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Epithermal gold mineralisation was discovered at the Muyup prospect during regional reconnaissance exploration in 1986. Further exploration utilising routine techniques of stream sediment, panconcentrate, rockchip sampling and geological mapping resulted in the discovery of five auriferous vein systems located along northwest-trending fault zones. Scout diamond drilling was conducted on two of the vein systems. Mineralisation is hosted by a poorly exposed, mid-Tertiary volcanic inlier composed of intermediate and minor felsic volcanic rocks intruded by intermediate hypabyssal por- phyries. Gold is wholly contained in narrow steep-dipping hydrothermal breccias and quartz vein stockworks in which chalcedonic silica and fine grained quartz is the predominant gangue with minor adularia, carbonate, and sulphides. Alteration zoning is manifested as intense fracture-controlled silicification mantled by narrow clay-rich envelopes which in tam grade outward and downward into propylitic alteration or unaltered host rocks. Late advanced argillic alteration is superimposed on the vein-related altera- tion assemblages. Alteration assemblages and fluid inclusion data suggest that gold mineralisation occurred in response to episodic hydraulic fractur- ing and boiling of low to moderate temperature, dilute alkali-chloride fluids. The Muyup prospect represents the shallow eroded remnants of an epither- mal gold deposit enriched in Au, Ag, As, Sb and Hg. Low sulphur fugacities reflected by vein and alteration assemblages support an adularia-sericite classification (Heald et al, 1987) for this epithennal gold deposit.

Jan 1, 1991

By Galecki G

The investigations conducted in the High Pressure Lab at the University of Missouri-Rolla demonstrated the ability of high pressure waterjets to excavate coal and minerals, disintegrate materials and as well as to comminute coal and minerals. Additional progress in comminution can be achieved if the compressive crushing principle commonly used at present is changed to one where particles are fragmented by the tensile growth of preexisting internal flaws or cracks, under internal waterjet pressure. This idea was studied in a number of tests. It covers tests with different jets imposed on coal and rock samples during compressive load as well as without any loading.

Jan 1, 1993

By Gang C, Changyi S, Liangde G

Geophysical and geochemical methods and techniques for gold exploration and their applications in China are summarised in the paper. Some case histories are also presented. The effect of prospecting for gold deposits using these methods is well illustrated through these examples.

Jan 1, 1997

By Raudsepp R

Since 1991, the Porgera Joint Venture has processed refractory sulphide flotation concentrate by pressure oxidation with the subsequent gold recovery, from the washed residue, via a conventional leach/carbon-in- pulp (CIP) circuit. The capacity

Jan 1, 1997

By Mendeckl A. J

Anglo American Corporation has always viewed technological development as vital and as such has placed research and the implementation of new technological practices high on its priority list. Support is given to a number of research institutes but a significant degree of reliance is placed on in-house research carried out at individual companies and at the Group's main laboratory complexes. The Corporation's interests are diverse with advanced practices and innovative technology ranging from new battery technology with wide application to deep level shaft technology with very specific application. In this paper, we aim to concentrate on a particular system developed primarily for use in seismically active deep mines. The system has proved to have far wider application and has the potential to be further enhanced to meet the needs of users across a broad range within the industry and even beyond. As the nature of this conference is to inform delegates of advanced mining practices, we should simply mention that we could have talked on subjects relating to the advances made in deep level winding technology including winder drive and brake control to alleviate dynamic rope loads, shaft steel design for high pay load high speed winding and shaft safety systems such as slack rope devices and moving lip loading facilities to cater for rope stretch. Other areas of interest relating to refrigeration using ice technology or non-explosive rock cutting using diamond wire or saw technology could also have been of interest. As the South African gold mines become deeper and the problems associated with depth become more acute, answers had to be found and systems developed to cope with very high rock stress and the related seismicity. The fundamental understanding of the behaviour of the rock mass has always been important but became critical on our mines to ensure the safe extraction of the orebody. Basic research into and the application of physics, applied mathematics, seismology, rock mechanics, electronics and computer technology have helped us to develop the Integrated Seismic System - Integrated because of the system's abilty to monitor seismic and non-seismic sensors simultaneously and because it encompasses data acquisition, processing and interpretation into one system. The system which is in use at all our gold mines has found application not only in South Africa but also in such locations as Australia, Chile, Canada, Europe and Japan. A highly motivated team of scientists under the leadership of Aleksander Mendecki developed the majority of the hardware and software needed for the system. In essence, the system allows us real time monitoring of energy release and stress transfer data that with the aid of modern computers is turned into useful information. The information so obtained has allowed us to improve our mine and extraction designs to minimise the inherent hazards. The system has proved to be an extremely useful management tool as substantiated by the demand for the product. The paper is intended to convey to the reader the technical concepts and the presentation is intended to demonstrate the usefulness of the system.

