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By M Ruhrberg, J Grassmann, C Bauer

Within the context of acid mine drainage (AMD) associated with mining activities worldwide there has been a tremendous research effort to determine the extent of AMD and assess the influencing factors controlling this process. However, the majority of the current approaches focus on local and regional scale case studies and do not provide a global scale picture of AMD potentials. This study attempts to develop a method aiming at a global environmental impact assessment related to AMD. To confine the complex topic this study concentrates on acidic emissions from heaps in consequence of copper mining processes. In order to pursue this approach two factors are of significant advantage: a comprehensive environmental data base of more then 600 copper sites worldwide and a method which has been developed and proven to be successful in assessing environmental impacts related to land use. Current and future research efforts focus on using this background knowledge to enable both a comparison between sites and a categorisation of sites according to emission estimates.

Jan 1, 2003

By Dawson RD

For the past 45 years, the casting of refined lead ingots by The Broken Hill Asso- ciated Smelters Pty. Ltd. (B.H.A,S,) at Port Pirie has been mainly by use of manually operated rotary casting wheels of Newnam design. This style of operation was quite satisfactory as far as standard of product was concerned, but was manually intensive and a relatively high cost operation. With most other large scale lead producers already using automated-casting equipment, an investigation which commenced in 1966, progressed through stages of enquiry, design and development until the present plant commenced trial operations in late 1973, and fully operative in late 1974. While certain features of the plant are sed on overseas practices the plant was signed and built within Australia to BRAS ecifications. As constructed it consists two almost identical casting lines each pable of producing 25 kg ingots at 25 tonnes r hour using straight line casting machines d automated stacking weighing and strapping

Jan 1, 1975

The provision of electrical power is an important consideration in project develop- ment. The first step to be taken in this area is to assess the power requirements of the project. The alternatives of taking a supply from a power authority or providing local generation can then be considered. This requires additional definition of the prob- able characteristics of the supply. The availability of authority power in Australia is limited by the extent of the state power grids. Recent developments now allow these grids to be extended and their load capacity increased to meet major load increases at less cost than was possible pre- viously. The options for local generation include diesel, gas turbine, steam, hydro, solar and wind, each having its particular performance characteristics and costs. The choice of fuel for diesel, gas turbine, and steam plant likewise involves consideration of a range of factors. The arrangements adopted for a number of development projects illustrate some of the aspects which influence the decisions on power supply.

Jan 1, 1986

Zinc concentrates from the newer mines and from proposed developments provide both opportunities and processing challenges to the conventional roast-leach electrowin smelters. These concentrates are often characterised by low iron, elevated silica, possibly high manganese, and levels of elements such as germanium which may cause concern. In addition, environmental constraints on residue disposal are forcing significant changes to some smelter practices. Iron in concentrate, and the resulting environmental impact of residue disposal are now major questions. However, normal concentrate tariff structure provides a disincentive against smelters taking high grade concentrate and oxide fume. Processing technology to cope with these changes is reviewed, as is de-watering and materials handling of ultra-fine concentrate. Within a few years, such fine concentrates will account for up to 1 000 000 t/y of contained zinc. New processing technologies including novel transport methods, siliceous leach circuits, manganese removal cells and front-end smelting will become significant in zinc smelting.

Jan 1, 1993

Good morning. I am very pleased to be invited to present the Opening Address to this inaugural New Zealand Minerals & Mining Conference. It is indeed a pleasure to see so many representatives of this industry, which is so important to New Zealand's economy, present here today.   I extend a warm welcome to all delegates, particularly those from outside New Zealand. To those of you who have travelled from offshore, please closely observe our industry, and do not hesitate to ask Crown Minerals staff here for any further information you may want. I trust you will soon come to the same conclusion that my two following speakers have; that New Zealand is a good investment destination, and further that many of you will decide to invest in New Zealand's minerals and mining industry.   In New Zealand the minerals industry - minerals, coal and petroleum - together constitute an approximate $2.5 billion per year business. In broad terms this is about 3% of our Gross Domestic Product.

