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By Watson K, Pollard D. M

The electrolytic recovery of metals from solution requires an understanding of the characteristics of the particular system employed, and the current efficiency and morphology of the deposit are influenced by such factors as cell design, metal ion and supporting ion concentration, acid concentration, temperature, impurity levels and cell design. The electrolytic deposition of both cadmium and silver present individual difficulties, and special cell designs are used for each of these metals. It was found that cadmium deposition was plate-like at lower cadmium concentrations, and at higher current densities. The presence of zinc in the electrolyte promoted nodular growth. Current efficiency remained high even at 50C in contrast to published information. Silver deposition morphology was relatively unaffected by changes in silver concentration, pH and current density. Current efficiency was reduced as temperature was increased.

Jan 1, 1989

By Fleming GJ

The Miwah prospect lies on the dilational 070¦ trending Miwah Lineament near its intersection with northerly oriented fractures within Pliocene volcanic rocks exposed between a NW trending segment of the dextral transcurrent Sumatra Fault, and the more northerly trending Samalanga-Sipopok Fault to the east. These faults reflect the continued interaction between stresses from the India-Australia plate located to the southwest, and spreading within the Andaman Sea to the north of Sumatra. A system of deep seated faults is believed to have facilitated emplacement of post-Miocene magmas and Quaternary volcanic centres at shallow crustal levels throughout northern Sumatra.

Jan 1, 1995

The implementation of a process information management system (PIMS) is to provide a single online, real-time information system. This system provides a unique and completely open view for everyone, based on the key business drivers. It is structured around the three key concepts: process, maintenance and stocks. It combines numerous applications and provides accessibility to common tools and reports, through a web-based user interface, for every one from the floor operator to the General Manager. This æunique and commonÆ view displays raw, online process information that provides a quick health check of the operation at a glance, highlighting areas that require further investigation. The system is based on a hierarchical system of views, from the overview of the whole plant flow sheet to the more detailed operational shop view. It provides a synthetic view between continuous and batch operations, enabling the tracking of each batch produced. The batch view displays the critical batch components, and a comparison with each component of an ideal batch. This enables detailed analysis of each batch to identify areas of improvement. The information system will consist of an online reconciliation of stocks and flow data. This enables focus on the recovery of each process unit on a regular basis. This paper discusses the design strategy for the Process Information Management System, to ensure a unique and open view on the key business drivers is achieved and implemented successfully.

Jan 1, 2005

By Wang Y. J

This paper describes a more generalised or generic approach for the mine ventilation network problem. More specifically, it defines the network variables in a manner that establishes the network problem in a nonlinear programming format. Assigned to each branch are three variables: air quantity, regulator pressure loss and fan pressure. Each variable is imposed with lower and upper bounds. Based on these, the generalised network problem for a mine ventilation network with B branches is presented as a system of B independent network equations in 3B unknowns (variables) with variable bound restrictions, and it is classified as a nonlinear optimisation. A nonlinear programming model has been developed for this generalised network optimisation problem. The model is formulated and transformed into a standard equality-constrained nonlinear programming form with given variable bounds. Then, MINaS (Modular In-core for Nonlinear Optimisation System) is used to obtain solutions. Examples are given to illustrate this nonlinear programming approach to the mine ventilation optimisation problem.

Jan 1, 1993

By Watson F. G

As an introductory paper of a series on the Melbourne (Australia) Underground Rail Loop extension to the extensive electrified suburban railway system the paper outlines the need for the Loop, legislative background, organizational establishment, engage- ment of consultants, design control, contracts, financial aspects, example of organizational flexibility and certification and transfer of the Loop to the Victorian Railways Board.

