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In comparisons of a trial extruded brick containing 33 per cent coalwash and 67 per cent clay and a trial pressed brick containing 100 per cent coalwash with a standard extruded clay face brick, the mixed feed stock trial brick compared favourably with the standard brick. If a highly plastic clay is used to mix with the coalwash, satisfactory results are obtained in respect to dimension, strength, water absorption, efflorescence, resistance to salt attack, hardness, colour, weathering, mineralogy and porosity. Although a brick containing only coalwash can be successfully manufactured in a press, its mechanical and physical properties are inferior. This mixed feed stock brickmaking technology leads to the utilisation of a by-product with a potential saving of raw material costs. The extent of use is likely to depend on the proximity of the coal washery and the brickworks and the economicsof transportation costs.

Jan 1, 1992

By Blom MS

Two well-developed styles of mineralization occur in the Nevados del Famatina mining district, Famatina ranges, La Rioja province, Argentina. Porphyry molybdenum- copper-gold mineralization and high level acid sulphate alteration/mineralization (Nevados del Famatina) are related to intrusion of the Pliocene Mogote rhyodacite porphyry complex. High sulphidation epithermal mineralization (La Mejicana) is developed peripheral to the Nevados del Famatina deposit. Both are hosted mainly by the Ordovician Negro Peinado metapelites.At Nevados del Famatina, five mineralized fracture events have been identified and correlated with four distinct alteration assemblages. Stage I (barren quartz) and stage II (molybdenite¦sphalerite¦pyrite) mineralization are associated with a K-silicate alteration assemblage of K-feldspar+biotite+quartz+magneti te¦ilmenite¦anhydrite. Stage III (bornite+pyrite+sphalerite+molybdenite ¦chalcopyrite¦idaite) and stage IV (chalcopyrite+pyrite +sphalerite+gold¦tennantite-tetrahedrite) mineralization are related to a quartz-sericite assemblage of quartz +phengite+illite+pyrite+rutile. Stage V mineralization is divided into two substages. Stage Va (chalcopyrite +pyrite+sphalerite¦ tennantite-tetrahedrite ¦ tellurides ¦ gold ¦enargite¦famatinite¦stibnite¦molybdenite) is related to a sericite-clay assemblage of quartz+illite+kaolinite ¦montmorillonite¦alunite. Alunite-kaolinite alteration (alunite+pyrophyllite+kaolinite+ aluminum - phosphate -sulphate minerals ¦illite¦fluorite¦corundum¦anhydrite) occurs in the upper part of Nevados del Famatina associated with the later stage Vb (quartz+famatinite +chalcopyrite+covellite + chalcocite ¦ marcasite ¦ enargite ¦ luzonite¦sphalerite¦melnikovite) mineralization.

Jan 1, 1990

The Junction Reefs gold bearing deposit is situated on the Lyndhurst Mining Field in mid-west New South Wales. It is located within a triangle of three country towns namely, Blayney, Cowra and Canowindra, all three townships are approximately 25 km from the current operational mining leases. The district is well developed, having been settled for more than a cen- tury. However, being close to the Cities of Orange and Bathurst it is real- lised, instantly, that mining leases have been pegged, in this area, almost boundary to boundary. The lease patterns are, with few exceptions, those which had been estab- lished more than seventy-five years ago. These types of lease patterns may not assist the proper exploitation of a large district where there have been many discoveries of gold, copper and other metals.

Jan 1, 1988

Design and construction techniques used to develop two highway tunnels in inaccessible mountainous terrain are described. Measures used to adapt the design to the unusual geology and topography are discussed, as well as measures to adapt the construction methods to available equipment, materials, and skills. Sharp local variations in geoloqic conditions resulted in field modifications to both design and construction techniques. The geology is a volcanic ash and breccia-agglomerate at one site, a jointed andesite at the other, which is also the site of a major landslide. Both rock reinforcement in the form of pretensioned and grouted rock bolts with a shotcrete lining,and rock support by struc- tural steel sets with a reinforced concrete lining were used. A canyonside location and high lateral in-situ stresses required modification of design procedures. Pilot tunnels at both sites resulted in adapting the designs to site conditions with large savings in lining costs, disclosing problem areas in advance of the main excavation, and cushioning of blasting pressure to minimize stability problems.

