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By Gillies A. D S

The paper presents a review of research in the area of explosible coal dust with respect to safety in the underground mining environment. Research over the last several decades has concentrated on generating dust clouds in small scale laboratory explosion chambers to study flammability limits and the physical and chemical variables which affect explosion propensity. The validity of this approach is discussed and the results obtained for a range of coal types compared.

Jan 1, 1994

By H Kundapen, B Bolton, S Miller

The Ok Tedi porphyry copper and gold mine is an open-pit operation located within the Star Mountains in the Western Province of Papua New Guinea and is situated near the headwaters of the Ok Tedi-Fly River system. The climate is equatorial sub-alpine with rainfall ranging from five to ten metres per year. Mining commenced in 1984 and to-date approximately 500 Mt of waste rock has been produced. A failing waste rock dump system operates whereby the dumps are eroded by tributary creeks of the Ok Tedi. It is estimated that approximately 250 Mt of waste is retained within the upper reaches of the river system. The waste rock comprises both potentially acid forming rock and limestone and to-date the overall waste has been acid consuming. However, the long-term mine plan identifies declining limestone production and hence an increasing risk of acid generation over the remaining years of the operation. A program was initiated to determine the net acid producing potential (NAPP) required (ie target NAPP) to minimise the risk of acid generation within the waste rock dumps. The results from this program provide guidelines for an operational target NAPP strategy to provide sufficient acid buffering across all size fractions in the waste rock dump for long-term ARD control. Implementation of this plan requires additional limestone to be mined and co-disposed with ROM waste rock.

Jan 1, 2003

By P J. A Lever

This paper presents details of CRC MiningÆs work with waterjet assisted blasthole drilling. The objective of this work was to investigate techniques that reduce the cost and increase the productivity of blasthole drilling. The focus is on a technology that uses a high pressure waterjet to assist the conventional rotary rock cutting action of a tricone drill bit. The potential benefits of this technique are increased productivity, reduced drill bit wear and reduced hole deviation and hence improved quality of drilling. This paper describes the results of a laboratory based experimental program comparing conventional tri-cone drilling performance to the proposed waterjet assisted approach. Additionally, work has been completed looking at the more practical issues around the collection and sampling of drill cuttings and water recovery (recycling) when drilling with a waterjet. These studies have demonstrated that waterjet assisted drilling can significantly increase the rate of penetration over conventional rotary drilling. For the best-case experimental result, the relative improvement was over 40 per cent. More importantly, it is a starting point for examining alternative uses of the additional drill productivity obtained from waterjet assisted drilling. For example, increased drill productivity could be used to improve rock fragmentation by drilling a tighter blasthole pattern in the same time period. an existing drill fleet, then the drill fleet size could be reduced, or improved rock fragmentation could be achieved by drilling a tighter blasthole pattern within the same time period.

Jan 1, 2004

By LeJuge G. E, McKenzie C. K

Innovative mining and blasting techniques were demanded at the Richmont Mines, Francoeur Mine in Quebec, Canada, by a narrow, shallowly dipping high grade gold ore body. The ore body being mined occurs as a thin tabular deposit varying in thickness between 1.5 and 3.7 metres, and dipping at 36¦. The mine proposed experimenting with open stoping techniques using small diameter drill-holes. The hangingwall required progressive, full face rockbolting after each production blast, utilising a specially manufactured machine which provided access to the hangingwall for both scaling and bolting. Blasted material is mucked from the stope by scraper and hoisted directly to surface without benefit of primary crushing.

Jan 1, 1992

The authors are looking at the behaviour of the mineral processing circuits by means of the simulators operating under random disturbance. The present paper deals with the fuzzy control systems in comparison with PID controllers. A series of tests are conducted on simplified prototype processes with (1) dead time plus first-order lag model and (2) diffusive model. In the next series of tests the self-sustained process model was introduced to improve control against dead time. In both cases fuzzy and PID controllers are optimised by EVOP method. Particular attention is paid to the effect of observation noise to analyse for the problems which can be fatal to practical applications in mineral processing. Finally the methods developed are applied to a closed-circuit wet grinding system simulator operating under random disturbance.