Jan 1, 1997

Before commencing design of a coal prepar ation plant, it is essential to have detailed information of the raw coal to be treated to- gether with a clear understanding of the products required. Prediction of raw coal size distribution, particularly the amount of fine material, is difficult and the methods employed should be large scale pilot plant studies or techniques to simulate coal degradation and shale breakdown in water. A detailed knowledge of well proven coal preparation processes and new developments allows processes and process combinations to be compared to'obtain the maximum economic recovery when using lower cost, less efficient processes within acceptable limits. Equipment should be selected bearing in mind its precise application and the location where it is installed. Plant layout should be carefully studied to minimise equipment requirements and to simplify construction. Measurement, control and automation should be an integral part of plant design in order to obtain the optimum performance of the processing equipment.

Jan 1, 1974

This paper outlines the mechanism of Stress Corrosion Cracking (SCC) and how it can cause premature failure of rock bolts. SCC occurs due to the progressive development and growth of cracks in the surface of a metal, and it is caused by the combined effects of stress and a corrosive environment affecting susceptible metals and alloys. It can occur in most metals including stainless steel. It is not a new phenomenon, but its effect on rock bolts has only been recognised recently.Rock bolt failures caused by SCC appear to be brittle failures which occur at less than the ultimate tensile strength of the bolt. In the mining industry, SCC failures of rock bolts can occur a few months, or after many years of exposure to stress and a corrosive environment. If SCC of rock bolts is suspected, then the rock bolts should be examined by a metallurgist, and steps should be taken to reduce the problem.

Jan 1, 1998

During 1995 a catastrophic accident took place at the No 2 Vaal Reefs shaft in South Africa, when a locomotive fell onto a cage, causing the death of 104 people. The subsequent Commission of Enquiry found that the safety detaching hook had opened when hit by parts of the falling locomotive, detaching the cage from the rope and allowing the cage to drop 400 m down the shaft. It was believed that had the hook not detached, the rope would have been sufficiently elastic not to have failed, implying that many fatalities may have been avoided. In addition, the risk of accidental opening of hooks due to impact with smaller falling objects in shafts became a concern. This paper deals with a comprehensive statistical investigation that was performed to quantify this risk, establish acceptable levels of such risks and to derive criteria for the resistance of detachment hooks against accidental opening caused by impacts. The investigation involved a survey, dynamic finite element analyses and Monte Carlo simulations.

Jan 1, 2005

By Thomas R. J

Following asmallnumberofpollutionincidents involving the death of cattle from ingestion of cyanide that had escaped from gold processing plants, the Queensland Government undertook to develop competent guidelines addressing this problem. These guidelines, "Queensland Government Guidelines on Prevention of Water Pollution from Cyanide Use in Gold Ore Processing", issued by the Department of Environment and Heritage, Department of Resource Industries and Water Resources Commission, cover hydrology and general house-keeping intended to reduce the likelihood of significant impact from a spill or unintentional dis- charge of contaminated material. There are three major advances for Queensland embodied in this Guideline: ò the use of a design approach that gives site specific standards rather than trying to give a multitude of standards broad enough to cover all situations, ò the use of hazard assessment and a "critical period" hydrologi- cal design technique, and ò new monitoring and reporting requirements. The guideline is presented here in a summary form:

Jan 1, 1991

By Fermino R

Reduction of waste oxides from steel plant operations was investigated in a laboratory tube furnace at different temperatures and furnace atmospheres. The results have shown that the waste oxide pellets are reduced rapidly to very high degrees of metallization irrespective of the furnace atmosphere and that the reduction is simultaneously accompanied by significant low- ering of the original impurities. It is shown, for example, that treatment at 1000¦C for 30 min. can reduce the Zn content from 0.98% to 0.0065% and K and Na contents from 0.19% and 0.76% respectively, to less than 0.01%. However, pellet strength at 1000¦C was low but this, as shown in the paper, can be very significantly improved by treatment at 1250¦C. The results indicate that the reduction of the waste oxide pellets of this investigation proceeds almost certainly by a chain reaction mechanism and that this principle could be advantageously extended to the reduction of iron ores and other oxides in general.

