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By J Chegwidden

Rare earths are a critical minor constituent of many advanced materials that are essential inputs to the manufacture of items such as mobile telephones, computers, televisions and autocatalysts. Although rare earths have a relatively high unit value, the impact of this cost has little, if any, impact on the selling price of the final item. Furthermore, as they are generally present in minute concentrations they are not recycled. It is for these reasons that rare earths are considered strategic materials. China dominates the market as it supplies over 85 per cent of world demand. It has recently taken steps to increase prices through the restriction of exports and support for minimum prices by an association of the major producers. This paper provides an overview of future opportunities for Australia in the context of the current dynamics of world supply and demand.

Jan 1, 2001

Chief Geologist, Groundwater and Engineering Geology Branch South Australian Department of Mines and Energy The six papers submitted for consideration during this session include two dealing with techniques for measing rock mass behaviour, including permeability, in boreholes, one describing the use of surface geophysical methods to delineate pollution plumes in groundwater together with analytical modelling of the plume, and one presenting a biological tracer technique applied to the determination of the origin of water entering underground mine workings. A paper describing dewatering at a base metal mine in Queensland includes an account of the investigation techniques employed to establish a conceptual model as a basis for the evaluation of various dewatering strategies. Of considerable interest is the use of a field gravity survey to delineate a zone of highly weathered rock which forms the major aquifer at the site.

Jan 1, 1988

By Moritz P

Thiourea has been recognised for a long time as an acid-stable complexant for gold. Generally, the use of thiourea has been shown to exhibit enhanced leaching kinetics compared to cyanide but suffers the disadvantage of excessive reagent consumption. Thiourea leaching is particularly com- patible with the extraction of gold from refractory ores. This is due to the need for an oxidative pretreatment to liberate the gold. Such pretreatments typically result in the production of an acidic residue. The application of novel thiourea leaching technologies to the extraction of gold from a bioleached pyrite concentrate was investigated. The interac- tion of leach variables with thiourea consumption and gold extraction was established. An economic assessment of thiourea leaching was compared with conventional cyanidation. The results indicated that gold leaching of the bioleached residue using thiourea compared very favourably with cyanidation.

Jan 1, 1991

Alluvial gold exploration is aimed at recognizing areas of anomalous gold content as evidenced by the nature of the drainage system, its age, geomorphic history and other features of the geological environment including the provenances. Subsequent studies to quantify the findings are governed by the need for accurate data based upon precise measurements. Computerization allows the use of more complicated mathematical procedures than are feasible manually, thus promoting the development of more advanced technological aids. Data banks provide the means of storing vast quantities of information for instant recall.Sample representivity is a major problem and a clear understanding of both sampling and analytical requirements is essential for dealing with problems arising from variations in sample size and particle size distribution. Field samples must always be large enough to ensure adequate representivity or the sampling has failed in its purpose.

Jan 1, 1984

The influence of strongly chemisorbed solutes such as oxygen and sulphur on the rates of reactions at the gas-liquid iron interface is briefly reviewed. Deductions from recent studies of the rates of decarbur- ization of carbon-saturated liquid iron indicate ideal adsorption behaviour for sulphur over a wide temperature and composition range. This is in fair accord with available infor- mation on surface tensions in the Fe-C-S system. Previously unpublished results for the kinetics of the 14C02-CO exchange reaction are in accord with ideal absorption of oxygen on liquid iron. The derived value for the ideal adsorption coefficient of oxygen at 1550¦C is in quantitative agreement with measurements of the depression of surface tension in the Fe-0 system. Consideration is given to the applicability of such results to the violently agitated systems of steelmaking.

Jan 1, 1980

The Ore Reserve System implemented at Mount Isa for Mount Isa Mines Limited is a comprehensive' computer system designed to process assay, geological, structural and survey data for Isa and Hilton Mines. This paper outlines the achievements of this system to date and by example, discusses the various reports and plotted output available. __ The impact of the ore reserve system particularly within the-Geology and Mine Plan ning Departments is reviewed in terms of new approaches to ore reserve calculations, evaluating the economics of various mining methods and reviewing preliminary stope designs. The compilation of metal distributions for both copper and lead orebodies at varying cut offs and reducing the involvement of skilled personnel in preparing non-standard plots of borehole paths are discussed. Options available through the system and their applications are outlined together with the planned future development of the system.

