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By Heidecker A

Several types of drainage structure providecost-effective environmental controls for water supply to Charters Towers and its mining industry. Drainage groves maintain bank-levee, channel, pool, and spring structures. Failure of drainage structures leads to anoxic fermentation of channel fill releasing residues, such as arsenic, which would otherwise pass harmlesly by fixed on sedimentary particles.Experiments along drainage structures indicate that productive agroforestry could be integrated with expeditious development of groves to cope with environmental change.

Jan 1, 1990

By R L. Verburg, R Johnstone

DeBeers Canada Mining Inc (DeBeers) recently submitted an Environmental Assessment (EA) for its proposed Snap Lake Diamond Mine located in Northwest Territories, Canada. As part of the EA process, a site water quality management plan must be developed. Plan development requires an integrated approach such that the key factors influencing water quality can be identified and managed to minimise potential impact. A system model was therefore developed to simulate the site-wide water quality conditions and mass loadings to the principal environmental receptor of concern, Snap Lake, during operations and post-closure. Requirements of the simulation included integrating hydrology, geochemistry, hydrogeology and site management practices in a dynamic way. A unique feature of the site was the need to accommodate a complex flow system that included a feedback loop between lake water and mine water. A system model was constructed using the GoldSim software package that integrated on-site water quality and flow measurements, as well as results from independent groundwater flow and geochemical modelling efforts. The GoldSim model simulated concurrently the movement of 39 solutes through the subsurface mine and surface facilities. Solute sources considered included four different waste rock and tailings types, explosives use in the mine, treatment plant discharge, and recycled process water for dust suppression. Separate solubility constraints were identified for different regions of the flow system (eg underground mine; treatment facility; surface water bodies). Kinetic test data were used to derive temperature-dependent rate constants for use in calculating mass inputs from surface sources such as waste rock piles. The model generated water quality estimates over time for a variety of management scenarios at several potential discharge locations. The integrated approach used by the model was effective in identifying the significance of key factors influencing overall water quality such as explosives use, mine water inflow rates, waste rock reaction rates, site/mine management options, and effectiveness of treatment. The model provides an example of an effective tool for comprehensive, integrated system evaluation and management.

Jan 1, 2003

The accurate calculation of ore reserves is one of the most important functions under- taken at a potential or operating mine. In recent years there has been a trend towards recommending more and more complex techniques for the calculation of reserves. However these are not always necessary and many improvements could be made by the use of all potential data and a heavier geological input. An ore reserve should be the result of geological not mathe- matical or engineering reasoning. All ore reserve estimates are wrong and the important thing is to.recognise why they-are wrong and to take action to minimize the errors. Geostatistics and other complex mathematical techniques may appear to answer all our needs for ore reserve accuracy but there are many drawbacks, not least of which is the communi- cation gap which may develop between the operator and both management and production Personnel.

Jan 1, 1979

Coal water mixture (CWM) is a mix of finely ground coal with water and a small amount of chemicals. It is a new way of transporting and handling coal. CWM can be transported, stored and burned like fuel oil in steam generating boilers. It also has some environmental advantages over both oil and bulk coal. A group comprising Ube Industries Limited, Nissho Iwai Corporation (both from Japan) and Coal & Allied Industries Limited has been working in Japan and Australia since 1987 on a joint feasibility study into the production, transport and marketing of CWM from Australia to Japan. The group has been studying the development of a large-scale CWM plant on Kooragang Island at the mouth of the Hunter River at Newcastle, NSW. The project concepts and engineering plans for the CWM plant are well advanced and other studies related to the project are continuing.