Jan 1, 1981

At the Nikkel og Olivin nickel mine near Narvik, Norway, Outokumpu has been the operator since 1993. The mine was opened in 1989 and in 1992 Outokumpu commenced operations to secure concentrate deliveries to Harjavalta's nickel smelter in Finland. Annual production is about 740 000 tonnes of nickel ore grading 0.5 per cent Ni, about 25 000 tonnes of nickel concentrate and about 2800 tonnes of nickel metal. All production comes from underground operations which makes Nikkel og Olivin AS perhaps the lowest grade underground nickel mine in the world today. Production is currently from one of two orebodies, which is known as the Western orebody. The Eastern orebody was worked out by 1995. During Outokumpu's operational period the Western orebody has been delineated and taken to production. The underground exploration and definition drilling involved about 15 000 in of diamond drilling, which was carried out during a nine-month period. Following this a feasibility study was undertaken and production commenced. Improvements were made to the mining methods. Previously the mine utilised open pit equipment underground and this resulted in an enormous amount of additional tunnelling. Grade control and ore delineation were previously based on sparse diamond drilling and all geological information was processed manually. The improvements included the use of underground sludge drilling to increase the amount of geological information, the of a new computer system for grade control and mine planning, new automated underground longhole drilling equipment and the of underground mining equipment which reduced the size of the drives. These changes produced a marked increase in the efficiency of the underground Mine.

Jan 1, 1996

HIGHWALL MINING - DECISION TO MINEUlan had completed operations in the first Open Cut area due to high stripping ratios and the presence of geological features which destroyed a significant portion of the coal in the upper part of the seam. The pit had been abandoned in 1994 and operations had moved to a new location to the north west.

Jan 1, 1998

By Harmse C

Gold mining in Vatukoula had been a low tonnage/high grade operation for much of its 55-year life. During 1991 it became clear that a change in direction was needed if the mine was going to continue to prosper. The challenges of ore reserves of only three years, the prevailing gold price and high infrastructure and fixed costs combined to force changes in mining strategy.A more productive mining method was required to lower the unit mining cost, lower the pay limit and make more effective use of the resource.The flat dipping mineralised faults or flatmakes had been mined by updip, handheld room and pillar methods with a more recent trackless development adaptation. Furthermore, up to 40 per cent of the resource was left in pillars and broken rock.

Jan 1, 1993

Over the last five years Du Pont (Australia) Ltd has developed a commercial range of new generation emulsion based explosives concurrently with the development of new explosives-placement systems. The paper outlines Du Pont's emulsion technology and history of product development from the initial emulsions (Tovex E & EL) to emulsion/ANFO blends (Tovex BE) through to the most recent development of Du Pont's SOL emulsion component. The paper also outlines the development of materials handling systems on site to load waterproof bulk explosives from the original pumper trucks through to the multipurpose agitator bowl blending and pumping units at the heart of Du Pont's SOL emulsion system currently available within Australia. The last section deals with some of the more important features of enhanced agitator bowl truck designs and outlines examples of the complete SOL emulsion system and methods of operations currently practiced at specific mines within the Bowen Basin coalfields.

Jan 1, 1986

The four major contracts for the construction of Museum Station are: 1) Installation of Soldier Piles, 2) Structural Contract including the temporary support, 3) Architectural Finishes which include Electrical and Mechanical Services and 4) Supply and Installation of lifts and escalators. Specific areas of interest include the fabrication, installation and removal of temporary support steelwork, the monitoring of ground loading, and the interface between the structure and. the temporary support. The information collated during construction confirmed the design assumptions and criteria. No major changes'were required in the design of the construction methods. The open cut excavation and construction of this major structure in an inner city area was significant by any standard and was successfully completed with minimum disruption to the public and without damage to adjoining or surrounding property.

Jan 1, 1981

The Comstock Lode, a world-class precious metal vein district near Virginia City in western Nevada, U.S.A. (Fig. 1), produced 8.3 million ounces (0.28 X 106 kg) of gold and 193 million ounces (6.56 X 106 kg) of silver during the period 1859 to present (Bonham and Papke, 1969). More than 95% of production was from the Comstock fault, while the adjacent Silver City, Occidental and Flowery vein systems produced about $10 million (U.S.). Within the Comstock fault high-grade ore bodies, or bonanzas, were distributed over 2.3 miles (3.8 km) along strike and persisted to >3000 feet (>900 m) below the surface (Fig. 2). Bonanzas consisted of as much as 1.4 million tons (1.3 million tonnes) of ore grading up to 1.9 oz./ton (65 gm/ton) Au and 30 oz./ton (1020 gm/ton) Ag (Table 1). Some bonanzas occurred in the main Comstock fault plane while others, including the highest grade bonanzas, formed in hangingwall frac- tures. After 1880 most ore consisted of lower-grade vein material surrounding mined- out bonanzas and large volumes of mineralized vein and wall rock in the Comstock hanging- wall that were mined from open cuts. Deep mining was hindered by large quantities of hot water and bad ground which ultimately defined the limits of underground production. The widths and richness of Comstock bonanzas strongly influenced U.S. mining law, milling and underground mining methods, and securi- ties regulations that are in practice today. Within the district Mesozoic metasedimentary rocks, metavolcanic rocks, and granitic in- trusions are overlain by Miocene volcanic rocks (Thompson and White, 1964). Veins cut all lithologies. Miocene volcanic rocks and their K-Ar ages (Vikre, McKee and Silberman, 1987) include Santiago Canyon rhyolite (22

