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Asbestos is a commercial term applied to fibrous varieties of several minerals, the properties of which are not generally appreciated by the majority of geologists. A thorough knowledge of these properties and of the uses of asbestos is of fundamental importance in the assessment of the economic value of an occurrence of asbestos. The varieties of asbestos that are used predominantly by the manufact- urers of asbestos products are chrysotile, crocidolite and amosite but chrysotile constitutes 95% of the world's usage. It is the properties of high tensile strength, 'heat resistance and large surface area that make chrysotile asbestos the most acceptable of the mineral fibres. There are no known exploration aids, other than direct visual inspec- tion of outcrops in ultrabasic environments, that could be used in the exploration of chrysotile asbestos. The surface exploration of an occurrence of chrysotile asbestos is relatively routine, though it lends itself to a unique form of bulk sampling by the use of a twelve inch diameter diamond drill core. The laboratory assessment of the prop- erties of the actual fibre requires specialized techniques and tests to assess not only the amount of fibre present but also its length distri- bution, inherent strength, filterability, dust content and other prop- erties. The way a fibre reacts to milling will determine what milling process- es must be implemented to ensure a product that is acceptable to the asbestos product manufacturing industry.

Jan 1, 1971

By Cousens DR, Benhamou M, French DH

Techniques appropriate to petrographic image analysis are being developed using digitized backscatter electron images of well characterized mineral assemblages obtained from a Cameca scanning electron microprobe. Emphasis is on developing descriptors for size, shape and association of mineral grains as these all convey important information concerning the nature of rocks and the processes that have operated upon them. Processes, for example, that could indicate the proximity of mineralization. For convenience, the work is being carried out on the PDP11/73 host computer of the electron micropt be, although it is recongnized that such a multi-user environment is not appropriate for practical image analysis. The eventual aim is to develop a low-cost microcomputer-based package for quantitative description of mineral textures and rock fabrics as an objective aid to the petrographic analysis of ores and host rocks.

Jan 1, 1989

Two main aspects need to be considered when analysing a potential petroleum development project. Firstly, an estimate of the recoverable reserves must be made, and in many instances, these reserves must serve as collateral to finance development if outside capital is required. Secondly, the likely production profile and cash flow has to be established, and this cash flow then must meet debt service require- ments and in addition generate the required profits. In making these crucial deter- minations, the impact on the project of a wide variety of risks has to be analysed. A computer model, which represents the project in its entirety, is a great aid in determining project viability. Such a model requires imput from geologists, engineers and economists, and interpretation of the model must also be a joint effort. Communications, and inter react ion amongst individuals and disciplines is essential if the best answers are to be obtained

Jan 1, 1983

Mining projects draw together stakeholders with various degrees of experience in managing and assessing financial risk. When this risk is not fully appreciated or quantified, the potential for making decisions not suited to investor requirements is significantly increased. A feasibility study provides key information on project development potential, requiring detailed technical investigations with thorough financial analysis. Centaur Mining and Exploration (CME) owned and operated Cawse Nickel Operations (CNO), one of three Australian projects to develop and process vast amounts of near surface nickel resources. A technical ædue-diligenceÆ and æbankable feasibility studyÆ confirmed the large resource base, newly applied yet tested technology and relatively low unit costs would produce nickel in the lower half of industry operating costs. A number of production variables including capital requirements, delayed start-up, nickel grade, processing, maintenance and product output were outside the feasibility estimate. This was combined with exchange rate fluctuations and lower Ni prices. The inability to generate adequate cash flow and service debt repayments ultimately led to receivership and liquidation of all assets. Following the sale of CentaurÆs gold and nickel divisions, $A 784 million remained outstanding to creditors. This paper aims to define key issues leading to CNOÆs collapse by reviewing feasibility parameters, valuation methodology and project development. Some methods of assessing project viability are discussed with the aim of increasing stakeholder risk awareness.

Jan 1, 2003

By Penney B. K, Baghdadi A. A

An electron probe micro-analyser, controlled by a dedicated mini-computer,has been operating at Imperial College since 1970. The data assessment capability of the computer was limited and, in order to make better use of the information produced by the analyser, extra computing facilities were needed. Following the initiation of a Laboratory Automation Project at Imperial College involving the use of a central computer linked to laboratory type computers and to further more powerful systems,it became possible to carry out much more detailed and extensive mineralogical analyses by connecting the mini -computer to the Laboratory Automation Network. The paper describes the techniques employed including hardware, software, inter- connection, analysis and operating methods.

