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By Lloyd F, Bayley F. J

The new South Mine in the Western Deep Levels complex is destined to become an ultra deep project extending to depths of 4 200 m below surface and where rock temperatures are likely to exceed 65 ¦C. Initial estimates put refrigeration requirements at 133 000 kWR. A surface refrigeration plant with an initial capacity of 42 000 kWR has been commissioned and will be used for mining the upper levels.

Jan 1, 1988

Subsurface information from the "Upper Coal Measures" of the Sydney Basin is interpreted by means of structure contour maps, isopach maps and geological cross- sections. Particular reference is made to recent coal drilling operations by the New South Wales Department of Mines. The study is restricted to the onshore portion of the Sydney Basin.

Jan 1, 1972

By Dimitrakopoulos R

Ore textures in base metal deposits are an important factor in the liberation of the economic components of the ore, metal recovery and reagent consumption during beneficiation. Optimising the mine profit requires knowing the relationship between ore texture and mineral processing behaviour, and the ability to predict the metal grade and the ore texture at a suitable scale. A new method that generates distributions of mesotextures for any mining block size or shape is proposed and includes: I . establishing a protocol for acquiring mesotexture data: 2. measuring the mesotexture spatial correlations using a multi-texture variogram; 3. generating multiple simulations of mesotextures; and 4. upscaling the simulations to generate the expected mining block/stope mesotexture distributions. Models of the ore textures built using the proposed methodology can be used to assess resources and reserves, enhance ore/waste discrimination and predict the metallurgical behaviour of parcels of ore.

Jan 1, 1997

By Coates D. F, Neil T. J, O&apos

A proper economic analysis of pit slope design must reflect the trade-off between the benefits and the increased risks of slope fail- ure inherent in steeper slope angles. However, no formal framework for a proper analysis existed to date. This paper describes the results of the past four years' effort in which a formal eco- nomic analysis framework was developed and tested through a case study. This framework, in essence, consists of the availability of tested procedures and com- puter programs. The procedures as well as the programs are divided into two broad functional categories; (1) the first category related to assessing the economic benefits and costs associated with various pit slope angles and (2) the second category that determines the overall financial impact which the assessed benefits and costs exert to the mine operator's overall economic stature.

Jan 1, 1977

By Clifford C. E

The Black Star and Racecourse orebodies below 15 level contain a major portion of the primary silver-lead-zinc ore reserves of 56 million tonnes at 150 g/t Ag, 6.4% Pb and 6.5% Zn at Isa Mine. Extraction from this area is scheduled to begin in the early 1980's. Mining in this block will be quite com- plicated as the ore is contained in a dozen separate orebodies varying in width from 3 m to 20 m with only narrow barren pillars between them in some cases. Mining objectives which consider metal recovery, costs, environmental and safety factors, operating requirements and rock mechanics are used to compare proposals. The planning work involved in formulating mining proposals considers disposition of reserves, scheduling factors, sequence of extraction, extraction methods, haulage set-up and ventilation requirements.

Jan 1, 1979

By Bogie I, White P. J

Active geothermal systems occur widely in Sumatra and in the Taupo Volcanic Zone (TVZ) of New Zealand. There are also many occurrences of epithermal gold mineralisation in Sumatra, some of which are economic. Minor sub-economic occurrences of gold have been reported in the TVZ but none have yet been mined. There are both similarities and differences in the nature of the active geothermal systems and mineral deposits in Sumatra and New Zealand, which can be systematically related to the tectonic setting. The thicker crust and consequent predominance of silicic volcanism in New Zealand leads to hydrothermal. systems which are little eroded and with limited lateral outflows. The systems in Sumatra are of mixed character, with some of the characteristics of those in andesitic island arcs such as Java or the Philippines, eg a higher proportion of systems with identifiable acid magmatic volatiles, a greater potential for deep erosion and lateral outflows than in New Zealand; but modified by the more oblique component of subduction and thickened crust so that some are localised in volcano-tectonic depressions and consequently have high piezometric levels of primary hydrothermal fluid. The unusual occurrence of calcic zeolites in veins associated with gold mineralisation in Sumatra is thought to be indicative of "satellite" boiling zones along de-gassed hydrothermal outflows.

