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By Wencai X

The conversion relationship between the Bond Work Index W1, specific output of mill and the energy efficiency of grinding were developed using dimensional analysis. These relationships were validated and the value of the conversion coefficient ~ was also obtained using a new installed device for measuring grindability of ores. With the new simulating algorithm the mill specifications, output and size distribution of grinding products of industrial mills can be calculated based on laboratory measured results. This algorithm is more accurate and simpler than any of the other empirical relationships. KEYWORDS: Conversion coefficient method, grindability, grinding Constant.

Jan 1, 1993

In recent years stricter requirements imposed variously by the Companies Acts, auditors and the Stock Exchanges have resulted in annual financial statements of mining companies becoming more detailed, informative and useful. Standards of reporting on ore reserves have not kept pace with the improvements in financial information disclosure, despite the fact that ore reserves are usually the most important asset of a mining company. The ore reserve reporting practices of fifteen leading Australian mining companies are analysed against important specific criteria. In terms of detailed and meaningful disclosure, there is scope for major improve- ments in annual ore reserve reporting Practices.

Jan 1, 1981

By V F. Kucherov, V A, V M. Kirienko

In the paper the problems of elaboration and building up the computer engineering system æSafety and stability of underground buildingsÆ as subsystems of the common automated computer system of geomechanical monitoring for deposits of mineral resources are considered. The theoretical bases and techniques of calculation of underground buildings stability are considered. The example of elaboration of such system for a Starobin deposit of potash salts (Belarus) is considered.

Jan 1, 2003

The mined-out Old Waite volcanogenic Cu-Zn deposit lies in the Noranda mining district of northwestern Quebec. The deposit has a distinctive pipe-like zone of alteration beneath the massive ore, extending into the stratigraphic footwall. The hydrothermal metasomatism within the alteration pipe produced a concentric zonation. with a peripheral quartz - sericite - chlorite mineral assemblage surrounding an axial core of magnesian chlorite - Phlogopite.

Jan 1, 1989

Controlled recirculation of nine ventila- tion air is becoming an acceptable practice world-wide. A brief review of operating and planned schemes is given which illustrates the various purposes for using controlled recircu- lation in different types of mines. A de- tailed description is given of the operating and proposed schemes on South African gold mines. This is followed by a description of some theoretical and experimental work which has recently been carried out into certain important aspects of controlled recircula- tion. This includes: safety systems, dust filtration, blast contaminant removal, radia- tion hazards and the development of an expert computer program for the design of controlled recirculation systems.

Jan 1, 1988

Strata bolting/dowelling reinforcement techniques are being reintroduced into the mines of the National Coal Board. There are strong reasons for the selection of the full hole anchorage principle of bolting and for the development of the wood/resin dowel. There are strong reasons also for the measurement of strata bed separation as the method of assessing the effectiveness of a roof bolting system. There are several designs of bolts. Instruments have been developed for investigation and control purposes. Different drilling and bolting machines have been employed in trial sites. In addition comparative laboratory model work has been conducted on simple non-bolted and bolted systems.

Jan 1, 1971

The first continuous pressure disk filter took up industrial-scale operation in Germany in 1976. This paper comments on major components of pressure filter facilities from the point of view of industrial-plant suppliers. For lack of time aspects of economy have not been commented upon. The paper elucidates a number of process-engineering inter-relations. It outlines important development trends from the angle of a machine-building company.

Jan 1, 1989

By Mukherjee R, Bandopadhyay S

Three applications of fuzzy logic in mineral exploration show the possibility of providing feasible solution and allow greater freedom in decision-making processes for geoexploration data which may be ill- defined, biased or where apriori infor

Jan 1, 1998

Jan 1, 2004

The current insurance market has been brought about by a number of pressures, including: collapsing investment returns; growing losses, both normal and catastrophic; and reserve strengthening. This is impacting most classes of insurance coverage, with the traditional characteristics of higher pricing and greater levels of retention, however it is now translating into a lack of capacity and reduced coverage. This presentation will explain how the market has arrived at this situation and will challenge whether this is the traditional insurance cycle or a structural correction. It will also address the anticipated time of correction.

Jan 1, 2003

Despite improving technology, better training and the use of modern monitoring and communication systems there is a disproportionate rate of diameter occurrences in the mining industry. The use of appropriate plans and a practical approach and managing risk can reduce the number of occurrences and ensure better control of emerging situations when they do Occur.

Jan 1, 1998

By Morris A. E

The thermodynamically-based pyrometallurgical simulation software STEPSOL (Version 3.0) provides for the modelling of activities using the Interaction Parameter Model, the Regular Solution Model, the Sub-Regular Three Suffix Margules Model, the Sub-Regular Four Suffix Margules Model and various simpler polynomial models. These are briefly reviewed, along with the major sources of data available in the literature, and the implementation of the models in the program.

