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By T Nixon

A common problem for many mines is insufficient total primary airflow or insufficient airflow in the correct places as the mine changes over its life. This has a number of impacts on the business operation and may result in the need for a major and unexpected capital upgrade of the system, cancellation of a planned production increase, reduction in production targets, increased operating costs, failure to provide contracted metals to customers or acceptance of substandard conditions in the workplace. In some cases, it can even result in premature closure of the mine. In recent times, higher metal prices have given an expected economic boost to many mines, potentially prolonging their life but simultaneously requiring the mine to develop to deeper depths or requiring assets such as shafts and fans to have their service life extended. Insufficient primary airflow is a particular problem in deeper mines as the ventilation circuits become longer, more convoluted, have higher shock losses and the actual airflow requirements increase due to a combination of leakage, dispersion of the workings and the problems of managing the additional heat loads due to higher virgin rock temperatures and autocompression. This paper discusses the reasons why mines experience unexpected shortfalls in primary ventilation capacity with its associated impacts on metal targets, profits and frequently on the health, safety and morale of the workforce, as well as its productivity.

Jan 1, 2008

By J Herbertson

æZero waste steel making productionÆ has already been the subject of several studies and also the successful result of some companies. Regarding waste and by-products, slags are the largest in terms of weight, although among the least hazardous. All steelmakers around the world are presently looking into profitable solutions, according to their local conditions: environment constraints, available markets, and mode of operation. Today the major technical methods of slag value capture include different levels of magnetic separation and screening to remove entrained steel, for production of aggregate in civil works. A survey of different retrieval processes shows that pyrometallurgical processing of steelmaking slags will increase the recovery ratio of iron and other metals. In the process, the remaining part of the material, a mixture of metallic oxides, can be easily transformed into hydraulic binder such as cement. Can steelmakers consider the slag as a co-product, and not only a waste or by-product? The ability of pyrometallurgical processes to treat other wastes and by-products generated in the steelplant is an opportunity for the steelmakers to reach the æzero waste productionÆ status. A technical survey of the experiences and possible solutions of pyrometallurgical processing is presented as well as technical descriptions of technological, economical and profitability analysis in relation with foreseeable markets.

Jan 1, 2002

By Johnston S

A blending trial was conducted on 60 per cent Perseverance/40 per cent Rockys Reward underground ore at WMC Resources Leinster Nickel Operations to compare the benefits between batching and blending treatment of the two ore sources. Milling, f

Jan 1, 1997

By J J. Frausto, G R. Ballantyne, M S. Powell, R Cruz, K Runge

Hydrocyclones are the most widely used device for classification in a grinding circuit. However, even the most efficient hydrocyclone has a bypass of fines from the feed to the underflow which reduces comminution circuit performance, as well as misclassification around the cut point. Fine screens classify only according to the particle size, allowing for a reduction in the recirculation of fines back to the mill. The development of high capacity multi-screens makes fine classification in a grinding circuit a viable option. Minera Saucito recently substituted hydrocyclones with screens in its grinding circuit. The change of classifier resulted in an increase in throughput and lead recovery but a decrease in silver recovery. This case study presents the changes in comminution and flotation performance that occurred after the installation of screens and uses historical operational data collected over 12 months of operation to investigate the reasons for these observed changes. CITATION:Frausto, J J, Ballantyne, G R, Runge, K, Powell, M S and Cruz, R, 2017., in Proceedings MetPlant 2017, pp 298–314 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

By Lawson F

The leaching behaviour of BHAS copper matte in oxygenated acidic sulphate chloride solutions at 85¦C has been studied using samples containing 34% copper, 41% lead and 12% sulphur. Copper sulphide in the matte, essentially Cu2S was found to leach in two distinct stages. Similar to the behaviour of pure chalcocite, copper dissolution in the first stage was affected by the availability of oxygen in solution. The presence of chloride ions in the leachant was essential if there was to be any leaching in the second stage (which usually commenced after about 40% of the copper had been taken into solution). Lead sulphide in the matte was oxidised to lead sulphate and formed a shell around the partially leached matte particles. Electrochemical studies showed that this lead sulphate and/or sulphur produced during leaching can form a passivating layer around the copper sulphide. However, this layer was disrupted when chloride ions were present. A Plackett-Burman analysis was used to determine the species in the recycled leach solution that affect the leaching of copper. Under the experimental conditions used, in the first stage the rate of copper dissolution was influenced by the concentrations of sulphuric acid, Zn(II), Cu(II), Fe(III) and Cd(II). In the second stage, the rate was futher modified by the concentrations of Cl(I) and As(V) ions. In solutions of low acidity and high As(V) concentration, insoluble copper arsenate formed which coated the partially leached matte particles and acted as a barrier to futher reaction.

