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By Brown P. L

A study has been made of the geochemistry of the Ronneburg mine district as input to the overall management strategy for the rehabilitation of the mine site. The study drew on the geological data and information store developed over the 40 years of mineral exploration and mining at Ronneburg, and on chemical data from the literature which described the chemical processes of weathering, oxidation, dissolution and precipitation of minerals. The geochemical processes were divided into three groups based on their rate of reaction. Fast processes were assumed to proceed to equilibrium and were modelled using equilibrium chemistry equations; slow processes were assumed to be proceeding at a quasi-steady state rate and were modelled using chemical rate equations; very slow processes were assumed to have no role in describing the geochemistry for rehabilitation purposes.

Jan 1, 1995

By Tyler MA

If the record of maj or proj ects in Australia is taken into account, it is apparent, the proper planning of an industrial relations strategy for many such projects has been ill considered by project developers. The recognition of the need to develop a plan from the initial feasibility study has been forced on those promoting new projects by the publicity given to the Australian industrial relations record. The delays in delivery caused by factors supposedly out of the project's control are often given for non-performance of contract and used as an excuse for limiting further development. Many of the problems experienced in project development can be overcome with sound industrial relations planning. The promises given in the euphoria of the early stages of a project relating to price and delivery often become a burden for the future because the complexities of the Australian Industrial Relations Systems are not understood or considered. The recognition by senior executives of their responsibilities in this area will contribute greatly to a new era of project development.

Jan 1, 1983

By Quast K. B

Samples of limestone and micaceous hematite have been ground in a laboratory batch mill using equal weights of either rods or balls. Values of the Schuhmann distribution modulus, a, have been shown to depend on grind time and do not remain constant as often reported. The linear reduction in a with grind time was attributed to a change in grinding mechanisms with time. The product sizing from ball milling limestone showed a bimodal distribution, but rod milling produced a unimodal size distribution. The product sizing from milling micaceous hematite was difficult to interpret due to the major influence of the shape factor on the transition from screen sizing to cyclosizing.

Jan 1, 1995

By Maxwell HW

Pacific Coal Pty Limited (a wholly owned subsidiary of CRA Limited) managed the interests of six members of a joint venture formed to mine and export eight million tonnes of export quality steaming coal from a mine developed at Blair Athol in the Bowen Basin of the Central Queensland coal fields. The mine is now operated by Blair Athol Coal Pty Ltd. Crooks Michell Peacock Stewart Pty Limited (CMPS) was awarded a project management and engineering contract for the total mine portion. Following a feasibility study, CMPS carried out an Optimisation Study which produced changes to the design of the project, thus resulting in the project budget being reduced by some A$13 million. In spite of a number of late additions to the scope of work, the project was completed at a final cost of A$148 million, many millions below the reduced project budget. The project was also completed several months ahead of schedule. Total services were provided to take the project from feasibility stage through to the establishment of an operational facility and included project management, planning and control, accounting and financial control, as well as the organisation of engineering, procurement, construction, industrial plant commissioning, and technical training matters.

Jan 1, 1986

Human creativity springs from the natural desire of mankind to know and its capability to learn. Explorers and discoverers possess these features in a high degree. They are driven by an unrelenting curiosity to go beyond the boundaries of the known, to explore into the nature of things, to reveal connections between ideas, facts, conceptions, to view things from new angles, to change perceptions. A well-known fact about the construction industry - and underground construction in particular - is that all projects are unique. The degree of complexity due to the intertwining of the variety of project-related parameters is higher than in many other industries, thus forcing contractors as well as suppliers to be truly adaptable and flexible. The enormous advantages of shotcrete as a construction and rock support process and the improvement of materials, equipment and application know-how have made it a very important and necessary tool for modern underground construction works. The development of modem wet shotcreting in particular has enlarged the field of underground construction work. Projects that were impossible to be realised, have now become practicable. Subsurface structures can be placed where they are needed, without regards as to rock and soil conditions.

