Search Documents

By Eggleton T, Taylor G

The lateral and vertical distributions of gold and a wide range of other elements in the regolith, close to Au and Cu mineralisation have been investigated at Goonumbla, NSW. Open cut mining has exposed deeply weathered profiles which have been used for this investigation. Determination of secondary mineralogy and micromorphology of profiles have facilitated the broad interpretation of processes that determine element mobility and dispersion from primary mineralisation as a result of weathering. This in turn has led to better interpretation of geochemical data and enhanced understanding and knowledge of regolith geochemical processes which are invaluable in the formulation of improved exploration Procedures.

Jan 1, 1997

Taiwan is situated between Ryukyu and the Philippines with 35,960 sq. km of area, being slightly larger than Belgium It has roughly a spindle-shaped outline with a longitudinal axis extending in a roughly north-south direction. Geologically, Taiwan is extremely complex in terms of its tectonic setting in the convergence zone between the Asian continent and the Philippine Sea Plate. To the east of Taiwan, the Philippine Sea Plate subducts beneath the Ryukyu island arc, and to the south of Taiwan the Philippine Sea Plate overrides the Asian plate along the Manila Trench. Taiwan, therefore, occupies an unstable region between these two well-defined subduction systems of opposite polarity (see the following block diagram).

Jan 1, 1987

Roasting of zinc concentrate at the Risdon Works of the Electrolytic Zinc Company of Australasia Limited, (E.Z.), is carried out in two fluid bed roasters capable of treating 450000 tonne/yr, or sufficient for the output of 220000 tonne of salable zinc. The furnaces were constructed by Lurgi, Australia, to the basic design developed by Vieille Montagne Company of Balen, Belgium. The advantages of fluid bed roasting include a higher metallurgical efficiency in sulphur oxidation from a feed which does not require any pre-grinding, mechanical reliabil- ity through the absence of any moving parts within the furnace and the capability of being scaled up to a large unit.

Jan 1, 1977

By A V. Nguyen

Spherical calcium dioleate particles (~10 ¦m in diameter) were used as AFM (atomic force microscope) probes to measure interaction forces of the collector colloid with calcite and fluorite surfaces. The attractive AFM force between the calcium dioleate sphere and the fluorite surface is strong and has longer range than DLVO (Derjaguin-Landau-Verwey-Overbeek) prediction. The repulsive AFM force between the calcium dioleate sphere and the fluorite surface does not agree with the DLVO prediction. Consideration of non-DLVO forces, including the attractive hydrophobic force and the repulsive hydration force, was necessary to explain the experimental results. The non-DLVO interactions considered were justified by the different interfacial water structures at fluorite- and calcite-water interfaces as revealed by the numerical computation experiments using molecular dynamics simulation.

Jan 1, 2005

By Mansor A. N

Results are reported for the computer simulation of heap leaching of mixed copper oxide and sulphide ores. They resemble those obtained from testwork in terms of a substantial peak in the copper concentration of the pregnant solution, an initial period when no copper emerges and a lengthy period towards the end when the copper concentration and the daily increment in copper recovery are low. The simulation can be used to forecast process results before any column or similar testwork is performed. Potential applications of the simulation to process design, operating strategy and optimisation are discussed. Three modes of operation are identified that correspond to different performance patterns and dependencies on ore and process variables. The relative merits of different operating strategies for approaching the ideal performance are being investigated. For process design and development purposes, the simulation may be used with a limited testwork programme to achieve significant savings in time and resources.

Jan 1, 1989

By Ramsden AR

The ability of the scanning electron microprobe to provide non-destructive qualitative and quantitative mineralogical analysis at the micrometre scale makes it a very versatile tool for the mineralogical characterisation of ore deposits and their host rocks. With the trend towards exploitation of large tonnage low grade depositsnd precious metals at the parts per million level it is becoming increasingly important to have full mineralogical characterisation and knowledge of the mineralogical residence of the valuable elements to assist formulation of a cost-effective exploration program and obtain optimum recovery in the case of exploitation. Mineralogical applications include

