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By Somerville M, Muray A, Bocking M

Australia has an extremely large total hot dry rock (HDR) resource above a depth of 5 km, equivalent to 7500 times its present annual energy consumption, of which 80 per cent underlies the Great Artesian Basin. The resources most likely to be exploited first are those residing in homogeneous granitic bodies beneath sedimentary basins containing insulating rocks such as shales and coal measures. In the Sydney Basin south of Muswellbrook, an area of high geothermal gradient corresponds to a gravity low thought to be a buried granite body at a temperature of possibly 250¦C. This locality is suspected to have the ideal geological characteristics for Australia's first hot rock test facility. Australia's high HDR potential is possibly unique in the world, in that the potential sites satisfy four independent, geological conditions, each considered as favourable for the creation of a resource, and for the ease of extracting that resource. They are: ò Higher crustal heat generating capacity than that of normal continental crust. ò Much of the Australian continent is covered by sedimentary basins which contain a high proportion of shales and coal measures that have low thermal conductivities, thus providing an insulating blanket for the heat being generated beneath. ò The sedimentary basins are in many places underlain by large untectonised granitic bodies that are not only a major contributor to heat generation, but also ideally suited to the establishment of HDR reservoirs. ò The crustal shortening stress field that is found in the majority of the Australian continental crust results in a vertical minimum principal stress orientation which should result in the development of favourably oriented horizontal stimulation cells necessary for maximising an HDR resource.

Jan 1, 1995

By Tilyard P. A

Recent exploration has established depos its of nickel sulphide in several areas of Western Australia. To assist in their develop- ment Amdel has investigated the beneficiation of many samples from these deposits and has estab- lished flowsheets for the recovery of nickel values by flotation. Metallurgical data are presented for the samples according to four factors which were encountered in their respective treatments.

Jan 1, 1973

By Fitter JF

Drilling and blasting practices at Groote Eylandt are undergoing a period of rapid change. Practices over the last ten years are reviewed and some specific blasting problems currently being faced are described. A move from percussion to rotary drilling is outlined, together with the reasoning behind a proposed return to ANFO from watergel explosives. A brief outline of the various firing patterns used is given, together with a description of the drilling and blasting recording procedures currently in use. Current and planned developments in drilling and blasting at Groote Eylandt are also outlined, emphasizing the success of wide patterns, fired in line with long inter-row delays.

Jan 1, 1982

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

By Oversby B, Wellman P, Wyborn D, McPhie J, MacKenzie D

The Bureau of Mineral Resources (BMR) and the Queensland Mines Department are engaged in integrated regional- and deposit-scale studies in the Burdekin Falls-"Conway" area, about 100km southeast of Charters Towers (Fig. 1). The regional work augments recent mapping in the Mount Coolon area farther south (Hutton et al., in prep.). These studies are aimed at improving understanding of gold mineralisation and its geological setting in the Drurunond Basin and associated rocks. Knowledge of the regional stratigraphic- structural framework and setting of mineralisation has until now been based on investigations dating from the early to mid 1960's (mainly Bowen 1:250 000 Sheet; e.g. Paine et al., 1974; Wyatt et al., 1971), and on regional syntheses (Olgers, 1972; Levingston, 1981). Some recently explored epithermal gold occurrences in the region have been interpreted on the basis of this early work as being hosted by the Late Carboniferous Bulgonunna Volcanics. The objective of our field research was to refine the regional geology, paying particular attention to the Bulgonunna Volcanics. The results summarised here indicate that unnamed Devonian-Carboniferous volcanics (DCv) of the northern Drummond Basin and mid to late Palaeozoic granitoids are much more extensive, and the Bulgonunna Volcanics much less so, than was previously recognised.

Jan 1, 1989

In eastern China, most of the copper skarn deposits occur in folded troughs which are controlled by the EW-trending faulted fold systems (the Pal-Asian geotectonic domain), and the NNE-trending rift or fault zones (the Marginal-Pacific geotectonic domain), particularly the later. From the north to the south, there are four troughs hosting the main copper skarn deposits in eastern China: the Yanliao Trough, the Yangzi River Trough, The Qiantang-Yuanshui Trough and the Zichen Trough. There are more than 30 copper skarn deposits in eastern China, and ore reserves of each deposit are between 30 to 100 Mt with average grades over 1 % Cu.