Jan 1, 1976

The underground coal mining industry in Australia has, in the last 30 years, undergone a revolution in production methods, techniques and results probably unparalleled elsewhere in the world. It can lay claim not only to leading the fight against pneumoconiosis and setting high safety standards generally, but has at the same time recorded comparatively high rates of increase in output per man shift. The latter has been achieved as a result of progressively matching the latest in production and underground transportation equipment with significant changes in seam development and extraction techniques and the introduction of stress-relieving extraction methods unique to the world scene. However, the seam recovery factor is still too low. Apart from the overall objectives of maximising production and commercial returns with the greatest safety, there must be a concentration towards maximising seam recovery, particularly in high seams. The search will continue for systems which are more completely continuous mining operations than the present stop-go operations, with longwall having long term potential in this regard, but as yet not sufficiently developed to engender confidence for its more general use. Techniques developed in the last 10 years make the development and extraction of deeper seams, perhaps to 2500 feet or more, feasible with continuous miners as well as longwall. The future will see a greater use of continuous shifts at mines, larger mines with more sophisticated management organisation, extensible belts at the face, better systems of immediate roof support at the face, remote operation of face equipment, greater use of roof bolts and the longer roof cables. With commercial confidence in coal mining now virtually assured to at least the turn of the century, the stage is set for heavy capital development in the industry which will undoubtedly include major research into the whole area of mining methods and equipment. We must ensure that our contribution to such research equitably matches other coal producing countries.

Jan 1, 1975

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

By Gordon N

The in situ behaviour of claystone floors associated with the Wallarah, Great Northern and Fassifem Seams has been studied using a comprehensive suite of stress and displacement monitors. The instrumentation was supplemented by in situ and laboratory testing of the claystone materials. The instrumentation demonstrated that the presence of claystone floors is associated with floor heave, extra rib spall, and settlement of the pillar into the floor. Horizontal floor extensometers showed that the depth of extrusion of clay was limited to 1-2 in. A pore pressure transducer installed in a claystone floor demonstrated the possible existence of short-term undrained behaviour of the claystone. Long term swelling of destressed claystone was also documented. Settlement of pillars into claystone floors can be analysed using simple elastic theory. The assumption of plane strain is valid for most claystone thickness/pillar width aspect ratios. Floor heave can be analysed using bearing capacity concepts. However, it is considered that heave is the result of local bearing capacity failure in the rib spall zone. The advantage of this model is that the bearing capacity equation can be applied without resort to unrealistically high factors of safety.

Jan 1, 1992

This report on the 5th International Conference on Underground Space and Earth Sheltered Structures, which was held at the University of Technology, Delft, the Netherlands, on 2 to 5 August 1992, was submitted to the members of the Australian Underground Construction and Tunnelling Association. The report describes the conference themes and outcomes and puts forward some observations about a growing world-wide interest in the promotion of appropriate uses of underground space. The report recommends the creation of an Australian centre for research to bring together a wide range of professional disciplines and to focus attention on the potential benefits of using underground space.

Jan 1, 1993

By Gillies A. D S

A device has been developed for modelling the behaviour of coal under conditions which may lead to spontaneous combustion. It is designed to model the behaviour of a stockpile of large mass. The apparatus can test coal samples taken from the flow stream from mine through washing, stockpiling and transportation to the point of utilisation. It tests samples in an as received' condition and so takes into account the effect of aspects such as particle size and moisture content on propensity for spontaneous combustion to occur. Results of the preliminary tests undertaken are given and future applications of the apparatus are Discussed.

Jan 1, 1995

By Wilson GR

Pellets were produced from carefully sized iron ore and silica sand fractions, under controlled moisture conditions, using a sealed balling drum. The strength of these pellets was measured as a function of moisture content and particle size. The results showed that the strength of the pellets could be adequately described by a model which equates the strength of the pellets with the negative pressure developed within the porous mass, provided that the particle size distribution was narrow and the mean particle size relatively large. However this model failed to account for the observed strengths of pellets produced from systems containing even small quantities of ultrafine particles (

Jan 1, 1972

Corrosion is a chemical or electro-chemical attack on a metal by the surrounding medium, and it can be stated in general terms that a non-corrodible metal possesses that property either because there is no chemical action between it and the medium, or because the medium reacts quickly with the metal to produce a thin protective coating.When iron or steel is attacked by dilute mineral acids, for example, the products of the reaction are soluble and the formation of a protective film cannot take place; on the other hand, rusting produces a porous film which flakes away and offers little protection to the underlying metal. However, when chromium is alloyed with iron, its resistance to corrosion is improved because the films produced on such alloys become more adherent and tenacious as the proportion of chromium is increased. Chromium is thus an essestial constituent of the corrosion- and heat-resisting steels.During the 40 years which have elapsed since their initial development, these alloys have made an important place for themselves in in<lustry and commerce, and it is the object of this paper to 'describe typical examples of the many types which are available; also, to give some indication of their particular properties, and applications in the mining industry.NOMENCLATUREVery few of the alloys which are about to be described can strictly be considered stainless, and most are not steels in the sense that they can he hardened by quenching from...