Jan 1, 1987

By Kaleta S, McTavish LP, Turner RD

Primary production blasting at Hamers- ley Iron began with seven inch holes at Tom Price in 1966 and has developed since then to large multiple row shots of 381 mm holes at Tom Price and 311 mm at Paraburdoo. Up to 1.3 million tonnes are initiated in a single blast with the average around 300,000 tonnes. Development can be traced through Anfo, AlAnfo, slurries, various boosters, initiation and delay techniques, hole loading and daily operating practices. A standard practice could be developed for the two mines for normal pro- duction blasts; this would not apply to such common variations as low "paddy" shots, pre- splitting, tight corners necessitating single row drilling etc. Because of ground variation three or even four sizes of drill holes may well be economic- al for blasting, even though this would be off set by complications in operation, supervision, store stocking and maintenance, particularly in Drilling.

Jan 1, 1978

By Whincup P

Hilton deposit comprises en-echelon silver-lead-zinc orebodies with reserves in excess of 50 million tonnes. The host rock to the ore is a dolomitic and pyritic shale/siltstone which dips steeply west. The shale/siltstone is deeply leached and porous, particularly over the Ore Zone where the depth of leaching continues down to 440 m below surface, and constitutes an extensive permeable aquifer system containing a large volume of saline acidic groundwater. Initial production commenced at Hilton in 1987 well below the aquifer. A dedicated dewatering and monitoring programme is in place to ensure security of stoping operations and allow extraction of ore close to the leached zone in future years. Dewatering is undertaken from controlled bores from underground sites. Mine groundwater discharge is presently at the rate of 4000 kl/day with plans to increase to 8000 kl/day. An additional 2000 kl/day of fill and service water and water from secondary aquifers is also pumped from the mine daily. Although recharge rate to the aquifer is minimal, studies indicate that due to the size of the aquifer and future extensions to mine development, dewatering will be a life of mine activity. The investigations which have been undertaken to determine optimum dewatering techniques and schedules are described. These include production bore tests, mine planning constraints and computer aquifer modelling. Gravity geophysical techniques have been successful in delineating the lateral and vertical disposition of the aquifer. The mine dewatering schedule, whose principal component is underground mine drainage, is also outlined.

Jan 1, 1988

A shift in the present day oil exploration scenario from West Coast can be foreseen keeping in mind peak of exploration in Cambay Basin and fast pace of development in Bombay High and its associated fields by the end of this century. Shifts in exploration from structural traps to stratigraphic traps, techno- logical development to drill in deep waters, improving economic situation for oil ventures and proven oil and gas potential of East Coast basins suggest that Indian oil explorat- ion scene will be at its peak along east coast during early 21st century. Hydrocarbon shows in Poonch and Jawalamukhi in Punjab Basin, improvements in drilling to greater depths, better seismic data aquisition, good source rock potential of Subathus and its equivalents and large geologi- cally mapped structures will reopen new avenues for explorationists. Not much exploration effort has been put up so far in Ganga Basin. Keeping in mind size of the basin, sedimentary thickness involved, presence of algal matter deposited in shallow marine environment & higher hydrocarbon indications warrant active exploration. Gondwanas in India having such a large sedimentary area can not be ignored keeping in view generation and production from the non marine sediments of Kenya, Chad, Sudan, Gadon and China. Gondwanas become all the more important in view of gas production from their equivalents-Karoos in Ethiopia and South Africa. In all, above mentioned changes can be predicted in Indian oil exploration scenario during 21st century.