Jan 1, 1974

By Sergeant G. D, Norman J. R

The importance of reducing the moisture content of fine coal, the nature of the retained water and the means of its removal are discussed. A statistical technique, using a balanced block design, was used to isolate the significant factors determining water content of a coal filter cake, The most significant factor was particle size distribution. A simplex evolutionary operation (evop) was used to determine the optimal quantities of additives required to produce the lowest moisture content for a selected coal size. For this optimum condition (18.6 lb xÇ20 per 100 lb dry coal), additions of 0.045 lb magnesium ion, 0.0026 lb separan A.P. 30, and 0.098 lb aerosol O.T., per 100 lb dry coal were required. The work illustrated the uses of statistical evop technique for the determination of optimal conditions in industrial research projects.

Jan 1, 1969

In the future to excavate sufficient coal for power generation, two dredgers would be required to dig overburden or interseam 70010 of the time and three dredgers 40010 of the time. One overburden system was not adequate for this requirement, making coal production reliability vulnerable. TS5 spreader is the new machine element of this system. The selection of the best type of machine configuration to suit the application was then subject to an internal SECV VE Study, a registration of interest and a tender for two machine alternatives. This paper outlines the reasons why SECV planned the Secondary Overburden System and how the Krupp machine met these requirements. It also identifies the main design features of the machine and its constructability which will allow the machine to be operational by the end of May, 1990.

Jan 1, 1989

By Singh DP, Singh TN

The present study attempts to critically review the pillar-design as required by Coal Mines Regulations of India vis-a-vis latest rockmechanics formulae. Equivalent material modelling was the approach adopted for testing the safety and stability of the pillar sizes predicted by various formulae. Two parameters, considered here for calculating pillar sizes was the stresses acting over the pillars and the strength of the pillars. Stresses acting on the pillars were calculated by the tributary area method. Based on the studies of Coates and Hustrulid, the stress obtained was reduced by 40 percent. For calculating the strength of the pillars, three formulae, namely Holland and Gaddy, Salamon and Munro and Central Mining Research Station, India, were used. The pillar widths were then determined by equating the product of recommended factor of safety and pillar stress with the pillar Strength.

Jan 1, 1992

For the past five years the University of Queenslandhas, through its various workshops, been preaching to Australia that there was a potentially hazardous situation from earthquakes for urban Australia. A few people outside The University accepted this, but largely the warnings fell on deaf ears.The 1989 Newcastle earthquake changed that per-ception. The most important lessons to emerge from Newcastle were (i)the realization that in continental areas small earthquakes cause widespread damage:(ii)the local geology of an area is of great importance in the damage done by an earthquake.These two factors clearly indicate that, in the future, we must take far greater account of the "Urban Geology" of an area. This paper discusses the need for urban geology and its impact on seismic risk and compares that with the traditional methods of assessing seismic risk.

Jan 1, 1990

Grade control aims to deliver quality tonnes to the mill via accurate definition of ore and waste. It comprises data collection and interpretation; local reserve estimation; supervision of development and mining; and stockpile management. The foundation of all grade control programs should be that of high quality sampling supported by geology. The requirement for quality grade control samples has long been recognised, where they should be representative, unbiased, safe and operationally timely. Underground sampling methods include chip and channel samples; grab samples; and drill-based samples. To achieve quality samples, collection techniques employed should minimise delimitation, extraction and preparation errors. Grade control staff should be well-trained and motivated, and mining staff should understand the need for grade control. This paper reviews grade control sampling methods and presents recommendations for best practice and minimisation of sampling errors.

Mar 1, 2010

The occurrence of metallic minerals in Australia to the time of the proclamation of South Australia as a Colony in 1836 was unknown. It is, therefore, perhaps, surprising that British settlers arriving in the Coromandel included among their number a German scientist Johannes Menge who had been appointed by the South Australian Company to the post of Mine and Quarry Agent and Geologist on 1 July 1836. His instructions were to `explore the natural productions of the Colony above and below ground and to superintend the working of quarries of stone and slate, the boring for water, metal, lead, coal and other mines at a salary of ú150 per annum for one year and for as much longer as the Company require your services not however exceeding five years'. In the event, he was to have little influence on those matter.

Jan 1, 1993

By Geisler P, Sutherland P

The technical limits for high-pressure transport of large particle solids by means of sludge pumps, piston pumps or the like lead to the development of the pipe-feeder system. The pipe-feeder is a type of pressure lock in which the high-pressure pump itself is not in contact with the solids. Simultaneous operation of the three chambers with corresponding control of the valves allows continuous flow in both the primary and secondary circuits. Initially the pipe-feeder was used only for the transport of solids. Today it also operates with great success in central mine cooling systems, serving as an alternative for high-pressure/low-pressure heat exchangers or Pelton systems. In addition to the technology applied up to now, the pipe-feeder is also capable of transporting ice slurry, thus increasing cooling output consider- Ably.