Jan 1, 1951

The proportion of coal production from underground operations in Queensland, is likely to increase in the future. A portion of this increase will come from mines working under farming areas. The degree of compatibility between underground coal mining operations and farming is examined. Two case histories are considered in detail. These relate to farming areas in the Moura and Emerald districts. Mining the Moura, area has been undertaken for the last two and half decades, while in the Emerald area, large scale underground coal mining is currently being planned. Interference to watercourses and water harvesting programmes, damage to crops, and ponding in cultivated areas have been experienced in mining areas. With expansion of underground mining in farming areas, the principle areas of likely conflict are the effects of surface subsidence on irrigation and erosion control structures. Other potential problems that may arise in particular circumstances include reduction in availability of water for harvesting, pollution, surface cracking and damage to surface structures. Finely textured soils and erratic and violent rainfall patterns make farming in central Queensland particularly vulnerable to severe soil erosion unless strict precautions are taken. Soil erosion control is an essential part of farming. Contour banks are used to ensure that runoff velocities are suitably low. Where steep slopes are encountered, grassing is the most effective way to prevent erosion.

Jan 1, 1987

By Dagbert M, Belisle J. M

Several packages for the estimation of porphyry type deposits exist and produce acceptable results. Recently, however, the need for really trying to obtain maximum information from drill holes has prompted the generation of geostatistical solutions to the problem of reserve calculation. It will be shown that an understanding of a few key points is necessary in order for these solutions (variogram analysis and kriging) to he really ptimal. The most important new fact to be ecognized in open pit ore reserve estimation is that block models do not give an accurate rediction of ore tonnage when a cut-off is pplied but often yield an overestimation of p to 25%. When checked against extensive roduction records, geostatistical methods provide a practical solution to this problem. t now seems that the model used here gives he best possible results. Inasmuch as all arge deposits present very similar geostatis- ical characteristics only a few days of work re necessary to produce a complete inventory f these. The techniques used will be demon- trated using examples from five deposits and pecial emphasis will be given to the accurate rediction of tonnages of ore and waste using he new "transfer function" technique of G.

Jan 1, 1977

By Quemard D, Troncoso J

The Gordonstone Project with a capital cost in excess of $500 million will become the largest underground coal mine in Australia. The project development decision was taken on 31 July, 1990 and at 31 May, 1991 construction was approximately 35 per cent complete. The first train of processed product coal will be railed to Gladstone during December 1992. The general theme of this paper therefore will address the planning and development processes at Gordonstone particularly the interrelatedness of technical, production, construction and environmental disciplines to ensure success during operations.

Jan 1, 1991

By Muldoon T

Water sprays on mining machines are generally put there to reduce dust; however, research by the Bureau of Mines and others has shown that considerable airflows may also be generated by these sprays. This recognition of water spray-gen- erated air movement led to the "Spray-Fan" - a continuous miner auxiliary ventilation system which was shown to reduce methane peaks by a factor of 15. Recent successes and failures of the Spray Fan are reviewed. More recently, the same principles were used in the design of the "Shearer- Clearer" for reducing dust at longwall shearer operators. The original design was successful; however, a new design is now available which is more practical to install and does a much better job of holding the dust against the face downwind of the shearer. The latest research objective is to eliminate the negative impact of spray- generated air turbulence on continuous miner dust control. Most coal faces in the USA are ventilated in the exhaust mode using "line curtain", and the forward airflow on the side of the heading opposite the curtain is inevitably weak. Air turbulence generated by sprays which are incorrectly located and/or operated at excessive pressures can cause roll back - in which the dust cloud at the face is forced unwind against the ventilation and spreads over the miner cnerator. The general approach to reducing "roll back." is reviewed and art anti-roll back water spray system is presented.

