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By DAVID C LAURENCE

The richer, shallower sapphire deposits of the New England region of New South Wales which have been traditionally mined by the small miner are almost worked out. Larger mining and exploration companies are replacing the small miner and exploring for the primary source of sapphire or lower grade alluvial deposits.Although in recent years considerable exploration effort has been directed at locating the primary source, commercial exploitation of sapphire is still restricted to the working of alluvial deposits.If the Australian industry is to compete against Asian and African producers it must use cost effective exploration, mining, processing and marketing methods.

Jan 1, 1990

By V S. Vutukuri, K Shariar

This paper present a modification of selected strength criteria for coal and rocks containing weakness planes. The three strength criteria, namely, Murrell (1965), Bieniawski (1974a, 1983) and Hoek and Brown (1980) have been assessed for coal (containing weakness planes) by using triaxial strength tests. Triaxial test results indicated that the strength of coal specimens depends on the weakness plane inclination with respect to the principal stress direction. However it is shown that with increasing confining pressure, the effect of weakness planes inclination on the strength of coal specimens is reduced. The constant parameters in the three failure criteria for coal are determined for each weakness plane inclination by using the Datafit computer program (nonlinear regression analysis) and the results are compared with other rock types.

Jan 1, 1999

Jan 1, 2004

By G W. Croft, L E. Krause

The current copper ore handling systems in use at Xstrata CopperÆs Mount Isa Copper Operations are up to 33 years old and have hoisted over 160 Mt at a rate of around 6 Mtpa. The mineÆs production profile is increasing in line with the optimum life of mine plan to over 6.6 Mtpa, which requires a system utilisation and reliability above that previously achieved. Copper ore is hoisted up the U62 shaft, which forms the central part of the U62 ore handling system. In theory this system can cope with the duty planned if the bottleneck is only the U62 winder. To achieve the planned production rate will require increased focus on reliability of each component in the ore handling system so that ore is available at the shaft for hoisting whenever the shaft is available, and the shaft is available for the maximum practical time. Increased availability will be achieved through the outcomes of the study of each component in the U62 system, and the internal ore handling systems that deliver ore from as far as 2 km laterally and 700 m vertically from the U62 shaft. The true capacity of each component is being determined and current performance is being measured with the aim of improving performance through root cause analysis and engineering out the causes of delays. The program began in March 2004 and this paper describes the progress achieved as of April 2005.

Jan 1, 2005

The appearance of the Cornish miner in South Australia was, in the simplest terms, the result of resource development economics. In Cornwall in the middle of the 19th century tin and copper mining was declining, while in the new colony of South Australia copper mining was booming. Experienced hard rock miners in Cornwall there- fore escaped unemployment at home by accepting an assisted passage to South Australia. There, in a colony where they were needed, they made their skills available and received good wages. There are many testimonies which support this simple thesis. Take for example the following extracts from contemporary newspapers in Corn- wall: Persons of small capital will find this an excellent opportunity for emigrating to the young and thriving colony ... The miner will find a rich and unbroken field for his operations. The Colony abounds with minerals... (West Briton, 19 July 1844) Miners make a great deal of money here (South Australia). All of them earn ú2 to ú3 per week and in many cases when they have a portion of the mine on tribute one person has cleared ú100 in a couple of months or so. (Cornwall Royal Gazette, 21 July 1848)

Jan 1, 1987

By Turco E, Pelizza S, Vona A

Within the project against pollution in the Gulf of Naples (Italy) it was envisaged to build a sewage collection tunnel whose tunnelling section is about 30 m2 and whose length is over 4 km. The formations to be bored through feature heteregeneous volcanic deposits made up of either lenses or lava, lapilli and pozzolan layers and ashstone silts. The cover ranges between 10 and 30 metres. The surface is heavily built-up requiring then an accurate monitoring and reduction of noise, vibrations and settlements. The building of the tunnel is therefore carried out by means of a boom tunnelling machine equipped with a mechanized shield. Support along the complete excavation perimeter is provided by linerplates together with an immediate cement grouting behind them. At a later stage the concrete lining will be cast in place.

