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By B Lindqui, M V. Knyazev, L S. Tsemekhman

Gipronickel Institute JS that is a Research and Development Centre affiliated to the worldclass Norilsk Nickel Mining and Metallurgical Company, and Outokumpu Technologies AB (Boliden Contech AB) have jointly developed the reconstruction project of Pechenganickel metallurgical operations using a two-zone Vanyukov furnace. The international expert group appointed by the Nordic Investment Bank has examined the project. The project financing should be partly executed by the Norway government. Current annual rate of sulfur dioxide emissions is 100 000 t. The aim of the project is to reduce it to 12 000 tpy. Pechenganickel Combine is owned by MMC Norilsk Nickel. Currently it produces nickel high-grade matte from sulfide copper-nickel concentrate with up to ten per cent MgO content. The existing production is in accordance with the following flow sheet: agglomeration û electric furnace smelting with matte production û converting in horizontal converters. Annual production capacity is about 36 000 t of nickel in high-grade matte. Converter gases report to sulfuric acid production. The principal results of studies on high magnesia materials smelting in two-zone Vanyukov furnace, engineering solutions, and technical and economical parameters are offered.

Jan 1, 2004

By Whittaker B. N, Reddish D. J

This paper presents the physical modelling results of subsurface fracture development associated with Iongwall mining operations and an application of image processing techniques to interpretion of the results. Physical modelling results haióbeen obtained by employing a large sand and plaster model loaded purely by gravity as a means of fracturing the subsurface strata above the longwall excavation. The results have shown fracture development and crack propagation as a longwall face advances and demonstrated that the strength of stratified rocks, the presence and position of a weak band-, and the extraction thickness, have significant effects upon the overall fracture patterns above the excavation. Binary images of fracture patterns were scanned from the black and white photographs of the tested models using an image analyser coupled to a video camels. These images were manipulated by a custom written C program which allows the images to be processed in both vertical and horizontal direction. The images were filtered to quantitatively differentiate between vertical and horizontal fracture intensities. The vertical fracture intensity is particularly important as vertical fractures are considered to provide the main avenues for surface and subsurface water inflow into the excavation. The use of the image analysis techniques has shown a promising improvement in image enhancement and in model results interpretation in a quantitative manner. The numerical nature of the image analysis results will allow further statistical comparison with other modelling techniques to be undertaken and significantly increase the scope for use of the modelling technique results.

Jan 1, 1992

With some notable exceptions, marine placers located just below, or just above, present sea level, are responsible for much of today's production of detrital ilmenite, rutile, zircon, and other minerals of value. The purpose of this paper is to discuss the paleogeographic and paleo-oceanographic factors which may have determined the location of presently submerged marine placers. These factors-include changes in sea level, burial by recent marine sediments, stream capture and other i changes in drainage patterns, and recent changes in climate. Selected geologic situations in the Yellow Sea off the coast of Korea, in the Atlantic Ocean off the coast of Portugal, in the Bering Sea off the coast of Alaska, and in the Arabian Sea off the coast of India, will be used to illustrate the author's point of view.

Jan 1, 1980

The major coalfields of Australia are almost unique in the occurrence in some areas of CO partly or almost completely replacing CH4,t1e normal seam gas from metamorphism of coal due to time and depth of burial. This CO2 situation has some benefits but mostly it introduces particular safety problems result- ing from the high density of CO2 relative to air, magnifying problems of gas dilution in ventilation, and the greater affinity which coal has for CO2 than for CH4 increasing proneness to gas-dynamic phenomena. The occurrence of most CO2 seam gas can be directly related to igneous intrusion and to its associated pneumatolytic injections. Whilst intrusions locally increase the rank of coal by their contact metamorphic effect, normal coal metamorphism due to time and depth of burial continues after intrusion and injection together with the ongoing metamorph- ic production of CH . This new CH slowly displaces any CO to leave some present-day intruded coals with seam gas with reduced CO2 or even without any significant CO2 associat- ions. The seam gas maps of the Bowen and Sydney Basins and more detailed maps of specific areas exemplify these situations. Mining progress, plus more searching studies of igneous-coal relationships provide improved understanding of the factors involved.