Jan 1, 1989

Potential hlghwaJl mining reserves in Australia are large, but geotechnical and operating conditions are quite different from those where highwall mining has evolved in the USA. In order to achieve safe and effective resource recovery, equipment and procedures should be developed to penetrate 250 m in the Australian mining environment. This paper identifies key auributes to be incorporated in such machinery and methodology. These suggestions are intended to promote discussion on innovations to satisfy Australian requirements for highly productive, safe and environmentally acceptable techniques.

Jan 1, 1993

Preparing for automated sample preparation has two facets; the need for better procedures as seen by the laboratory Manager and the approach to be adopted as envisaged by the equipment manufacturer. Both have many options and during the 1990s some at least of these options will be tried. As automation of sample preparation is only just beginning, can it be said that there is a real need for better procedures. What does automated sample preparation have to offer? Does it have real advantages or is it just a marketing tool to sell equipment?

Jan 1, 1976

By Potter OE

There appears to have been a swing away from the study of mathematics, the physical sciences, foreign languages and the classical humanities subjects by many students in high schools in Victoria. The same trend is believed to be occurring in other states as well. This has the direct result of many students entering tertiary studies inadequately prepared academically. This is particularly true in engineering and commerce. The position as far as postgraduate training in the areas of concern to the minerals industry is critical with almost no Australian nationals undertaking advanced technological studies.

Jan 1, 1981

The mineralogy of ten trihydrate bauxites and their leached residues from bomb digestion tests at 140, 180 and 2400C was investigated and the resultsòcorrelated with analytical data. It is shown that increased recovery of alumina at high temperatures is due to. the dehydroxylation of goethiteòrather than the presence of alumina monohydrates. The effects of aluminous goethite -on the interpretation of "available alumina". results-and normative analysis are discussed and it is concluded that,'cautionòmust be exercised in interpreting the results of bomb digestion tests in terms of alumina hvdrates.

Jan 1, 1973

Acid rock drainage (ARD) derived from sulphide oxidation and the associated metal leaching is the most significant environmental issue facing the mining industry today. Under given hydrological and biogeochemical conditions, the local geology and mineralogy largely control the formation of ARD. The involvement of a geologist is therefore essential in minesite ARD assessment and prevention. The relevant tasks that a mine geologist may undertake at three major phases of a mining project are briefly described. Additional knowledge that a mine geologist should acquire in order to achieve proficiency in ARD assessment is also suggested.

Jan 1, 1993

In the last 100 years, statistical sampling theory for particulate materials has developed to a stage where sampling systems can be confidently designed to provide assay results of known and controlled variance for a chosen time period. The two independent sources of sampling variance, namely intrinsic and distributional heterogeneity are defined and explained quantitatively. Intrinsic heterogeneity is characterised by the sampling constant for the material and distributional heterogeneity is quantified by the process steam variogram or covariance function. The means by which sampling systems can be designed to an accuracy specification is described.

Jan 1, 2002

By Williams JK, Bolitho BC

Laverton Gold NL (Laverton) is the first junior Australian mining company to establish a viable mining operation in Indonesia. It successfully commissioned the Rawas plant in Sumatra this year with an average anticipated production of 85 000 ounces of gold equivalent (as gold and silver) per year, a feat of which Laverton is justifiably proud.Working in Indonesia and South-East Asia generally is very stressful for juniors and stretches human and financial resources to the limit - more so than in medium to large companies which can absorb the workload in-house more effectively.

Jan 1, 1997

Urban railway systems need high invest- ments, especially if their routes and stations have to be placed in the subsurface. In the FRG the construction and equipment cost of urban underground railway systems are in the range of 60 to 100 Mill DM per km tunnel. For this reason, track sections on the surface and on elevated structures are used as far as that is possible. Considering whole systems, the costs are in a range from to 45 Mill DM per km length for a metro system with about 80 % of its tracks and stations in tunnels and from 20 to 25 Mill DM per km for a light railway system with about 25 % subsurface infra= structure. The amount of route lengths in tunnels depends on the size of a city, the situation regarding above ground structure and free space on the surface, the level of service quality which has to be achieved with the railway system etc. Despite of the urgent needs to improve the transport conditions there very often arise doubts if an urban railway system is really necessary and can be justified in an economic sense. The experience from many cities around the world shows, that there arise a lot of benefits from urban railway systems, especially with larger sections placed under- ground. They are to be found in the interests of the operator (f.e. operating costs), the user (travel time, quality of service etc.) and regarding social aspects (environmental protection, accidents, consumption of energy Etc.).

Jan 1, 1987

By Lama RD

The paper outlines the development in the control of dust in Australia over the last 20 years. Factors influencing dust make at the faces are discussed. The effect of high production systems is analysed. Changes in dust standards and results of dust sampling on longwalls and continuous miner panels are given. Research conducted on air curtains and water infusion on dust control on longwall faces is presented along with recommendations for future research. It is found that both dust curtains and water infusion can cut dust mak by 50" each when applied separately.