Jan 1, 1995

By Beeby C. j, Fernando W. J, Ming M. Q I, Guang Li Xi

Removal of moisture in steam-fluidized, mainly steam-heated, fluidized beds makes possible significant energy savings over conventional forms of large-scale drying. The systens are described and their applications to brown coal and alumina hydrate are reviewed. In application to brown coal the use of the system to permit meeting diurnal variation in power station output, and the use of triple-effect drying to minimise coal usage and to avoid the necessity of recovering in the turbines the energy in the steam from the last dryer are discussed. To facilitate the rapid adoption of the systems proposed, studies are being made of heat-transfer to dried coal, of moisture equilibrium in pressurized and vacuum systems, of tapered beds as a means of reducing carrier steam and permitting wider size variation, and of the use of carrier solids for drying lump materials.

Jan 1, 1989

The Ok Tedi open pit mine will have final wall heights in excess of 750m. The behaviour of these excavated slopes will be influenced by the presence of numerous defects. This paper discusses the identification of possible failure mechanisms within the pit walls based on mapped fault and joint data. Results from analyses using these data have formed the basis for the ultimate pit design.

Jan 1, 1994

By Sen A. K

The Chiria Iron Ore deposit falls within the well-known Horse-shoe-shaped Singhbhum-Bonai-Keonjhar belt in India, where most of the deposits supplying ore to various steel works of Steel Authority of India Limited (SAIL) and Tata Iron and Steel Company (TISCO) are located. With an estimated reserve of about 2000 million tonnes of ore (at 55 per cent Fe cut-off) spread over four contiguous blocks, it is the largest iron ore deposit in India and one of the largest in world. The present study is confined to only one of the four blocks of Chiria viz North Block, comprising an area of 2.11 km2. `Corporate Plan 2005' of SAIL envisages development of a large open cast mine at Chiria to meet its enhanced requirement of iron ore by 2001-02 AD.

Jan 1, 1995

By Williams M

Sheet flotation is a new two dimensional column flotation cell that produces continuous spectrum of products. Analogous to a shaking table in its performance and analysis, sheet flotation is a sheet of bubbles rising through packing contained between two walls. Feed enters the sheet at the lower left and the product exit along the top and right edges. Iligh grade materials exit at the top left, middlings exit at the top right comer and low grade waste materials exit at the bottom right. As in the case of a shaking table, two motions are required: up and right. Bubbles furnish the upwards movement for hydrophobic particles, slanted packing the rightward movement for hydrophilic particles. The sheet flotation cells is analysed as a 40 x 40 array of simple cells. In practice, 1000 x 1000 arrays of simple cells may be expected. With larger arrays, excellent separations may be expected. Because there is no recycle, there is no build-up of middlings in

Jan 1, 1993

By Muir D. M

Highly saline process water has a number of implications for the CIP process during the leaching, adsorption and recovery of gold. The reduced oxygen solubility in saline water can seriously reduce the rate of gold leaching, while dissolved oxygen meters do not necessarily reveal actual oxygen concentrations in saline water. High levels of magnesium in the ground water necessitate operation at lower pH (-9), with the potential for greater cyanide loss via HCN stripping. In addition increasing salinity renders viscosity modifiers largely ineffective.The adsorption capacity of aurocyanide onto activated carbon is improved with increasing salinity, but misleading results can be obtained in assessment of gold loading kinetics of plant carbon samples already loaded, or partially loaded, in saline water if subsequently tested in fresh water. Elevated chloride levels in the Zadra elution process can cause severe anode corrosion in the elecuowinning cell. The Anglo elution process is tolerant to only slight increases in water salinity, but elution times can be reduced by ethanol addition. Care is required in carbon regeneration, as salts can catalyse carbon decomposition as well as increase kiln corrosion.

Jan 1, 1994

By Ennis P. C

The Mt Keith ultramafic intrusive extends for about 200 kilometres from Agnew in the south to Wiluna in the north. It forms the host for a number of nickel sulphide orebodies including Mt Keith and Honeymoon Well. Long fibre minerals are associated with the orebodies. The presence of these minerals impacts on the issue of tailings disposal from several standpoints, particularly the slurry beaching properties and dust generation from dry beaches. Central thickened discharge (CTD) is an innovative method of tailings disposal that involves stacking tailings in a low conical hill instead of storing them in cells. In appropriate circumstances this leads to savings in capital costs and operating expenditure. The method was introduced to Australia in 1981, and is currently employed at four operating mines, Elura and Peak Gold, both at Cobar in NSW, McArthur River in the Northern Territory, and Union Reefs near Pine Creek, also in the Northern Territory. It is the proposed method for Century Zinc and Ernest Henry, both in Queensland. The paper describes laboratory test work and design parameters for the application of the method to tailings disposal at Honeymoon Well and compares them with comparable data for other CTD systems. Of particular relevance for design purposes are beach slope, density, and water recovery. Wind tunnel tests were conducted on the Honeymoon Well tailings samples to investigate dust generation from the dry beach surface and it was concluded that dust generation from an undisturbed beach would not occur because of crusting.