Jan 1, 1986

The Nelson province was chosen as the prime area for rhenium sampling, based on its mineral associations. Sample preparation involved benefication by grinding and flotation. A modification of published procedures for rhenium analysis was developed and the results compared with those obtained for molybdenum on the same samples using atomic absorption spectroscopy. The results of the analysis for both metals is discussed and the relationships between rhenium and the molybdenum mineralisation of this region is commented on. A metallogenic province is defined for molybdenum and rhenium and the tectonic setting for this is discussed. Some consideration has been given to rhenium possibilities in Fiordland and the Coromandel Range.

Jan 1, 1980

By Slechta JJ

The performance of a hydrocyclone treating fine coal has been examined over a wide range of feed and operating conditions.The results were expressed in terms of partition curves from which the water split to the oversize flowstream,the corrected separation size and reduced partition curves were determined-.The following conclusions were obtained. (a) The water split to the oversize flowstream was found to be dependent upon the vortex finder and spigot diameters of the cyclone and the flowrate and solids content of the feed slurry. (b) The corrected separation size was dependent on the solids content of the feed,and the vortex finder and spigot diameters.The hydraulic pressure (or flowrate) of the feed slurry did not have a significant effect.This phenomenon could be explained in terms of crowding of the particles at the Spigot.

Jan 1, 1984

FaulIing west of the Mount Isa mine is described and is shown to be related to three groups of folds that have been recognized in the area. The first period of faulting postdates the first generation folding; these faulIs are regional faults (tectonic discontinuities) which are folded by second generation folds. The faulting accompanying the second generation folding divides the area west of the Mount Isa mine into four structurally and metamorphically identifiable blocks. The most prominent of these second generation faults is the Mount Isa Fault, which is characterized by a number of distinct zones of intense second generation folding and the presence of localized layers of mylonite. Only limited evidence for brittle deformation has been observed and the major movement appears to be associated with the plastic deformation of the rocks. Confined to the areas of second generation folding in the Mount Isa Fault are numerous third generation kink folds. A detailed description of the Mount Isa and other faulIs is presented together with evidence for their existence. The displacement accompanying this faulting cannot be established because of the complexity of the structure.Postdating these faults and all the folding of the area are minor cross faults.

Jan 1, 1973

By Partridge AC

In order to provide a'valid description of the performance of size classifying equipment it is necessary that a standard procedure be established for testing and for the subsequent expression of results. Such a standard would permit the valid comparison of alternative equipment and may provide a basis for the prediction of performance. An Australian Standard (AS 1634-1974) has been used as the starting point for an International Standards Organisation-(ISO) working group (of which the authors are members) charged with the preparation of an ISO Standard for the expression and presentation of the results of tests on coal size classifying equipment. The approach taken is applicable to all types of sizing equipment (cyclones, screens, dedusters, etc.) and should be suitable for adoption in the minerals industry as well as by coal preparation engineers. The background to the proposed Standard, is given,including a critical review of other frequently quoted performance measures, the procedures described in the draft are discussed, and an example given.

Jan 1, 1984

By Virtanen M

Grinding has been one of the areas of major development at Outokumpu's concentrators. During its early years the company used entirely rod and hall mills, but due to the high costs of metallic grinding it began the testing of autogenous grinding as early as the 1950s. In the late-1970s, the company's own modification for two stage autogenous grinding was ready for industrial use. Surprisingly late, in the 80s - 90s, an interest rose to check also the effects of grinding methods on flotation results. This paper firstly gives a short history of the development work of Outokumpu type autogenous grinding, called 'Outogenius'. The effects of some grinding methods on the process results of two nickel ores are then reviewed. The tests to date show notable effects of grinding methods on flotation.

Jan 1, 1996

An empirical kinetic model is discussed that enables the number of stages in a carbon-in-pulp plant and the amount of carbon in each stage to be calculated for any desired metallurgical performance. It is shown that a knowledge of the kinetics of gold extraction by activated carbon in each stage assists plant operators in the important' areas of process control and optimization. Factors such as mixing efficiency, concentration and distribution of carbon through the plant, bypassing of pulp through a stage, and carbon poisoning are examined. The resin-in-pulp process for the extraction of gold cyanide is also discussed, and the chemistry of absorption and elution on strong- and weak-base resins is examined. In addition, operating results from a small-scale resin-in-pulp pilot plant are presented, and various applications in which resin-in-pulp may be preferable to carbon-in-pulp are discussed.

Jan 1, 1982