Jan 1, 1995

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

By Jena, Anand S, Das R. P

Leaching studies were carried out on Indian Ocean manganese nodules using sulphuric acid as the lixiviant. By leaching the nodules with 8 per cent sulphuric acid for 12h at 100°C, copper and nickel could be completely extracted along with 50 per cent cobalt and 6.2 per cent manganese.94.2 per cent of the iron was also dissolved. To increase manganese and cobalt extraction, charcoal was used as a reductant. The role of charcoal was to reduce the manganese dioxide and render it soluble as manganese sulphate as well as to facilitate solution of the cobalt minerals associated with the manganese dioxide. Various leaching parameters were studied including acid concentration, amount of reductant, leach time, pulp density and leach temperature. It was found that by leaching the nodules with 10 per cent sulphuric acid at 100°C for 4h using 5 wt/wt per cent charcoal (0.05g of charcoal per g of nodule) almost complete extraction of copper, nickel, cobalt and manganese could be achieved. However, under these conditions all the iron present in the nodules was also leached.

Jan 1, 1989

By Mallett C

Coal mines are dynamic systems that change continually in size, shape, and condition. Large quantities of data about production, coal quality, ground stability, ventilation monitoring, equipment performance and location, vehicle and personnel movements and geology, are generated from all parts of the mine.Internet technology and virtual reality technology are now being combined to provide an intuitive, multi-dimensional information system which can simultaneously display any information that can be collected and stored by a computer. Physical information is directly displayed as 3-dimensional objects in the mine model. Numerical and text information is dynamically linked to these objects and accessed by "clicking" on them.

Jan 1, 1998

By Kuganathan V

The processing of black coal in Australia segregates waste in the form of coarse reject and fine tailings. The coarse reject is relatively easy to handle, while the tailings can be problematic. Conventionally, the two waste materials are disposed of separately, the coarse reject in dumps, and the tailings in man-made containments. Aqueous tailings slurry is pumped to a 'wet' tailings storage, where the fine particle size of the tailings limits dewatering. Their low bearing capacity and high compressibility result in tailings deposits being difficult to rehabilitate. Disposing of the waste streams separately moves away from the heterogeneous mixture in the undisturbed ground, and concentrates potential problems with each waste stream. The feasibility and desirability of the co-disposal of tailings and coarse reject by combined pumping is demonstrated. This technique is in operation at Jeebropilly Mine and is proposed for a number of other coal mines.

Jan 1, 1992

The Australian bulk explosives industry has matured significantly over the last five years and it would appear that the rest of the world is following suit. This maturity is characterised by the technical sophistication of modem bulk explosives, an increase in the technical competence of the explosives consumer and a greater openness in the debate on the quality and performance of explosives. The principal mechanism by which these advances have been made is undoubtedly commercial competition in the market place although a new element, technical competition between manufacturers and independent professionals, has and will continue to play an important role in the development of the industry. The relationship between the explosives manufacturer and consumer is necessarily both complementary and competitive. This paper identifies the need for the consumer to take a more prominent role in the critical analysis of the performance of explosives and to use his commercial influence to direct explosives manufacturers at least in the direction required for the future technical development of the industry.

Jan 1, 1990

By Case JE

Complete Bouguer and isostatic anomaly maps compiled for Costa Rica provide new insights into the crustal structure and mineralization. Terrain corrections were approximated from the station to a radial distance of 167 km by computer using a 3- minute digital elevation model of Costa Rica and surrounding areas. Isostatic corrections, based on Airy-Heiskanen compensation, were also calculated from 0 to 167 km using the 3- minute elevation model and from 167 km to 180 degrees using combined topographic and isostatic reduction maps. Costa Rica can be divided into four main terranes based on gravity data: a Pacific coastal region, a Pacific inland area, a central region, and a Caribbean coastal region. Negative gravity anomalies along the Pacific coastal margin correlate with an offshore sedimentary basin, and large positive anomalies correlate with mafic and ultramafic igneous rocks on the Santa Elena, Nicoya, and Osa Peninsulas, and at Puerto Quepos. Pacific inland anomalies are separated from the Pacific coastal region by a steep gravity gradient, and over the Coast Ranges a major gravity low overlies a thick section of low- density sedimentary rocks. In the central region, a major gravity low occurs over a thick low-density Quaternary volcanic complex in the Cordillera Central, north of San Jose. A prominent feature of the Caribbean coastal region is an interrupted gravity low over the Limon Basin that reflects a thickening of low-density sedimentary rocks. A conspicuous gravity lineament, trending northeast separates northern and southern Costa Rica. The lineament is defined by the termination of several major gravity anomalies including those over the Coast Ranges, Cordillera Central, Puerto Quepos, and Limon Basin. In addition, the lineament correlates with other geological and geophysical data including: northeast-trending faults, the southern limit of large Quaternary volcanoes, the segmentation of the middle America volcanic belt, and a seismicity gap. This lineament may be the expression of a previously unrecognized major northeast- trending fracture zone in central Costa Rica. An important economic implication of the gravity lineament is a correlation with the termination of gold and porphyry copper deposits in Costa Rica.

