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By McMullen P. H

Mining of copper ore at Mount Lyell has been continuous since 1893. The operation has always been marginal and the depressed copper Market over the last decade has seen mining continue on the basis of a series of short term plans. In 1985 it was determined that the mine would close in 1989 on completion of the 40 Series mining block. Significant changes in the value of the Australian dollar in 1986 and the subsequent effect on profitability dictated a review of the Company's operations. Lower level ore reserves, mining methods and ore handling systems were re-examined and a plan proposed for mining of the 50 and 60 Series mining blocks. The improved economics of this plan, together with workforce and State Government initiatives resulted in an extension of mine life to 1994.

Jan 1, 1988

Quite apart from economic considerations, the following performance parameters must be considered when selecting an explosive for a particular blasting operation. 1. total energy yield/kg, and more particularly, strain energy/kg and bubble energy/kg of charge 2. charge weight/m of blasthole 3. sensitivity of the charge 4. water resistance of the charge The effective division of an explosive's total energy into strain energy (SE) and bubble energy (BE) is explained as is the influence of each energy component on blast results. Because some rocks require a high strain energy for effective breakage, while others are most satisfactorily fragmented by bubble energy, values of SE and BE are more meaningful than those of total energy. Unfortunately, our extensive knowledge of the effects of certain variables on total energy has not yet been completely supplanted by the influence of these variables on SE and BE values. Relative SE/kg and BE/kg values are presented for a range of explosives. The 'charge density of ammonium nitrate/ fuel oil (ANFO)-type explosives is essentially constant throughout the length of the charge; because of their compressibility, slurry

Jan 1, 1974

Australian continental crust has accreted and consolidated by thirds: 1/3 during Archean time, 1/3 during Early to mid-Proterozoic time, and 1/3 during latest Precambrian to mostly Paleozoic time. The progression of orogenic systems and the crustal consolidations they represent seem not fundamentally different in basic orogenic processes from better known Mesozoic-Cenozoic examples in that accretionary, continental margin, collisional, and intraplate intracratonic inverted and/or reactivated systems are all recognizable in the tectonic evolution ofAustralia.

Jan 1, 1995

By Aylmore M. G

Samples have been taken from a two-stage industrial gold roaster treating a pyrite/pyrrhotite/arsenopyrite concentrate, in order to describe the mineralogy, composition and surface area of the calcines. Sulphides oxidised to produce a porous magnetite in the first stage and a porous hematite in the second; pyrite predominantly roasted via a pyrrhotite intermediate. Sulphur was eliminated in both the first and second stages whereas arsenic was eliminated in the first but retained in the second, partly as rims on hematite particles. The finer sized particles from the cyclones and electrostatic precipitator, while having the greatest surface area, were the most refractory with respect to gold solubilisation, probably as a result of incomplete decomposition (through short-circuiting) in the first stage, and through a combination of factors such as overheating and entrapment of sub-microscopic gold in the second stage.

Jan 1, 1992

The Mount Morgan massive sulphide body occurs in a volcanic sequence of Lower or Middle. Devonian age, which is subdivided in the mine into "Upper mine porphyries", "Banded mine sequence", and "Lower mine porphyries". This sequence is intruded by latite, Mount Morgan Tonalite (360 million years), and late Permian dykes. Distribution of macroscopic ore textures and minerals in the orebody are discussed and evidence is presented indicating the pre-Tonalite, Devonian age of the orebody.

Jan 1, 1974

By Buisman C. J N, Koch R. O

Soil and groundwater beneath the Budelco zinc production plant at Budel-Dorplein (The Netherlands) are contaminated with metals and sulphate. To avoid contamination of nearby drinking water aquifers in the very distant future, a geohydrological containment system (GCS) and a microbial treatment plant for extracted contaminated groundwater have been developed. As a first step in the design of the system groundwater data from over 150 wells and geological profiles were used to model geohydrological conditions beneath the site. Several configurations of water-extraction wells were deduced from the model. Data gathered during additional fieldwork were then used to improve the model. Finally results that were calculated for the various configurations were used to select an optimal groundwater containment system. Currently some 5000 m3/day groundwater are extracted from a combination of 12 shallow and deep wells. Heavy metals and sulphate have to be removed from the extracted water before it can be discharged into the river system or used as process water. Several water treatment methods have been studied and pilot-tested at the site. The preferred and selected process is based on the activity of sulphate reducing bacteria (SRB) and combines sulphate removal and heavy metal removal in one single step. The anaerobic bacteria reduce the sulphate to sulphide resulting in the precipitation of metal sulphides. A pilot plant gave promising results and a commercial-scale plant has been designed. The proposed design has been tested in a demonstration plant which included all main process units. Test results for all process units are presented. The collected information was then used to optimise the design of the commercial-scale plant. Special attention was paid to automation and safety items. Construction of the plant was finished in May 1992. Start-up, commissioning and operational experience are reported. The concentrations of metals and sulphate in the effluent of the SRB water treatment plant are well within the limits set by the authorities for discharge to public waters.