Jan 1, 1991

By Corrans I. J, Yan D. S

The CIP process for gold recovery has enjoyed widespread application in most gold-producing countries. The development of a mathematical model of the CIP process has value for use in process design, process optimisation, and process control. Mathematical model development through laboratory experimentation is an important step in the design and optimisation of the CIP process. For this purpose, data has been generated through small scale laboratory leaching and adsorption tests both in batch and continuous mode. This test program has been carried out on specific ores of various types prior to the application of the models to production CIP plants utilising these ores. The applicability of leaching models derived from batch experiments was tested in a continuous five stage CIP pilot plant. The models were then adapted to scale-up the batch to the small scale continuous operation.

Jan 1, 1991

By P Waters, P Hollings, M Baker, D R. Cooke

Over the last three million years, porphyry and epithermal mineralisation in the Baguio Mineral District has been driven by calc-alkaline magmatism associated with the subduction of the South China Sea plate and the Scarborough seamounts beneath northern Luzon, Philippines. Coupled with extreme uplift and exhumation rates, mineralisation in the Baguio District has been responsible for the emplacement of over 922 million grams of gold. As one of the oldest intrusive bodies associated with the Baguio District, the Black Mountain Cu-Au deposit consists of at least five intrusive phases overprinted by potassic and propylitic alteration and sulfide mineralisation. Gold ore grades are low and molybdenum grades high with respect to other porphyry Cu-Au deposits in the Baguio Mineral District. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By E Drueppel, M Mistry, J Pateiro

As mining undoubtedly influences the natural environment future challenges of copper ore mining are minimisation of land use in area and duration, proper land rehabilitation as well as tailings management. One possible solution to avoid these negative impacts could be the application of underground mining with backfilling tailings compounds. This approach would definitely increase the production cost. Against this background the project analyses the influence of an æecologically satisfyingÆ copper ore mining on world market prize and demand as well as on the environment. In the project 261 copper ore mines accounting for 98 per cent of world copper production have been examined. After modelling a backfill plant, analyses of applied backfill techniques were conducted. Afterwards a method of cost estimation was developed and then the backfill plant model was applied in three case studies. The results were transferred into scenarios. The work closes with a short discussion and gives an outlook to forthcoming research. The results presented in this work have been generated within the Collaborative Research Center (CRC) 525 entitled æResource-orientated view of metallic raw material flowsÆ. This interdisciplinary project was established at Aachen University of Technology (Germany) in 1997 and is funded by the Deutsche Forschungsgemeinschaft (DFG). The long-term goal of this research program is the identification of options for the resource-sensitive supply and processing of metallic raw materials. In order to address the sustainable development challenges facing the metals and minerals industry an integrated resource management system is to be developed and tested for important metallic raw materials. Case studies for aluminium and copper are being conducted by the CRC 525 in order to provide useful and efficient tools for decision makers over the entire life cycle of these materials.

Jan 1, 2003

By P Cameron

The Julius Kruttschnitt Mineral Research Centre (JKMRC) has recently commercialised a variety of new products for the mining industry through its commercial division (JKTech). Although the products cover a wide variety of niche applications, a common thread runs through the Research, Development and Commercialisation (RD and C) process: they have emerged from industry sponsored projects. The development history of JigScan (a control system for the mineral-processing jig) is a good example of how this RD and C process works in practice. It involves building mutually beneficial partnerships between the JKMRC and the mining industry through several incremental projects with one or more industry sponsors. All research projects have objectives to demonstrate but these projects also feature a degree of product development to actively encourage and support the longer-term vision for the mature commercial technology. The process to develop JigScan as a commercial product worked because each incremental project recovered costs, provided an immediate benefit for the sponsor and contributed to the longer-term development objectives of the JKMRC. Integrating development with research need not greatly increase the cost of research objectives generally provides a more robust research outcome for the sponsor and greatly reduces the overall development risk. Successful projects often feature industry mentors actively participating in the RD and C process. Additional funding from government appears to be easier to obtain when such close partnerships with industry are apparent. Finally, the business structure of the JKMRC within the University of Queensland ensures that commercial outcomes, developed within the contractual arrangements of the underlying RD and C projects, are used to benefit and support further RD and C with the mining industry. This paper tells the story of the development and commercialisation of JigScan, and draws conclusions about this kind of RD and C model.