Jan 1, 1986

By Szymanski J

Although efforts towards producing a `total quality rockfill product' have allowed cemented rockfill costs to be reduced considerably, there is still tremendous potential for further cost reductions. Cemented rockfill costs range from approximately $7 to $12 (US) per tonne of fill placed. Approximately 50 per cent of the rockfill costs are associated with cement costs. A large portion of the remaining 50 per cent is associated with labour and materials handling costs. Several Canadian underground mines utilise haulage trucks and/or conventional belt conveyors to distribute the rockfill. However, due to the restrictive nature of the underground environment, these current materials handling systems have limitations (ie spillage from trucks, dust from conveyors). The Sicon conveyor system (developed in Sweden) has considerable potential for replacing these current methods. The Sicon conveyor utilises a revolutionary approach - the conveyor belt is folded over upon itself (forming a tear drop shape) so that the transported material is completely encased within the belt. The Sicon conveyor's ability to negotiate very tight comers (without transfer points) makes the conveyor very appealing for underground mining applications. An analysis comparing the pros and cons associated with the Sicon conveyor system versus conventional materials handling systems will be presented in this paper.

Jan 1, 1995

By Ofori-Ansah K

The zeta potential on the surface of activated orit carbon were estimated in lhe presence of selected cations and anions that are normally associated with gold bearing ores in Kalgoorlie area of Western Australia. Additions of such ions to solution of varying pH shifted the isoelectric point of carbon from pH 4.45 to pH 7-8.3, while the anions moved Lhc isoelectric point 10 less than pH 3.2. In the presence of gold cyanide SoluLion additions of spectator ions indicated the isoelecLric poilll to be aL pH less than 3.2; the only exception was for Fe" ion where the isoelecLric point was at pH 5.9. The decrease in zeta potential appeared to be related to the counter-ions present. The decrease may also be related to the adsorption of hydroxyl ion complexes that are likely to be formed when cations are present in the solutions.Gold adsorpLion by activated orit carbon from gold cyanide solution seem to be indicated by the magnitude of zeta potential on the carbon surface. An attempt is made to relate gold adsorption and zeta potential on carbon surface with the pH of the medium.

Jan 1, 1984

The recent installation of top gas temperature probes in blast furnaces at Australian Iron & Steel Pty. Ltd. - Port Kembla, has provided the means for studying radial gas flow distribution in blast furnace shafts. This paper describes the top gas temperature probes and outlines their development and results of initial studies aimed at obtaining a suitable relationships between temperature profiles and furnace parameters. The effects of various combinations of burden materials have been outlined by the results reported. The use of probes has also helped to clarify the effect of casting cycles on furnace operation leading to increased emphasis on the reduction of the interval between gun-up and drill-out. Areas for future studies are also broadly Outlined.

Jan 1, 1975

By I Taylor, M Nugus, C Gordon

Resource estimation and selective mining of structurally complex, high nugget orebodies presents a major challenge to the Mine Geologist. At the Golden Pig BIF-hosted gold deposit in Western Australia, an estimation method has been developed that replaces an assay-based resource estimate with one based on mineralisation intensity. Subjective coding of the mineralisation intensity has a more robust connection to local grade than drillhole assays. Indicator variograms of the five mineralisation codes are well structured with anisotropy directions similar to observed structural controls. The proportion of each mineralisation code is estimated and a weighted average of the average grade of each code calculated for a block. Initial validation has shown that the model is a good predictor of the mineralisation intensity, and the application of appropriate local average grade for each mineralisation code gives a reliable block grade estimate.

Jan 1, 2003

By Gray J, Krouse HR, Changkakoti A, Morton RD

A group of stratabound-stratiform Fe-Ba-Zn-Pb-Ag deposits within the La Minita mining district of Michoacan, southwest Mexico have been investigated. The results of the study show that these deposits were generated around submarine hot-springs issuing in a Cretaceous island-arc environment. The exhalative mineralization, which is both epigenetic and syngenetic in character, was developed above fault-systems which constituted the loci of both volcanism and subsequent hydrothermal systems.Fluid inclusion data suggest two hydrothermal events during ore mineralization, one at 240¦C and the other at 161 to 205¦C, with salinities between 2.1 and 12.8 wt.% NaCl equivalent. Stable isotope data support a marine origin for the ore-fluids, as well as, for carbon and sulfur. Strontium isotope data suggest that Sr in the barites was extracted from the volcanics and limestones by circulating seawater. The ore-depositional environment was one of shallow, sub-tropical marine character, where mineralization was in part geochemically controlled by carbonate reefal facies within the volcanic/pyroclastic suite.

