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By McNabb KE, Ward B, Dyer G

Roof conditions at Southern Colliery, the second longwall mine to be established at German Creek, were found to be much stronger and more massive than at the earlier longwall mine on the lease. Investigations were made to ascertain the level of face support required for longwall extraction under the changed geological conditions. Geotechnical information was provided from drillholes and highwall exposures. Downhole geophysical logs, notably the sonic velocity log, were used to obtain a distribution of the major lithological units over the mine area. A representative type section of the strata and geomechanical properties was compiled to form the basis for numerical modelling. Two-dimensional finite element methods were used to predict strata movements and chock loads under cantilevered roof conditions. The model incorporated a 6.3 in thick roof beam either bonded or detached, with either a 2 in or 5 in overhang. The solid rib, immediate roof, chock support and goaf were modelled as distinct parts, in addition a front abutment stress profile, derived from three-dimensional displacement-discontinuity analysis, was superimposed on the model.

Jan 1, 1992

By Canterford JH

Current and future methods of data acquisition in hydrometallurgy are reviewed. Hydrometallurgical operations involve a wide range of chemical and physical processes for the recovery of metals and other products from ores and concentrates. Control of such operations requires information on the different liquid/solid and liquid/liquid mixtures being processed. Continuous. data acqui-sition for the liquid phases uses procedures already commercially exploited in other types of chemical plant. The major problem is the lack of robustness of measuring probes. Continuous analysis of the solid phases is much more difficult to-achieve because of the sampling and analytical techniques involved.

Jan 1, 1985

Proceeding from statistical data on the development of waste volume, an endeavour was made to characterise waste materials with regard to the applicability of treatments based on mineral processing. Many types of waste are characterised by a high heterogeneity. The separation processes used for processing raw minerals can also be used for separation of various waste mixtures. For some waste mixtures, differences in properties can be utilised for separation which are mostly less distinctive for raw minerals. State-of-the-art technology is illustrated with selected Examples.

Jan 1, 1993

Traditional methods for calibrating the most customisable forms of GyÆs formula for the prediction of sampling variances involve a large amount of experimental work. This work is often extremely sensitive to outlier treatment and often relies on assumptions. A general methodology called æthe consistency methodÆ, however, has proven efficient in guiding these critical steps and adding objectivity to these subjective tasks. After a quick exposition of its principle, it is shown how it can also be used to reduce the amount of experimental work when dictated by budgets.

Jan 1, 2008

By Arbuthnot IM

It is the commonly held belief that, because the separation of liquids from solids takes place considerably faster in high rate thickeners than in conventional thickeners, high rate thickeners (HRT's) must use more flocculant than conventional thickeners. Data collected from a wide range of thickener users in Australasia and data presented in the literature is analysed. In addition, pilot plant data, with direct comparisons between HRT's and conventional thickeners, is presented. It is concluded that the flocculant consumption for both thickener types is in the same range.

Jan 1, 1991

By Restarick CJ

Plant data are presented which indicate a relationship between flotation rate constants and pulp density in zinc cleaning circuits at Broken Hill. The data were obtained from down the bank sampling of cleaner and recleaner banks at North Broken Hill and New Broken Hill Consolidated Concentrators. It was found that, under normal plant operation, flotation rate constants increased at the lower pulp densities existing in the later cells of cleaner banks. The addition of dilution water to the feed to the bank increased flotation rate constants, thereby confirming the relationship. It is shown that the relationship between flotation rate constant and pulp density is size dependent, being most pronounced for larger sized particles. In contrast, the effect is not markedly dependent upon mineral type. Possible consequences of this relationship for control of cleaner operation are discussed with the aid of some simulated results.

Jan 1, 1978

By Dickerson A. W

The most important mining problem facing many of the established surface coal mines in the Bowen Basin area of Queensland is the rising cost of overburden stripping associated with increasing depths to coal. The Dragline-Hopper-Truck Project is one of a number of responses to this problem, and involves the design and construction of an experimental hopper followed by field evaluation of a dragline-hopper-truck mining system.Such systems, if proven feasible, could be used for a range of applications, eg prestripping, extension of depths for single pass dragline operations and solution of geotechnical problems.

Jan 1, 1992

Mary Kathleen Uranium Ltd. recommenced operations in early 1976 following a twelve year period of care and maintenance. Several sections of the plant were modified or completely changed for the second operation. The most important change was the replacement of ion exchange with solvent extraction as the means of purifying and upgrading uranium rich Isolutions Most of the problems experienced in the solvent extraction system originate from the leach liquor which has a strong tendency to form stable emulsions. This has been countered by some careful control of leaching conditions and by closer observation of operations in the solvent extraction area. Most problems have now been resolved and plant recoveries are quite Satisfactory.