Jan 1, 1987

The basic flowsheet for the Kalgoorlie Nickel Smelter and Kwinana Nickel Refinery are discussed in relation to the mineral components of Kambalda produced nickel concentrates. Both processes handle violarite and pentlandite satisfactorily but the smelter has limitations where high copper recovery is required and in its ability to handle magnesia containing minerals. While the latter can be more economically handled at Kwinana the limitations of this tolerance are discussed together with problems arising from treating pyrrhotite, pyrite and precious metals by the Sherritt Gordon process.

Jan 1, 1973

By Savory P. J

Uranium mining operations commenced at Ranger mine site, Jabiru NT Australia in May 1980. The Ranger orebodies, totalling approximately 110 000 tonnes contained U305 had been indicated by airborne radiometric survey in 1969 and confirmed by drilling the following year. Both diamond and percussion drilling methods were used to define the mineralisation and samples were analysed using a combination of radiometric and neutron activation techniques. Ore reserve estimates were calculated from conventional and geostatistical methods, and following the mining of 15 million tonnes of ore, reconciliations with before mining estimates are well within acceptable industry standards. In-pit grade control employs radiometric techniques including a radiometric truck discriminator built in Australia to mine specification to meet production requirements and improve productivity. Environmental requirements associated with uranium mining are a daily consideration.

Jan 1, 1993

By Muto S, Okada S

At Tamano Smelter, part of the furnace settler is electrically heated by electrodes placed internally. This practice provides good control of the settler conditions. The authors have been investigating improvements in furnace operations, especially to decrease the copper content in the slag discarded from the settler. The important operational points on the control of magnetite in liquid matte and slag are discussed on the basis of the thermodynamic calculation method developed by Prof. S. Goto. The behaviour of magnetite in the practical furnace has been studied by using a torsion magnetometer and a solid electrolyte oxygen-sensing cell.

Jan 1, 1980

Traditionally, surface coal mines in the Western United States have been limited by economics to depths between 150 to 200 feet. Utah International Inc., however, is now planning to strip coal its San Juan Mine in Northwestern New Mexico to depths ranging up to 400 feet while uncovering 20 feet of steam coal. This method is cost-competitive with nearby shallower coal deposits and underground mining of the same property. How trucks and shovels can pre-strip for a dragline, along with results of the planning process, comparison with alternate systems, capital requirements, operating costs and comparisons with other coal sources are all detailed. Also discussed are the major problems anticipated, how they might be corrected, and potential improvements to the concept. Introduction The San Juan Deep Stripping Project will be situated at Utah International's San Jean Mine. The mine is in the Four Corners region, so-called because four states enjoy a common border point about 30 miles to the northwest.(see Figure 1). The area is a semi-arid plateau region with an average elevation of 5,200 feet, receiving an average of 6 inches of precipitation annually

Jan 1, 1981

By Carter NB

A statistically-designed experimental program has been used to study compositional and processing variables which influence the development of strength and reducibility of iron ore pellets. The effects of chemical composition and processing variables were investigated by indurating laboratory-made green pellets, of known composition, under approximately isothermal conditions in a pot- grate simulator. Some findings from a six- variable study are summarized in the form of contour diagrams and emphasize the importance of interactions between the variables. Production of strong, highly reducible pellets is possible over a considerable range of combinations of temperature and firing time. Abrasion index (AI) and cold compression strength (CCS) improve as both these variables increase, but reducibility (R) declines, so a compromise is required. When the lime level is too low to form enough slag for bonding, the AI and CCS may be inadequate. Larger additions of lime tend to improve AI and CCS, with only slight effects on R. Finer grinding of the balling feed (i.e. higher Blaine index) tends to improve Al and CCS without

Jan 1, 1980

By Getliffe RK

It is becoming more and more difficult to operate mineral and metal processes profitably, as operating costs rise, quality demands in-crease, international competition becomes more fierce and Government charges remain at their current levels. Profitability today depends upon efficient operations, which can only be achieved through precise and dependable con-trol of each process unit comprising thetotal plant.Modern process control systems utilise distributed architecture with microprocessor-based controllers, data acquisition devices and VDU operator stations. Honeywell intro-duced this control technology in 1975 with the "Total Distributed Control" System. Now, building on the proven performance and re-liability inherent in TDC hiway modules, Honeywell has extended the TDC system to inte-grate both management information and control by providing distributed processing modules on the new TDC 3000 Local Control Network (LCN).