Jan 1, 1995

This paper will discuss Fordertechnik dawatering screens and their application in process industries. Fordertechnik screens were designed for the dewatering of deslimed, wet fines materials encountered in the mineral beneficiation, sand and coal processing industries. However, these screens have also been used in such industries as municipal waste treatment, paper pulp, chemicals and the food industries. Fordertechnik screens are of simple design and, as a result, offer low capital and maintenance costs. The design is based on the use of twin counter-rotating vibratory motors which provide high frequency, low amplitude linear movement of the screen deck which is essential for high production requirements. Fordertechnik dewatering screens are engineered and manufactured in Australia by Mitchell Cotts Engineering under licence to Fordertechnik GmbH of Mulheim, West Germany

Jan 1, 1984

By Hall S, Upton D

WMC Resources Ltd nickel operations have expanded significantly over the last three years. Production capacity has increased at mine/concentrate, smelting and refinery processes to such an extent that WMC now ranks within the top three or four producers of nickel metal in all forms. The stainless steel industry remains the dominant user of nickel. WMC's forecast is for stainless steel production to grow at 2.8 per cent per annum off of the 1995 peak, with much slower growth in the short-term as the stainless steel inventory overhang unwinds, followed by a return to higher trend growth rates. WMC's forecast for the long-term growth in demand for primary nickel is three per cent per annum off the 1995 peak; again, slower growth in the short-term before a return to higher long-term trend rates. This projection is towards the optimistic end of the range of industry experts. It equates to a requirement for new primary nickel of 25 000 to 30 000 tonnes of annual capacity each year.

Jan 1, 1996

This paper reviews the issues of mining machinery automation with special emphasis on underground applications. Automation is desirable because it offers the following advantages: ò increased safety by reducing human exposure to hazards of underground mining; ò higher productivity; and ò reduced wear of equipment. In spite of these advantages and in spite of numerous attempts over the past several decades, mining automation has been a difficult proposition, partly because no two mining operations are exactly alike and these operations are carried out in an unpredictable environment. This is the main difference between automation in factories and in mines and that is why mining automation has been lagging so far behind factory automation. Automation is possible only when the machine 'knows' its workspace. In a factory, this workspace can be 'described' to the machine because it is sufficiently controlled. In a mine, the environment undergoes continuous change and the only way the machine can 'know' its workspace is through real-time sensing.

Jan 1, 1995

With the recent wider introduction of friction hoists of the Koepe type. for winding from depths of more than 3000 feet it has been found that failure by fatigue is the most common form of rope deterioration. Large numbers of wire breaks occur near the centre of the rope cross-section and it is difficult to detect these with certainty using the preferred d.c. magnetic test. For best results with conventional search coils their dimen- sions should be related to the typical wire break field pattern surrounding the longitudionally magnetised rope. The field of a broken wire was experimentally determined, using a Polish type MD6 Defectograph wire rope testing magnet and a short prepared length of rope with a movable simulated broken wire. The external field distortion perpendicular to the rope was measured by means of a gaussmeter and Hall probe. The advantages of this method are that terrestial magnetism and inherent rope "noise" have no effect on the results.

Jan 1, 1971

By Chamberlain A. C, Fisher N, Avraamides J

The thermal decomposition of sodium ethyl xanthate (SEX) adsorbed onto activated carbon was studied by coupled thermogravimetric analysis-Fourier transform infrared spectroscopy (TG-FTIR). Two discrete mass losses were observed, in the temperature ranges 100 - 230¦C and 200 - 340¦C. The same two gases, carbonyl sulphide (COS) and carbon disulphide (CS2), were the main gases evolved in each of the mass losses. Samples of activated carbon from two industrial plants were obtained and analysed by TG-FTIR. COS and CS2 were not detected in one of the samples. The other sample did show evidence of COS and CS2, which indicated that fouling of the carbon by SEX was still present. Other organic compounds were detected in the evolved gas stream of both samples, indicating the presence of organic reagents other than SEX.