Jan 1, 1996

By Shklyar FP, Babushkin NM, Bokovikov BA, Fedotov PB

A mathematical model for gas flow dynamics and heat and mass transfer processes occuring in the tuyere raceways and in the zone of the final for- mation and heating of pig iron and slag has been developed and simulated on a digital computer. It takes into account the formation and size of the raceway zones, combustion of coke and its substit- utes, oxidation of the metal, radiation from the gases to the raceway boundaries, physical heat losses and the direct reduction of the pig iron elements below the raceway zones. To evaluate the distribution of heat produced by the oxidation of metal between gases and prod- ucts of smelting, the problem of heating the mat- erials in the raceways with the sources of heat in the materials under conditions of intensive gas circulation in the raceways is solved. To determine the amount of heat transferred by radiation from the gas to the boundaries of the raceways, the problem of radiant heat transfer be- tween two grey bodies forming a closed system is solved. Using the structural parameters of the furn- ace, the inlet parameters of the combination blast and exit parameters of the melt, the model permits the calculation of the temperatures of materials entering and leaving the raceways and also the res- idual temperature of the gases, which qualitatively differs from the theoretical combustion temperature. Analysis of the operation of several different blast furnaces has shown that the overall picture of the interaction between gas flow dynamics, mass and heat transfer processes occuring in the race- ways and in the zone of final product formation, obtained with the aid of the model, now permits us to approach from a different position the deter- mination of the limiting factors in furnace operat- ion. It also allows us to explain certain phenom- ena observed in blast furnace practice and to dis- cover new relationships which may be used in analy- sis and control of the smelting process.

Jan 1, 1981

Developed and built in 1982 for simultaneous bathy-metric and reflectivity mapping of the deep ocean by the Hawaii Institute of Geophysics, SeaMARC II was a breakthrough in sea-floor mapping technology. The design was developed cooperatively by industry and academia, and the system has served as a prototype for a new generation of mapping tools for operation in both shallow and deep water.Research programs using the SeaMARC II system have focussed on basic research into the geophysical evo-lution of the Pacific, ranging from intra-atoll mapping to surveys of the deep-sea trenches. During the past few years most work has been concentrated on detailed investigations of the morphology of mid-ocean spread-ing centers, seamounts, and the subduction zones which surround the Pacific. The detail provided by the high resolution, 10-km wide side-scan sonar images of fault and fold structures, combined with the swath of bathy-metric information obtained simultaneously, allow previ-ously unattainable analysis of seafloor morphology and are leading to development of detailed models for ocean crust genesis and deformation.

Jan 1, 1990

By Montini A

The dynamic behaviour of the load in a pilot-scale ball mill has been measured as a function of axial position within the mill, end plate lifter design, load volume J (percent of mill volume), percent solids in the slurry S and mill speed N (percent of critical speed). Conductivity probes were inserted through the shell of the mill to provide online measurements of the dynamic orientation of the load in the mill. It was found that 1. the height of the shoulder of the load is increased by increasing J, S or N. 2. Measurements of the effect of S on the location of the shoulder of the load should be very useful in mill control strategies. 3. The axial centre of gravity of the load in the mill is not affected by operating conditions. 4. The presence of lifters on the feed end plate does not affect the torque drawn by the mill. 5. Holdup of slurry in the mill is a strong function of slurry viscosity and a weak function of mill speed.

Jan 1, 1986

Unprecedented political, economic, and social change throughout the world will have an increasingly profound effect on the dynamics of the world's mining industry. Analysis of the early financial trends in this development (statistics on exploration expenditure, and investment flows) gives some insight into the magnitude of structural change and its implications for established mining economics and companies.Increasing confidence in the stability of many third world and developing countries is attracting exploration and investment capital that had previously been largely directed to established mining economies in North America, Australia, Europe and Southern Africa. Some of the projects requiring capital and technology in the CIS, Africa and Latin America are technically very attractive. The end of the 'cold war' and the influence of the IMF is gradually changing their risk profile for mining investment.

