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The Filblast Cyanidation Process incorporating intense high shear mixing, high gas mass transfer efficiency and high oxygen concentrations under conditions of elevated pressure has now been been successfully applied in gold cyanidation mills since May 1993. The first commercial unit had a slurry capacity of 110 cubic metres per hour. Since then 230 and 450 cubic metre per hour units have been installed and a 1000 cubic metre per hour unit has been designed. Laboratory and pilot plant Filblasts have also been built.The reactor is a robust, compact in-line or end-of-line device and may be constructed out of a wide range of materials including wear and corrosion resistant alloys and ceramics. The Filblast Process may be applied to high temperature leaching of refractory gold ores and base metal concentrates.

Jan 1, 1997

The concentrated efforts now being directed towards the development and application of monitoring and control techniques have now resulted in their widespread use in UK mines together with evidence of benefits resulting from their application. There is little doubt that the longwall method of producing deep mined coal will continue but will be made more reliable and efficient with the aid of control technology. The major fields of research and development work are concerned with planning and design of mines and mining equipment; management and engineering information; and automation of coalface, tunnelling and transport systems. The principal achievements now in widespread use are: the standard computer system MINOS, widely applied to mine transport, coalfaces and mine environment; extensive use of machine condition monitoring leading to condition-based maintenance; underground automation of conveyor systems and guidance systems for ranging drum shearers and boom-type roadheaders are being widely introduced.

Jan 1, 1985

Field investigation of surface subsidence events associated with both active and abandoned underground coal mines in the United States has established criteria that enable the prediction and classification of mine-related subsidence. The key was establishing the role of geology in all types of subsidence and the recognition of beam subsidence in specific geologic settings. The classification is based on overburden thickness, variations in stratigraphy, topography and mine plan. Types of subsidence are Pit, Room, Sag, and Beam. Pit subsidence is associated with three geologic settings: shale overburden, seasonally wet unconsolidated overburden, and perched water table in unconsolidated overburden. Room subsidence occurs where the roof across the width of the room fails to the surface and a shallow depression develops.

Jan 1, 1992

The strategy of adjusting operating conditions to maintain optimum process performance as the feed quality varies - adaptive optimisation - is being investigated by computer simulation of chemical processes for the treatment of ores. Those ore-process systems that are most likely to yield substantial benefits from adaptive optimisation are being identified as a guide to the selection and development of systems for practical application. The generalised mathematical representation of the cost structure, ore quality variations, process kinetics, reactor characteristics and operating variables for ore-process systems is described. Results are summarised for temperature, reagent concentration or residence time as the manipulated variable. For almost all systems, adaptive optimisation was economically beneficial, although a few exceptions have been identified where there is a significant synergistic effect between poor-performance and good-performance materials in a blended feed. The sensitivity of the benefits of adaptive optimisation to a range of economic and technical factors is summarised.

Jan 1, 1985

Material sampling theory is well established in mineral process monitoring, improvement and control. It has been much enhanced by fundamental contributions due to Gy. When GyÆs sampling theory is applied to sampling inspection and monitoring, it provides estimates of average quality or extent of contamination. It also provides estimates of uncertainty, but these often ignore uncertainty in estimated variograms or other measures of variability. Risk assessment is often an implied task in sampling inspection and quality monitoring. A valid technique of risk assessment needs to take into account the uncertainty in the variational measures themselves. Standard statistical tolerance limit calculations which do take such uncertainty into account can be adapted to develop a technique for handling uncertainty in variational measures such as the variogram. Data from a published example is used to illustrate the technique.

Jan 1, 2005

In Europe there are many regions, where coal or lignite is mined with surface methods. In most of these regions coal/ lignite is mined below groundwater table and mining opera- tions require pumping big volumes of water. Drawdown of groundwater table has influence on surface water and ground- water on adjacent areas. Mine drainage requires purification and its discharge changes flow in existing streams. Some of mine water is used by mining companies themselves, some is used by other industries, some for communal purposes and some for irrigation. However, majority of mine water is dis- charged to rivers without use. The above issues are discus- sed on the background of general, technical and water charac- teristics of such regions in B European countries. Conclu- sions and prospects for future complete the paper.

Jan 1, 1988

A number of small copper deposits occur in the Pernatty Lagoon-Mt. Gunson area. Textural and mineralogical differences distinguished the lagoon sulphide deposits, which occur in a water filled basin of permeable bedrock immediately under the lagoon floor, from the largely oxidized deposits which occur in the low hills adjacent to the lagoon deposits.Groundwaters are carrying copper, and to a lesser extent zinc, downstream to the lagoon. Several species of sulphate-reducing bacteria are widespread in the groundwaters and lagoon muds.It is suggested that copper sulphides were first deposited at the same time as, or soon after, the host Proterozoic sediments, and that during the present cycle of erosion the lagoon deposits may have been enriched, or largely formed, by bacterial precipitation of copper sulphides from laterally migrating cupriferous groundwaters.

