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By U E. Sibilski

A pilot plant evaluation of the Savmin process, for the purification of mine water was commissioned by Anglogold and conducted at the Stilfontein Gold Mine, Margaret Shaft at Stilfontein in the North West province of South Africa. The purpose of the project was to obtain the operating conditions and operating costs, to produce different qualities of product water, as well as design parameters for upscaling to an industrial plant. The project was undertaken by AngloGold and Mintek of South Africa.

Jan 1, 2003

By Lu Fujun, Chen Xuewei

This paper will analyse the cause-effect relationship of the main factors influencing the production of the fully-mechanised coalface by mainly using the basic system dynamics theory. On the basics of the analysis, the simulated model of the sy

Jan 1, 1998

By G Hobart

Laboratory flotation tests were conducted to investigate the role of pH, zinc sulfate and potassium metabisulfite in the flotation of galena and marmatite in the Broken Hill orebody. Marmatite was depressed under alkaline conditions alone, however the addition of the two depressants, either individually or combined, resulted in the greatest selectivity. The use of zinc sulfate under alkaline conditions resulted in good selectivity whilst maintaining a high lead recovery. The addition of potassium metabisulfite under alkaline conditions reduced zinc recovery, but high additions reduced lead recovery. The addition of both depressants at alkaline pH produced the best result, with a lead concentrate of 72.6 per cent at 98 per cent recovery with less than four per cent zinc recovery.

Jan 1, 2005

The kinetics of the hydrogen reduction of iron oxides in granular calcined bauxite were studied at 550-1,050°C in a shallow bed reactor. The iron oxides behaved as a dispersion of particulate iron oxide in a porous alumina matrix in which the iron oxide particles were reduced independently. The observed rates of reaction were found to be virtually independent of the bauxite grain size. At 800,°C and above, the reduction was multistage, Le.1. Fe203 +2Al203 (matrix) ?2FeAl204, and2. FeAl204? Fe0 +Al203.Reaction 1 was very rapid. Reaction 2 was much slower, the latter stages being controlled, at least in part, by phYSIcal changes of the Fe0 and a-Al203 produced in the reaction. Owing to the observed nature of the material, the reaction rate controlling steps could not be determined.

Jan 1, 1972

Modern off-highway trucks have evolved over 30 years from small 20 ton units to vehic- les with capacities of up to 170 tons. Diesel engines are used by all manufacturers while transmissions are either mechanical or electri- cal. Development over the years has kept pace with component availability from engine, trans- mission and tyre manufacturers.Computer simula- tion studies are recognised for purposes of vehicle evaluation and costing under various op- erating conditions. Several manufacturers are currently manufacturing or evaluating vehicles with capacities of up to 260 tons. This paper describes the essential facts associated with the operation of off-highway trucks of the rear dump type in the mining industry.

Jan 1, 1973

By Angove JE, Johnson GD

Sulphide concentrates are produced in a wide range of mineral processing operations. In the case of base metals they are further treated by smelting and/or hydrometallurgical techniques. In the case of refractory gold ores, sulphide concentrates containing gold are roasted or oxidised by various hydrometallurgical processes. This paper discusses the development of the Activox(R) Process which can provide an alternative method for treating sulphide concentrates. This process consists of fine or ultra-fine milling, followed by mild pressure oxidation to produce solutions of base metals or to liberate refractory gold. Base metal solutions (eg of nickel and cobalt) can be further processed by solvent extraction and electrowinning, while refractory gold can be recovered by cyanidation. The economics of the Activox(R) Process are often better than alternative oxidation techniques.

Jan 1, 1993

The production of copper by the Outokumpu direct blister process commenced in July 1988. The problems and incidents encountered in commissioning the main smelter equipment are outlined. Early difficulties were encountered in process control, hot metal handling, dust buildup in the off gas handling equipment, waste heat boiler tube failures, foam over of hot metal into the waste heat boiler and failure of ancilliary equipment.

Jan 1, 1989

The Victorian State Government recognises that the extensive brown coal deposits in Victoria are one of the State's key competitive strengths for economic development. The unique properties of the coal, together with the ease of open cut mining, make it suitable for a variety of new applications. Research and development activities are centred around applications which take advantage of the natural attributes and unique properties of the coal. The high reactivity and low ash content of the coal led to its selection for the Japanese brown coal liquefaction pilot plant currently operating in the Latrobe Valley, with support from the Victorian Government and the Coal Corporation of Victoria. Research and development of new brown coal based products together with many other areas of applied and fundamental research are being conducted in Victoria by Government research organisations, tertiary insti- tutions and private industry, with the objective of establishing new indus- trial developments based on Victoria's vast brown coal resource.

