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By Mayer TE

The Granites Goldfield is located 550 km northwest of Alice Springs. Mineralisation was discovered in 1900 and intermittently worked along nine km of strike until the early 1950's, yielding a recorded production of 470 kg of gold. The geological environ- ment, pre-existing exploration drilling results, and an optimistic view on gold, prompted acquisition of the property by North Flinders Mines Limited in 1975. An agreement was signed with the Central Land Council in August 1983 and drilling commenced in the same month. In the past, gold was won from alluvial deposits, rich quartz veins and lower grade, disseminated stratabound mineralisation. The last is contained within a distinctive unit in the Mt. Charles Beds, of the Early Proterozoic Tanami Complex. This informally named "Host Unit" is a metamorphosed, chemical- pelitic sediment. The schist contains variable proportions of amphibole, quartz, garnet, clinopyroxene, carbonate and sulphide, inter- calated with recrystallised chert beds. Free gold occurs in several mineralised horizons within the Host Unit, generally conformably distributed within lithologic bands or at lithologic contacts. The Host Unit occurs within a sequence of metamorphosed pelitic sediments and intermediate volcanics. Although mostly confined to the Host Unit, stratabound gold mineralisation also exists in both Footwall and Hanging Wall Schists, usually within zones displaying certain Host Unit characteristics. The deposits may be loosely categorised as being of banded iron formation (bif) type, although some important differences are noted between them and classical bif type orebodies.

Jan 1, 1984

By Filmer AO

In contrast to the '50s and '60s, the period of the '80s and '90s seems likely to have low growth in demand but much greater levels of technological change. In such a climate there will be pressure on costs, productivity will continue to rise and competitiveness will be closely associated with maintenance of the most effective technology. The penalties for inappropriate investments, whether short sighted or mistakenly based on a particular view of the future, will be greatly enhanced. Accordingly, there will be a need for significantly improved anticipation of technical change and thus for better planning. Study of the funding and direction of the world's R&D effort can provide a useful input to the planning processes within industries and individual firms. Such a study also suggests some insights into the characteristics of those countries which have achieved substantial growth and high standards of living over the past two decades. These characteristics may offer significant reminders for our own development. The particular implications for the Australian minerals industry include the need for direction that is sensitive to changing market requirements and customer practice. This is not simply "more of the same." In particular it appears essential for both basic and applied R&D to provide a sound basis for the purchase and ongoing development of the new technology required to achieve international Competitiveness.

Jan 1, 1986

By I Canbulat, G Si, Y Duan, X Luo

The presence of unfavourable geological structures such as faults and dykes often can contribute to coal burst risk. Seismic events associated with rock fractures tend to cluster around these structures and it is important to understand the characteristics of seismicity for coal burst risk management. In an Australian underground longwall coalmine, two clusters of seismic activities close to the longwall face and within a section of the maingate roadway which was intersected by a major dyke were respectively identified. The induced seismicity in the dyke-roadway area was closely related to the longwall mining. These seismic events were located and the distribution of seismic events shows that more fractures were distributed on the inbye side of the dyke. The spatial-temporal changes of the seismic event locations delineate the fracture propagation as the longwall mined through the dyke. The frequency-magnitude relationship of seismicity was analysed and it was found that it changed significantly when the longwall was mining towards, through and past the dyke. The monitoring results demonstrate that because of the stiff dyke, the seismicity was intensified in the roadway section. It proves that the dyke promoted stress re-distribution and seismicity in its vicinity. More fractures were induced in the hanging wall of the dyke, whereas less strain energy was accumulated and released in the footwall of the dyke.

Nov 29, 2022

The treatment meIhods selected for the concentrator at Cobar Mines Pty. Ltd. called for a high degree of automatic control of both the grinding and flotation sections.The resulting concentrator layout includes a central control room overlooking both grinding and flotation sections. The control room houses process recorders, controllers, and indicators. together with motor stopstart stations and alarms.Plant instrumentation includes load cells and variable speed hydraulic drive feeders for feed-rate control of autogenous mills, together with nuclear density gauges, differential flow transmitters, and pneumatic control valves for water and pulp density control.Flotation cell pulp levels are controlled by floats and pneumatic actuators; flotation reagent controls include magnetic flowmeters and time-operated solenoid valves.

