the Ni-Sn-S system, liquid phases (NiS- and SnS-rich mattes and liquid metal) and solid phases (Ni1+xSn, SnS, Ni3Sn, FCC-Ni, Ni1-xS, NiS2, Ni3Sn4, SnS2, Sn2S3 and β-Ni3S2) were observed. A new Ni3Sn2S2 phase was found to melt incongruently. For the Cu-Sb-S system, liquid metal, matte, FCC-Cu, digenite, Sb, CuSbS2, Cu3SbS3 and Cu3SbS4 phases were observed. For the Cu-Sn-S system, liquid metal, matte, digenite, SnS and Cu3Sn phases were found at liquidus.

Jun 17, 2024

Mining is still a significant economic activity within the Hauraki District. The Martha project is particularly significant. Estimates are that in the order of 850 direct and indirect jobs are derived as a consequence of the Martha project within the Waikato Region. The Resource Management Act 1991 (RMA) is New Zealand's primary piece of environmental legislation. It sets out to provide the framework for the control of the use, development and protection of almost all physical and natural resources. Minerals are excluded from the sustainability requirements of the legislation but as mining invariably involves the use of land, all the other elements of RMA apply. The Council's role in dealing with mining changed with the introduction of RMA. It became responsible for administration of those matters that fell within the functions set out in section 31 of the RMA in respect to existing authorisations. Mineral development needed to be considered in the development of the District Plan that the Council is required to prepare. Implementation of the Act has been a challenge for not only local government but for many industries and resource users since it came into force in 1991. There have been, and are, differing views on both the way it is administered and its intent. The Hauraki District Council has been at the forefront of some of the challenges that are a consequence of the Act. Its reactions to these challenges have been consistent. It treats mining in the same why it treats any other industry. At times this approach has not been understood and without challenge from sections of the community.

Jan 1, 2000