Jan 1, 1978

By Tapponnier P

In North Vietnam, large ductile shear zones are observed along the Red river fault and the Dienbien fault. Left-lateral sense of the Red river shear zone is related to the direction of shortening E-W. NE dipping foliation planes is subvertical. Stretching lineation is subhorizontal ( 25¦). Left-lateral slip observed in the Oligocene Yansun granites demonstrates the major tectonic phase in Neogene, The stress field established from microfaults observed in triassic limestones, Oligocene granites and Neogene Conglomerates. Measurements of striations on fault mirors are used for calculating the stress tensor and for separating tectonic phases. Two tectonic phases in tertiary are separated : first tectonic phase related to the compressive direction E-W corresponds to the major tectonic phase represented by NW left-lateral shear zone. Second phase having the compressive direction N-S associated with the right-lateral movement of the Red-river fault zone opening of the Eastern sea and the Red-river and the Red-river delta is associated with the left-lateral movement along the Red-river.

Jan 1, 1990

By U Rehm

The biggest hard rock double-shield tunnel boring machine (TBM) in the world, with a diameter of 12.4 m, is currently excavating the North-South Bypass, which includes a crossing under the Brisbane River, Brisbane, Australia, to relieve the often congested road traffic in the city centre. Ten years ago a 10.7 m Mixshield giant helped to handle the Olympic Games in Sydney linking the airport with the city centre for an improved transportation of fascinated visitors. In Shanghai, currently the biggest TBM in the world with 15.43 m diameter presents excellent performance rates; and in Paris a convertible Mixshield could be quickly changed from earth pressure balanced (EPB) to slurry type in order to handle the very heterogeneous ground conditions. In Madrid a 15.2 m EPB giant finished its tunnel job four months ahead of schedule. Large-scale TBMs have proved their economic and innovative potential to create the current and future underground architecture of mega-cities. TBM technology has made further large innovative steps in the last decade. State-of-the-art is a TBM for very heterogeneous ground conditions comprising hard and soft rock with additional high groundwater pressure. The machine concept is adapted to the various ground conditions and allows for a quick and flexible application. Ground treatment by means of additives developed to a helpful tool in this connection. To meet the special challenges of urban tunnel projects of nowadays it is of very high importance, beside applying highest developed technology of TBM, to have a comprehensive technical support during the project phase and to develop positive relationships between all participants of the project which last longer than only for one project.

Jan 1, 2008

The short review of hydrogeologic conditions in the three Polish coal basins have been presented as the background for the prevention measures against water inrushes being underta- ken in coal mines. The Polish mine safety regulations concerning water inrush prevention have been discussed, namely: - classification of sources of the potential water inrushes, - levels of water inrush risk and conditions of mining operation in the mines facing particular risk levels, - determination of the -di.mens.ons.of protecting pillars to prevent water inrush to mines, protection of surface water reservoirs and their earth embankments in regions submitted to mining deformations. Three examples of coal mining being carried out under water bodies have been presented.

Jan 1, 1988

By Miller M. J, Bauer J. C

The continuous copper drossing process operated at Port Pine since 1962 has had limited copper removal capacity as determined by a maximum tolerable Cu/S ratio in feed and the level of sulphur in blast furnace bullion. Recent process development has been to overcome these limitations to meet increased copper throughput requirements. A sulphur addition system was developed and installed in August 1987. The system has capacity to increase sulphur input by over 150%, meeting the increased copper capacity requirement and also allowing independence from the upstream process for sulphur supply. Developments in process understanding have been applied within the limitations of the existing furnace design with a 10% increase in the maximum tolerable Cu/S ratio.

Jan 1, 1989

By Ritchie I, Fleay J

The key issues in the conceptualisation and testing of treatment options for gold and base metals mineral processing projects are discussed. A prerequisite of this process is the need for close interaction between geologists, mining engineers and metallurgists to facilitate an understanding of the orebody based on the parameters impacting on each discipline. Typical testwork programs for unit operations, including comminution, flotation and gold processing are Described.

Jan 1, 1997

By Shinnosuke U, Zhang HE, Qian X

In this paper it is recommended that pyrite is to be separated as froth from arsenopyrite by selective depression of arsenopyrite in strong alkaline medium (1), by oxidation with chlorinated lime (II), by co-use of chlorinated lime with sodium carbonate (III), and by modification with `L' reagent (know-how) without filtering to get rid of residual copper ions after Cu activation (IV). The corresponding principles of these (new) effective methods were briefly discussed. The artificial mixture (1:1) of pyrite and arsenopyrite could be successfully separated, and concentrates of pyrite containing 2.12 per cent (I), 7.00 per cent (II), 2.60 per cent (III) and 3.16 per cent (IV) arsenic with recovery of 90.9 per cent (1), 89.5 per cent (II), 89.0 per cent (III) and 81.4 per cent (IV) respectively can be obtained by only one flotation. Some effective precautions were suggested to improve the separation of arsenopyrite and pyrite (or other sulphides) by flotation.

Jan 1, 1993

By Singer RP

The Latrobe Valley brown coal deposits are one of Australia's major energy resources with measured and indicated reserves amounting to some 162 billion tonnes. Economically recoverable reserves are estimated at some 65 billion tonnes, 47 billion tonnes of which are classified as available for mining (VBCC (1983)). These deposits contain one of the lowest grade fuels used anywhere in the world. Typical Net Wet Specific Energy values range from 6 to 9 MJ/kg. Despite the low energy value of the raw coal, the Latrobe Valley deposits represent approximately 90% of Victoria's indigenous non-renewable energy resources. Utilisation of this vast primary energy resource has been a key factor in the economic development of Victoria.

