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By Jiang G

The Chinese Central Government attaches great importance to the development of its coal industry. Besides carrying out the policy of simultaneous development of large, medium and small coalmines,the main strategy is to gradually modernize coal mining areas and coalmines and to increase the output from individual coalfaces. There are particular implications, processes and main experiences of coalmine modernisation in China.Ensuring a coal output of over one M tonne/yr from one coalface is a very complicated system-engineering project which deals with a wide range of problems. The most important measure used for achieving an output of over one M tonne/yr from a single coalface is the analysis of affecting factors on coalface production by means of the theory c reliability. Thus, as far as possible , the production stoppages caused by mechanical equipment failures and other factors are avoided, the equipment recovery rate is increased and the working hours of shearers are extended so as to ensure a high output and high efficiency.

Jan 1, 1991

Maintaining and improving the economics of open pit mining in the future requires understanding of the characteristics of open pit mining that are different to other mining or business activities, designing mines in the first place to be less susceptible to changes in these important characteristics, and adopting strategies which yield reliable returns despite unforeseen change. Planning and production personnel require guidelines and performance standards that are based on sound economics not solely on production criteria. The guidelines adopted for long-term implementation must assume a declining price for mineral products along with declining real costs, with research efforts directed at development of both evolutionary and revolutionary ideas aimed at implementation. Decision-making must focus on risk and probability criteria rather than just simple return-on-investment criteria, and the approach for management of personnel must support the higher level of communication essential for fast decision-making in the new environment of continual change.

Jan 1, 1992

Classifications of Ni-Cu deposits are based on petrology, geochemistry and the geotectonic setting of host igneous bodies (Naldrett and Cabri, 1976; Besson et al, 1979; Nadrett, 1989). The four major classes in Naldrett's (1989) division rest on the geotectonic setting of the igneous complexes and the classes are further subdivided on the basis of the petrology and geochemistry of the intrusion. A more common subdivision of mafic and ultramafic igneous rocks is based on the environment of rock-forming processes, endogenic or exogenic, intrusive or extrusive, and this subdivision has been applied, in practice, to the classification of sulphide Ni-Cu deposits, too. The extrusive deposits, Class I in Naldrett's (1989) classification, are directly related to volcanic processes whereas all the others refer to the intrusive environment. This paper looks at the differences between the extrusive and intrusive groups of Ni-Cu deposits and presents generic, genetic and structural features of the intrusive group.

Jan 1, 1996

By P Heppner, J Schell, R Newell

The effect of various methods of conditioning on subsequent flotation performance was reviewed, where complex interactions involving attrition, aggregation, dispersion and surface cleaning were discussed. The present study focussed on the influences of standard laboratory cell conditioning, ultrasonic dispersion and high intensity conditioning on copper mineral flotation characteristics. The effect of substituting demineralised water for the WMC plant water was also examined. It was found that higher copper concentrate grades were often obtained using demineralised water, however the use of high intensity conditioning in mill water gave the highest copper recovery and highest flotation rate constant. This process should be considered if copper grade and recovery in this section of the plant drops, especially if the drop is due to surface oxidation of the copper minerals. Other methods of conditioning (cell and ultrasonic techniques) improved the rate of copper flotation above that obtained in the virtual absence of conditioning, showing the importance of conditioning on subsequent flotation operations.

Jan 1, 2000

The global recession of the 1980s drove commodity prices down and intensified cost competition. The 1990s saw a restructuring of the mining industry with the survivors adopting new technology, significantly increasing workplace productivity and reducing capital and operating costs. Major changes in mining industry business strategies evolved in the late-1980s including the development of miner - supplier - manufacturer - partnerships, cultural changes in work practices and common goals between the partners to reduce the cost of production. These industry trends are putting new demands on mining machine manufacturers and dealers both on the `hard' side of the machine business, such as research and product development programs, and on the `soft' side in terms of business processes, use of human resources and communication. The paper describes several mining industry trends as identified by a large supplier to the industry, and discusses the impact they are having, and will have, on mining machine development and the provision of product support services to the industry.