Jan 1, 1995

By Gonzalez JM

The Pao gold prospect in N. Luzon, is an example of a high sulphidation epithermal gold system hosted in Mid-Tertiary alkaline volcanics, in the Philippine Arc. Styles of mineralization include: quartz-enargite veins, vuggy silica alteration bodies, and pervasive low grade (0.5ppm) gold mineralization, associated with kaolinite-pyrite-quartz alteration, and geochemically characterized by high As and Hg. Early magnetite-epidote-chlorite alteration linked to an unexposed granitoid is overprinted by an extensive zone of advanced argillic alteration (kaolinite-pyrite-quartz). No alunite is recorded. Important controls of mineralization include; a broad anticline intersected by axial faults, permeable pyroclastic units, and upward confinement of the alteration system by a highly impermeable, clay-rich volcanic unit. At this stratigraphic position the most important mineralization waz developed. The Pao high sulphidation system is not closely related to a stratovolcanic centre, and has formed subsequent to deformation of the volcanic field. It may, however, be related to an unexposed comagmatic intrusion.

Jan 1, 1990

This paper details a proposal for integrating the use of the Pilbara Iron Ore Classification (PIOC) and stratigraphic data for fine tuning blast. pattern design on Mt Whaleback. The main thrust of the proposal is based on the assertion from Haqan and Harries (1979) that rock properties influence blasting results more than explosive properties. This premise is supported by a literature search, which indicated that blasthole burden, spacing, stemming and subdepth lengths are also determined by rock properties if the same explosive and blasthole diameters are used. A brief explanation of the PIOC is provided during which it is noted that the classification is based on physical hardness, mineralogical and genetic characteristics of the ore. The classification also extends to the two main waste rock types LBIF (banded iron-formation) and shale]. Ore type plans produced from face mapping indicate that many areas on Mt Whaleback can be divided into various PIOC zones and regions thus making it more useful in blast pattern design. Several recommendations for blast pattern design experimentation are made for hard, medium and soft ores as well as for the waste rocks, the most important being the use of expanded patterns to blast. soft BIF and medium hard to soft shales.

Jan 1, 1986

By Toomey P. T

In many open cut coal mines, rivers and large creeks can cause planning and operating difficulties, both in the terms of the more obvious location of the current watercourse, but, and sometimes more importantly, past meandering of the watercourse. Prevent and past flow regimes may have deposited large alluvial sequences within the current mining areas. The presence of groundwater within the alluvium further complicates the planning and operating practices.A situation exists at Saraji Mine in which alluvial sediments overlie a massive sandstone sequence which in turn lies at about one metre above the coal seam. The problems encountered include high levels of groundwater ingress to the pit, highwall instability, and an unacceptably high rate of blast hole collapse (prior to charging with explosives). Other aspects of the dragline stripping operation were also affected.

Jan 1, 1992

Scale build-up in titanium palladium alloy spent electrolyte heat exchangers in the residue treatment plant commissioned at Risdon, Tasmania in 1971 was shown to be a mixture of manganese dioxide and anhydrite (CaSO4). The manganese dioxide was deposited as a result of thermal decomposition of permanganate ions present in the spent electrolyte. It was shown that deposition of manganese dioxide and associated anhydrite scale could be prevented by prior reduction of permanganate ions to the manganous (Mn++) state by the addition of ferrous ions. In the plant this was conveniently accomplished by injecting into the inlet line to the heat exchangers sufficient zinc plant solution containing ferrous sulfate to decolourise the spent electrolyte. This action prevented deposition of such scale for another 21 years, until the heaters were finally decommissioned in March 1992. Measurements indicated that addition of the reducing solution lowered the anodic potential of the titanium alloy by 200 - 300 mV (depending on the solution resistance), but that it was still +300 to 400 mV with respect to a standard calomel electrode. It was shown that, if necessary, a small impressed current could be applied to provide anodic protection. Before scale deposition was overcome by the addition of ferrous sulfate solution, badly scaled heat exchangers were cleaned by recirculating a solution of hydrogen peroxide in spent electrolyte or dilute aqueous sulfuric acid, after laboratory testing of a variety of possible solvents for the scale. Corrosion tests indicated that attack on the titanium alloy by the acidic peroxide cleaning solution was insignificant.