Jan 1, 1989

Over the last thirty years production of heavy minerals from Australian deposits has dominated the world market. The main incentive has been to suoply the raw material for titanium dioxide based pigments. These ~ninerals include ilmenite, rutile, leticoxene and more recently, synthetic rutile. Inevitably the viabilit/ of developing placer type deposits has seen influenced by other heavy minerals present, such as zircon and monazite, but these have been of secondary importance. For most of the sixties and seventies, Australia supplied the 'najority of free world rutile and zircon, and a large proportion of the ilmenite. With the run-down of rutile- rich reserves in eastern Australia, the emphasis has s:iifted in several countries, including Australia, to fill }the gap with i l Wen i to and its derivatives, leucoxene, synthetic rutile and titanium rich slag. over the next 15 - 20 years, as high grade beach placers in Western Australia are mined out, less traditional sources for mineral sands products will be opened up. Low grade placers (particularly those dominated by ilmenite) will be reassessed in Australia, U.S.A., Africa and Asia, and exploration will shift from beach and dune environment, to heavy mineral concentrations in alluvials, lake deposits and continental shelf deposits. At the same time, production of anatase and bastnaesite will be expanded, as required, from the huge resources contained in carbonatites in 3razil, U.S.A. and China.

Jan 1, 1986

Prospecting in arid terrain can produce substantial environmental impacts, comparable to or greater in magnitude than the impacts associated with actual mining or petroleum production. Impacts are likely to be particularly severe where prospecting involves intensive geophysical exploration, especially in areas which have escaped degradation by other land uses such as pastoralism. With appropriate environmental planning and management, however, the environmental impacts of prospecting in arid terrain can be greatly reduced and mitigated, at low cost. In many countries, prospecting licences, exploration leases and associated tenements now carry a range of conditions relating to environmental protection. The assessment, avoidance and mitigation of environmental impacts is therefore an important component of and-zone exploration. My aim here is to give an overview of some of the main aspects of an environmental planning and management (EPM) programme for prospecting in arid terrain (PAT). Detailed operational prescriptions for environmental protection procedures are necessarily specific to particular areas and types of prospecting: see. e.g., Buckley (1982a, 1984, 1985a, 1986a), Klepacki et al. (1985) and Stone (1986). The intention here is to provide a checklist rather than a recipe book: as an aid in incorporating environmental aspects into the overall planning and management of an exploration programme, and in liaison with company environmental staff, consultants and regulatory bodies. I also hope to show that whilst some of the techniques used in particular environmental disciplines certainly require specialist expertise, the overall design of an EPM programme is not in the least esoteric, but simply an exercise in straightforward common sense. Perhaps this paper could be subtitled: "Demystifying environmental Planning".

Jan 1, 1988

By R G. Alford

Braeside Borefield, located 120 km southwest of Mackay, is owned by BHP Mitsui Coal Pty Ltd (BHP Mitsui). The borefield provides water to BHP MitsuiÆs South Walker Creek and Riverside Coal Mines and communities in the northern portion of the Bowen Basin. Braeside Borefield has also provided water for other users in the region, including the Peak Downs, Goonyella and Saraji Coal Mines owned by BHP Billiton Mitsubishi Alliance (BMA). Water is sourced from alluvial sediments at the confluence of Nebo and Denison Creeks, and transferred a distance of almost 100 km to Riverside Mine and other users. Since commissioning in 1983, monitoring and maintenance programs have been key elements in borefield management. The impact of pumping on groundwater resources is monitored at the borefield, upstream and downstream over a distance of about 50 km. Current annual pumping is of the order of 4000 ML, and in excess of 50 000 ML has been pumped since the commencement of borefield operations. Detailed reviews of borefield performance are conducted every two years. BHP Mitsui actively participates in community consultation on groundwater issues arising from operation of the borefield. Declining groundwater levels from prolonged drought conditions have increased community interest in management of the borefield. Rehabilitation of existing production bores and augmentation of the borefield is currently being investigated to more evenly distribute pumping rather than to increase overall capacity.