Jan 1, 1990

There are two mechanisms in the flo- tation process by which particles are transported from the pulp to the con- centrate: bubble-mineral aggregation and entrainment. It is the chemical processes which occur in the pulp which are critical to the success of flotation since they control the floatability of different min- erals and the selectivity which can be obtained. However, these chemical pro- cesses are so complex that metallurgists are still limited in their ability to predict the floatability of particles in industrial circuits by consideration of the minerals present and the chemical environment. The alternative approach to understand- ing flotation is to examine the behaviour of minerals in industrial flotation pro- cesses, to recognise similarities and differences, and to define the "laws" which appear to apply. Using this ap- proach it has been found that minerals float at a rate which is proportional to their concentration in the pulp, and that the rate of flotation of different min- erals is influenced by variables which' affect the pulp or the froth phase. The ultimate application of this approach is the use of models for circuit simulation purposes. It is this alternative approach which is the theme of this paper. One of the most important problems in understanding the technology of flotation has been in defining the characteristics of the particles being floated. Particles entering flotation vary widely in size and mineral composition, and different par- ticle types float at different rates. These rates do not change uniformly as operating variables change. It has been conventional practice to assess flotation performance in terms of the metal contents of total streams because no better method has been available, and this procedure has obscured important effects which occur in

Jan 1, 1984

By McMahon DW, Schapper MA

Hard rock underground mining has been wedded to the drill-blast method of breaking rock. Current practice and technology have focused on greater efficiencies in the blasting and handling of ore, on the basis that thelower costs that come with larger scale operations compensate for the waste dilution associated with the bulk methods. However, it is suggested that new technology is available or is on the horizon that could completely change the shape of hard rock mining in the 21st century. Hard-rock continuous-mining machines, possibly assisted by high pressure water jets, coupled with automated sorting and materials handling systems, could re-orient the miner's focus to winning metal rather than mining tonnes of ore. More continuous mining processes could accelerate the penetration by high technology in the hard rock underground mine, with the potential of greater manpower productivities and lower costs per tonne of metal produced. This new technology will be important in maintaining a competitive supply of metals, given the falling headgrades of the orebodies remaining for development and the increasing market threat from manufactured substitutes.

Jan 1, 1985

By Fabjanczyk MW, Guy RJ, Tarrant GC

The design of the reinforcement systems required to stabilise mine roadways has developed through the application of field measurement techniques. These techniques have allowed the level of security of a given opening to be determined from an assessment of the loading within the reinforcement, the extent of roof deformation and experience. The design systems developed are now used extensively in a wide variety of geological environment. Recent interpretative techniques have been developed to improve the level of confidence when designing roadway reinforcement. The techniques are particularly applicable for roadways subject to either weak materials or extreme stress levels. A second area of application is where roadway advance rates and hence the timing of reinforcement placement are critical. The newly developed techniques include both analytical and computational models. The validated computational techniques allow a more rational approach to investigation of the effect of varying reinforcement type, timing of placement and density on the level of stability achieved.

Jan 1, 1992

By Wu Y. H, Lu J. P

Slope stability has now become a practical tool in the design and oper- ation of open pits. The stability of rock slope depends on many factors, including not only structural geology, the existence of weak layers, ground- water, blasting and weathering, but also the virgin stress field. This paper presents an application of a numerical method to investigate the effect of the virgin stress on slope stability. The finite element method is employed to simulate the excavation of open pits. Redistributed stress fields in the slope of open pit are computed for several different virgin stress fields. Based on the redistributed stress fields, the shear force which tends to produce sliding of a rock mass and the frictional resistance to sliding are evaluated. The possibility of potential failure is assessed by the limit equilibrium method. The combination of the finite element method with the equilibrium method provides a powerful analytical tool for slope stability. The significant effect of virgin stress on the stability of slopes is shown by studying a typical case.

Jan 1, 1989

By Valenti M

A by-product of the lead smelting operations at BHAS is a copper-lead matte typically containing 35% copper, 38% lead and 12% sulphur. A hydrometallurgical treatment process has been developed for the treatment of this matte to recover copper as cathode and results in a lead-sulphur residue which is recycled to the lead smelter. A commercial plant with a nominal capacity of 4000 tpa utilising this process was commissioned during 1984. This plant has been shown to be capable of producing copper cathode at rates approaching 4000 tpa over short periods of time.

Jan 1, 1989

By R McConnochie, J V. Rowland, J L. Mauk

The Sovereign prospect in the lower Waitekauri Valley of the southern Hauraki Goldfield occurs in daciterhyolite flows and volcanic breccias of the Waipupu Formation. The lower Waitekauri Valley contains a series of NE to NNE-trending normal faults, and the Sovereign prospect lies in a NW-striking graben. The structure of the Sovereign prospect is complex. NE to NNE-trending veins and normal faults dominate the area, however WWNW and N to S-trending structures occur locally. Kinematic analysis of these structures indicates predominantly dip-slip movement, with a local strike-slip component. At least two sets of veins occur in the area: 1.        steeply dipping veins; and 2.       low angle veins, which cross-cut and locally offset the steeper dipping        vein set. Mineralization appears to have formed during normal faulting in an extensional regime.