Jan 1, 1993

This paper records the observations of faulting in the Black Star mine workings. By classifying the faults into two groups, i.e., strike faults and transverse faults, and by pointing out the differences between the groups and their effects on the silver-lead-zinc orebodies, a time relationship between the two groups of faults and the sulphide mineralisation is suggested.GENERAL GEOLOGY AND MINERALISATIONFolding and faulting are closely related to the mineralisation in the shales by silver-lead-zinc and iron sulphides.Commonly the various sulphides are fine-grained and closely associated with one another. However, exceptions do occur locally, where massive coarse galena, sphalerite, pyrite, and to a lesser extent chalcopyrite, have been observed singly or closely associated one with the other.In the main, the sulphide mineralisation forming the orebodies occurs as replacement of, and infilling along, the sheared bedding planes of the finely bedded shale host rock.The shales in general strike north-south with an average dip to 60° to the west; strong shearing along the bedding planes is evidenced by much slickensiding and slaty cleavage.Sequences of finely bedded shales of varying stratigraphic thicknesses alternate with very. massive beds, and it is in the more highly sheared thinner beds that the greatest concentration of sulphides occurs. The unmineraIised massive beds of shale, 11 in. up to 12 in. in thickness, occur singly or in groups between, and to a lesser extent. within, the orebodies. The massive beds resisted sulphide replacement and impart to the orebodies a most prominent banded structure.

Jan 1, 1953

By Bensley C. N

In June 1995, BHP announced that it would build a Hot Briquetted Iron (HBI) plant and associated beneficiation, materials handling and infrastructure facilities at Port Hedland, Western Australia. This plant, the first direct reduction plant in Australia, will convert beneficiated iron ore fines into metallic iron for briquetting into HBI. The reduction plant will be based on the FINMET fluid bed technology jointly developed by Fior de Venezuela and Voest-Alpine Industrienlagenbau. Electric Arc Furnace steelmakers in the Asia Pacific region will be the principal customers for the product. This paper presents an overview of the facilities to be constructed by the project as well as discussing some particular technology and design engineering issues associated with the project.

Jan 1, 1996

By Allnutt S. L, Carswell J. T, Mutton A. J

The Dugald River Zn-Pb-Ag deposit occurs within the complexly deformed and metamorphosed sediments of the Middle Proterozoic Cloncurry Terrane, Eastern Succession, Mount Isa Inlier. The sedimentary sequence comprises a thick package of variably carbonatic argillitic and siliciclastic sediments of the Corella Formation, Lady Clayre Dolomite and Knapdale Quartzite. A slate and calc-argillite unit locally referred to as the Dugald River Slates is the host to the economically significant deposit. The deformational history of the Dugald River area involved three phases of ductile deformation. The present geometry of the Dugald River Main Lode is recognised as a strike extensive steep westerly dipping tabular sheet, within which a steep north westerly plunging zone of pronounced thickening is evident. This zone is interpreted to have formed during folding via remobilisation of the sulphides into a shoot-like body, the geometry of which was controlled by stretching associated with the folding. Further modification of the shoot and sulphide re-distribution has resulted from late phase transgressive shears. The sulphide mineralisation is characterised by three distinctive sulphide types, laminated, banded and breccia, the distribution of which define two broad zones. The northern zone is a narrow I - 5 m thick stratabound unit comprising finely laminated and banded sulphide mineralisation within a well bedded fine grained argillite sequence. This is part of the Lady Clayre Dolomite sequence and is a predeformational precursor form of mineralisation. The southern zone comprises the thickest development of mineralisation (up to 30 m) characterised by slate-sulphide breccias and veins derived from complex polyphase remobilisation of the sulphide mineralisation. It is this zone which forms a stratabound locally transgressive body within the high strain Dugald River Slates and which contains the main body of economic mineralisation. Sulphide mineralogy comprises sphalerite, pyrite, pyrrhotite, galena and traces of chalcopyrite, pyrargyrite, tetrahedrite, marcasite and arsenopyrite. The present resource for the Dugald River deposit stands at 38 Mt grading 13.0 per cent Zn, 2.1 per cent Pb and 42 g/t AS. The Dugald River Zn-Pb-Ag deposit is regarded as an example of a syndiagenetic stratabound sulphide accumulation which, as the result of polyphase deformation and upper greenschist to middle amphibolite facies metamorphism, has undergone extensive remobilisation and Rccrystallisation.