Jan 1, 1995

A new national-scale geochemical survey is under way inAustralia with the aim to provide energy and mineral explorers with state-of-the-art precompetitive data and information about the continentÆs potential resources. This low-density geochemical survey will provide a national geochemical data layer using consistent sampling medium and sampling, preparation and analytical methods. Large-scale geochemical patterns thus revealed are expected to point to new areas of exploration potential. The project is funded under the Onshore Energy Security Program. It is hoped that this new national geoscience dataset will help make Australia a more attractive destination for energy and mineral exploration investments. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By Clark G

The latest addition to the grinding circuit at Bougainville Copper Limited is another 5.5m by 7.3m primary mill (No.13). The mill can operate in a primary or secondary mode. Its distinguishing feature is its capability for speed variation, by means of a cycloconverter-fed synchronous ring motor. The engineering and metallurgical reasons for selecting such a drive system are described together with aspects of the installation and commissioning. Results of investigations into the relationship between mill speed and grinding efficiency are presented. It is concluded that mill speed variation within the range 70 to 80% of critical speed has very little effect on grinding performance. Beyond this range, grinding performance deteriorates. The same conclusions were reached when mill speed was varied at reduced ball charge levels.

Jan 1, 1986

By A M. van Niekerk, W Mey

Coal mining has an impact on the water management of the water scarce Upper Olifants River Catchment. A prefeasibility study was carried out by Anglo Coal and Ingwe Collieries Limited to establish the water supply and demand in the catchment. A geohydrological model was used for the coalfields to determine the stored water and excess water available. Two distinct collective and treatment systems were proposed for the Witbank and Middelburg municipalities to treat excess water from the Anglo Coal and Ingwe Collieries Limited. The Emalahleni Water Reclamation Project for Witbank was initiated first. Water management and treatment experience gained at Anglo Coal was the cornerstone to develop the collection, treatment and distribution system. A full enquiry was issued to Keyplan, Veolia, Bateman Africa and IST Technik to construct, commission, operate and maintain a 20 ML/day desalination plant to treat acidic, saline mine waters to a South African National Standard (SANS) 0241 Class 0 potable water. After the technical and financial adjudication, Keyplan were awarded the contract. An integrated regulatory process was adopted through consultation with all the relevant regional and head office staff of the Department of Minerals and Energy, Department of Water Affairs and Forestry and the Mpumalanga Department of Land Affairs via an authorityÆs steering committee. A rock engineering evaluation was done to select both the plant and waste disposal sites as all possible sites are undermined. Various contracts are required with the individual mines for water supply, the Emalahleni Local Municipality for the delivery of potable water and for the disposal of wastes.

Jan 1, 2006

Interest in the sampling of refined copper cathodes has heightened over the last ten years. This has followed the increasing importance of cathodes as the principle trading form for metallic copper. It has also been given impetus by recent trends for quality certification of manufacturing inputs, specifically the AS3900 and IS09000 series of standards.

Jan 1, 1976

By Walker G. S

Infrared and Raman spectroscopy have been used to study a range of solid state and aqueous solution species which are of interest in extractive metallurgy. In the solid state new Cu(II)/CN'/NH3 complexes have been detected, iron impurities in kaolin characterised, aluminium substitution in hematite and goethite quantified, and the crystallinity and orientation of zircon determined in heterogeneous crystals. In aqueous solution metal cyanide complexes and equilibria were readily characterised, the thermal decomposition of SO2 monitored and products identified, and complexation of AI(III) by hydroxycarboxylates observed. Attempts to monitor the early stages of the gelling of silicate solutions were less successful, with only changes in the gel being detected. However, the degradation of 12-tungstosilicic acid was readily monitored as a function of both time and pH.

Jan 1, 1996

By Moyes A. J

The Intec Copper Process uses a strong chloride electrolyte at atmospheric pressure and 80 - 85¦C to produce high purity, 99.99 per cent copper granules and elemental sulphur. A recent, exhaustive study by an independent, major Australian corporation has shown the capital cost of an Inter plant to be approximately half that of a copper smelter at the 200 000 tpa capacity level and approximately half the operating and capital cost at the 50 000 tpa level. The Inter process costs were also shown to be greatly superior to the best available leach/SX/electrowin technology. The process utilises a multi-stage counter current leach at 80 - 85¦C with the addition of air at atmospheric pressure to precipitate iron as a goethite type compound, followed by a two-stage purification process separating impurities in metallic- and other forms. Purified cuprous chloride/sodium chloride solution is fed to an electrolytic diaphragm cell where high purity copper granules are produced at current densities of 1000 - 1500 A/m2 withoutthe need for conventional electrode stripping. Power consumption is approximately half that of the cupric route. The product is suitable for the direct powder metallurgical conversion of the granules to products such as wire or strip. All the steps in the 'furnace free' conversion of copper mineral to product have been demonstrated The process can treat low grade and contaminated concentrates without penalty, thereby offering greater returns to the miner. Lead, zinc and silver may be recovered as metals, with the high oxidation potential of the electrolyte allowing extraction of gold at high efficiency. The gold is selectively precipitated on activated carbon with negligible copper and silver contamination.