Jan 1, 1985

By Staunton W. P

The presence of cyanide soluble copper in gold ores can give rise to serious operational and economical difficulties in CIP and CIL operations. Cyanide consumption can result in the ore being uneconomic to treat by conventional means. Loading of copper onto carbon can also have deleterious effects on gold recovery and subsequent stripping and bullion recovery. The recovery of gold from high copper ores has been previously reviewed by Muir, LaBrooy and Cao (1989). Work undertaken for Mt Gibson Gold Project by Australian Mining Advisors with the assistance of the Chemistry Centre (WA) resulted in the patenting of a process and subsequent construction of a plant at Mt Gibson to overcome some of the difficulties encountered with copper. This paper discusses some of the work which was undertaken during laboratory investigations prior to commissioning of the plant and some further considerations for the treatment of high copper gold ores.

Jan 1, 1991

Gold mineralisation at the Kerimenge-Lemenge prospects is a classical example of myltiple, overprinting events, associated with intrusive-related hydrothermal systems. Repeated emplacement of high level dacitic porphyry bodies (Edie Porphyry; 2.4 - 3.8 Ma) was accompanied by a phreatomagmatic eruption which formed a diatreme-maar complex. Later hydrothermal fluids utilised permeable fault zones and diatreme contacts. Mineralisation took place during two main events. Stage I consists of early quartz - illite/sericite - carbonate phase with associated pyrite-arsenopyrite mineralisation. This phase is zoned from quartz - sericite-pyrite/arsenopyrite in the south at depth, to dominantly manganocarbonate - illitic clay - arsenopyrite- pyrite_s significant base metals in the north and at shallow levels. The majority of known gold (18.1 Mt @ 2.0 g/t Au) at Kerimenge is associated with Stage I activity. The gold occurs primary within the lattice of the sulphides and is metallurgically refractory. Fluid inclusion studies indicate early boiling and progressive cooling and dilution of hydrothermal fluids during the evolution of the Stage I event. Near paleosurface condensation of gases, which evolved off the boiling system at depth, produced abundant low pH bicarbonate fluids. During the waning phases of Stage I activity, these bicarbonate condensate fluids descended down permeable structures and formed banded manganocarbonate veins. High grade non-refractory gold mineralisation during Stage II event is restricted to favourable structures at relatively shallow levels and in the northern regions of the prospect area. Gold in this event exhibits a distinctive Au - Ag - Te -Cu geochemical signature, and is associated with hessite - tennantite - chalcopyrite mineralisation within quartz veining. Alteration and fluid inclusion studies indicate that this style of mineralisation is a result of the quenching of pulses of hot, late magmatic mineralised fluids by the cold condensate waters.

Jan 1, 1997

The South Junction deposit of St Barbara Mines Limited was discovered in 1989 by the geologists of Ross Atkins Mining.The deposit occurs in the lower part of the Gabanintha Formation of the Lukes Creek Group in the Mt Magnet -Meekatharra greenstone belt. Country rock is predominantly talc-chlorite schist. Gold mineralisation is associated with north-south shear zones, quartz-carbonate-fuchsite alteration of the ultramafic rocks and in particular close to deeply weathered quartz-albite porphyry. For a detailed description of the geology of the South Junction Deposit see Fiala (1992).

Jan 1, 1993

The South Mine, property of Broken Hill South Limited, is situated at Broken Hill, NSW, Australia, towards the southern end of the main lode. The leases (MLs 7 and 8) cover a length of 2400 feet along the lode outcrop and the workings extend, at this date, to a depth of 1940 feet below the collar of the original main shaft and to 825 feet below sea level. Mining operations have been continuous for about 58 years and during this period nearly 12.5 million tons of ore have been mined. The monthly tonnage extracted approximates 30 000 tons in normal times.The ore is a mixed sulphide containing galena and marmatite; the gangue minerals are principally calcite, rhodonite, quartz and garnet. A typical assay for a monthly period is 14.4 per cent Ph, 5.6 ozs Ag, and 11.6 per cent Zn. The whole of the ore is concentrated on the property by combined gravity and flotation methods. The lead and zinc concentrates produced are railed to other centres for the extraction of the contained metals.