Jan 1, 1989

New Zealand's Land and Income Tax Act 1954 contains unique incentives for companies engaged in mining certain specified minerals or petroleum. Sections 152 and 153 provide for the taxable income of such companies to be based not on profits made but on dividends paid to shareholders. A significant saving in tax results, particularly where profits are not distributed: but the Act attempts to ensure that undistributed profits are used for further mineral exploration and development. To encourage investment in the mining industry, persons taking up shares in a company mining for the specified minerals or petroleum are entitled to a one-third deduction in respect of monies paid on the shares and used by the company for its purposes; and company shareholders may make loans to the company and write-off such loans for tax purposes to an amount of up to half their taxable income. Maximum utilisation of the tax incentives calls for careful consideration as to whether a mining or petroleum company should be financed by way of loan capital or share capital.

Jan 1, 1971

By Sturgul J. R

ZC Mines investigated a proposal to replace the present underground train haulage system with rear dump trucks. The number of rear dump trucks required to achieve target output and the required mix of trains and trucks during the changeover was of importance to the designers, and a GPSS computer simulation model of the operation was constructed using GPSS/PC, a recent form of the language for the personal computer. Three models were 'constructed to simulate initial and final configurations of underground haulage systems to transport ore from ore passes to the crusher and then to the skip for transport to the surface. The initial model simulated train operation on two levels and rear dump truck operation on a third level. The second model simulated rear dump truck operation on two levels with ore being loaded through the crusher to the skip as in the previous case. The third model replaced the rear dump trucks on the lower level with a train to establish the relative merits of the two methods of transport. The simulations identified equipment numbers, required operating hours and critical points in the operation which can then be addressed by the mine designers.

Jan 1, 1988

By Durao F

A multi-layer feed-forward neural network was trained (using the error back-propagation algorithm) to learn a subset of rules designed to stabilise the performances of the copper flotation section of a complex sulphide processing plant and then tested in order to evaluate its expert performances. Two types of neural networks were compared: the classical ones, fully connected between one layer and the adjacents (with different architectures), and entropy networks, partially connected and generated according to a methodology that simplifies its building up. The advantages and drawbacks of both were analysed and compared with classic (rule based) expert systems.

Jan 1, 1995

FIRST TOWN PLANNING PROPOSALS Initially, accommodation at the minesite was provided at the Pastoral Homestead situated some seven kilometres north-east of the mine and between 1963 and 1966 was the base of the exploration camp. Tents were used for sleeping of 100 men and the Homestead used for dining and office facilities. With the beginning of ore production and shipment due to commence in 1969 a permanent town location was sought. Early town planning studies had been commissioned by Amax Inc. and Colonial Sugar Refining Co. Ltd. and in 1967 The Broken Hill Proprietary Company Ltd. took over the responsibility for putting them into effect. The location chosen was about four kilometres due east of the mine. Certain dominant factors influenced this choice. It was near enough to the mine to share services, yet far enough away not to be affected by dust and noise and received the additional shelter of a range of hills separating it from the mine. A predominant slope to the east provided good drainage and the ground was easy to excavate for services.

Jan 1, 1976

By Callcott R

Prediction of raw coal size distributions and those generated by processing are examined using spreadsheets and the matrix analysis of breakage processes. Run of mine coal size distributions are predicted from the lithotype properties using a

Jan 1, 1998

By Just J, Nguyen G, Dunn J. G, Graham J

A sample of pyritic gold concentrate was investigated by wet chemical and electron optical techniques. Sub-samples were roasted in a laboratory scale fluidized bed roaster in the temperature range 400-700¦C. The calcine was characterised, and cyanide-leached using a standard bottle rolling test. Gold extraction efficiencies varied with roasting temperature. At temperatures of 400 and 450¦C gold ex- tractions of less than 40% were achieved, but between 500-700¦C the extraction had increased to 93--98Z. The surface area of the calcine varied with roasting temperature, reaching a maximum at 500¦C. There was no correlation between the surface area of the calcine and the efficiency of gold extraction.