Jan 1, 2007

By Casale G

This paper discusses a long range mine plan development at the Santa Fe Pacific Gold Twin Creeks Mine based on the reserves of Mega pit. The key constraints of the schedule development included two types of mill ore targets (sulphide and oxide mill ore), consideration of blending of six chemical constituents (sulphide sulphur, carbonate, organic carbon, the ratio of iron/[arsenic, antimony]), and mining of acid generating and acid neutralizing waste at pre-defined proportions. Solution approaches, selected results, and project experiences are discussed.

Jan 1, 1995

The 250 metric tonnes of gold and 360 000 metric tonnes of copper recovered from the Mt Morgan Mine in Central Queensland justify its fame. The mine ceased operation before the advent of three-dimensional computer graphical modelling of orebodies became common practice in mine planning. The Mount Morgan Mine records however remain and are the database for this study. The Mount Morgan project takes ore deposit modelling one step further by examining the relationship between grade distribution within the orebody and key geological features, as a tool for exploration and development.The Mount Morgan gold and copper mineralisation is shown to be strongly lognormally distributed. The deposit has been split into three areas, using geological boundaries, each with different geostatistical characteristics. Important features include: the spatial relationship of near-vertical, high grade shoots with a ring dyke thought to be related to the North Dyke; separation of the high grade eastern stopes from the others along the Andesite Dyke; and lack of concentrated mineralisation along the Slide Fault.Recognition of these features is useful to those currently exploring the Mount Morgan district for similar style deposits, by stressing the importance, or lack thereof, of the geological features.

Jan 1, 1993

The excavation of a tunnel through rock and mixed ground of basalt and silty clays presents a challenge to engineering organisations. Such was the situation facing the Melbourne and Metropolitan Board of Works (MMBW) in constructing the 15.3 km, 5.5m dia. tunnel component of the new Western Trunk Sewerage System. The tunnel geology showed that there were two distinct components to the excavation - rock and mixed ground. By drawing on extensive experience in the use of Tunnel Boring Machines (TBM's) used previously by the MMBW and using techniques developed for predicting TBM per- formance, a comparison of the options of drill and blast versus TBM was made. The conclusion was that TBM methods would provide the best solution to the problem. Tenders were called for the supply of a TBM. A performance specification was used to attract tenders offering designs which re- flected the state of the art on an internation- al level. Particular features required by the MMBW were included in the specification. The excavation planning and operation are described in this paper. The production achieved has shown that the TBM can very adequately handle rock excavation (best weekly production 167.9m). Extreme conditions of mixed ground with heavy groundwater inflows have been handled using an auxiliary thrust system to maintain gripper reaction through the soft ground encountered.

Jan 1, 1987

Following unprecedented high market prices for tin and gold in 1980, significant advances in both mining technology and geological knowledge took place in northeast Queensland. These led to a rapid growth in mining activity. Production of these traditional metals reached levels comparable to those of the heyday of mining activity at the turn of the century.Although tin and tungsten prices have since collapsed, the geological knowledge gained and significant discoveries made during the boom, have created a potential for mine development when prices rise again. For other discoveries which are not workable because of treatment problems, future technological advances are required to raise their potential.

Jan 1, 1990

By Voermans F. M, Hoyle M. W H

The Archean geological sequence in the West Pilbara region (Fig 1), a deformed greenstone volcano-sedimentary succession regionally intruded by layered mafic/ultramafic lopoliths, batholithic granites, granite stocks and transected by swarms of dolerite dykes, has prompted several companies to search for a variety of base metals and and platinoids (Fig 2). In the first instance, detailed aeromagnetic surveying was completed, producing patterns of marked magnetic anomalism which proved substantially successful in the demarcation of areas warranting geological reconnaissance and detailed follow-up. Revelant to this paper were the obvious magnetic features overlying outcropping and buried mafic/ultramafic bodies which ultimately were proven to be host to Ni-Cu sulphides, pgm, Ti, V, Cr and, more recently, Ag and Au mineralisation. Routine stream sediment, soil sampling and ground geophysical techniques of the day appear, in most cases, to have been adequate in the detection of mineralisation, except in the case of Radio Hill massive sulphides where the Turam E.M. (1972) signal essentially failed to detect the blind conductor (Peters, de Angelis 1987).

Jan 1, 1988