Jan 1, 1984

By Glastonbury J. R

Commercial operation of the Sherritt Gordon process in Australia for the leaching of nickel sulphides has promoted an investi- gation of the factors which influence extraction kinetics. This portion of the investigation has been directed towards the physical and chemical nature of the concentrate and the physical evi- dence of the mode of extraction. Details of the particle size distribution, mineral composition and chemical composition are given. The dis- tribution of various minerals in different size fractions and magnetic fractions is discussed. An electron microprobe was used to determine the composition of individual grains in the concentrate. The solid residue from an ammonia oxi- dation leach was subjected to microphotograph- ic examination, X-ray diffraction analysis and scanning by an electron microprobe. Clear evidence was obtained for a shrinking core mode of kinetic extraction with an amorphous iron oxide product layer contrary to previous reports that the latter is pseudomorphic with the original mineral.

Jan 1, 1973

By Doyle J

The direct method of gas content determin ation developed by McCulloch and Diamond of the U.S.B.M. has been adapted to estimate the gas content of coal seams from slim exploration borecores in the Southern Coalfield. Emphasis has been placed on the measurement of this parameter without the physical destruction of the core which is required for subsequent chemical analysis. In field and laboratory equipment is simple and inexpensive. It enables the determination of lost and desorbed gas from a fresh geological core. Residual gas is not measured but is considered to be relatively low and of no consequence in ventilation considerations. Results to date show good correlation with those obtained from underground face samples. Gas contents from the mined seams varying from 2 m3/tonne to 14 m3/tonne have been measur- ed with this apparatus. Gas desorption characteristics of South Coast coals have been found to closely follow exponential mathematical Models.

Jan 1, 1983

By Mazandarani M, Chabot L, Vichion K

Pitch-steering models have been developed for discretely advanced mining machines (such as heading machines and coal shearers) using small-angle geometry and there are illustrative examples of simulator predicted performance. Although simple linear models result from the analysis of open-based machines, sledge mounted machines require execution of a Linear Programming energy minimisation to determine the attitude of the machine base at each advance over the previously cut floor steps. An analytical approach is based on elastic beam concepts developed for such applications as longwall face conveyors, caterpillar tracked machines such as continuous miners and longhole drills. Simulation results for longhole drills show the expected performance of an automatic guidance system and the destabilizing effects of sensing deviation too far behind the drill bit. Certain drill bit boundary conditions are expected to assist TBM. steering studies in three dimensions.There is a real role in mining machine steering for the mathematical models used in flight simulators.

Jan 1, 1991

By Kruse JW, Kjar AR

Recently there has been increased recognition o'f the cost savings that can be achieved by the greater use of offsite preassembly for the construction of industrial plants. Preassembly is a method of construction which involves considerable offsite assembly of complete sections of an industrial plant in established fabrication shops. The preassemblies are transported to the plant site, often by large and oversize transport systems where they are set on prepared foundations, finished and interconnected to other sections of the plant as required. The concept of preassembly is not new, but widespread interest has been shown because site construction costs in all parts of the world have increased rapidly and often at a greater rate than in established fabrication areas. Particular interest has be focused on remote, isolated and inhospitable plant site locations. These areas require the import of skilled labour, the payment of high labour rate premiums and the development of infrastructure to support the workforce for the duration of the construction period.

Jan 1, 1983

By Marois R, Hauff P, Kowalyczk P, Lipton G, Bedell R, Neville R, Edmundo G, Ehling M, Kern R

The Canada Centre for Remote Sensing (CCRS) has developed an airborne sensor, the SWIR Full Spectrum Imager (SFSI) which detects in the Short Wave Infrared range of the solar spectrum from 1220 to 2420nm. In June of 1995, a demonstration flight was undertaken in the state of Nevada with the support of the companies listed above. The focus of the flight was to collect image data over well known mineral deposits with the objective of evaluating the applicability of this sensor to alteration mineral mapping. Some of the Nevada sites chosen include Cuprite and Goldfield, volcanic hosted acid sulfate systems; Yerington, a structurally complex porphyry copper deposit; and Virginia City, a Quartz- Sericite-Pyrite vein system with advanced argillic pods. Ground spectral data was collected with the PIMA-II spectrometer. Solar reflectance calibration was done by Desert Research Institute personnel at Virginia City and Cuprite. This paper will discuss the configuration of the sensor and present image and ground data for Goldfield and Virginia City.