Jan 1, 1987

Laboratory high tension roll separation and the commercial machines available for this purpose are discussed. The shortcomings of these machines are indicated and a machine that overcomes some of these undesirable character- istics is described. A procedure for evaluating laboratory high tension roll separation is described. The use of this evaluation procedure in conjunction with the laboratory separation is described with examples taken from the Dunwich and Hexham processing plants of Associated Minerals Consolidated Limited. Evidence that laboratory testwork results may be directly transposed to operating plants is given. A discussion of the effects of variables in high tension roll separation of mineral sand concentrates concludes the paper, and uses in support results obtained in the metallurgical laboratories of Associated Minerals Consolidated Limited, Southport, Queensland.

Jan 1, 1972

By F Palkovitz, S Wilson, F Felipe

The management of waste from mining operations is a significant aspect of bringing a mineral commodity to final market. The ore beneficiation process and transport/disposal of waste involves significant consumption of costly resources. A number of options exist to dispose of mill waste on surface and as a backfill material. These range in complexity, risk, capital cost, operating cost and ultimately business performance. This paper discusses the value delivered to a business in using dewatering systems including paste as opposed to conventional slurry tailings disposals. This is illustrated through various case studies and serves to demonstrate how paste can add value and reduce risk to a successful business.

Jan 1, 2009

By Pak DL

Over the last decade computers have become an essential element in assessing the economic feasibility of mining new mineral deposits and in assisting a variety of related support functions. A broad overview is given of the many technical application areas where computers are contributing to the mining industry with reference to work being done on the evaluation of drill hole information, mineral inventory modelling, ore reserve estimation, financial analysis, process simulation, process control, workshop job scheduling, PERT applications, and com- puter aided drafting. In all these areas the computer has greatly reduced the manual effort involved in looking at alternatives. It has had a significant effect in eliminating delays in revising calculations, or rescheduling activities to incorporate new data or cater for changing conditions, while at the same time providing more accurate and prompt information for the management decision making Process.

Jan 1, 1980

By Lyman GJ, Davis JJ

Models which have been presented in the literature consider only selected aspects of dense medium cyclone operation, are empirical in nature and generally relate only to severely limited ranges of operating parameters. This paper reports progress towards development of a more comprehensive and robust model. The data base consists of partitioning parameters developed using density tracers and conventional coal sampling and analysis techniques, together with recordings of parameters such as cyclone dimensions, feed pressure, medium size distribution and product media densities.. These data were drawn from 15 Australian coal preparation plants. To elucidate the effects of important operating parameters on medium behaviour and on the partitioning of large particles a series of pilot scale tests was also conducted. The present model consists of eight sub-models which relate to particular aspects of dense medium cyclone operation such as medium flowrates and densities, or size- by-size separation densities and Eps. The model structure follows a logical progression which clearly demonstrates the importance of understanding medium behaviour before attempting to predict partitioning performance. The model also attempts to define the conditions under which yield losses due to unstable "surging" discharge may occur.

Jan 1, 1987

Geological. engineering is a field of engineering practice concerned with design and construction of excavations and structures in soil and rock masses. The role of geological engineering in mining practice is defined in this paper, and the scope of the various disciplines in engineering science and geoscience which support geo-engineering research is discussed. The current national research capacity in geo-engineering is considered, and current and future needs for geo-engineering research for mining practice are proposed. Education programmes to sustain the proposed level of research and its industrial implementation are Suggested.