Jan 1, 1990

The Coal Corporation of New Zealand Ltd (CoalCorp) is the largest coal producer in New Zealand, with extensive properties in both the North and South Islands. CoalCorp's North Island operations are kilcmetres to the south of Auckland. opencasts, are located in the catchment wildlife, historical and scenic values. in this catchment is the single most mining operations. centred on Huntly, a town some 80 Five coal mines, four of which are of Lake Waahi, a lake with significant The discharges of mine lodgement water important environmental constraint on Throughout New Zealand the use of water is controlled by a statute called the Water and Soil Conservation Act 1967. All industrial water users are required to hold Water Rights, which are in effect licences to take, use, dam, divert or discharge water. Water Rights are obtained through a legally defined process and any potentially affected party has the per to object to their granting. A special tribunal hears the evidence for and against an application, and issues its decision, which is reviewable in a higher court on Appeal. Rights, if granted, are issued subject to conditions and, in the case of mining discharges, limits would be set on flaw rate, suspended solids concentrations, turbidity, pH and the concentrations of any potential toxicants. This paper presents a case study of an integrated, catchment wide water management plan for Lake Waahi, that was prepared by the author, and others while the author was in the employ of CoalCorp, and its predecessor, State Coal Mines. The author is grateful to CoalCorp for their permission to submit this paper.

Jan 1, 1988

By B G. Lottermoser

Phosphate induced stabilisation has been used to create passive iron phosphate coatings on pyrite and pyrrhotite. The formation of solid phosphate coatings on sulfide grains thereby inhibits sulfide oxidation. The aims of the study were to determine whether phosphate induced stabilisation could control sulfide oxidation and metal mobility in partly oxidised, polymineralic, sulfidic mine wastes. Waste materials were obtained from the acid mine drainage generating, abandoned Montalbion silver mine site, far north Queensland, Australia. The waste consists of quartz, kaolinite/illite, sulfide minerals (galena, chalcopyrite, tetrahedrite, sphalerite, pyrite, arsenopyrite), and pre- and post-mining oxidation products (hydrated Fe, Cu, Pb and alkali mineral salts). SEM observations of waste material treated with potassium orthophosphate showed that metal, metal-alkali and alkali phosphate coatings developed on all sulfides (with the exception of tetrahedrite). The abundance of phosphate phases was dependant on the availability of cations in solution for complexation with the phosphate anion. In turn, the release of cations was dependent on sulfide oxidation or the dissolution of efflorescent mineral salts. Experiments aiming to dissolve these phosphate coatings û using a strongly oxidising solution û showed that the phosphate coatings remained stable, preventing acid generation and metal release. The results of this study demonstrate that liquid phosphate stabilisers can suppress sulfide oxidation and immobilise metals in partly oxidised, polymineralic mine wastes.

Jan 1, 2003

The excessively high cost of production in underground coal mines has made the survival of many coal mines around the globe economically non-viable. The global competitive coal market speaks itself of the desirability of a lower operating cost in conjunction with a higher productivity performance, particularly in underground coal mines, and calls for an optimal production planning under a host of constraints. Such a task of optimal planning is not an easy exercise like that of traditional planning based merely on intuition, experience and subjective judgement. It essentially demands a thorough understanding of the complex interaction of mine sub-systems for judicious application of optimisation tools and techniques available with operations research. A few large mines around the globe have made an effective use of a sizeable number of operations research packaged programs for optimal decision-making (Grayson, 1989). The success of practical applications of operations research techniques made in a variety of mining problems in large mines in different parts of the world will hopefully make inroads to smaller mines in years to come. The present paper is an addition in the series of such applications of operations research tools to mining problems, particularly with reference to an underground coal mine in India. The paper is based on research work (Jawed, 1990) and deals with the development and use of a mathematical model for production planning in underground coal mines under multiple objective environment subject to a host of constraints.

Jan 1, 1995

By Szymanski J, Planeta S

For many hard rock mines with near surface deposits, the surface crown pillars form the first line of protection for the immediate underground workings. Underground stopes are typically contained by crown pillar, which protects the level above, rib pillars, and a sill pillar through which the ore collection system is cut. This paper discusses the mining of these pillars, with particular emphasis on the overall stability of the mined out upper part of the mine areas. An area of interest is located in the Canadian Shield, where the mining has progressed below four thousand foot level in the ultramafic high grade sulphide type of orebody.

Jan 1, 1995

The mining industry views with the utmost concern, legislative or administrative action that inherently reduces the scope for exploration activity. Is there any basis for this concern in relation to Victoria? This paper will outline the role of the Department of Minerals and Energy and the main features of legislative provisions affecting exploration effort. The practical difficulties that confront the Department and explorers alike will be examined. The importance of industry representation to influence the direction that policy and legislative review might take, will be highlighted. Above all, the paper will establish that one essential duty of government is to ensure the provision of appropriate mining titles and security of tenure.

Jan 1, 1982