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By Skaviniak M

Some better perspectives applying to the exploitation and dressing of polymetallic ores in the Banskfa. gtiavnica-Hod- rusea Ore District are supposed to be achieved after a suc- cessful investigation and proving there the existence of deep-seated mineralization as well as due to increasing de- mand for non-ferrous metals and consequently to higher mar- ket prices of those recently noticed. With respect to the present situation in mining and to the further technical development as well, a several times higher exploitation may be in this region expected, especially in the deeper .eated parts of the deposit. When solving the tasks of a complex economic exploitation over the whole region, consi- derable attention is paid to regional relations and impact studies (due to expected exploitation and ore dressing but also to very difficult problems of dewatering (drainage pro- blems-). It will be first of all necessary to find there an equilibrium between the consequences resulting from the re- naissance of mining industry and environmental requests un- dispensable for the city of Banska 9tiavnica and the other neighbouring towns in the vicinity of mining plants.

Jan 1, 1988

By Patridge A. C

Hydrocyclones have widespread use as classifiers in applications such as mine fill preparation and coal preparation. A fundamental conflict often exists between recovery of all of the valuable material and maintaining the quality of the product. This conflict is a result of a portion of the feed material passing through the cyclone, effectively without undergoing any classification. This paper describes an investigation, undertaken as an undergraduate project in mining engineering at the University of NSW (Brook, 1994), into aspects of cyclones in which supplementary water injection is used in an attempt to reduce the amount of misplaced fine material reporting to the coarse product and hence improve the overall classification efficiency. In particular, the study concentrated on the effects of different modes of water injection. Two methods of introducing wash water into the cyclone body were investigated. A series of tests were performed on a laboratory hydrocyclone having provision for radial water injection at different levels through small orifices in the wall of the conical section, and a preliminary study was made of the performance of a novel cyclone in which the conical section had walls of a permeable polyethylene, permitting a uniform introduction of wash water over the entire surface.

Jan 1, 1995

This paper presents a summary of the technical achievements of the Port Pirie Smelter in 100 years of lead smelting and refining. It also aims to give where possible the reasons or circumstances that led to the achievements. The major achievements took place in the areas of sintering, blast furnace, copper drossing, copper recovery, lead refining and slag fuming.

Jan 1, 1989

British Coal has made a practical progressive approach to improving the reliability of its mining equipment. Reliability must be addressed at the specification stage but does not end there and routine procedures are used to procure equipment of adequate reliability. The techniques used to monitor and improve reliability during the operational phase of the equipment, providing engineers and operators with detailed printouts, together with the types of maintenance employed, ensure high levels of availability. Finally, the methods of repair and overhaul of British Coal equipment and systems ensure that the initial reliability targets outlined on the specification, can still be achieved.

Jan 1, 1991

By M E. Rakidjan

The DOZ underground mine at PT Freeport Indonesia is a copper and gold mine in Indonesia with current ore production of 42 000 tpd. Because of the mine expansion into the West DOZ more ventilation raises are needed to create a safe and healthy work place. All ventilation raises that connect the extraction levels to the underlying gallery exhaust drifts at DOZ are now developed using drop raise techniques. This paper describes the improvements undertaken to increase blasting efficiency, to decrease cost and reduce safety risks. This was achieved by using deck loading and presplitting, changing of stemming materials and prevention of excessive raise collar cratering (blow up).

Jan 1, 2005

This study introduces a new probabilistic approach to seismic stability analysis of embankments and slopes. The approach is based on Sarma's solution, which is modified through presentation of the seismic force by its horizontal and vertical components; i.e. the force may have an arbitrary inclination. The probabilistic modelling includes Monte Carlo simulation of the shear strength parameters of the soil mass, which are assumed to have a normal distribution. The probability of failure is determined based on the seismic co-efficient, which is treated as a random quantity. The probabilistic approach is illustrated through a solution of a numerical example from an opencast coal Mine.

Jan 1, 1992

By McPherson M. J

An experimental investigation was carried out to determine the various gas flow characteristics of bituminous coal samples. Adsorption and desorption tests were first conducted to estimate the quantity of methane that is retained by coal, and the rate at which it is released. Experiments were then carried out to study the variation in coal permeability with changes in applied stress and gas pressure - factors that change continuously with time. To further understand the phenomena involved in retention, release, and flow of gas, electron microscopy was used to study the microstructure of coal and how it affects these characteristics of coal.