Jan 1, 1969

New technology is a significant factor in the present upsurge in world, and Australian, gold extraction and production. The main technologies in current use for gold production are described, referring to overseas developments. Areas where existing techniques have shortcomings or new methods are needed are pinpointed and discussed. Much research work on gold metallurgy is under way round the world, and many new developments have potential. Many of the current research activities round the world are covering unusual and striking areas, with surprising results starting to come through. Some of the "blue sky" techniques reportedly under investigation are identified, together with consideration of when changes in technology are of value. The consequences of new technology for personnel involved in gold plant operations will be raised, including the new education now required.

Jan 1, 1986

By D R. Lueking

A technology involving separate unit processes for the generation and use of ferric ions for the oxidation of sulphidic minerals has been developed. The technology utilises a stand-alone automated bioreactor for ferric-ion generation (termed SAAB-FIG) and produces a low pH, ferric ion-rich leach liquor with a high oxidation potential. This leach liquor is then employed, in a separate unit process, to oxidise sulphidic minerals and regenerate ferrous iron that may subsequently be recycled to the bioreactor for the continual generation of ferric ions. The technique was successfully applied for the recovery of copper from chalcocite (Cu2S) and chalcopyrite (CuFeS2), as well as other ores and concentrates containing copper sulphide minerals. Coarse ore, ground ore and concentrates were treated with acidic solutions containing 8 to 12 (g/L) Fe(III) ions at a variety of temperatures. This process yielded over 50 per cent of the contained copper from both chalcopyrite and chalcocite samples. Maximum reaction rates and copper recoveries were found to be highly dependent upon temperature and pH and leach liquors containing bacterial cells displayed little difference in their leaching efficiency when compared to cell-free leach liquors.

Jan 1, 2000

The impact of moves to introduce Abori- ginal land rights was felt in the Northern Territory as early as 1972 when the Federal Government froze the processing of all appli- cations for mining interests over vacant Crown land. The Aboriginal Land Rights (Northern Territory) Act was finally proclaimed on Aust- ralia Day 1977 and since that date the mining industry and the Territory legislature have struggled to make the Act work. Despite these efforts long delays have been experienced by those required to negotiate mining and explor- ation agreements under the Act. In fact explor- ation on Aboriginal land has been effectively stiffled since the introduction of the Abori- ginal Land Rights Act. The Northern Territory government and the mining industry have both sought amendment to the Act to remedy some of its more onerous problems. These efforts have generally been fruitless. Some of the recommendations put forward by Mr Justice Toohey following his recent review of the Act would provide relief in some important areas. However, any such improvements are more than offset by a number of Mr Justice Toohey's recommendations which would severely disadvantage the vast majority of Territorians. A recent survey of mining companies seeking exploration licences over Aboriginal land indicates that many of the existing diffi- culties could be overcome without significant amendment to the Act but rather by the adoption of a positive administrative approach by the Land Councils. It is now up to the Commonwealth and the Land Councils to demonstrate that their Act can work without crippling the Northern Territory economy and its mining industry.

Jan 1, 1984

The most frequent initiation of coal dust explosion results from the ig- nition of high methane volumes, often at low concentration close to the minimum flammability limit, by a weak ignition source, e.g. frictional sparks. Tests performed in the 400 m underground test gallery of 7.5 m2 cross section indica- ted the following: 1. Methane at 200 m3 volume and con- centration 4.0 - 5.0 % CH4 may initiate the coal dust explosion. 2. Suppression of explosions result- ing from such initiation is very difficult, even when employing triggered, barriers.

Jan 1, 1988

Exploration for uranium in Australia has so far discovered reserves equal to 17.5% of the Western World's. The Australian uranium industry, when fully developed, will be one of the largest producers and possibly the largest exporter in the world. The world's nuclear industry is young, rapidly developing in size and technology and is subject to more social, political and regulatory controls than any other industry. This paper considers the probable development of Australia's uranium industry against a background of normal commercial parameters together with other factors which are peculiar to the nuclear industry. As the theme of this conference is "Australia's role in the World Mineral Indus- try" this paper concentrates on the commercial and practical aspects associated with the development of Australia's uranium resources in a world context.