Jan 1, 2000

The mining industry has had lengthy experience with risk management involving technological situations imposing risks to people and property. In such situations the relevant parameters can be fairly well defined, the outcomes can be broadly predicted and probabilities of these can be estimated. Accordingly quantitative risk assessment can be applied. In recent years there has been increased emphasis in risk management on a broader set of potential consequences. These include potential impacts on the flora and fauna of ecosystems. These are typically poorly understood and this is especially true in Australia where the vast size of the continent and sparse population make gathering a comprehensive data base on biological resources a difficult task. The resulting scientific uncertainty and ignorance regarding the potential for serious or irreversible harm to the environment mean not only that quantitative risk analysis techniques are not appropriate, but also that the precautionary principle (PP) needs to be applied as a complement to qualitative ecological risk analysis. The potential for significant impacts is particularly high in Australian ecosystems. These comprise one of the 12 æmegadiverseÆ regions of the world in terms of biodiversity and, hence, have global significance. Moving from risk management to application of the PP by the mining industry provides a significant challenge. Application of the PP has no clear guidelines to follow and, to-date, has been highly unpredictable. However, there is much to be gained for industry in embracing this challenge and taking a pro-active approach in exploring methods that will provide for clearer guidelines and hence more certainty in outcomes of environmental management decisions involving precaution. As well, there could be considerable other advantages for the mining industry in terms of reputation assurance, community acceptance and greater certainty in terms of access to resources.

Jan 1, 2000

By J Webb

Anoxic limestone drains (ALDs) have been widely used in the passive treatment of acid mine drainage (AMD), but their effectiveness has often been less than anticipated. Iron hydroxide often precipitates around limestone particles and inhibits neutralisation. To determine the conditions under which iron hydroxide precipitates, a small-scale laboratory ALD system was built to enable a detailed examination of the chemistry of iron within the drain. For one experiment, a mixture of limestone and quartz was introduced to the drain to assist in the determination of the key mechanism governing iron precipitation. Synthetic anaerobic acid mine drainage containing Fe2+ (~130 ppm), SO4 2- and H+ was pumped at a rate of 30 mL/min up a 90 cm tall, 15 cm diameter vertical column filled with limestone gravel of 98 per cent purity. Three sampling ports were fitted at equal intervals along the column; water was periodically extracted for analysis at the sampling ports over an 11-hour period. Experiments were run at influent pH levels of 2 and 4. Results show that acid neutralisation to pH greater than 6 occurred at the inflow end of the drain. The greatest amount of iron precipitation (19.5 per cent) also occurred in this area. The lack of iron precipitation on the quartz surfaces in the quartz/limestone mixture indicates that neutralisation is the key mechanism for the precipitation of iron hydroxide on limestone particles. A pe-pH stability diagram derived for the laboratory ALD system indicates that ALDs will not be effective for AMD with pH 2. Influent waters with pH 2 require a pe of -2 (Eh: -118.4 mV) to avoid Fe precipitation upon neutralisation. Influent waters of pH 4 require a pe between -2 and -4.

Jan 1, 2003

Neutralisation, normally using lime, is the most widely used method for treating high flows of acid mine drainage (AMD). Lime costs can be very high however. If carbonate sources could be used to achieve pH values above six, costs could be greatly reduced. For example, use of locally quarried limestone at Mt Lyell could potentially reduce alkali costs from about $A 3.5 to $A 1 million/year. Methods for enhancing the effectiveness of limestone and magnesite for neutralising Mt Lyell and Savage River AMD respectively have been examined through a series of investigations. Small-scale testwork found that the maximum pH economically achievable with ground limestone was about five, due to slow dissolution rates and surface armouring. The problems of surface armouring were greatly reduced by the use of crushed limestone or magnesite at high pulp densities (75 per cent solids w/w), enabling pH values >6 to be achieved in a practical time frame. The use of particle sizes in the range 6 mm and finer also reduces costs by avoiding the need for grinding, and reduces the problems of solid-liquid separation and solid recycling that arise if large additions of ground carbonate are used. Pilot scale tests were carried out using tumbling drum reactors with limestone and Mt Lyell AMD and a pulsed-bed static reactor with magnesite and Savage River AMD. pH values averaging 6.2 and 6.4 were achieved with Mt Lyell and Savage River AMD respectively. Approximately 80 per cent of feed acidity was neutralised. A preliminary engineering design and cost estimate has been completed on the pulsed-bed reactor and shows that the concept is technically feasible and, if results are confirmed, economically attractive. Further pilot testing is planned.

Jan 1, 2002