Jan 1, 1988

By Kennewell G. J

This paper aims to present the evolution of the mining method in the Prince Lyell orebody. Initial strategy and practical experience are detailed as are the reasons for and benefits of changes to the method since 1972 when underground mining began. This section of the paper starts with ten series and concludes with 40 series which was completed in 1989/90.In addition, to update the series of papers written by various authors over the past ten years on Mount Lyell, a review of the experience in the current 50 series lift of mining will be given. As well, the basic planning guidelines are discussed for 60 series - the final lift of the Prince Lyell orebody.

Jan 1, 1992

By S Gannon, J Abols, T Hughes

In the past year, two very innovative gold ore processing plants have been designed, built and commissioned by Gekko Systems Pty Ltd. The first plant in Vietnam utilises conventional crushing and ball milling followed by gravity concentration (Inline Pressure Jig (IPJ) and Falcon concentrator), flotation, intensive leaching (GFIL), the first industrial scale use of AuRIX«100å ion exchange resin and a cyanide destruction circuit. The second plant, in Australia, uses a three-stage crushing circuit to crush the gold ore to minus 1 mm, followed by gravity concentration utilising a rougher, scavenger, cleaner circuit of IPJs and a Falcon concentrator. A direct smeltable gold concentrate is produced as well as a lower grade concentrate for future intensive leaching or sale. Both plants were designed and built within very tight time frames and budgetary constraints. The experience gained during the plantsÆ design, commissioning and operation are discussed.

Jan 1, 2006

By Seedsman RW, Duncan Fama ME

Mine design procedures will be revolu- tionised by technological developments in computers, software, database construction and management, and numerical modelling programs. Developments in geotechnical databases will be required which utilize geological and geomechanical tests to supply appropriate input for numerical models. Techniques utilizing sedimentological and structural modelling are described. The capacity of current numerical models in mine design is outlined and a program for developing a fully integrated mine design package proposed.

Jan 1, 1987

By Storey AG

Following initial plant scale work on the development and performance of 'spray' oil lances, a full scale room temperature model of the blowpipe-tuyere region of a blast furnace was built to study the basic aerodynamic features of auxiliary fuel injection procedures. Mobilwax 2305 was used as a substitute for Bunker C oil fuel in view of its similar physical properties and the fact that the atomised droplets could be frozen in flight and size, distribution analyses made for various operating procedures. It was shown that secondary atomisation processes far outweighed the importance of any primary atomisation procedures in determining mean Sauter Diameters particularly at high windrates typical of current blast furnace technology. It was also found that good spray dispersions across the blow pipe could only be obtaind for liquid fuels and that the lateral rate of spray dispersion was substantially enhanced by primary atomisation procedures. Mean particle diameters of sprays were found to be predictable on the basis of elementary stability theory and fell within the size range necessary for good combustion at all liquid fuel rates studied. The possible effects of high oil injection rates on flooding phenomena in the furnace bosh were considered. Comparisons show that high oil rates can lead to significant increases in the hanging factor (e.g. 'V 10% at 135 kg oil/thm) owing to increased gas flow rates/thm resulting from the presence of hydrogen.

Jan 1, 1975

By Cutler JL

At the present stage of the Rundle oil shale project planning, with depressed world oil prices, early development of the resource is unlikely. However, this postponement is being used to carry out technical studies required to evaluate alternative rehabilitation strategies and establish a sound environmental planning basis. Major technical data from the following studies are reviewed: Resource: - mine planning; material characterisation; retorting; geology; Environmental: - meteorology; surface water management; laboratory and field leachates; revegetation; waste characterisation; hydraulic and chemical modelling; dust suppression; plant/water interactions; and impact evaluation. These studies have shown that topsoil replacement, seeding mixtures, fertilizer application rates, subsoil quality and handling, waste pile slope and most importantly soil water storage are key factors in successful rehabilitation.

Jan 1, 1987

By Snowdowne J. B H

Rand Mines, Limited, located in Johannesburg, Republic of South Africa has recently completed feasibility studies which have lead to the initiation of two major coal strip mining ventures. A minicomputer based mine planning system was developed to perform the feasibility studies. The broad approach of this system is to utilise inter.-actively the specialist skills and interpretative abilities of mining engineers and geologists. This paper reports briefly on the outline of the system and at greater length upon certain aspects of its use.