Jan 1, 1979

The Directional Drill Monitor (DDM) is an advanced instrument for real time in hole surveying. It was developed by Du Pont (Australia) to suit Australian gassy coal mining conditions. The instrument consists of three units: i. Down hole transmitter ii. Acoustic transducer iii. Data receiver processor unit (i.e. up hole unit). This paper describes the function of each unit in detail and highlights the importance of the DDM in long hole drilling efficiency. Surveying is carried out independent of hole depth. Each survey takes 2-3 minutes to complete, the frequency of surveying to control borehole trajectory is determined by the accuracy required for a particular hole.

Jan 1, 1992

By Wright R, Stock E. C

The Windarra nickel deposits known to date comprise two sulphide orebodies located at Mount Windarra and South Windarra. These orebodies, which are 15 km apart, lie within an ultramafic complex at or near its footwall contact with a banded iron formation. The Windarra deposits are 270 km north-northeast of Kalgoorlie in West- ern Australia which was the centre of a major nickel exploration programme fol- lowing the discovery of nickel deposits at Kambalda in 1966. Surface indications of the Mount Windarra orebody were discovered in 1969 by Mr. Ken Shirley while prospect- ing the Laverton area for Poseidon Ltd. (then NL). The mineralisation was loc- ated by systematic prospecting for goss- anous material associated with aero-mag- netic anomalies and ultramafic rocks. The South Windarra deposit was dis- covered in 1971 by the Union-Hanna- Homestake Joint Venture, by exploring along the strike extension of the mount Windarra ultramafic-banded iron format- ion contact. A detailed ground magnet 1. Acting Operations Superintendent, Windarra Nickel Project, Windarra, W.A. 2. Senior Geologist, Windarra Nickel Project, Windarra, W.A. 3. Mine Geologist, Windarra Nickel Project, Windarra, W.A.

Jan 1, 1973

The kinetics of chlorination of alumina and bauxite with CO/CI2 mixtures were studied in the range 300-1100°C. The temperature of prior calcination is critical in determining the reaction rates. An optimum chlorination temperature in the range 600°C-750°C was demonstrated such that there is no increase in reaction rates with increasing temperature. This lack of rate sensitivity to rising temperature is largely a function of the influence of gaseous diffusion gradients in the porous alumina together with a progressive decrease in surface area.

Jan 1, 1976

The Myally Beds, Surprise Creek Beds and Mount Isa Group form the upper part of the Proterozoic Western succession of rocks in northwest Queensland. The latter two units are partly equivalent, and are important for their base metal content at Mount Isa and elsewhere. The arenaceous Myally Beds lie unconform- ably or disconformably below the Mount Isa Group and Surprise Creek Beds; they contain four mappable units which were deposited on a broad, shallow shelf washed by east-trending currents. Emergence of the Myally shelf initiated a series of parallel, possibly intra- cratonic, troughs to the east and west. In the east, the Surprise Creek Beds were deposited between the emergent shelf and base- ment rocks, and consist of a shelf and trough facies divisible into 7 and 10 units, respectively. Trough sediments are continuous north-south, and show turbidite character- istics; algal dolomite characterizes the shelf facies. To the west in the Mount Isa trough, an orthoquartzite facies, the Warrina Park Quartzite, defines the base of the Mount Isa Group. Hinge zones between the shelf and trough environments are marked by east-west facies changes, and provide a focus for later major north-south faulting. However, some penecon- temporaneous faulting near Mount Isa is best explained as complex post-depositional faulting of a disconformable sequence. Subsidence and deposition in the Mount Isa trough continued for a longer period than in the Surprise Creek trough, allowing accumulation of lead and zinc deposits in the upper half of the sequence. The Surprise Creek Beds appear equivalent to the lower half of the Mount Isa Group, and are probably not prospective for lead and zinc. Turquoise and possible other secondary copper minerals are widespread in the Warrina Park Quartzite and equivalents in the Surprise Creek Beds, and further investigation of these formations seems warranted.