Jan 1, 1996

Previous methods for the assessment of the explosive potential of gas mixtures have required the plotting of apeexplosibility diagram. These became cumbersome if a large -number of assessments of various sampling locations over a period of time wererequired. This may make the approach of a dangerous situation more difficult to predict. With the aid of a programmable calculator, a new method for the rapid assessment of the explosibility of coal mine sample gases has been developed. This method does not require that an explosibility diagram be drawn to indicate the explosive status of a gas mixture. Simple Cartesian co-ordinates representing the explosive potential of,mixtures are obtained, which may readily be plotted to show changes with time.

Jan 1, 1981

Drilling has disclosed a sequence of Cainozoic sediments immediately to the west of the Ediacara mineral field containing little or no dolomitic debris in the lower and middle sections, but with gravel beds of dolomite derived from local rocks in the upper part. It is suggested that the lower and middle sequence of Cainozoic strata was deposited over the area of the Ediacara Range, and that this range was uplifted, probably as a horst block, during Quaternary times and was first exposed to subaerial erosion during the upper Pleistocene epoch.Lower Cambrian dolomites with associated stratiform lead mineralization, which formed the target of drilling on the western downthrown block of the Ediacara Fault, were eroded before deposition of Cainozoic sediments.Intense leaching of basal Cambrian dolomites around the periphery of the Ediacara Basin took place during Mesozoic and Tertiary times. This leaching process has resulted in enrichment of copper and lead mineralization in a thick marginal zone of residual clayey material overlain by dolomitic collapse breccia. These zones of leaching and enrichment were preserved under Cainozoic sediments which have subsequently been eroded. The Ediacara Fault appears to have been a major conduit for mineralizing fluids and is the main lineament of the Torrens Hinge Zone. Contemporaneous movements on this fault have controlled rates of depositionand thickness of sediments across the fault during Adelaidean and Cainozoic times. Though latest movements of this fault have been west block down, the predominant movement has been east block down with associated thickening of sediments to the east in the Adelaide Geosync1ine.

Jan 1, 1972

The estimate of an ore reserve is a vital statement made about a mineral occurrence by an evaluator. It is important that such a statement communicate reality to all groups involved in a mining project, be they technical, financial, company directors, Stock Exchanges or the public. Ore reserve statements should state both resources and recoverable ore reserves. Resources may be important in very long term considerations, (because mining, metallurgical technology and economics change with time) but recoverable reserves are todays reality. The important factors contributing to recoverable reserves (in a general sense) are geology, mining method (and its impact on dilution and ore loss), metallurgical recovery, costs and commodity prices. These all need to be reflected in the ore reserve statement. In this paper recoverable ore reserve concepts across a wide range of orebodies are considered and discussed with respect to geology, mining method and ore reserve calculation procedures.

Jan 1, 1987

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

One of the features of modern life has been the increasing speed of change. We see this in many facets of activity, but in few areas more clearly than in the financial sector. The speed of communication and the advent of screen trading have made world markets one.We have titled this presentation "Cycles". It has been the conventional wisdom that Economies, Metal Prices, Equity Markets, etc. move in cycles. The objective of our presentation is to examine these cycles, to comment on the interrelationships, and to postulate where we are in The Current Cycle". We will draw conclusions as to where one should direct effort in the Mineral Scene over the next decade or so.Throughout this discussion we will use various terms to describe Time. The "Short Term" is typically meant to refer to the next six months: the "Medium Term" is one to two years; and the "Long Term" is the three to five year horizon.

Jan 1, 1990

By McManus D

Situations where in-pit bench stripping methods are favourable are introduced. Examples from Peak Downs Mine are used as a guide to the range of methods available.A number of geological and geotechnical conditions adverse to successful in-pit bench stripping are described. In all cases bench, floor, and/or final lowwall instability can develop and compromise the economics of extraction.

Jan 1, 1992

An increase in the silver to gold ratio with increase in depth in the main ore shoot of the Crown-Crescent lode in the Emperor gold mine, Fiji, was found to be due mainly to vertical zoning of gold-silver tellurides. The zoning resulted from a two-stage sequence of ore mineralization.The application of some recent studies of the synthetic Au-Ag-Te system to natural gold-silver telluride assemblages is discussed.