Jan 1, 1993

By Ibil S

The Gameta Gold Deposit is located on the north-eastern corner of Fergusson Island in the D'Entrecasteaux Islands of Milne Bay Province, PNG, at lat. 9¦ 25' 5, long. 150¦ 47' E or AMG co- ordinate 256740 E/8959000 N (Figure 1). The area is covered by the Fergusson (SC56-05) 1:250,000 scale Topographic Map Sheet and the Koitabu (9079)1:100,000 scale Topographic Map Sheet. The property is held 100% by Union Mining NL (UMG) and lies 105 km NNE of Alotau and 33 km to the ESE of UMGs recently developed Wapolu Gold Mine, a Joint Venture between UMO (51%) and Macmin NL (49%). The inferred resource estimated from surface results and 105 RC drill holes, currently stands at 1.89 million tonnes at 2.6 git gold (1.0 g/t Au cut-off) or 155,000 oz. Evaluation of the property is currently proceeding. To date 111 RC holes have been drilled for a total of 4611 m.

Jan 1, 1997

By Wilson AC

Permian coal from Western Australia's only producing coalfield at Collie is the dominant fuel used in generating electricity for the State's interconnected grid. Collie coal is sub-bituminous, non-coking and has a low ash, medium volatiles and high moisture content. The seams were laid down in a fluvial basin which extended beyond the Collie Basin and included the Wilga and Boyup Brook Basins at least. Adjacent parts of the southwest Yilgarn Block are prospective for Collie-type basins. In the past few years significant deposits have been delineated within the Perth Basin, specifically on the Vasse Shelf and in the Hill River area. In the former area high quality steaming coals are correlated with the lowest coal bearing member at Collie. The seams are amenable to underground mining and because of their high quality, the coal may have export potential. Sub-bituminous coal deposits of Jurassic age are present in the Hill River area. Exploration has down-graded the prospectivity of the Carnarvon and Canning Basins for sub-bituminous near-surface coal deposits. Tertiary lignite deposits are present in palaeo-drainage systems in the southern part of the State and their potential for development is being evaluated.

Jan 1, 1986

By Muldoon T

Water sprays on mining machines are generally put there to reduce dust; however, research by the Bureau of Mines and others has shown that considerable airflows may also be generated by these sprays. This recognition of water spray-gen- erated air movement led to the "Spray-Fan" - a continuous miner auxiliary ventilation system which was shown to reduce methane peaks by a factor of 15. Recent successes and failures of the Spray Fan are reviewed. More recently, the same principles were used in the design of the "Shearer- Clearer" for reducing dust at longwall shearer operators. The original design was successful; however, a new design is now available which is more practical to install and does a much better job of holding the dust against the face downwind of the shearer. The latest research objective is to eliminate the negative impact of spray- generated air turbulence on continuous miner dust control. Most coal faces in the USA are ventilated in the exhaust mode using "line curtain", and the forward airflow on the side of the heading opposite the curtain is inevitably weak. Air turbulence generated by sprays which are incorrectly located and/or operated at excessive pressures can cause roll back - in which the dust cloud at the face is forced unwind against the ventilation and spreads over the miner cnerator. The general approach to reducing "roll back." is reviewed and art anti-roll back water spray system is presented.

Jan 1, 1983

By Semple DG, Leach TM

A continued exploration programme has further defined the geology of the Tolukuma vein system, verified the resource indicated by Newmont, and identified potential for additional mineralisation. The resource at Tolukuma Hill, designated as Zone C, is a measured 440,000t @ 17g/t Au and 46g/t Ag with an additional indicated resource of 120,000t @ 16g/t Au. A diatreme breccia localised at an intersection of structures, and a relationship of gold to base metal sulphides, are highly indicative of a porphyry association. Typical epi-thermal features such as crustiform banded quartz and quartz pseudomorphing. platy calcite are also present and locally contain lesser gold mineral-isation. Pre-existing dilatant structures have acted as a host to the ore fluids, resulting in the formation of the semi-continuous Tolukuma-Gulbadi veins over a 1100m strike. A fluid flow model suggests that mineralising fluids were sourced from the diatreme margins and migrated laterally along dilatant structures. Bonanza gold grades are derived through fluid quenching in the flexure between a hanging wall split which hosts much of the Tolukuma Hill resource and the feeder graben structure. Thus, the relationship between the pre-mineral structural geometry and fluid upflow at the margins of a diatreme breccia, controls the ore setting. Potential for more ore remains within the Gufinis and the 120 veins as well as in the outlying Prospects.

Jan 1, 1994

By Roddick F

From its mining lease at the northern end of Cohens Reef at Walhalla in the North Gipps- land mountains, the Long Tunnel Extended Gold Mining Company produced 13,695kg of gold, which at 1982 prices represents a value of about $140 million. In the period 1885 to 1908 the mine was one of Australia's principal reef gold producers, being top Victorian producer in six of these twenty-four years. Prior and subse- quent occupants of the lease produced an addit- ional 160kg of gold. The Extended and the other mines on Cohens Reef whilst contributing importantly to the financial resource of Victoria, were the sole important support for the substantial town of Walhalla that had grown up around them. When the mines closed, Walhalla gradually reduced from a bustling developed town to the present attractive mountain village so favoured by tourists.

Jan 1, 1982