Jan 1, 1995

By R F. Johnston, I D. Sommerville

This paper presents an overview of the researches carried out in our laboratory on the application of plasma in recovery of alloy elements from waste slags and the treatment of lean ores, which are examples of advanced materials processing. After briefly reviewing the early work on the reduction of nickel, chromium, manganese, vanadium and titanium oxides, and a short investigation of the reduction of titanium oxide from the slag resulting from the blast furnace smelting of a titanomagnetite ore, the paper concentrates on the more recent studies on the reduction of an Australian scheelite. In some of these experiments, aluminium was used in addition to carbon as a reductant, in virtually all cases complete reduction was achieved within a relatively few minutes even with carbon alone during plasma processing. It therefore appears that this technique provides a possible processing route to facilitate the recovery of valuable alloying elements from non-traditional sources, or to permit process step elimination.

Jan 1, 2000

By Gregg PEH, Stewart RB

Reclamation field trials commenced in 1985, two years before the granting of the Mining Licence. The level of pasture production on varying soil depths (0 cm, 5 cm, 15 cm and 25 cm) overlying both tailings and oxidised waste overburden was assessed. After seven years, the rate of increase of N, C, P and S, losses of S and P and pH changes were investigated on the plots where grass seed was sown into bare tailings. It was determined that on these plots it would take approximately 24 years to reach the original carbon and nitrogen levels at the mine site.

Jan 1, 1995

By Di Pasquale S, Osler GD

Mount Isa Mines Limited recently commiss ioned an 800 tph Heavy Medium Preconcentration Plant for lead/zinc/silver ores. The decision to build this plant was made in late 1979 based largely on investigations conducted in the Company's pilot plant on a variety of ore types including Hilton ores, between 1972 and 1978. The paper reviews the historical develop- ment of the pilot plant heavy medium circuit through this period and illustrates the extent to which this work impacted on the final design criteria. This review also includes a description of plant operation, manning levels, process equipment and metallurgical performance Achieved.

Jan 1, 1978

Currently there are in excess of 200 companies listed on the New Zealand Stock Exchange and the total market value of all the listed shares amounts to $4.6 billion. The number of listed mining companies stands at nine and with a market value of $35 million accounts for less than one per cent of the total market capitalisation. In comparison, the Australian mining and energy sectors account for nearly 50 per cent of the total market capitalisation, which currently exceeds A$41 billion. Surprisingly the share markets in both countries were primarily founded on the discoveries of minerals last century.

Jan 1, 1982

Consideration is given to the factors affecting raceway activity and the hearth design of a zinc-lead blast furnace. Results of measurements made on operating furnaces are given and comparisons are made with published data both from operating iron blast furnaces and from dynamic models of the zinc-lead blast furnace. Indication is given of the methods used for assembly of the relevant information into the specification of a commercial furnace design. A discussion on the comparative merits of furnaces of circular and essentially rectangular plan is given based on the concepts explained in the paper.

Jan 1, 1981

This paper suggests the models for determination the optimum life of machines on the basis of sum and difference of investment and maintenance costs. The economic-mathematical models are based on complex percentage method taking into account the time factor of referring cost. The following strategies of maintenance policy have been considered in machines repair: a strategy without investment, a strategy with continuous investment and a strategy with step-like investment. The effect of value of investment in repairing and time interval of investment on optimum machine exploitation life has also been considered. An illustrative example is presented.

Jan 1, 2003

Until recently, the Australian mining industry received unquestioning encouragement from both State and Federal Governments. Now governments adopt a more questioning outlook about, for example, the proportion of local mine income accruing abroad, about the contrib- ution of the industry to public revenue, and about the industry's impact on the environment. This paper reports on attitudes at a recent industry-government-academic conference on planning and problems for the minerals sector in the next decade and beyond. It also examines a government policy review in Canada, which has undertaken some change in direction of mineral policies in the last few years.

Jan 1, 1977

The Olympic Dam Mine is a large, mechanised, underground operation currently producing 2.2 million tonnes-per-year of copper/uranium/gold ore. The mine is accessed via one shaft and one service decline. An additional 13 raise bored ventilation shafts have been completed to-date.Ventilation requirements are stringent in order to provide adequate dilution and removal of diesel fumes, radon gas/daughters and heat generated from both engines and wall rock.Due to the nature of the orebodies, the mine workings will continue to expand laterally necessitating the addition of at least one major surface raise every year.