Jan 1, 1974

The success of any industry depends on the planned integration of the policies and resources of the key components of the Australian economic and political structure - government, industry management, education, research, and the human resources of the industry. The Australian Mineral Industry, like Australia itself, has grown and developed at a rate not foreseen by many of our founding fathers and early industry leaders. Hence, now, as we approach the 21st Century, we need to re-think our approach to the significant new problems that are beginning to face both government and the Mineral Industry. Government initiatives, government information and support services, industry re-structuring, and research and development support, need to be carefully re-evaluated, re-diredted,. and strengthened, so that government, the community, and the Mineral Industry produce and receive the optimum education and research strategies and services. The support of academics and researchers, the development of facilities, and the design of new Courses for the future successful and beneficial exploitation of minerals need particular consideration.

Jan 1, 1986

The Perth Mint receives gold and silver from various sources for evaluation and refining. The metals are received in many forms and vary widely in assay. Refining is carried out using the Miller Process and the and the resulting market quality bullion is sold in a range of weights and alloys to suit the international bullion market and public demand. INTRODUCTION The Perth Mint was established in the late nineties as a branch of the Royal Mint, London, to refine the gold from the newly established gold- fields in Western Australia. The branch was opened for business in June, 1899. After refining, the bulk of the gold was used in the manufacture of sovereigns and half-sovereigns. Nowadays, although most of the gold received comes from the W.A. goldfields, some gold is deposited by producers in other states and in Papua-New Guinea, as well as scrap and trade wastes from manufacturing jewellers and old jewellery from the general public. Silver is deposited in the form of old silverware, recoveries from-photographic processes etc. Gold or silver may be lodged at the Mint in person, through a bank or other agency or by registered post. Telegraphic advice is usually given when gold is sent by the latter, so that insurance may be effected.

Jan 1, 1982

By J Parmenter

Issues around water û its quality, use, availability and environmental value û can be a major point of tension between mineral projects and local communities. Failure to manage these issues appropriately can jeopardise the obtaining of regulatory approvals for new projects and place at risk the æsocial licence to operateÆ of existing operations. Conversely, there may also be significant opportunities for companies to engage constructively with communities over water issues and to make a positive contribution to the sustainable development of these communities. Using case studies, this paper will explore the various types of social risks and opportunities associated with water and mineral resource development and identify key learnings relating to the management of these issues.

Jan 1, 2006

By G MacDonald, B Forsyth, D Corkery, T

An investigation was carried out at Diavik Diamond Mines Inc (DDMI) to identify and quantify the mechanisms through which ammonium nitrate (AN) was entering the mine discharge water. The goal was to develop and complete an investigation of the potential AN loss mechanisms in order to assess their contribution to ammonia in the mine water system. The initial phase of the project involved the collection and analysis of blasting and water quality data that were used to determine the mechanisms by which the ammonia enters the mine water system and to establish a baseline data set for comparison with results from future trials designed to reduce AN loss. Three potential options for reducing AN loss were identified through the first phase of the project. The second phase of the project involved conducting a series of monitored trials with changes made to the drilling and blasting process. The results of these trials were compared to the baseline data set to determine if the changes introduced for the trials had reduced AN losses while producing satisfactory blast results. This paper describes the process for the collection of the baseline data, provides an analysis of the resulting data, discusses the changes made to blasting operations in order to minimise AN loss and describes the results observed subsequent to these changes.

Jan 1, 2007

By Fernando N, Guang LX

Brown coal in Victoria in spite of its substantial reserves is not utilized greatly because of its high moisture content(-65% w/w). Transportation and handling costs of raw brown coal, on an available energy basis are so expensive that 93% of production is burnt for electricity generation on or adjacent to the coal deposit in Victoria. With direct firing of moist brown coal in power stations, approximately 20% of the gross calorific value of the fuse is used to evaporate the water contained in the coal. This energy is lost as vapour with the flue gas which is vented to the atmosphere. Also there is a 25% increase in flue gas volume and the size and cost of most of the units through which it passes must be appropriately larger. Since there are large quantities of water present the flame temperature is significantly reduced. For zero excess air and no air pre-heating the theoretical flame temperatures are: 609'o wow moisture 1450¦C 40% ª ª ª 1790¦C ZOO ª ª ª 1990¦C As a result of this there is a reduction in radiant heat transfer leading to a requirement for a two fold increase in radiant tube area. A boiler of much greater size and cost is thus required to house the additional tubes. Figure 1 illustrates the relative sizes of a boiler fired with 60% moisture brown coal with a boiler or similar output fed with a British bituminous coal, 14% moisture.