Jan 1, 1992

By Enever J, Walton R, Wold M

Photoelastic and equivalent material model ling techniques for studying stresses and defor- mations and modes of failure in geological and engineering structures are described. The appli- cation of these techniques to the solution of tunnelling design problems is outlined. Models may contain heterogeneous components to simulate geological and man-made structures and may be two- or three-dimensional. Prototype construc- tion procedures and time dependent behaviour may be modelled. Examples of recent model studies carried out for the design of underground railway tunnels are given. Development of photoelastic and equi- valent material modelling techniques and facili- ties at the CSIRO, Division of Applied Geomech- anics are described, including a biaxial and triaxial frame for testing large scale two and three dimensional equivalent material models and components of full scale prototype structures.

Jan 1, 1976

By Kovscek P. D, Thimons E. D

The Bureau of Mines equipped a longwall shearer with a water- jet-assisted cutting system and measured dust levels during the cutting of a simulated coal block. The block was cut dry, at a conventional water spray pressure of 1 MPa and with water-jet-assisted cutting pressures ranging from 7 to 40 MPa. At water pressures of 20 MPa and higher, dust concentrations were reduced by as much as 85 % via water-jet-assisted cutting in comparison with conventional water sprays. This reduction was achieved without any increase in the water flow rate.

Jan 1, 1988

By C J. Adams, H J. Campbell, T Popham, A Goodall

Pounamu is a MSori collective term for semi-precious stone scientifically referred to as nephrite, semi-nephrite, jade or bowenite (tangiwai) that is composed predominantly of metamorphic tremolite in a felted, fibrous texture. It is Aotearoa/New ZealandÆs icon mineral material. Ownership and management of this important taonga (treasure) has been vested in Te Rnnanga o NgSi Tahu as part of a Treaty of Waitangi settlement process. Increasing demand from the tourist, jewellery, fashion and sculpture industries, as well as cultural renaissance, has placed pressure on the pounamu resource. This had led to nephrite importation, allegations that foreign material is being marketed falsely as New Zealand pounamu, and wider concerns over the potential for exploitation/over-use and theft of genuine pounamu.   Research is underway to characterise different pounamu source regions by defining their ægenetic fingerprintÆ. The geological age and radiogenic isotopic composition of Aotearoa/New Zealand pounamu is distinguished from other nephrite jade occurrences overseas, due to relatively young cooling ages. Strontium isotope ratios distinguish pounamu from different source areas within Aotearoa/New Zealand (whakapapa), with signatures reflecting the host terrane rocks (their family) and their position in a sequence of metamorphic events (their generation). The research will provide a tool for archaeological research, trademark and resource protection.   Mineral resource assessments normally aim to define the total volume/tonnage present, which is generally assumed to be finite, applying drilling and geostatistical modelling. Pounamu resource assessment requires a different approach, as its intrinsic value is insufficient to warrant modern exploration methods (eg drilling, geophysics). Pounamu is only known to occur at a restricted few in-situ (hard-rock) localities. It is primarily found in transported (alluvial) detrital river and glacial outwash deposits, where collectable material has short term variability due to erosion and transport processes. A new methodology is being developed aiming to define: +        the total resource present, +        the relative rate of change in the availability of that resource through erosion and other geological processes, +        active areas where new material is likely to be exposed (eg by erosion), and +        appropriate extraction rates for sustainable use. The methodology will provide a holistic overview of the resource in different regions of Aotearoa/New Zealand, and may be applicable to other transient or restricted natural resources that occur within geologically active environments (eg supplies of driftwood on beaches).