Jan 1, 2003

By Tilyard P. A

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

Jan 1, 1973

By Davies S. G, Jayaweera A

The oxidation of nickel sulphide and copper sulphide concentrates, and coal, has been studied under non-ignition and ignition conditions using Differential Thermal Analysis (DTA) and Thermogravimetry (TG). The non-ignition reaction was favoured by slow heating rates < 10°C min-1), low masses < 10 mg) and an air atmosphere. Under these conditions, the typical stepwise oxidations of the various sulphide minerals present in the concentrate were observed as resolved exothermic peaks in the DTA curves and weight losses in the TG curves. Above a heating rate of 10°C min-1 , sample masses in excess of 10 mg and an oxygen atmosphere, an ignition reaction was induced, as indicated by a major high energy exotherm in the DTA curve and a major rapid weight loss in the TG curve. The ignition temperatures of the minerals under ignition conditions, found for 15 mg samples heated at 20°C min-1, were 434°C for the nickel sulphide concentrate, 372°C for the copper sulphide concentrate, and 230°C for the coal. By plotting a curve for mass against ignition temperature at constant heating rate and extrapolationto zero mass, a value of 470°C was obtained for the mass independent ignition temperature of the nickel sulphide concentrate. Ignition temperatures and extents of reaction at various temperatures were obtained using the TG technique in a novel manner which produced heating rates of 4500°C min-1. Under ignition conditions, the oxidations approximate to flash smelting conditions.

Jan 1, 1985

By Ross T. J

Renison Limited operates an underground tin mine employing both cut and fill and open stope methods, at Renison Bell on the west coast of Tasmania. Mining in the region commenced in the 1890's. Development of the current mining operation commenced in 1965. The ventilation system used at Renison in its present configuration is a function of current mining methods, orebody characteristics and prevailing Tasmanian Department of Mines Inspection Regulations.

Jan 1, 1988

Silver and gold bearing ore from the Palmarejo mine, located within the Mexican state of Chihuahua, contains a complex mix of electrum, native silver, silver sulfides and silver chlorides. This paper presents a case study that describes the selection, development and engineering of a tailored process plant for the recovery of silver and gold from this ore. Process circuit feasibility study modelling, metallurgical test work and engineering studies are outlined. Options considered to optimise the recovery of the contained silver and gold are compared, based upon cost, operability, recovery and engineering aspects. Concentration by flotation was found to be the preferred primary recovery route. Intensive leaching of the flotation concentrate resulted in solution grades sufficient to allow direct electrowinning to be evaluated against the more traditional Merrill Crowe process. The flotation tailings stream is processed through a separate leaching stage as there is sufficient economic metal extractable from this stream. The processing flow sheet, which is designed to maximise the recovery from both the flotation concentrate and tailings, and to utilise a common metal production facility, is presented.

Jan 1, 2009

Since the introduction of the Neil George Five Point Safety System, to the underground sections of The Zinc Corporation, Limited and New Broken Hill Consolidated Limited mines in March, 1969, the Disabling Injury Frequency Rate has been halved and shows signs of contin- uing to fall. The total accident frequency rate has also fallen, although the decrease has not been as significant. Before the introduction of the Neil George Safety System, analyses of the direct causes of accidents showed that approx- imately 25 per cent were caused by "unsafe conditions", while 75 per cent were attribu- table to "unsafe acts". Within twelve months of introducing the system, these percentages had significantly changed to 7 per cent unsafe conditions and 93 per cent unsafe acts. Today, the figures are 3 per cent and 97 per cent respectively, and these figures clearly show that the main emphasis in the current programme must be directed towards making the operating men safety conscious. The effort must be focused on changing the minds of men.

Jan 1, 1975

By Yokozawa K, Yamamoto T, Kameoka Y

Japan Construction Method and Machinery Research Institute has been conducting various field surveys of tunnel works and other excavation works, and the cost and efficiency of these two excavation methods have been studied. Based on these data, the costs of blasting excavation and mechanical excavation represented by roadheaders were calculated. The costs were calculated and compared for rocks of various hardness. When the total construction cost is considered, the degree of overbreak becomes one of the most influencial factors, because the overbreak area must be filled up with expensive shotcrete in NATM. So, in the next step, the relation between the excavation costs considering overbreak and the rock hardness was studied using the data on overbreak obtained by the field survey.