Jan 1, 1993

A great part of the research on froth flotation of gold ores deals with ores containing gold associated mainly with sulphides, resulting in a largely accepted view that what takes place with sulphides (eg pyrite) in a flotation cell also happens to gold particles. This paper is concerned with the influence of some inorganics (CuSO4, CaO and NaCN) on gold particles flotation, using ethyl or amyl xanthates as collectors. The bench-scale tests were carried out with ground quartz and gold particles mixtures. Some findings stemmed from this study: flotation of the gold particles of size 0.16 mm was efficient adding only frother; larger gold grains were better recovered by the use of stronger collector CuSO4 did not seem to be an activator for gold; the addition of NaCN up to 200 g/t or CaO up to 2000 g/t did not depress the gold grains when amyl xanthate was used as collector although with ethyl xanthate the gold depression was verified.

Jan 1, 1993

Gold recovery by catalytic copper ammonium thiosulphate solution has been studied. Such a process strategy is very attractive for leaching certain difficult-to-treat ores and presents lessened lixiviant toxicity compared to cyanide. Newmont Gold Company has evaluated the ammonium thiosulphate heap leach process for gold recovery from low-grade carbonaceous sulphidic refractory ores following biooxidation. The ammonium thiosulphate leach process has been studied in laboratory, pilot plant and demonstration scale. Satisfactory test results support the continuation of process development. However, the thiosulphate leach chemistry was found to be very complex. Maximum control of the stability of the leaching system is a key factor for success, especially for the heap leach process. Important solution chemistry is discussed in this paper.

Jan 1, 1997

The general theme of the paper is a resume of factors which induce management to explore for oil, gas, coal and uranium in Australia. It is non-technical in the sense that apart from brief references exploration techniques are not covered. The central theme is the interplay of such diverse factors as taxation, mining 'regu- lations, exploration costs, availability of competent personnel, potential markets within and outside Australia, projected prices of sources of energy and their distortion by governmental action including restrictions on international trade for economic or political reasons, the role of the so-called multi- national companies, extreme views by pressure groups on the preservation of the environment, the availability of funds for exploration and the possible returns to the providers of exploration monies.

Jan 1, 1974

By E House, V Lisitsin

Recent whole-rock geochemical data from nearly 900 fresh drill core and underground samples taken from seven central Victorian gold deposits confirm the presence of distinct and identifiable primary alteration haloes surrounding the deposits. Ferroan carbonate alteration extends for up to several hundred metres away from turbidite-hosted gold mineralisation outside of contact metamorphic aureoles. A less distinct phyllic alteration zone can be identified using geochemical molar ratios or short wave infrared analysis. It generally overlaps a sulfidic halo characterised by disseminated pyrite and in close proximity to mineralised structures, arsenopyrite. The extent of the sulfidic halo can be traced using low-level analysis of pathfinder elements such as S, Au, As and Sb. Recognition of these alteration features enlarges the target for exploration and provides a tool by which drilling can be directed towards mineralised structures. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By U JSger

The Westerschelde tunnel will be the first permanent road link between the Dutch regions of South Beveland and South Flanders. Two tunnel tubes, each 6.6 km long, will be driven using the shield tunnelling method. The difficult ground conditions and a water pressure of up to 6.5 bar make great demands on the design. This paper describes the problems and their solutions.

Jan 1, 1999

Two examples of risk assessment and risk management in action are discussed. The first is in a management context in relation to Kingsgate Consolidated LtdÆs Chatree operation in Thailand. Kingsgate has conducted an over-riding risk management program to assess and manage risk across its complete business from the Sydney and Bangkok offices through to the Chatree Mine and the companyÆs exploration group. This example addresses how Kingsgate has applied risk management, particularly to the process operation, and the benefits that have been gained. The second is in an operational context in relation to Minara Resources LtdÆs Murrin Murrin operation in Western Australia. The subject is the methodology and outcomes of a risk assessment across the Murrin Murrin operation specifically to identify and assess risks with potential impacts from $1 M to $7 M. This section of the paper then shows how the outcomes of the risk assessment were integrated into MinaraÆs strategic plan to debottleneck the plant and increase nickel production.