Jan 1, 2005

Segregation studies in ternary systems of glass ballotini, iron ore and coke particles (with size range of 1-8 mm in each) in filling and emptying a laboratory size Paul Wurth hopper are described. In-bin segregation is shown to be a function of the position in the hopper, the nature of the material and the feed composition. The in-bin results are correlated by the equation C = C0k, where C and C0 are the size compositions (wt per cent) in the hopper and feed respectively, and k is an experimentally obtained segregation constant. The results of now pallern measurements show that material discharges from the hopper according to the sequence; core now - wall now - scaffold now, where the latter represents stagnant material at the hopper wall that discharges last. Size segregation in the discharge stream from the hopper is shown to be a function of in-bin segregation and hopper now pallern. A method of predicting discharge segregation from these two sets of data is suggested. The results of the model studies are also compared with industrial data and these show satisfactory agreement. Discussion of the hitherto ignored effect of size segregation on hopper now rates, stoppages and other operating problems is also included.

Jan 1, 1985

By Wang Y. J

This paper describes a more generalised or generic approach for the mine ventilation network problem. More specifically, it defines the network variables in a manner that establishes the network problem in a nonlinear programming format. Assigned to each branch are three variables: air quantity, regulator pressure loss and fan pressure. Each variable is imposed with lower and upper bounds. Based on these, the generalised network problem for a mine ventilation network with B branches is presented as a system of B independent network equations in 3B unknowns (variables) with variable bound restrictions, and it is classified as a nonlinear optimisation. A nonlinear programming model has been developed for this generalised network optimisation problem. The model is formulated and transformed into a standard equality-constrained nonlinear programming form with given variable bounds. Then, MINaS (Modular In-core for Nonlinear Optimisation System) is used to obtain solutions. Examples are given to illustrate this nonlinear programming approach to the mine ventilation optimisation problem.

Jan 1, 1993

By B BussiFre, J Molson, M Aubertin, G W. Wils

Waste rock piles containing reactive sulfide minerals can serve as long-term sources of acid mine drainage (AMD). Within these piles, many physical, geochemical and biological processes can contribute to the production of AMD. The flow of water, for example, depends on internal pile structure, which depends on the dumping methods used to construct the pile. In this paper, the internal structure and grain size distribution of typical waste rock piles are first reviewed with respect to their effect on internal water flow. A numerical model is then applied to simulate unsaturated flow within a waste pile assuming two primary waste materials, different atmospheric conditions and several geometric configurations. The simulations suggest that water movement can be controlled by introducing fine-grained material layers within the coarser host material. However, these layers should not be horizontal because they can lead to localised high-saturation regions as well as preferential flow favouring the production of AMD. A shallow slope towards the pile boundary may be introduced to force drainage to the outside while maintaining low saturation within the interior, thus reducing the production of AMD.

Jan 1, 2003

By Sibson RH

The gold province of Otago occupies an area of upwarped basement, the Otago Schist, comprising predominantly quartzofeldspathic and volcanogenic metasediments. This assemblage is the product of collisional tectonic deformation and associated metamorphism, mainly to lower greenschist facies, during the Rangitata Orogeny (200-100 Ma). Historically this region has produced 240 tonnes of gold, 4% (10 t.) of which was from the mining of Cretaceous gold- quartz mineralised vein systems. Auriferous vein systems in the Otago Schist are mainly hosted within NW trending normal fault-fracture arrays, however NW trending reverse fault-hosted vein systems also occur. We propose that the Late Cretaceous-mid Tertiary Otago Schist structure represents a regional anticlinorium containing flexural folds of at least two wavelengths. The anticlinorium structure has been quantified by determining variations in angular discordance between schistosity and the Otago Peneplain, a Late Cretaceous-mid Tertiary erosion surface covering most of the Otago district. A structural model for the evolution of the post-collisional anticlinorium requires the cooling surficial zone (carapace) of a retrograding metamorphic belt to behave as an elastic lid. Erosion of topographic load on the carapace drove isostatic uplift, which was greatest in the tectonically thickened core of the orogen. In this way differential uplift produced flexural deformation in the elastic carapace, expressed as a large scale arching of the orogenic belt. Flexure created tangential longitudinal strains in the outer-arc, leading to extension and the formation of mineralised normal faults. These structures are separated by a neutral surface from shortening and associated mineralised reverse faults in the inner-arc. Our structural model predicts that the distribution of auriferous lodes should be localised about zones of maximum flexural curvature, where the tangential longitudinal strains are highest. As a result, NW-SE hinge regions separating schistosity dip domains in the Otago gold province may have new found significance as potential exploration targets.