Jan 1, 1971

By G Swayn, J Harpley

Spent Pot Lining (SPL) is an unavoidable waste product of the electrolytic process in the smelting of aluminium. SPL is considered to be a hazardous waste in various countries because it contains significant quantities of absorbed fluoride along with traces of cyanide. The disposal of SPL has been primarily in landfill because of difficulties in the development of a successful techno-economic SPL treatment process. Increasing concern about SPL landfilling practices is resulting in regulations in some countries to ban this form of disposal. As a consequence stock piling of SPL is occurring in an increasing number of countries pending the development of a successful treatment process. In 1992 Portland Aluminium investigated a SPL treatment process based on pyrometallurgical technology and approached a company called Ausmelt in Dandenong, Victoria, Australia, to ascertain if their submerged lance technology furnace process would be suitable to treat SPL. This approach resulted in Portland Aluminium, Alcoa and Ausmelt personnel working together on trials during 1992 - 1994 in Ausmelt's demonstration furnace to produce a slag and off gases containing hydrogen and sodium fluoride. The trials also evaluated the effect of oxygen enrichment to increase the concentration of hydrogen fluoride and the ability to recycle sodium fluoride particulate produced as the furnace off gases cooled. Other separate developmental work by Portland Aluminium, using CSIRO, resulted in the production of aluminium fluoride from the offgases from the pyrometallurgical process. The results of these projects influenced Portland Aluminium and Alcoa to authorise up to $A26 400 000 in December 1995 to construct a Research and Development processing facility to treat SPL at Portland. The Portland Aluminium unique gas treatment process converts hydrogen fluoride in the furnace offgases to aluminium fluoride in a multistage fluidised bed reactor, designed by Portland Aluminium. The aluminium fluoride produced in the reactor has been trialed successfully in Alcoa's aluminium smelting process as a replacement for imported aluminium fluoride. The installation in mid-2001 of a slag granulation system has enabled the production of a granulated vitreous slag having leachability qualities that conform to Victorian EPA criteria for the unrestricted use of the granulated vitreous slag from 'The Alcoa Portland SPL Process'. The unrestricted use of the granulated slag successfully completes 'The Alcoa Portland SPL Process' which treats the hazardous waste material SPL and converts it into non hazardous useful products.

Jan 1, 2002

Much of the theory upon which the Sublevel Caving (SLC) method is based was developed in Scandinavia many years ago. It was based mainly on æbinÆ theory and æellipsoid of drawÆ configurations derived from sandbox models. In many cases, classical SLC layouts influenced by these early theories obtained relatively poor results. Early dilution entry, low tonnage factors and low recoveries were commonly experienced. SLC soon gained the reputation of being a high dilution, low recovery and development intensive method. This led to SLC falling into disfavour generally, other than as a pillar reclamation method used at the end of the life of mines. More recently a number of mines, notably those in Australia, have adopted SLC as a primary extraction method and have achieved good recovery results. The reason for the better results is believed to be an outcome of modifications in some of the basic design parameters and operational procedures. This has led to questions being raised regarding the original æbin theoryÆ assumptions and classical SLC layout designs. It is clear that the fragmentation and flow characteristics occurring in a choke blast situation (compaction of waste, variable size and shape of fragmentation throughout the ring) conflicts significantly with the assumptions of regular loose flow of uniform, fine grained, material in a bin. Interactive versus independent draw conditions can also materially effect the outcome of a SLC operation. The good results obtained more recently can only be explained by using ænewÆ models of behaviour, which have to a large extent been borrowed from block caving. If these models are correct, they point to a number of design and operational changes that can be applied to improve the effectiveness of SLC. This paper discusses the factors that may not have been fully considered in early SLC design and modelling. It emphasises the importance of delayed dilution entry as a primary objective of sound SLC design and provides a basis for efficient SLC design and operation.

Jan 1, 2000

The paper contains the publication of timber shapes recovered from the Burra Mines during open cut operations in the 1970s. The timber was in the process of being disposed of for fire wood. All timber shapes still in existence in September 1990 were drawn.The collection revealed a number of different types of caps and legs. There were also end plates and wall plates from what appeared to be a hanging sets of shaft timber.

Jan 1, 1993