Jan 1, 1977

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 Kuzugundenli OE, Nagaraj DR

Organic complexing agents have received special attention over the past few decades in the search for reagents for improved flotation separation of minerals, especially non-sulphides. The majority of such reagents that have been proposed over the past few decades have remained largely a laboratory curiosity, except perhaps alkyl hydroxamates, because their selection is seldom based on commercial viability. In this regard, the choice of complexing agents such as oximes may be more realistic because of their widespread use in solvent extraction of copper. Our earlier studies have confirmed that they are also effective as collectors for copper oxide minerals, including chrysocolla which is the most difficult copper mineral to beneficiate. The flotation behaviour of chrysocolla for several structurally-related hydroxyoximes were studied as a function of pH and oxime concentration and the role of structural features examined. The structural changes studied included substitutions in both chelating and non-chelating parts of the molecule. The results indicated that, contrary to expectations, many of the structural changes in the basic molecule, salicylaldoxime, do not have a positive effect on collector efficiency. The reduction in collector efficiency is rationalised on the basis of possible steric factors affecting complexation and packing of the collector species on the mineral surface as well as effects due to changes in electron density brought about by substituents. Introduction of alkyl substituents on the oximic carbon of salicylaldoxime yielded the highest collector efficiency.

Jan 1, 1993

By Carter LC

Following the perception by the Groote Eylandt Mining Company of a need to further beneficiate a fines product, and preliminary metallurgical testing to demonstrate the feasibility of such beneficiation, a comparison was made of the various configurations of cyclonic heavy medium separators available. This comparison consisted of (i) a pilot plant test in which a dynawhirlpool (DWP) and a pump fed cyclone were compared, and (ii) a survey of operating plants using the systems under consideration. Little metallurgical difference was found-between the different systems. The gravity fed cyclone configuration was finally chosen based on a particular need to minimise degradation of ore and on a desire, in so isolated a location, to use established and locally supported technology.

Jan 1, 1987

Mining of the silver-lead-zinc orebodies at the George Fisher Mine officially started in 2000. A review of mining performance to date shows that many of the extracted primary stopes have experienced some degree of hangingwall dilution. The degree of hangingwall failure in the stopes became progressively more extensive throughout mining of the orebodies in 2001 and 2002, culminating in the unplanned catastrophic failure of the 744D stope in which the ore between 13C (2683RL) and 12L (2714RL) sublevels caved into the previously mined cavity between 13L (2654RL) and 13C sublevels. This was followed several months later by another unplanned caving event in a nearby stope, 740D. As a direct result of these unplanned failures it was decided to mine the stopes with a smaller span than had been previously planned and in a primary-secondary pyramidal stoping sequence. To limit the exposure of the stope hangingwall, a hangingwall drive is no longer developed and therefore geologists no longer have access to the detailed geological information that this provided. Geologists at George Fisher Mine have had to be adaptable and flexible in response to these proposed changes and rely more on data from drilling than mapping for their geological interpretation. The result is that the drilling cycle has become much more critical in the planning process.

Jan 1, 2003

By Mahoney M

For gas content analysis in recent years, it has been standard procedure to report results on a 'dry ash free' (daf) basis, under the assumption that gas only adsorbs onto coaly material. In order to test the relationship between ash and sas content, samples of various rock types were taken from two drillholes in the Newcastle Coalfield. The results of this study confirmed the correlation between gas content and ash, providing an accurate means of relating gas contents for all carbonaceous rock types.

Jan 1, 1995

By Noreen D

At Bougainville Copper Limited comparison testwork was conducted between "horizontal" cycloning and conventional vertical cycloning. Horizontal cycloning reduces circulating load and allows increased ball mill throughput. Cyclone efficiency is the same or better as a result of the reduction of fines short-circuiting to the underflow. Operationally, horizontal cyclones are less likely to suffer from blocked spigots and high cyclone feed pump sump levels. Cyclone feed pumping power is reduced. High horizontal cyclone underflow density provides the option to optimise grind by manipulating water addition to the ball mill feed.

Jan 1, 1988

By M Chappell

This paper describes the design of the steel fibre reinforced precast concrete (SFRC) segmental lining for the intake and discharge tunnels for the Gold Coast desalination plant in Queensland. In addition, the key design requirements and design methods for the lining of these 2 km long, 2.8 m internal diameter tunnels, including structural, durability and maintenance requirements are discussed. Details of the segment configuration and erection process are presented along with information on the manufacture and trial testing of the concrete for the segments. The paper also gives a brief introduction to steel fibre reinforced concrete behaviour. Construction of the tunnels commenced in April 2007, and the authors believe this is the first application of this technology in Australia.

Jan 1, 2008

By Kabel J. G

While a per onnel location system is primarily used to check that nobody is left in the mine at firing time, it is also useful for contacting people, uch a foremen, shiftbosses and tradesmen, who travel over several mine levels during a shift. The system installed at The Zinc Corporation, Limited, Broken Hill, uses punched coded plastic identity tags, with "In" and "Out" tag readers on each level. When entering a level, the employee inserts his tag in the "In" reader, and when leaving, in the "Out" reader. Each reader is connected to a central computer which shows who is still in the mine and their location.The system has been used on 3 levels by 21 men for a trial period of 4 months. It ha proved reliable in an underground mining environment, and employee acceptance has been good.