Jan 1, 1994

This paper examines the latest advances in mine drive and motor systems. In the last decade, the drive technology employed for large mine winders has migrated from the traditional dc technology to ac motors with cyclo convertor drives. Recent advances in pulse width modulation (PWM) drives have resulted in these being applied to large winder drives. While having many advantages for the winder system, the PWM drive must be carefully designed to ensure long-term reliable operation. When combined with induction motor technology, the PWM drive presents the ideal solution for winder drives. This paper examines the factors in choosing a suitable PWM drive for a winder installation. Factors under consideration include: winder duty cycle, drive rating restrictions, choice of power semiconductor device, cooling, and low speed operation.The cage induction motor is the motor of choice for large winder drives and has a number of advantages over the synchronous motor. The induction motor is ideally suited to integrated winder applications where the motor is built inside the friction drum, as installed at WMCÆs Olympic Dam site. The challenges of integrating the induction motor into the friction drum will be detailed, including: assembly, ventilation, air gap adjustment, and position sensors.

Jan 1, 2005

The Wild Dog gold-silver-copper deposit represents a new ore-deposit type in Papua New Guinea. The telluride vein mineralisation is associated with a Tertiary caldera and has similarities with that from the Baguio district, Philippines, Vatakoula, Fiji, and the San Juan Mountains, southwestern Colorado. The deposit, discovered in July 1983, has negligible stream silt and concentrate anomaly, and a float-train limited to within 300m of the prospect. The comparatively recent exposure of the vein system may explain the limited stream expression of the deposit. At least three major veins occur in the deposit; the vein system strikes north- northeasterly, dips 78¦W, and has a maximum strike length of 1350m. Veins are enveloped by a wallrock dominated by an assemblage of quartz-illite-pyrite. Four types of silicification related to multiple vein filling events have been defined on the basis of field relationships, drill-core intersections, petrology and fluid inclusion study. To December 1986 a total of 22 diamond drill holes (2304m) and 40 reverse circulation drill holes (1833m) have been completed on the deposit, defining a 750m zone of interest. The upper 30m of the deposit is oxidised. Much of the high-grade mineralisation in both the sulphide and oxide portions of the deposit is restricted to ore- shoots which strike parallel to the overall vein structure and are vertical to steeply westward dipping. They are defined geochemically by the lg/t Au cutoff and geologically by the relative increase in the vein density of auriferous grey-black sulphidic silica, the final vein filling event. Metallurgical studies and the results of close-spaced drilling have demonstrated the very good repeatibility on duplicate assays, and the extremes of grade variability of mineralisation over very short distances. The good assay agreement on duplicate samples .s indicative of fine, dispersed gold.

Jan 1, 1987

The first mining in Western Australia probably commenced some 40 000 years ago when Aborigines arrived and began quarrying stone for tools and weapons, and ochre for decoration. The earliest documented mining by European settlers took place in 1850 on a small lead vein in the bed of the Murchison River, reported by the explorer A C Gregory. However, it was the discovery of gold in the Kimberley region in 1885 that first drew wider attention to the State's mineral potential.

Jan 1, 1992

By Rosengren KJ

Geotechnical conditions often have a critical influence on the design of new open pit and underground mines, but they are often considered of secondary importance in relation to other factors, such as detailed geology, orebody geometry and grade distribution. As a result, geotechnical studies may not be carried out during early project investigations or, at best, may be given only superficial attention, often to the overall detriment of the project. Technically and economically, it is logical that geotechnical studies should be integrated with geological investigations as soon as it becomes evident that the particular deposit may prove to be economic. The paper discusses the use of geotechnical information in the selection of mining methods and mine design for underground mines and for wall design and assessment of excavation characteristics in open pit mines. It then considers methods of obtaining the relevant data, with particular reference to exploration boreholes. Selected case studies on the application of geotechnical data to mine design are Included.

Jan 1, 1986