Jan 1, 1983

Mining operations have been carried out at Mt. Lyell for the past century. Until the 1970's the location of the mines in relation to the surface topography has enabled the mines to drain their copious inflows of water by gravity. Deeper mining has forced the Company to undertake pumping of increasing inflows of water. A major pumping facility is being established near the base of the known ore reserves with a view to serving the future requirements of the mines. The system has a design capacity of 600 litres per second. Run of mine water will be treated in Vertical Flow Settlers to produce clear water and thickened mud, each of which will be disposed of separately. The clear water will be pumped by six 1000 kW conven- tional centrifugal pumps. The thickened mud will be removed by a Hydraulic Displacement System. The rising mains for both the mud and the clear water are stainless steel cased bore- holes.

Jan 1, 1982

The large, high grade 3000 and 3500 copper orebodies at Mount Isa lie greater than 1200 m below the surface, and partly beneath the silver-lead-zinc mining operations at the Isa Mine.Since discovery over 30 years ago, the primary data acquisition programs have been integrated with long-term copper production strategies. These potentially sizeable and distinctly separate accumulations of copper mineralisation are the only sources capable of supplementing a decline in output from the 1100 orebody in the 1990s. Within a decade these deeper copper orebodies will become the major source of copper ore.

Jan 1, 1993

By Nguyen G. H, Graham J

A laboratory-scale fluidised-bed roaster has been used to examine the effect of temperature and duration of roast on the morphology of the calcine produced from a pyritic gold-bearing concentrate. Two mechanisms of oxidation, which depend on the roasting temperature, have been identified. For samples roasted below 550°C, direct oxidation of the sulphide occurred to form hematite with a porous fine-grained concentrically-layered texture. The surface area of the calcine increased with an increase in roasting temperature in the range 400 to 500°C. For samples roasted above 550°C, the first reaction was the evolution of sulphur vapour to produce pyrrhotite, which underwent increasing grain growth as the roasting temperature was increased. This had the effect of decreasing the surface area of the calcine. The pyrrhotite was subsequently oxidised to produce hematite.Leaching studies using cyanide solution indicated that gold extraction around 95 per cent was achieved at temperatures of 500°C and above, with optimum extraction, taking into account rate and cyanide consumption in the range 550 - 700°C. Hence recovery did not decrease with decrease in surface area of the calcine. Observed gold in leached calcines was mainly enclosed in thin oxide walls of the hematite, with minor quantities enclosed in quartz and silicate minerals.

Jan 1, 1995

By R J. Butcher

Many deposits have been evaluated as potential block caves over the last 20 years due to the perceived benefit of low operating costs. However, block cave projects are typically capital intensive, with mass mining providing high throughput rates that required large investments in mining, processing and utilities infrastructure. While the key economic metrics in deciding to proceed with a caving project are typically net present value (NPV) or internal rate of return, these may not represent the best decision metrics for some companies. Where a caving project is competing for scarce capital amongst other projects in a company’s portfolio or where the caving project is the only project being evaluated by a company trying to raise capital, other metrics may be more appropriate. This paper explores the use of present value ratio and the minimising of maximum negative cash flow as suitable metrics in determining alternative strategies. Trade-offs between optimising for economic value and capital efficiency measures allow for decision-makers to evaluate potentially higher-risk, higher-capital and maximum NPV projects against lower-risk, lower-capital projects.CITATION:Stewart, C A and Butcher, R J, 2016. Block cave evaluation, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 809–816 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By Ash M

The world-class iron ore mines at Mt Whaleback, Torn Price and Paraburdoo located in the Hamersley Province of Western Australia must mine the Mt McRae Shale to obtain high grade ore from the Dales Gorge Member of the Brockman Iron Formation. The Mt McRae Shale contains a black pyritic shale lithology that reacts with ammonium nitrate-based explosives. This paper provides an overview of the problems associated with mining this reactive rock type as well as the development of a comprehensive procedure to safely and efficiently blast, excavate and dispose of this material. The strategy used to develop the procedure involved raising the awareness of relevant site personnel to the risks associated in mining the Black Pyritic Mt McRae Shale, obtaining the commitment of these personnel that a detailed procedure was required and that any procedure developed must be followed, otherwise the potential risks such as premature detonation were high. It was also necessary that an on-going training program be implemented so that all relevant new employees would be educated as to the reasons for adhering to the Black Pyritic Shale Procedure.

Jan 1, 1995