Jan 1, 1984

In recent years a large number of Horizontal Belt Filters have been installed in the Australian mining and chemical industries. This paper deals briefly with the general background and advantages leading to the selection of this type of filter. Several different applications are described and particular reference is given to the simplification of the fines treatment circuit at the South Bulli Coal Washery.

Jan 1, 1989

The paper discusses the characteristics of Be-zymianny activity during the last 2500 years. Three periods of increased activity have been identified which are the eruptive cycles lasting for 100-400 yrs. The periods of high activity fall on the fol-lowing time intervals: 2400-1700 yrs ago, 1350-1000 yrs ago and from 1955 ixp to the present time. The 1955-1956 catastrophic eruption after a long period of repose (about 900-1000 yrs) opened a new cycle of activity of the volcano which is continuing to-day. Several decades are distinguished in activity which differ in character and intensity of eruptions.

Jan 1, 1990

By K E. Barns, P J. Sharman, S A. Thomas and

This paper presents the development of a regrind facility design at BHP BillitonÆs Leinster Nickel Operations (LNO) in Western Australia. The recovery opportunity was identified from an analysis of plant operating data together with scanning electron microscope (SEM) measurements on relevant tailings streams from LNO. A laboratory procedure was developed to determine the potential recovery improvement of installing a regrind facility at LNO. The last step in formulating the process flow sheet and defining the process design criteria was to construct and operate a pilot plant, which incorporated four banks of flotation cells and an Xstrata M20 Isa Mill. Pilot plant on/off trials were used to define the expected metallurgical benefit. A prefeasibility engineering design and cost estimate was completed. Following a successful internal business evaluation, a feasibility study is currently underway.

Jan 1, 2007

By Pollard D, Meadows N

The presence of impurities which are electropositive to zinc in acid zinc electrolyte causes changes to deposit morphology and reduced current efficiency. Glue may be added to control some impurity effects, but assaying for animal glue concentration is difficult and seldom done. Measurement of the activation overpotential for zinc deposition by cyclic voltammetry is used in some plants to monitor electrolyte quality and control glue additions.The deposit morphology and current efficiency of zinc deposition from commercial electrolyte were investigated for various glue additions in the presence of increased levels of antimony. Cyclic voltammetry was investigated as a method of optimising glue additions in the presence of antimony.Scanning electron rnicroscopy showed deposits characteristic of the impurity element present and the glue addition rate. Cyclic voltarnmetry measurements showed some correlation between current efficiency and activation polarisation potential. The importance of using tankhouse electrolytes where results are to be related to tankhouse operation was noted.

Jan 1, 1988

The Carnilya Hill Mine, a joint venture project between Western Mining Corporation Limited (WMC) and The Broken Hill Proprietary Company (BHP), is a nickel sulphide deposit being developed by the Kambalda Nickel Operations (KNO) of Western Mining Corporation. Seven months elapsed from the time a decision to proceed with the project was taken until the first ore production. During the first month of operation a new KNO record for decline development was set. Equipment used includes an electro- hydraulic drill jumbo, 4 cubic metre front end loaders, and 35 tonne haulage trucks.

Jan 1, 1981

By Boontanjai C, Boyapati ER

Reagents used for batch flotation tests were Aeroxanthate-343 & 350, Dow Z-6, & reagent-4037 (from Benambra) as copper collectors; Na2SiO3 & Na2S2O3as gangue depressants; lime & HCl as pH regulators; and pine oil & MIBC (methyl isobutyl carbinol) as flotation frothers. A Denver Sub A flotation cell of capacity 250 gms was used for the batch flotation experiments. Atomic absorption spectrophotometer was used for copper assays and microscopy for selectivity and liberation studies. Melbourne tap water was used throughout the experiments. Unless otherwise stated, the following parameters apply to the flotation experiments: flotation impeller speed - 1300 rpm, pulp density during flotation- 22%, reagents addition - in 4 stages, total conditioning time for collectors - 8 minutes, total flotation time- 9 minutes. A variable quantity of copper mineral collector according to the test in question was added, then conditioned the pulp for 2 minutes. The froth was removed by hand, scraping the full length of the cell at constant depth every 10 seconds. No frother is required for this copper tailing flotation. Four concentrates were collected after addition of collector and conditioning at 2,4,6 and 9 minutes. The pulp volume was maintained at a constant level to yield a constant froth depth.

Jan 1, 1990

This paper will be a discussion of the geological exploration and drilling carried out on the Mt Davy Block, Greymouth Coalfield. A brief summary of the geology of the Greymouth Coalfield will be given to put the Mt Davy Block into perspective.

Jan 1, 1979