Jan 1, 1993

By Wright D. J

Successful heap leaching depends on three major factors: 1. Chemical conditions appropriate for the dissolution of the valuable metal; 2. Contact between the leach solution and the valuable metal particles; and 3. Movement of the leach solution through, and out of, the heap. Given that appropriate chemical conditions can be provided, and the individual particles have sufficient permeability to allow solute/solvent contact, the problem of getting the solution to and from the particles remains. Non-uniform percolation of solution throughout the heap, caused by the presence of fines, is a common problem which occurs, to some extent, with all heap leachable ore. The conventional solution to this problem is agglomeration, which involves the attachment of fine particles to larger particles, effectively modifying the size distribution by preventing the fine particles from acting on their own. While agglomeration must be considered as an extremely effective technique with virtually no limit to its application from a technical point of view, its application is limited by economic considerations. A new technique has been developed which is not only a low cost alternative to agglomeration, but also has the potential for enabling the application of low cost heap and vat leach techniques to a significantly wider range of ores than current practice would suggest. The new technique, known as Electrokinetic Leaching, utilises electro-osmotic flow to enhance percolation through the heap. This paper describes and presents results of the laboratory testing, pilot heap operation and commercial application of Electrokinetic Leaching of a low grade gold ore and a tailings deposit. Comparative cost analyses between conventional and the alternative processing techniques are presented.

Jan 1, 1994

Exploration risk increases with time, due to a general decrease in prospectivity as the more accessible deposits are found, and be- cause of rising costs and demands due to an improving standard of living. Risk is separated into financial risk, which increases sharply at the development stage, and the risk of failure which is at its peak at the outset of exploration. Risk is also divided into internal and external factors; some of the latter cannot be offset, viz. the systematic overall risk for any enterprise. The recently emergent risk embodied in withdrawal of large areas from exploration access is discussed. An appeal is made for objective multiple land-use policies to be applied so that land remains available at reasonable cost and with appropriate environ- mental safeguard conditions. Risks specific to gold exploration are discussed. As gold now accounts for over 50% of all mineral exploration, and most other metals are depressed, any sharp decline in gold will have grave effects on the ex- ploration industry. Gold exploration will become more difficult and expensive in about five years, after most of the readily accessible deposits in Australia are found. Government's role is important in pro- viding stability and basic data at reasonable cost. Exploration for specific minerals or of particular areas could be stimulated by extending the 150%.tax deductibility of R & D to aspects of exploration of strategic im- portance, particularly in the event of a downturn. Exploration is classic scientific research, at least through to the proving Stages.

Jan 1, 1987

By Rose CW

Typical rehabilitation programmes for spoil piles and waste dumps in open cut coal mines involve the spreading of topsoil to assist vegetation growth. In the early years of rehabilitation before a protective vegetation cover has been established, this topsoil is susceptible to erosion during rainfall events. Since the long term success of rehabil- itation procedures is sensitive to adequate topsoil maintenance and since, on many mine sites, topsoil is a scarce resource, erosion losses of topsoil (particularly once fert- ilised) can severely restrict rehabilitation Measures.

Jan 1, 1983

The bulk and surface chemistry of metal ion hydrolysis and precipitation and the redox chemistry of metal ions, sulphur, and other species is central to an under- standing of flotation. The paper contains a review of general hydrolysis-redox chemistry appropriate to the flotation process, and a model of natural and collector-induced flotation of sulphides is constructed. The practical application of the model to real flotation systems is then explored with a view to better under- standing of the chemistry of selectivity and grade control.

Jan 1, 1984

When a thin film of volatile matter is deposited under vacuum on a polished coal surface, and the coated surface is examined microscopically in piano--polarized reflected light, colour changes are observed characteristic of the various macerals present. The colour changes appear to be mainly due to interference between light reflected at the upper surface of the film and at the film/coal interface. A variety of source materials for the volatile matter required have been tested, including powdered bituminous coal, coal tars, boron oxide, and certain resins.

Jan 1, 1969

By Billingham R

The Department of Mines Tasmania employs a Drilling Section for specialised drilling re- quired by government and semi-government bodies. The section has a complement of nine crews oper- ating auger, cable tool, rotary and diamond drilling plants. For some years the Department has been involved in site investigation drilling of the Derwent River. The experience gained indicated that drilling methods should be altered. In 1976 an urgent programme was requested and the opportunity was taken to solve many problems associated with previous investigations. Equipment and methods are discussed in detail. The improved technique contributed to the suc- cessful completion of the Phase 1 site investi- Gation.