Jan 1, 2005

By K Baskaran, T McKenzie

Sustainability is becoming increasingly important in the mining and mineral processing industries and must incorporate the associated waste products. Acid mine drainage (AMD) is one such by-product and is one of the most serious environmental problems facing the minerals industry today. The oxidation of sulphidic mine wastes often continues for a substantial period of time after mine closure, resulting in difficult and costly remediation and rehabilitation works. Mining companies are often reluctant to spend increasing amounts of money on waste treatment when the mine life is limited or even finished. Hence a simple, low maintenance and low-cost method of treating AMD is required. Whilst this paper does not address the issue of AMD, it does propose methods for removal of individual species from AMD with potential benefits, including raising AMD pH. A novel concept of using biosolids as a biological adsorbent, or æbiosorbentÆ, of metals from AMD is being investigated at a laboratory/pilot scale level. Biosolids are a by-product resulting from the biological treatment of wastewater, and have been previously shown to adsorb metals from aqueous solutions. This could lead to an environmentally sustainable or ægreenÆ method for treating both AMD discharges and disposing/reusing the biosolids. The result of a laboratory-scale study of the biosorption of Zn(II) is presented in this paper. Physical parameters including reaction kinetics, mixing speed and solution pH were investigated. Solution pH also rose an average of 2 pH units over the 24 hour equilibrium time û a valuable side effect when treating acid mine drainage. The outcome of the study highlights the usefulness of biosolids as a biosorbent for the removal/recovery of metal ions from acid mine drainage. A simple, low-cost treatment technology requiring low maintenance would be beneficial to the mining industry to address some issues relating to AMD and would help integrate environmental and economic considerations into sustainable environmental management.

Jan 1, 2002

IN preparing a sample of refined lead for analysis, it is necessary to exercise great care to avoid contaminatien, as the amounts of the various impurities present in market lead are very small. The lead is cut into convenient-sized pieces, which are flattened out with a hammer, so that, on putting tbe lead through the rolls, strips of about one inch in width and Ij32iu. in thickness are obtained. The hammer, anvil, and rolls should be carefully cleaned before use. The strips oflead are cut up into pieces of about one inch square. If the lead is roIled out very thin and cut up into small pieces there is considerable risk of the acid acting too violently and causing loss through frothing over. A blank assay on all the reagents used should becarried right through, along with the actual analysis of the lead. This is of the greatest importance, particularly with regard to the determination of such impurities as iron, sulphur, arsenic, and antimony.METHOD OF ANALYSISThe method of analysis is as follows: Take two lots of 600 gIm. each, place in a large beaker, add 2000 cc. distilled water and 750 cc. concentrated HNOs. Cover with a clock glass and warm on a hot asbestos plate until all action ceases. (If any white precipitate forms, filter off and examine for Sn and Sb.) Add 420 cc. H2S04 (1-1), and stir well while adding the acid: Allow PbS04 to settle, pour off the clear liquid into a 12-in. porcelain evaporating dish, and start evaporating down, the dish being placed directly on an 8-in. ring gas burner. Wash the precipitate three times by decantation using approximately 1200 cc. hot water for each washing, and stir well...

Jan 1, 1922

By Lacy JC

Human habitation of the Pacific Rim began when mankind began migrations out of its place of origin in the Rift Valley of Central Africa c. 4million years ago. This migration was erratic and largely controlled by advances and retreat of the various Ice Ages which, while limiting advances in areas of intense cold, at the same time aided migration thro-ugh the creation of land bridges as ocean levels declined during periods of glacial advance (Fig.l).Mankind began its trek to the Pacific from Africa across India then north into southern China and south into Indonesia (Fig.2). In part, these migrations stimulated early technological develop-ments to fulfill needs and adapt to environmental conditions; thus, these nomads developed stone and bone tools, animal skin clothing and the use of caves and other simple shelters. The earliest evid-ence of mankind's use of fire can be found at Zhou-koudaian near Beijing, c.400,000 BP.From China, the completion of the Pacific Rim's population can be attributed to the last Ice Age that dropped the ocean level by more than 300 feet and created land bridges about 40,000 BP allowing migration across the Bering Strait into Alaska and to Australia from Indonesia. The American migration reached Mexico about 30,000 BP, and by 6000 BP the occupancy of the Pacific Rim was complete when the first human settlers reached the southern tip of Chile.

Jan 1, 1990

This study begins with the semivario- gram modelling of variables rutile grade and clay content from a beach sand rutile deposit. This is followed by two dimensional block kriging. The deposit was divided into blocks of 30 x 30 x 1.5 m dimensions and the kriged estimate together with the associated kriging variances for each variable within each block were determined. Finally, using the results of the krig- ing program and considering the acceptable limit of clay content together with the cutoff grade for rutile, a method for optimization of mineable thickness and hence the tonnage of ore was applied and the results were dis- Cussed.