Jan 1, 1977

By Chowdhury P. J R, Biswas S. K

Recovery of metallic values from lean-grade raw materials as well as from secondary/intermediate industrial products is of immense importance to a country like India which is not endowed with extensive sources of copper and nickel. The results of a few studies carried out in this area are described in Part-I and Part-II in this article. A novel anode casting system, specially designed for a small copper refinery which had been set up to produce copper wire bars/rods is described briefly in Part-III.

Jan 1, 1992

The preferred alternatives in heap design and their motivation are identified as- -normal heap leaching, to be generally applied wherever possible, - flooded vat leaching, to be appliedwhere wetted ore lacks adequate cohesion or if limited space necessitates it,- thin layer leaching, to be applied where deleterious vat chemistry necessitates it.A number of the following features would probably be incorporated in the optimization of normal local heap leach operations- pre-cyanidation - pre-agglomeration - retaining walls- staged (counter-current) heap treatment- control of calcium levels- reduced pH and trickler irrigation

Jan 1, 1984

By Mann T

The use of dolomite as a refractory began in England about 1870 when the basic Bessemer process for the removal of phosphorus from steel was developed by Thomas and Gilchrist.Knowledge of dolomite as a refractory in this country goes back to the early part of this century, at the time when the Hoskins Brothers took over the Lithgow Iron and Steel Works from W. Sandford. The practice then was toimport burned dolomite in casks from England. It is reported that much of the material was powdered when received, but was still serviceable. The earliest. used sources of local stone were in the Bathurst and Mudgee areas of New South Wales, and these dolomites were first used raw. Later, dolomite was burned in cupolas at Havilah near Mudgee, coke being obtained from the South Coast of New South Wales. This plant supplied burned dolomite to the Lithgow steel plant, later to the Australil1n Iron and Steel plant at Port Kembla, and also to the electric steel furnaces at Newcastle, Sydney and Melbourne until the plant was closed down in 1946.The Broken Hill Proprietary Company first obtained its dolomite from George's Plains near Bathurst (this was, really a magnesium limestone) and later from Mount Knowles, a deposit near Mudgee, which was eventually taken over by the CO:plpany in 1918. In 1936 Australian.Iron and Steel acquired from the Southern Portland Cement Company a deposit at Mount Fairy in the Federal...

Jan 1, 1951

of the multitude of physiographic problems of immediate interest in volcanic terranes, it is the origin of the magma forming the magnificent volcanoes that is perhaps the most mysterious. Unlike anywhere else on earth, the possible locations of magma production beneath the convergent margins are strongly limited in depth and areal extent. Yet the exact process by which magma is produced still stands elusive, even in light of tremendous gains in analytical and physical insight. The principal aim here is to discuss some of what has been revealed about the physics and chemistry of the origin and evolution of island are magmas.

Jan 1, 1987

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

Exploration for economic nickel sulphide mineralisation has often been directed by rationalisations based on poorly understood genetic models. Among those that have enjoyed popularity over the past decade are the "layered gabbro" model and the "basal ultramafic" or Kambalda model. The new discoveries in the Mt Keith-Agnew area could well become a model for future nickel search. Exploration based on even the crudest state- ment of the Kambalda model - prospect the basal contact of Archaean ultramafic complexes for gossanous expressions of sulphide mineralisa- tion - has met with remarkable success. Refine- ments to this model, besides satisfying the geology of any particular deposit, have the major virtue that many of the genetic options - magmatic segregation, hydrothermal transport, sulphurisation, replacement sedimentary, structural control, etc. - are still open. Recent descriptions of highly magnesian silicate melts associated with the ultramafic rocks, do however, place some constraints on the formation of these deposits. Further evidence, from experimental studies on sulphide-silicate and sulphide-oxide phase relationships, and nickel-iron exchange in pyrrhotite, is taken with descriptions of sulphide nickel occurrences in Western Australia to examine genetic models for existing ore bodies.

Jan 1, 1972

By Barclay C, Jacobsen M, Towsey C

The Emperor Gold mine at Vatukoula, Fiji, is a nine million ounce gold telluride deposit. In January 1992, the mine was on the verge of closure when the current management team took charge. Losses had been incurred for two consecutive years and the published resource amounted to less than five years of production. Relationships with the workforce, the government and the general public were poor. Today, the mine has recorded three consecutive years of profit, has resources that will support the operation for at least 20 years and has excellent relationships with employees, government and the general public.

Jan 1, 1997