Jan 1, 2004

By Kuruppu M

Geotechnical design plays a key role in mine design. A proper geotechnical design provides a safe working environment and facilitates efficient mining operation. There are mainly three design approaches: (i) judgmental, based on observational and experiential facts, (ii) empirical, based on empirical design formulae; and (iii) analytical, incorporating numerical analysis. Most design applications are based on the design methods one and two as mentioned earlier. However, complexities arise in deep underground mining operations and deep open pit mines. These complexities and difficult geological environment introduce more uncertainties and simple empirical formulae would not be adequate as a design tool. These situations require numerical modelling and analysis of the design problems including interpretation of the results obtained from the analysis. There are several tools available for performing the numerical modelling and analysis. A brief review of the available tools is provided. The authors selected ANSYS (a general purpose finite element analysis tool) for use in mining geomechanics and geotechnical design. This paper includes several examples demonstrating the applicability of this software in designing mining structures. The authors hope that the design examples will demonstrate the use of the numerical modelling and analysis applications in excavation design.

Jan 1, 1995

The efficient development and exploitation of an orebody relies on an understanding of the mineral characteristics of the deposit. This information is valuable throughout the mining cycle - during exploration, assessment, testing, design, operation and rehabilitation. Problems can arise at each stage if there is an inadequate appreciation of the mineralogy involved and its effects on the treatment process. Modern image analysis systems now permit a more quantitative understanding of the mineralogy of an ore to be gathered. Where previously the metallurgist had to rely on qualitative information to guide technical decisions, it is now possible to give numerical estimates to the compositional and textural properties which govern the mineral concentration processes. Ore samples can be characterised according to modal abundances, mineral grain size parameters and mineral associations, all of which affect the liberation and concentration of the values. The paper will discuss the application of quantitative process mineralogy by considering a number of case studies. These include: ore characterisation to assist in exploration, assessment and mine planning; modal analysis of complex mineral suites to assist in the evaluation of ores, the deportment of values between products and the recovery or loss of these values; liberation analysis for ore testing, plant optimisation and performance monitoring; and characterisation of tailing to guide estimates of leachability, stability and rehabilitation options.

Jan 1, 1998

The rapid growth of world civilisation will have a significant impact on the way humans live in the future. As the global population increases and more countries demand a higher standard of living, the world must provide more food and greater energy and mineral resources to sustain this growth. The difficulty of doing this is compounded by three broad trends: the conversion of agricultural land to development uses; the increasing urbanisation of the world's population; and growing concern for the maintenance and improvement of the environment, especially regarding global warming and the impact of population growth. Underground space utilisation offers opportunities for helping address these trends.

Jan 1, 1993

Mathematical economic models for assess ment of technological progress in the mining industry in the USSR are discussed. The models are based on a simple index, TT which approxi- mates the rate of growth of the people's living standards. However, for application in the mining industry it is necessary to incorporate various parameters to account for the dynamic charges in the geological, mining and other technological conditions. Derivations of the models are shown and examples of results are Included.

Jan 1, 1977

By Gray J, Krouse HR, Changkakoti A, Morton RD

A group of stratabound-stratiform Fe-Ba-Zn-Pb-Ag deposits within the La Minita mining district of Michoacan, southwest Mexico have been investigated. The results of the study show that these deposits were generated around submarine hot-springs issuing in a Cretaceous island-arc environment. The exhalative mineralization, which is both epigenetic and syngenetic in character, was developed above fault-systems which constituted the loci of both volcanism and subsequent hydrothermal systems.Fluid inclusion data suggest two hydrothermal events during ore mineralization, one at 240¦C and the other at 161 to 205¦C, with salinities between 2.1 and 12.8 wt.% NaCl equivalent. Stable isotope data support a marine origin for the ore-fluids, as well as, for carbon and sulfur. Strontium isotope data suggest that Sr in the barites was extracted from the volcanics and limestones by circulating seawater. The ore-depositional environment was one of shallow, sub-tropical marine character, where mineralization was in part geochemically controlled by carbonate reefal facies within the volcanic/pyroclastic suite.