Jan 1, 1995

By Partridge AC

In order to provide a'valid description of the performance of size classifying equipment it is necessary that a standard procedure be established for testing and for the subsequent expression of results. Such a standard would permit the valid comparison of alternative equipment and may provide a basis for the prediction of performance. An Australian Standard (AS 1634-1974) has been used as the starting point for an International Standards Organisation-(ISO) working group (of which the authors are members) charged with the preparation of an ISO Standard for the expression and presentation of the results of tests on coal size classifying equipment. The approach taken is applicable to all types of sizing equipment (cyclones, screens, dedusters, etc.) and should be suitable for adoption in the minerals industry as well as by coal preparation engineers. The background to the proposed Standard, is given,including a critical review of other frequently quoted performance measures, the procedures described in the draft are discussed, and an example given.

Jan 1, 1984

The provision of electrical power is an important consideration in project development. The first step to be taken in this area is to assess the power requirements of the project. The alternatives of laking a supply from a power authority or providing local generation can then be considered. This requires additional defmition of the probable characteristics of the supply.The availability of authority power in Australia is limited by the extent of the state power grids. Recent developments now allow these grids to be extended and their load capacity increased to meet major load increases at less cost than was previously possible.The options for local generation include diesel, gas turbine, steam, hydro, solar and wind, each having its particular performance characteristics and costs. The choice of fuel for diesel, gas turbine, and steam plant likewise involves consideration of a range of factors. The arrangements adopted for five recent Australian remote development projects indicate how some of these aspects influence the decision on power supply.

Jan 1, 1990

The Beaconsfield Gold Mine within the township of Beaconsfield in northern Tasmania has been established in recent years to exploit a known resource in the Tasmania Reef which was mined to a depth of 450 m below surface between 1877 and 1914 yielding 850 000 ounces of gold. Activity at Beaconsfield over the past 30 years has involved drilling to assess the resource and rehabilitation of the top 100 m of the Hart Shaft that had collapsed since the original closure. More recently the mine has been dewatered to the 375 m Level and work is well advanced establishing infrastructure aimed at recommencing production during 1998 - 99. This paper reviews geotechnical studies undertaken to-date and provides a brief overview of some practical methods of analysing ground conditions. It pursues simple observation and analysis as a tool for assessing mine design and ground support options without recourse to extensive monitoring and measurement and avoids the use of elaborate models before the basics are understood.

Jan 1, 1997

The Honeymoon Well nickel sulphide deposits are located in the Agnew-Wiluna greenstone belt, about 45 km south of Wiluna. Both disseminated and massive sulphide nickel deposits are hosted by komatiitic rocks within the deformed and metamorphosed Honeymoon Well ultramafic complex. Fresh ultramafic bedrock is covered by up to 50 m of highly conductive transported material which greatly hampers both exploration and understanding of the bedrock geology. In the early-1970s, mineralisation was discovered by diamond drilling geochemical anomalies defined by wide-spaced percussion drilling over ultramafics that had been outlined by ground magnetics. Subsequent drilling has defined a resource of 158 Mt at 0.71 per cent nickel (based on 0.4 per cent nickel cut-off, 300 m below surface, December 1995) in four deposits. Over the life of the project a wide range of geophysical techniques have been used including airborne and ground magnetics, time domain clectromagnetics (EM), induced polarisation (IP)/resistivity, gravity and downhole techniques including EM, IP and physical property Measurements.

Jan 1, 1996

By Weller K. R, Trahar W. J

The Mount Lyell Company treats some 2.3 million tonnes of ore annually, mined from a number of orebodies on the field. Blended ore is essentially a quartz-sericite schist containing about eight per cent of pyrite and three per cent of chalcopyrite. Four-stage crushing and two-stage ball milling are followe by selective flotation for copper. Pyrite is recovered from the coarse fraction of dopper circuit tailings. A detailed survey involving examination. of 82 samples provided information on the size- by-size behaviour of the principal ore constituents throughout the grinding, copper flotation and pyrite flotation sections of the circuit. Results for the copper and pyrite flotation sections are presented in the paper, and it is shown that over half the copper reporting to the final tailing (5% of copper in the feed) is plus 100 microns and that the major pyrite loss is in the desliming cyclone overflow. These data proVide a basis for assessing potential methods of circuit optimisation.

Jan 1, 1977