Jan 1, 1992

This data is intended to provide a quantative cost comparison of one 40 800 kg. pull down rotary blast hole drill versus two smalter drills in the 18 100 kg. pull down class. While this cost analysis is affected by blast design, this paper is not intended to be a treatise on blasting theory and therefore places more emphasis on costs than on blast design. All costs, prices and production rates in this paper are estimates and should be used for comparison purposes only. The drills are sized in order to maintain a production rate sufficient to stay ahead of a dragline that is excavating in an average overburden (sandstone and shale). The large drill will use 270mm bit and penetrate at a rate of 0.012 m/s (scheduled basis). The small drill will use 170mm bit and penetrate at a rate of 0.010 m/s (scheduled basis).

Jan 1, 1986

By S Servant, T J. Bidwell

Paste backfill technology is gaining rapid acceptance in the Canadian mining industry. The authors were able to work on four different mining sites employing paste technology in their operation. In each site the paste backfill is prepared with very fine tailings containing significant amounts of sulphur minerals. The research program involved laboratory testing on samples prepared in the laboratory, on control samples obtained at the backfilll plant during pouring into the stopes and on core samples obtained from drilling in backfilled stopes. The laboratory testing provided detailed knowledge of the mechanical behavior of the paste backfill. The need for a means of measuring the in-situ mechanical properties of the backfill became clear. A review of various trials published in literature and an evaluation of available technology suggested the Cambridge Self-boring Pressuremeter. A first field campaign confirmed the efficiency and dependability of this instrument leading to the conclusion that it offers a very good method for the in situ measurement of paste backfill properties.

Jan 1, 1998

The energy crisis and the general increase in fuel prices have changed the position of coal in the world. Countries need to review their policies on coal, depending on available reserves and their accessibility. On the demand side, a distinction should be made between the steel industry's specific demand for coking coal and the needs of power stations where coal is used in competition with other sources of energy. Coal consumption in these two sectors is expected to increase considerably over the foreseable future. Some countries have sufficient coal of their own to meet this increased demand but others will have to rely on imports. As a result, the tonnage of coal transported by sea may double by 1985. The coal industry lacks flexibility. The opening of new mines and the construction of a transport system to ship the coal takes time. This time-lag, coupled with the enormous expenditure involved, makes long-term contracts between producers and consumers essential.

Jan 1, 1975

By J Shooter

Pezzimenti Laserbore designed, fabricated and commissioned the first microtunnelling machine in Australia in 1986. The System was initially a very basic one, developed in isolation to the overseas explosion in microtunnelling growth headed by Japan and Germany. Market needs in Australia have demanded increasing flexibility in microtunnelling capacity-longer distances, variable ground conditions and larger diameters. The one constant throughout the development process is in maintaining high accuracy û the attribute which most readily differentiates microtunnelling from other limited steering techniques.This paper will highlight the features of microtunnelling by drawing on case studies of completed projects.

Jan 1, 1999

The first introduction of automatic control systems for flotation occurred about fifteen years ago. The early control work coincided with the introduction of on-line assaying using XRF techniques. This OSA availability, coupled with the emergence of small digital computers suitable for process control in the late 1960-s, meant that the necessary process information and control hardware existed for flotation control experiments. A period of intensive research related to flotation control. ensued. A great deal of effort was devoted to the development of mathematical models of flotation. Plant experimentation sought to understand the effects of a range of flotation variables on the process. Finally, control loops were proposed and plant tested. An evolutionary pattern emerges when the range of flotation control installations is examined. The earliest systems had as objectives process stabilisation using reagent control. There were also some early attempts at flotation optimisation procedures, again using reagent variation. Current work is still associated with the same objectives. One of the difficulties with flotation control has been to recognise and define clear and precise control objectives. More emphasis is now placed on cleaner control which has the advantage that the objectives are usually well defined. A number of flotation control systems which cover a range of control system types is discussed. Based on this accumulated experience,a list of good and bad practice in flotation control is Proposed.

Jan 1, 1983

I stand here as a financial advisor who has been particularly close to the whole concept of reporting, independence and all the issues that are brought together in Release 149. However, I was asked to introduce this session by dealing with matters of Prospectuses, Part B's, 3J3's, 12G's and other requirements to report. Now I find it very interesting that one of the keynote issues is whether or not one should have a panel from which one chooses the so-called expert, and this is to deal with the question of independence.

Jan 1, 1989

By Koppe J. C, Dimitrakopoulos R, Costa J. F

Grade control and the delineation of ore/waste in open pit operations is traditionally based on the comparison of estimated grades with an economic cut-off. This paper deals with an alternative approach to grade control based on estimating gra

Jan 1, 1998