Jan 1, 1988

An international raw material partnership, a $164 million 900,000 long ton per year aluxAna plant; an ideal location at Gladstone, Queensland, Australia - this is Queensland Alumina Limited, on stream in 1967 expanded 50 per cent by the end of 1968. Queensland Alumina Limited is the world¦s most modern alumina refining operation which is owned by an international consortium of four companies; Kaiser Aluminum & Chemical Corporation of the United States with 52 per cent; Alcan Aluminium of Canada with 20 per cent; Pechiney of France with 20 per cent; Conzinc Rio Tinto of Australia, 8 per cent. Q.A.L. operates as a co-operative -- the partners do not draw profits from the venture. Instead, each member of the consortium draws alumina in proportion to his share of the ownership. The method of disposal of this alumina is for the partner to decide.

Jan 1, 1969

Traditional techniques for extracting pillars in thick underground coal seams in India are reviewed. Problems encountered are principally control of roof strata and low recovery. Recently developed mechanized methods and projected newer techniques are discussed.

Jan 1, 1986

By Dobos K

The Clermont Goldfield, from which about 300,000 oz of bullion have been extracted, was one of the major gold producers in Queensland. This paper is derived from a systematic study of the mineralogy, geochemistry, and stable isotope geochemistry of the deposit, based on detailed field work and logging of 57 reverse-circulation percussion drilling holes at the Black Ridge Gold Deposit (Fig 1), aimed at addressing the long debated question of gold-ore genesis at Clermont, i.e., whether it is of fossil placer or hydrothermal origin.Detailed petrologic and mineralogical studies indicate the hydrothermal alteration at Black Ridge is dominated by extensive siderite (+rhodochrosite-ankerite) veinlets and stockworks, which are concentrated along the deformed unconformity between the Anakie Metamorphics and basal conglomerates of the early Permian Blair Athol Coal Measures. Siderite alteration is also moderately developed in all other rock units represented at Black Ridge, including the Tertiary basalt. Weak to moderate phyllosilicate alteration is common throughout the deposit, including chlorite-sericite along the shear zone of the unconformity, and sericite-clay in the conglomerates. A sulphide-oxides zonation also has occurred, including pyrite below the unconformity, (pyrite)-chalcopyrite-marcasite-(hematite) along the deformed unconformity, and marcasite (hematite, pyrite) in the conglomerates.

Jan 1, 1990

Edie Creek is located in the Morobe Goldfield about 17km by road from Wau in the Morobe Province of Papua New Guinea (PNG). Four distinct periods of mining development have occurred since discovery of rich alluvials in 1926. During the two years following discovery, individual expat-riate miners with gangs of native labourers mining rich alluvial gravels dominated the field. After the discov-ery of hardrock mineralisation in 1927, companies accumulated leases and devel-oped extensive underground mines and mechanical processing plants at Day Dawn Mine and Edie Creek/Karuka Mine between 1929 and 1942. After the Second World War, the underground operations were not re-opened, and mining activ-ities mostly concentrated on working alluvial and eluvial deposits. From 1962 onwards, Papua New Guinean miners became increasing producers as company activities declined. In 1990, Edie Creek Mining Company Pty Limited, a joint venture company involving Wau landowner groups commenced operations on New Guinea Goldfield's leases. It currently mines by open pit methods, rich quartz stringers and is invest-igating the open pitting of the Edie Creek/Karuka underground workings.This paper describes the mining and processing techniques employed during the various phases of develop-ment at Edie Creek in the past 70 years. The problems and hardships of operating on a new and remote goldfield are outlined.Abstract

Jan 1, 1994

The process of refurbishment is not a precisely defined one. It is under- stood to mean an upgrading of a plant which is normally performed only once. The application of refurbishment in the field of materials hand- ling equipment poses particular problems because complex plants con- sist of individual components having quite different remaining service lives. For this reason, a systematic, proven procedure is proposed for the refurbishment of large materials handling equipment, designed to ensure economic implementation in accordance with the company goals. Rheinbraun2 has been using materials handling equipment since 1900, the largest units today being bucket-wheel excavators with a daily capacity of 240,000 bank cubic metres of overburden and a service weight of up to 13,500 t (metric tons). Since 1975, more than 50 large-scale refurbish- ment projects have been carried out in the company. In the process, refur- bishment has turned out to be the proven alternative to replacement of large materials handling equipment. Rheinbraun Engineering,3 a Rhein- braun subsidiary, carries out planning, consulting, and supervising work in the implementation of refurbishment projects in Germany and abroad. The most recent example is the refurbishment of Dredger 11 of the State Electricity Commission of Victoria in cooperation with Krupp-Australia, Melbourne.

Jan 1, 1989

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