Jan 1, 1971

Equilibrium in the reaction H2(g) + [%0] (in liquid copper) = H2O (g) was investigated at temperatures between 1200 -and 1350°C with p(H2Oj/p(H2) ratios between 1 to 15. A semi-microbalance was used for direct measurement of dissolved oxygen in molten copper. Oxygen was found to obey Henry's law under the experimental conditions used. The standard free-energy change for the above reaction is given by Equation 1where 1 weight per cent solution is the standard state for dissolved oxygen.For the dissolution of oxygen in copper according to 1/2 O2(g) = [%0] (liq. Cu), the standard free energychange is given byEquation 2.

Jan 1, 1973

The processes most likely to be adopted for beneficiating ores or concentrator streams containing a large proportion of particles finer than 10 um are froth flotation, selective flocculation, wet magnetic separation and selective leaching. Flotation will be made more efficient for very fine particles if ways can be found to selectively flocculate the valuable mineral beforehand (floc-flotation), to produce smaller bubbles and to reduce entrainment of ultrafine gangue. Schemes for selective flocculation have proved difficult to implement because of the delicate balance between surface forces (electrostatic, dispersion, hydrophobic) and hydrodynamic forces, that determines flocculation, and the changes which occur to particle surfaces through hydrolysis, oxidation-reduction and cross-contamination between minerals in aqueous suspensions. The search for a better understanding of selective adsorption of flotation collectors and flocculants continues and will be particularly important for the practical success of selective flocculation and selective magnetic coating.

Jan 1, 1986

By J Brown, C Roberts

The scope of this paper is to recount the development of segmental linings used in tunnel construction, starting with its inception as an improvement to the brick-lined tunnel approach of Brunel in England and moving through the history and development to the present day, before finishing with a few insights into what the future might hold. The paper also discusses the motivation for the relatively recent move towards replacing conventional steel reinforcing cages with steel fibres and the reasons why steel fibre reinforced concrete (SFRC) is rapidly becoming the material of choice for manufacturing precast concrete segmental linings.

Jan 1, 2008

By P Alspach, R Buxton, C Morgan, C Ross

Mining companies worldwide have an increasing interest in restoring indigenous ecosystems following mining. Low levels of plant nutrients and organic matter, pH extremes, heavy metals, physically challenging media, and difficult climatic conditions all hinder revegetation of steep rockdump slopes. Our techniques use colonising pioneer plants to accelerate natural soil development and plant succession processes on minesites that are difficult to revegetate with locally sourced plants by traditional techniques. Suitable treatments and pioneer species must first be identified for each rocktype. Field trials at the Stockton Coal Mine in Buller have shown that successful acceleration of moss and pioneer plant establishment is possible. Best plots showed a mean of 15 per cent moss cover and 3.3 per cent vascular cover after 12 months compared with 0.1 per cent and nil respectively for controls. Techniques have been extended to field-scale trials, using hydroseeders and dryblowers. These techniques show potential for practical land rehabilitation, whilst conserving local biodiversity.

Jan 1, 2003

By Rintoul AH

Studies of many types and purposes are being carried out constantly by mining, minerals processing and other operating companies. Frequently, the staff requirements and special skills lie outside the resources of the operating companies, and needs arise for external consult- ing services. We examine the natures of a range of studies, the factors that influence whether they be carried out in-house or externally and then discuss the manner of execution. Aspects of both good and bad practice are highlighted in order to arrive at the basic principles that give the most benefit from study work. While the bulk of the discussion relates specifically to the execution of external studies of process plant projects, many of the observations can be applied equally to the execution of studies by one department of a large organisation for another, and also to studies of capital projects other than those involving process plant facilities.

Jan 1, 1975

A good deal of criticism has been levelled at Mines Division over the slowness of processing mining privilege applications, some of which is justified and some which is not. There are many reasons for delays in the processing of applications and not the least of these delays are caused by the applicants themselves.

Jan 1, 1982

Optimisation of mining projects is directly related to effective and efficient management of risks through the life cycle of mining projects. Effective and efficient management of risks must include explicitly all aspects of Occupational Health and Safety (OHS) through the life cycle of mining projects. This paper presents a different scale of OHS in the context of the optimisation of mining projects. Meaning of risk through the project life cycle is explained. Complex relationships between numerous risk, safety, knowledge, culture and change variables, and project life cycles are shown. The key element developed in this paper is a multi-disciplinary knowledge base that is necessary for constructive development of risk management and OHS models through the life cycle of mining projects.