Jan 1, 1986

The United StatesÆ reporting standard for the mining industry for securities purposes is contained in the Security and Exchange CommissionÆs Industry Guide 7. It defines proven and probable Reserves using its own definitions, and prohibits the disclosure of quantitative estimates, for all mineralisation other than those two Reserve categories (though disclosure of Measured and Indicated Resources as quantitative mineralised material estimates is now informally allowed). Similarly, it restricts disclosure of value estimates to Reserves only, which SEC policy generally requires to be on an historic cost accounting basis. The SEC does not maintain a formal Competent or Qualified Person policy. In March 1999, the US-based Society of Mining, Metallurgy and Exploration (SME) released an update of its 1991 guidelines for definitions to be used in reporting of Mineral Resources, Reserves and Exploration Information, closely abiding by the 1997 CMMI recommendations. However, without SEC recognition, reporting under the SME and CMMI definitions is effectively barred for US companies. The SEC intends to adopt the International Financial Reporting Standards (IFRS) of the International Accounting Standards Board (IASB). This will occur within just a few years, when the convergence project for development of the IFRS has reached a satisfactory point. The US is the largest financial supporter and participator in IASB. The Extractive Industries Standard of the IFRS will likely terminate Industry Guide 7. However, the effect of this international replacement will likely be equally restrictive. This could possibly neutralise the benefit of a CMMI-based global reporting standard. SME, the US society encompassing the widest range of mining industry professionals, does not have a Code of Ethics. It has no mechanism for requiring members to abide by a professional standard. SME is presently looking into possible solutions for this deficiency. US-based professional societies that do have a binding Code of Ethics, generally cater to a single profession, and are not just mining industry related. The American Institute of Professional Geologists (AIPG) and the American Institute of Minerals Appraisers (AIMA) are examples. The SME is considering creating a subsidiary body with an enforceable Code of Ethics. To support a CMMI-based global reporting standard, competent persons will need to work across international borders. A standardised mechanism for qualifying and registering competent persons will be needed. National rules and laws must allow competent persons to easily enter countries to perform their work. State issued licenses are increasingly required for much of the work performed in the US mining industry by engineers, geologists and minerals appraisers (valuers). Such licenses are not required by the SEC for Reserve reporting in the US, may not be required for valuation of mineral properties under certain circumstances, and except for real property valuer licenses, they generally do not have a binding code of conduct. However, state licensing of professionals forms a substantial and increasing barrier to interstate trade in professional services, and can be a prohibitive barrier to professionals from outside the US. Any rationalisation of this confusing patchwork of regulations confronting US minerals industry practitioners will only occur as part of larger, national change, hopefully aimed at compliance with international standards and protocols. The US does not have a valuation standard aimed specifically at the mining industry. The Uniform Standards of Professional Appraisal Practice, the national valuation standards, often must be applied to mineral property valuation, but contains no specific instructions for minerals. The author has campaigned against development of minerals valuation standards proposed by US minerals institutes. Instead he encourages the mining industry worldwide to place its support behind the initiative of the International Valuation Standards Committee (IVSC) to include an extractive industries section in its International Valuation Standards (IVS). This should provide a global set of valuation standards for the mining and petroleum industry within two years. This addition to IVS will provide essential valuation standards reference support for the extractive industries financial reporting standard of the International Accounting Standards Board. The IVS has achieved a high level of acceptance in the developed and lesser developed countries of the world. It provides a comprehensive framework of Generally Accepted Valuation Principles for the valuation profession internationally, for valuation of all property or asset types. IVSC is effectively a sister organisation to IASB. The IASBÆs International Financial Reporting Standards (IFRS), previously known as the International Accounting Standards (IAS), reference and quote IVS in some instructions for determination of fair value. IVSC is a non-governmental organisation (NGO) member of the United Nations and maintains liaison with many important international economic, accounting and financial agencies, such as the OECD, IMF and WTO.

Jan 1, 2002

By La Brooy S R, Fenton K

A low grade copper flotation tailing from Telfer containing 1.2% Cu as chalcocite and cuprite and 5 gt-t Au was leached with ammonia, cyanide and ammonia-cyanide mixtures to extract copper and/or gold. Direct cyanidation extracted both copper and gold but consumed about 30 kgt 1 NaCN. Pre-leaching the tailing with an aerated ammonia solution containing 28 kgt 1NH3 and 17 kgtl(NHa)2S0a at pH 10 readily extracted up to 95% Cu in about 6 hours under optimum conditions. However pH and total ammonia concentration were critical factors. Subsequent cyanidation ex- tracted 80% Au using 6 kgt NNaCN. Ammonia-cyanide mixtures werefound to selectively leach gold over copper depending on the concentration and relative proportion of NH3 and CN. The best composition for leaching up to 80% Au from Teller tailing was 1.6 kgt t NaCN and 1.1 kgf 1 NH3 in the presence of 0.3 kgt t Cue+. Such a mixture left only 50 mgL-1Cu in the final solution after precipitation of some of the initially dissolved copper.

Jan 1, 1991

Mining software systems have provided a basis for integration of resource, survey, and design functions. They can similarly provide a basis for incorporating ground conditions into the process.Exploration and mine geologists have a prime role to play in this process, extending their responsibilities further across the geological spectrum, into exploration of ground conditions, analyses of results, and assessments of their implications for mining. Ground conditions are as much a part of the geology of a prospect or mine as its mineralisation, and can have critical imnlicationa for mining.

Jan 1, 1993