Jan 1, 1987

Experimentation with new methods, materials and machines to improve primary drilling and blasting is a continuing practice in the hard rock quarry operations of the BMI Group. These experiments will continue in the remote hope that one day we may produce a perfect feed for the primary crusher. As this day is still a long way off, the necessity to break oversize boulders will be a problem to be faced for the foreseeable future. To gauge the efficiency of primary blasting from this point of view, BMI monitor the tonnes of material crushed in the primary crusher for each boulder requiring secondary breaking. Over a period of about 10 years, this figure has improved from 30 tonnes througi the primary crusher per boulder, to 100 tonnes per boulder at our largest operation, which produces in excess of 2 million tonnes per year. Evan with this improvement, 25,000 boulders require secondary breaking each year This paper does not provide the solution to this problem, as like primary blasting, it will have to be constantly reviewed as new products and techniques become available. The paper sets out all of the methods tested or considered for test by BMI and our nnnn1iicinnq nn Chair PffPr.tivPness . Economic

Jan 1, 1978

By Hayashida O, Numata Y

Ultraviolet and infrared spectroscopic analyses and the extended lluckel molecular orbital method were applied to determine the electronic and binding states of 2-mercaptobenzothiazole and the adsorption system of 2-mercaptobenzothiazole on pyrite. 2-mercaptobenzothiazole exists rather in thione form than in thiol forru and the two adsorption peaks in solution were assigned to both 7t--?rt* transitions. 2-mercaptobenzothiazole chemically adsorbs on pyrite mainly due to forming the bond between iron (pyrite) and sulphur (2-mercaptobenzothiazole).

Jan 1, 1993

Heavy media separation serves to upgrade mill feed and reduce unit operating costs, allowing ores to be mined which could other wise be uneconomic. At the Aberfoyle mine at Rossarden in north-east Tasmania, a simple heavy media operation using a converted Akins screw classifier as a separating vessel, removes barren quartz from mineralised material. At the Cleveland mine at Luina on the west coast of Tasmania a more complex ore mix requires a versatile operation combining hydro-dynamic and static separation equipment to provide an efficient beneficiation circuit. The two operations are briefly described with a background of basic heavy media separ- ation practice.

Jan 1, 1978

By N Ozawa, R Kaneko, M Arimit

The Mitsubishi Higashitani limestone mine is a ten million tonne per annum operation located near the city of Kitakyushu on JapanÆs western island of Kyushu. Higashitani is one of the largest limestone mines in Japan and accounts for about five per cent of national production. Blasting practices at the Higashitani mine involve the use of bagged ANFO, dynamite primers and non-electric detonators. Regulations in Japan prohibit the use of site mixed bulk explosives. Blast size is usually around 17 000 tonnes with 20 holes in a single row, two or three blasts are fired per day at a powder factor of between 0.25 and 0.32 kg/m3. As part of a program looking at oversize reduction Mitsubishi, Asahi and Orica agreed to conduct a joint project at the Higashitani mine to investigate the relationship between the powder factor and fragmentation. The first stage of the project was to benchmark the current blasting performance. Five blasts were monitored in each of the 210 (hard rock) and 220 (soft rock) areas of the mine. OricaÆs Powersieve« software was used to measure fragmentation and total rock breaker hours were also recorded for each blast. OricaÆs computer blasting simulation model Sabrex« was used to prepare revised blast designs with a higher powder factor and predict their performance. The performance of these blasts was monitored using the same methods.

Jan 1, 2004

By Molloy GR, Eaton RA

The crusher development programme for 7ft Super Extra Heavy Duty (SXHD) Symons cone crushers commenced in 1984. The main objective of the programme was to run the crushers at maxi- mum power for the full life of the liners. This would give a finer product sizing enabling grinding and flotation plant throughput to be maximised. The study was conducted along two basic lines of attack, the first main- taining an effective profile through the life of the liners, the second improv- ing the properties of the liners. It has been found that crusher liner life can be extended and crushing efficiency improved by modification of liner composition and profile.

Jan 1, 1988