Jan 1, 1990

The paper examines the possibility of applying the monolithic packing technique developed in the UK to the division of wide development drivages in Australia, so enabling double entries for longwall retreat panels to be created from shortwall units. The monolithic pack of the UK therefore becomes a monolithic partition in this proposed Australian application. A method developed for the analysis of the load development in packs installed behind longwall advancing faces is adapted and used to predict the support performance of the monolithic partition. Conclusions are made regarding partition construction and possible rates of advance.

Jan 1, 1986

By R J. Nicholson, J M. F Clout

As part of an overall strategy to make significant new technological advances for the sustainability of the mineral processing and related process industries CSIRO Minerals has developed a new dry separation device. It represents a technology breakthrough and has the potential to radically change the way in which dry particle size classification is achieved in the minerals industry. Conventional dry separation techniques have limited applications and often suffer from low productivity, high operating costs, low separation efficiency, the need for dust control and a lack of flexibility. In the absence of efficient dry techniques, wet processing is often used. The use of wet processing either requires the introduction of water into a separation process, which causes environmental concerns through the need for water supply and tailings dams or the use of æunfriendlyÆ chemicals for dense media separations that have considerable impact on handling and disposal. Wet processing also increases operating costs due to plant instability, materials handling, thickening, filtration and product drying. The new CSIRO technology exploits a combination of natural and applied forces to achieve specific particle motions that produce size separation. In doing so, many of the traditional shortcomings of dry separation have been overcome. The CSIRO Dry Particle Size Separator is ideally suited for dry size separation applications within the size range 1 mm to 30 ¦mfor moderate moisture levels (2 per cent), have low unit throughput, produce a fixed cut size and are therefore impractical where very high unit capacity and low operating costs are required. This paper presents a review of dry separation devices together with details of the new Dry Particle Size Separator and typical results for a number of materials, including iron ore and quarry dust.

Jan 1, 2002

By Thomas L. J

A series of tests on rock stress measurement devices used with the overcoring method indicated that improvements could be made in their construction. A prototype inclusion cell was developed with strain gauge rosettes bonded to a 0.05 mm thickness stainless steel sheet which was formed into a cylinder around two end pieces. The finished diameter was slightly larger than previous cells so that the thinner plate and the reduced annulus of Araldite cement in the installation borehole gave a better response in the laboratory than the other cells tested, especially in simulated bedded rock. It was less affected by inhomogeneity and temperature changes. Its high sensitivity should make it suitable for both absolute stress measurement and field monitoring. A table of comparative readings is given for the new cell and for four other devices used in simulated in-situ rock conditions.

Jan 1, 1992

Detailed cash flow forecasts have always been almost essential as a basis for judging the viability of proposed new mining projects. In recent years attempts have been made explicitly to take account, in such forecasts, of the uncertainties surrounding the assumptions upon which they are based. With the risk analysis approach, Monte Carlo simulation of the cash flows indicates in probability terms the combined effect of these uncertain basic assumptions. While the use of risk analysis has been widely discussed, few specific applications to real projects have been reported. The application of such an analysis in the feasibility study of the large new Deelkraal gold mine presently being established on the Far West Witwatersrand gold fields by the Gold Fields Group in South Africa is described in the paper. The paper also indicates how one of the major sources of uncertainty, namely the gold content of the ore, can be`quantified in objective probability terms. This feature distinguishes the application fran other published accounts in which only subjective probability assessments have been utilised.

Jan 1, 1977