Jan 1, 1995

By Carlson BL, Overton DD

This paper compares the designs of heap leach facilities for four precious metal mining projects in the southwestern United States. These four proposed projects are of small-to medium-size relative to other operating mines in the United States, and are either permitted or in the final stages of permitting. The differences and similarities in the heap leach facility designs are compared with respect to site conditions, operating conditions and regulatory requirements. This comparison provides a summary of the state-of-practice for heap leach facility design in the southwestern United States and identifies current issues in project development and process material containment.

Jan 1, 1997

The progress between 1983 and 1989 towards Management Guidelines for R16 was extremely slow and painful because protection of the mining heritage was a new function and administrative activity not referred to in any Queensland mining law. Also, until 2 December 1989 the Queensland political climate was anti-preservation. Therefore an understanding had to be achieved between John Hay, the Mines Department and the National Parks and Wildlife Service, to ensure preservation of the mining machinery in situ rather than being removed to a town site such as in Ravenswood.

Jan 1, 1990

By T Roache, K Yang, M Quigley, C Young

In late 2004 a large-scale evaluation of a new suite of tools for semi-automated core logging was carried out in the Eastern Goldfields of Western Australia. Known as HyLoggingÖ Systems, these combine rapid hyperspectral mapping of mineralogy and very high resolution digital imaging of cores and chips in their original containers. The resulting data is very information-rich and provides information about host rock, alteration and regolith mineralogy. This, in turn, can be used to test geological models about fluid/rock interactions, ore system architecture, ore feed characterisation and generally improve the objectivity of the normally manual and variable logging process. Results were obtained from the Kanowna Belle and St Ives gold deposits in the Kalgoorlie region, as well as numerous holes from across Western Australia stored in the Kalgoorlie Core Library. At the Kanowna Belle gold deposit critical spatial trends in the proportions of white mica, the chemistry and species of those micas, the presence of selected carbonate species and the absence of chlorite proximal to ore zones have all contributed to improved ore deposit understanding. Significantly many of these trends are not discernible to the naked eye, nor easily quantified, previously, across many thousands of metres of core from separate drill holes. At St Ives, the HyLoggerÖ was able to show that low-Al (phengite) and high-Al (paragonite to muscovite) white micas are spatially associated with D3 foliation zones that are proximal and distal to Au mineralisation, respectively. D3 foliation zones are also associated with the depletion of metamorphic chlorite and amphibole, and their replacement with biotite, relative to unaltered mafic host-rocks. The HyLogged GSWA drill holes yielded mineralogical characterisation of classic deposits, including Kambalda (Ni), Fimiston (Au), Teutonic Bore (Cu, Zn, Ag), Black Swan (Ni) and Hannans (Au), illustrating a wide variety of mineralogical trends due to both host lithologies, previously unrecorded lithological subdivisions, and alteration patterns. During 2005 a unique thermal infrared HyLogger was developed to map the important remaining silicates, such as feldspars, quartz, olivines, pyroxenes and garnets. This was successfully tested on a 9000 m subset of the same cores as the earlier study. Interpretation has focused, in particular, on silicification, albitisation, and the mineralogy of several high-grade, less hydrous deposits.

Jan 1, 2006