Jan 1, 2003

Before exploration programmes or minerals developments are formulated, a mining company ought to assess how capital can be returned if the project is successful. A fact not well appreciated by the minerals community is that it is often difficult to get money out of many Pacific Rim countries due to special foreign exchange controls or restrictions on dividend or capital repatriation. On top of this risk are factors such as creeping expropriation through administrative, fiscal, or corruption pressures; environmental regulations; terrorists; and organised labour and political activists. Political risk is much more than just expropriation or nationalisation.Political risk factors can make or break a project in many PacRim countries and just the cost of delays and negotiations can insidiously affect project economics. This unpalatable thought, however, can be readily addressed by either legal structuring e.g. offshore proceeds accounts, offset/back-to-back currency hedges, or political risk insurance for the equity as well as any subsequent project development debt.

Jan 1, 1990

By James DG, Turner JH

This paper describes laboratory testwork for the beneficiation of a medium grade iron ore, using Wet High Intensity Magnetic Separation (WHIMS). Factors leading to the selection of machine type for this method of separation are discussed and the design of the WHIMS section flowsheet of an iron ore beneficiation production plant are described including methods to achieve operational flexibility and adequate protection of the WHIMS separating chamber. The results of the commissioning and operation of the production plant over several years are described, together with experience developed in plant operation. Data on recovery of hematite over the full range of size fractions treated is presented and compared with data in the literature. Potential methods of improving plant performance are discussed. KEYWORDS: Iron ore beneficiation, plant design, wet high intensity magnetic separation.

Jan 1, 1993

Portland cement is a finely ground mineral powder obtained by intergrinding a mixture of 95 parts of clinker and five parts of gypsum. It is the generic name for hydraulic cement a man made product which hardens in the presence of water. Today's cement started formally with a patent granted in 1824 to Joseph Aspdin, a Leeds bricklayer. He called his patented cement 'Portland' because it resembled a gray brown stone quarried on the Isle of Portland off the coast of England. The first cement to be made in the southern hemisphere is accredited to Nathaniel Wilson, a pioneer farmer who with his brother John began experimenting in 1874 with the limestone on their property near Warkworth. In 1884 they produced the first Portland Cement to be made in this part of the world.

Jan 1, 1978

Immigration has influenced Australia's development more than any other factor. As well as being critical to our economic growth and development, it has made a major contrib- ution to our population growth, to the richness and diversity of our society and to our inter- national relations. Migration from the United Kingdom has been the mainstay of our settler intake for many years, but its relative importance has declined in recent decades. Non-British European migration formed an important part of our post-war intake and, in the past few years, migration from Asia has reached significant levels - particularly through our resettlement of Indo-Chinese refugees. In planning our future immigration, it is important to look beyond short term direct economic consequences. Australia has looked to its resources for progress, but Japan, Korea, Taiwan and Singapore have achieved dramatic economic progress without resources, based on the will and dynamism of their societies. Immigration can contribute greatly to the development of a dynamic, outward looking Australian society able to make the most of our great resource potential.

Jan 1, 1982

By Hughson B

The need to prevent the sterilisation of coal stems directly from the fact that it is a non-renewable resource. In N.S.W. a vast amount of coal resource is located under major public utilities such as freeways, railways, stored waters, pipelines carrying gas, water and sewage, and transmission lines. Total extraction has occurred under freeways, transmission lines and pipelines with little or no damage. Where damage has resulted, the cost of restoration was only a small fraction of the value of the coal recovered. However, coal at present is being sterilised and perhaps lost for ever under stored waters and railways. If engineering solutions are available for mining under these improvements economically and with maximum safety, then coal should be extracted and utilised to the benefit of the State.

Jan 1, 1986

The paper reviews recent valuations of mineral properties, many of which are at an early stage of exploration. The various methods used are outlined. The problem of comparing, in terms of whether it is fair and reasonable, a highly subjective opinion of the present value of a portfolio of exploration tenements with a vendor consideration, the real value of which, in most cases, lies at some indeterminate time in the future because of the application by the Australian Stock Exchange (ASX) of escrow conditions, is highlighted. Examples are given of some of the questionable logic used by consultants in handling this difficult issue. A proposal for revision to current flotation and listing practice which, the author believes, would circumvent the problem and at the same time provide better protection for the investing public is offered for Consideration.

Jan 1, 1994