Jan 1, 1987

Since the introduction of the Neil George Five Point Safety System, to the underground sections of The Zinc Corporation, Limited and New Broken Hill Consolidated Limited mines in March, 1969, the Disabling Injury Frequency Rate has been halved and shows signs of contin- uing to fall. The total accident frequency rate has also fallen, although the decrease has not been as significant. Before the introduction of the Neil George Safety System, analyses of the direct causes of accidents showed that approx- imately 25 per cent were caused by "unsafe conditions", while 75 per cent were attribu- table to "unsafe acts". Within twelve months of introducing the system, these percentages had significantly changed to 7 per cent unsafe conditions and 93 per cent unsafe acts. Today, the figures are 3 per cent and 97 per cent respectively, and these figures clearly show that the main emphasis in the current programme must be directed towards making the operating men safety conscious. The effort must be focused on changing the minds of men.

Jan 1, 1975

Magmatism and mineralization are features of the New England Orogen in late Palaeozoic- Mesozoic time. Voluminous silicic and mafic magmatism, both orogenic and post-orogenic in association, was accompanied by abundant mineralization in the earlier phases. Later activity passed transitionally into less vol- uminous felsic to mafic intraplate basaltic volcanism, with possible migratory hot spot activity through the flanking Oxley and Sydney Basins. Only minor mineralization took place at this stage. A new inerpretation links these magmatic and mineralizing events to a major thermal cycle. A New England hot spot(?) complex evolved in latest Carboniferous/early Permian time. Its activity was partly obscured by orogenic magmatism as Australia moved slowly over magma sources in the deep lithosphere. In Triassic time Australia's movement changed direction and faster drift over the waning hot spot complex produced multiple migratory intraplateòactivity. The volume of magma and hence abundance of ancillary mineralization was related to age of the hot spot, speed of the continental movement over thermal sources and extent of accompanying orogenic activity. The New Eng- land Orogen hot spot(?) possibly existed for 165 Ma, with mineralization changing over this Period.

Jan 1, 1987

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

Results of blasting trials conducted at Gregory Mine, a large open cut coal mine situated in the Bowen Basin, show that fragmentation was improved or equalled whilst reducing the amount of explosives previously required. This was achieved by a system of deck loading whereby two or more explosive charges, separated by air gaps, were positioned in the blast hole, thereby extending the effective explosive column whilst minimizing the total explosives required. In the three trials to date, a saving of approximately 213 kg of ANFO per blast hole was achieved. This represented an approximate 20% reduc- tion in ANFO requirements.

Jan 1, 1989

By K McNabb, M H. Turner, P A. Jenkin

Mining of the Agnew nickel deposit commenced in 1970 using a variety of underground mining methods, though with mixed success due to the difficult ground conditions. WMC Resources Ltd acquired the operation in 1989, and commenced nickel production with an open pit. In 1995 all production reverted to the rejuvenated underground mine, using exclusively SLC (sublevel caving) methods. Currently the mine produces 1.4 Mt per annum, at an average grade of 1.74 per cent Ni. Underground mining of the Perseverance orebody has always presented significant challenges due to the difficult ground conditions in the weak and altered ultramafic rocks. The range of problems include areas of swelling minerals, intense and extremely weak shear zones, relatively high in situ stress, and in other areas very brittle rocks. Under these conditions rock mechanics input has been and remains a critical element of the mining strategy. Severe ground behaviour difficulties down to a depth of 500 m below surface prompted a review of the mining strategy for the large disseminated nickel orebody, including evaluation of alternative mining methods. However, sublevel caving was ultimately selected as the preferred method, and a re-design of the SLC cross-cut layout followed. A selection of rock mechanics investigations of interest are described, including complex virgin stress measurements, detailed ground behaviour monitoring, and the use of non-linear stress analyses to re-design the mine layout. Subsequent ground behaviour, support design and production scheduling are also described.

Jan 1, 2000

By Sorokin M. L, Komkov A. A

Flash smelting of nickel sulphide concentrate has been practiced at WMC's Kalgoorlie Nickel Smelter for 20 years. The mineralogy of the concentrate from the original mines was particularly suited to this process. However, taking a strategic view, potential new processing routes should be fully evaluated as possible replacements for the current technology. The Vanyukov process has been under development in Russia for the past 40 years and has been successfully applied on a large scale to the smelting of copper concentrates, at two locations - Norilsk and Balkhash. The potential for the application of the Vanyukov process to the smelting of nickel concentrates offers a number of processing advantages, including smaller reactor and decreased dependence on fuel oil. This paper reports on preliminary investigations into the application of the Vanyukov process to the smelting of nickel concentrates. At this stage the investigations are limited to semi-quantitative comparisons and modelling studies.

Jan 1, 1992