Jan 1, 1986

Here, in what is partly a review and partly a personal viewpoint, I take stock of changes in emphasis and comprehension on the subject of basaltic volcanism in the decade that has passed since the completion of the landmark Basaltic Volcanism Study Project (1981). I concentrate attention on the relatively neglected physical-volcanology aspects (in 1988 it was still possible to publish a 340-page book on flood basalts with barely any mention of physical mechanisms).I adopt the useful unifying concept of "volcanic system" to embrace the invariably-present intrusions as well as the volcano; I consider controls exercised by magma-supply rate and modulator-mechanisms on the nature of the system;I emphasize that sheeted-intrusion complexes, consisting either of dikes or inclined sheets (depending on the ability of the system to expand laterally) occur in all eroded major systems and fuel geothermal systems; I show how constraints set by cooling of narrow intrusions cause such complexes to be wedge-like and produce considerable rotations; I consider the role of the level of neutral buoyancy in making magma chambers possible, causing lateral subsurface magma flow and localizing intrusions, while the LNB itself can be accentuated by intrusions; and I examine the possibility that underwater systems could have very different internal structures from systems on land.

Jan 1, 1990

The geographical and geological situations of the two mineral sand deposits currently being mined by Western Titanium Limited and the mining methods in use are briefly described. Production scheduling involving the ability to vary the proportions of the major minerals produced, together with maintaining a constant feed grade to the wet concentrator has been assuming greater importance to the company in recent years as the relative value of these minerals, due mainly to technological advances and environmental considerations, is subject to significant and rapid change. Manual calculation, even using a programmable calculator, became a trade-off between man hours and data usage. Schedules were updated infrequently and only a fraction of the avail- able data was used. In July 1975 a Data General NOVA 2/10 minicomputer with a 24K word core and three cassette drives was purchased. A suite of programmes was developed using BASIC to assist in production scheduling and these were opera- tional early in 1976.

Jan 1, 1977

The Broken Hill (BH) Block contains a wide variety of mineralization, with comrodities including Pb, Ag, Zn, W, Cu, Co and Sn. Much of the mineralization is stratigraphically controlled. Fe, Cu and Co-rich mineralization is dcminant in the Thackaringa Group; Pb, Ag, Zn and W is dcminant in the BH Group and Sn mineralization is present above the BH Group. Some mineralization occurs as concordant syngenetic deposits, but other types have been partly or completely remobilized by metamorphism, magmatic activity or hydrothermal fluids. Almost all of the non-syngenetic mineralization, including stratabound, vein and intrusive-related types, has formed from the "recycling" (remobilization and redeposition) of metals originally deposited with the sediments and volcanics of the Willyama Supergroup.

Jan 1, 1983

An intensely sheared and mineralisedIzone occurs in the Quartz Dolerite Greenstone (or Younger Greenstone) mass on, the western limb of the Kalgoorlie Syncline. This zone comprises the western part of the Golden Mile and has produced the greater part of the 33,000,000 ounces of gold produced to date from the main mining belts. A study of.th e general geological and structural features gives rise to the expectation that the lode shear system,will continue southward on a pitch similar to that of the maln syncline whose axial plane may be referred to as the "Boulder Dyke". Although payable ore has recently been found further south than previously, the expectation of large quantities extending southward from the present mining areas is Problematical.'

Jan 1, 1964

By James D, Dawson N

The alternate mineral dressing tech-niques for the production of ilmenite roaster feed from heavy mineral concentrate and the reasons for the selection of wet high intensity magnetic separation (WHIMS) at Richards Bay Minerals are outlined.Initial flowsheet studies were under-taken using laboratory scale equipment followed by on site pilot testing. Flowsheet development culminated with an extensive test programme conducted at Readings of Lismore in 1975.

Jan 1, 1986

High precision GPS systems for mining are accurate to within a few centimetres. Typical systems consist of one or more GPS antenna, GPS boards, sensors to detect the position of the blade or bucket of the machine radios to pick up correction signals, a computer to control the system and a display screen to give instructions and information to the operator. GPS systems offer two benefits û they give information to the operator to get his job done faster and more accurately and they can send information to management about how the job was done. On dozers, GPS systems allow the operator to accurately complete earthmoving jobs with no survey pegs. On hydraulic excavators the systems can be used to accurately locate the position of the bucket teeth for selective mining. On blasthole drills the systems can guide the operator to each hole and record accurate as-drilled plans. By reporting the position of the blade or bucket in three dimensions it is possible to continuously upgrade a mapfile of the excavation. From this file it is then possible to report productivity numbers in real time. High precision GPS works best with a minimum of five satellites visible. This may be difficult in a pit. Systems which also access the Russian GLONASSS satellites offer significantly better uptime. GPS systems will become indispensable for efficient mining operations in the future.

Jan 1, 2003