Jan 1, 1977

The Quioma Mine is located along the axis of the Cordillera Oriental, 130 km southeast of Cochabamba, South Central Bolivia. Silver, lead, zinc, antimony, and gold have been intermittently produced from veins in the Quioma area since Colonial times. Mineralization occurs within steeply dipping fissure veins transecting moderately folded Lower Ordovician sediments. Tectonic activity is early to mid-Tertiary and the vein system parallels the fold axis of a major northwest-southeast striking, doubly plunging anticline. Vein sets occur within a 2 km wide band over a strike distance of 13 km along the northeast limb of the anticline. Economic mineralization occupies syntectonic pre-mineral fault zones developed in more competent stratigraphis units of Lower Ordovician clastic sediments. Veins average 55 cm in width, although mineralized structures up to 3 m wide with a known strike length of several hundred meters have been mined. Mineralization consists of siderite, argentifferous galena, sphalerite, and quartz, with minor amounts of chalcopyrite, barite, and bournonite. Pyrite is rare except at the Boston vein where it occurs with stibnite that contains trace amounts of gold. A marked characteristic of veins in the district is evidence of repeated stages of movement during mineralization. Intrusive rocks are rare in the Quioma area. Narrow porphyritic dikes of Andesitic composition averaging 1 m in thickness have been observed. These dikes occasionally show a close spatial relationship to the veins and are often kaolinized and carbonitized. Vein and dike contacts are sharp and alteration does not appear to extend into the wall rock. Mineral zoning is suggested by antimony mineralization observed in peripheral areas of the anticline.

Jan 1, 1987

By T J. Sheer

The removal of airborne pollutants from underground ventilating air is discussed. The work concentrates on the removal of CO, CO2, NOx, SO2, radon gas and respirable carbon particles. The investigation combines techniques for multiple contaminant removal using forced chemical absorption and oxidation. Both dry and wet scrubbing techniques are employed. Mixed success has been achieved in the tests carried out and this paper is seen as a progress report on the work done to date. The interference and interaction of the gases on the individual removal efficiencies is a very important factor in the finalisation of a macro air conditioner (MAC) design for treating underground ventilating air. This necessitates a specific sequence of contaminant removal. Efficiencies are discussed and recommendations made. Wet forced chemical absorption and oxidation processes, though efficient in terms of removal efficiencies, cannot be employed in the confined underground environment due to safety and health risks. Impacts on the internal water reticulation systems of the mine have been analysed to determine the effect of future large-scale macro air conditioning practices, including blow-off liquids discharged into the water circuits. To engineer the safety and health risks out of such designs can be costly and it is for these reasons the research now concentrates on dry scrubbing of the contaminants from the underground ventilating air. The paper concludes with statements on the benefits of macro air conditioning in deep hot mines, in both recirculating and series air ventilation distribution strategies. These benefits include reduced re-entry times after blasting and increased production rate opportunities.

Jan 1, 2005

According to our experimental results, the following oxygen probe recommended, that is, the magnesia stabilized zirconia was employed as a solid electrolyte and Fe.FexO solid elect- rode was used as a reference electrode. Using such an oxygen probe, we tried to measure the oxygen potentials in molten metals, mattes and gases in the following fields of non-ferrous metal industry, molten copper in the side launder before casting, molten crude lead in the forehearth of ISP blast furnace, molten copper mattes in the forehearth of blast furnace and in the settler of flash smelting furnace, gas in the settler of copper flash smelting furnace and flue gas in the electric furnace for ferro-silicon. In the past ten years or so, many experi- mental results in the field of fundamental studies have confirmed that the equilibrium oxygen potential could be measured conveniently and accurately by an electrochemical method using a zirconia solid electrolyte. Recently, such an electrochemical technique has been also applied to a device for physicochemical invest- igation or process control in the non-ferrous metal industry. Such a device consists of an oxygen con- centration cell with stabilized zirconia, and it is commonly called an "oxygen probe" or "oxygen sensor".

Jan 1, 1980

Before the arrival of the first Europeans, Aborigines living in the northern Flinders Ranges mined ochre - an earthy form of haematite used for pigment.The discovery of copper ore at Kapunda and Burra in the 1840s stimulated the early settlers to prospect further north along the ranges. Many of the new discoveries were not properly evaluated and companies were floated on the most tenuous evidence.

Jan 1, 1993

Feasibility is a value improvement process for projects. At any stage in project development, a feasibility study can be undertaken, but although the scope generally remains unchanged the extent of detail and level of accuracy usually increases with time. The main scope elements are a business definition, project description and an execution plan. The studies are designed to assess the potential of the project and to secure funding for on-going examination. Invariably, the investigations loop back to earlier stages to establish more appropriate development criteria but a critical stage is reached when a project construction decision is requested. This feasibility study requires very detailed presentation and analysis to a higher accuracy for the owner(s) and their potential lender(s).

Jan 1, 1997