Jan 1, 1989

Distillation of the large and growing greenhouse literature indicates that: ò Global warming has occurred over the past century or more; ò Build-up of CO2 (and lesser greenhouse gases) in the atmosphere is a fact; ò This build-up is likely to cause further global warming. It does not appear possible to conclude that the observed C02 build up and observed global warming are linked; nor is it yet possible to forecast global or regional climate variation with conviction. The dominant greenhouse gas is C02 with about half the warming potential of those gases emitted by man's activities; and about 80% of anthropogenic C02 emissions are from the burning of fossil fuels. Fossil-fuel C02 emissions arg divided about equally between the developed countries of OECD and the rest of the world. However C02 output growth over the past decade was about 4% for OECD and some 40% elsewhere. Population growth and pressure for better living standards will ensure continued higher growth outside OECD. Uncertainty about the impact of increasing C02 emissions on climate, and the long lead-times involved in limiting the increase in atmospheric C02 concentrations, are good reasons for taking action now. Australia accounts for about 275 million tonnes a year or just over 1% of the CO2 emitted from the world's consumption of fossil fuels, and the fight to control global emissions will be won or lost elsewhere. Australia's participation will be by wise conselt and by example. In view of the uncertainties involved, it appears premature to take actions that might place an additional financial burden on our hard-pressed country. However, much can be done now that makes good economic sense and has the added benefit of limiting the growth in Australia's CO2 emissions. Natural gas emits less C02 per unit of energy when burned than either coal or oil. Furthermore, new gas-fired power stations utilise energy at considerably higher efficiency than is the case today with coal or oil. Because of much lower capital costs, there is a compelling economic case for permitting natural gas to compete freely with coal in the Australian power generation market.

Jan 1, 1989

By Beattie T

For many years explosive sensitized explosives were assessed using the ballistic mortar. The standard test used lOg of explo- sive initiated with a detonator. Over the past 30 years many non- explosive sensitized explosives and blasting agents have been developed. Most of these new explosives and blasting agents cannot be tested in the ballistic mortar as they are not initiated by a detonator. It is also known that all explosives have a criti- cal diameter. When the cartridge diameter is less than the criti- cal diameter a stable detonation cannot be produced and the explosive fails to propagate. For many blasting agents the criti- cal diameters are greater than 50mm and such large diameters cannot be tested in the ballistic mortar. The underwater test allows explosives to be tested in diameters greater than the critical diameter and to be adequately initiated with suitable boosters. The effects of the explosive on the water are easy to measure and the test provides a safe, convenient and reproducible means of assessing explosive performance. The reaction products are allowed to expand to a low final pressure. The underwater test can therefore be used to give a measure of the total expansion work of explosives. The detonation of an explosive induces a shock wave in the surrounding water. The profile of the shock wave can be meas- ured 3-6m from the charge and the energy in the shock wave cal- culated. Measurements over a range of distances show that the shock wave is attenuated as it travels through the water and the attenuation is different for each explosive. This makes it difficult to estimate the energy dissipated in the water between the charge and a single gauge. The reaction products continue to expand and displace water. The bubble continues to expand until the kinetic energy of the water is zero. The gas pressure in the bubble is now lower than the hydrostatic pressure and the bubble radius is a maximum. The higher external hyrdostatic pressure causes the bubble to implode. The bubble energy is the work done displacing the maxi- mum bubble volume against the hydrostatic pressure and can befound from the bubble period. It is not always easy to find a large enough pond for the bubble to expand undisturbed by the water surface and the containing boundaries. This makes it difficult to determine the bubble energy accurately in shallow Ponds.

Jan 1, 1988