Jan 1, 1992

By Coppock BW, Scott TC, Firkin GR

The pollution control measures taken on the Imperial Smelting Process (ISP) operated at Cockle Creek are described together with environmental monitoring strategy and the statutory restraints applied in New South Wales. An outline of developments in the gaseous, liquid and noise control areas is given.

Jan 1, 1975

Refractory gold concentrates and their roasted products have been examined by mineralogical and chemical methods, and the distribution of gold in the tailings after leaching has been Investigated.

Jan 1, 1989

Construction of Western Mining Corporation's nickel refinery at Kwinana, Western Australia, commenced in July, 1968. Production of 15,000 tons per annum of refined nickel metal will commence early in 1970, The plant will also produce approx- imately 150,000 tons of ammonium sulphate0 The ammonia leach process which was developed by Sherritt Gordon Mines Ltd., and has been in operation at their plant at Fort Saskatchewan, Alberta, Canada, for the past 15 years, will be used at Kwinana. The refinery will cost approximately 435 million, and will employ upwards of 250 people.

Jan 1, 1969

By Lynch AJ

Comminution within rod mills has been investigated by izse of a matrix analysis of breakage processes. A para,~ meter, the number of breakage stages, has been introduced and cornfninut-ion within all rod mills has been expressed in terms of the¦1-number of breakage stages- and a function which des--cribes' the feed rate, mill diameter and mill speed.'The effect of variation in feed rate, feed sizing analysis and mill speed on the number of breakage stages-is-,-discussed.

Jan 1, 1963

The Argyle Diamond Mine came on stream late in 1985 as the world's largest diamond producer in terms of carat output. The design of the process plant, including the heavy medium separation (HMS) facility which provides the initial stages for separation of diamonds from gangue, evolved over a lengthy period of feasibility study and site investigation into the final form described in this paper. The commissioning was carefully planned and co-ordinated, and culminated successfully with handover of the plant on schedule and within budget. Problems encountered during .within were minimal and since then the plant has achieved greater than design throughput during its first year of operation. Darvr_ontmn

Jan 1, 1987

By F Melcher, M Wiedicke, A Wittenberg

Ferromanganese nodules form a specific category of widespread marine mineral deposits. The tremendous increase in metal prices during the last decade raised new economic interest in their exploration. The German Federal Institute for Geosciences and Natural Resources (BGR), which had been engaged in nodule research in the 1970s and 1980s, renewed its activities on this subject based on an exploration contract with the International Seabed Authority, signed in 2006. BGRÆs licence area û comprising 75 000 km2 û is located between the Clarion and the Clipperton Fracture Zones. In this so-called nodule belt north of the equator the sea floor reaches water depths of >4000 m. About 900 million tonnes of manganese nodules are expected there. In this study the fine-scale distribution of important elements in manganese nodules and crusts from a variety of locations was investigated. Besides 11 samples from the RV SONNE cruise SO-25, numerous samples from additional locations were included in this study for comparison. In general, the sample suite includes two genetic types of precipitates, manganese nodules and Co-rich crusts. A detailed characterisation of the distribution of major, minor and important trace elements in manganese nodules based on in situ microenergy dispersive X-ray fluorescence (¦-EDXRF) analysis is presented here. The data are compared with bulk major, minor and trace element data as well as with quantitative electron probe microanalysis (EMPA) data sets. The element distribution maps and profiles produced by ¦-EDXRF analysis with short or extended (in case of profiles) counting times, allow precise selection of æregions of interestÆ for further detailed investigation using high spatial resolution techniques (eg scanning electron microscope (SEM)-EDAX; laser ablation-inductively coupled plasma mass spectroscopy (LA-ICPMS); isotopic studies).

Jan 1, 2008

By T Leach, I Pringle

The Bowdens Silver Deposit is a low sulfidation epithermal silver-base metal deposit that has formed on the northern margin of a hydrothermal system within air-fall breccias, ignimbrites and crystal tuffs of rhyolitic composition. The deposit lies near the north-eastern margin of the Lachlan Fold Belt and the rhyolitic host rocks are of Early Permian age. The silver mineralisation occurs as flat-lying zones of disseminations and silicic fracture-filling within the Rylstone Volcanics and is closely associated with sulfides of iron, arsenic, lead and zinc. High-grade silver mineralisation is also found in steeply-dipping fracture zones which host banded sulfide veins. Studies of the alteration products indicate that high temperature fluids, flowing from south of the current project area, resulted in quartz (¦adularia) û illite/sericite alteration. Cool, low pH steam-heated waters on the northern and eastern margins of the prospect area resulted in siderite û smectite-illite clay û Fe-carbonate û marcasite û kaolinite alteration. Mixing of the two fluid types resulted in the deposition of iron and base metal sulfides, a decrease in both sulfur activity and pH of the mineralising fluid, and subsequent silver mineralisation.

Jan 1, 2004

A novel solvent extraction process, called the SOHNEX process, has been developed at the University of Utah. In this process, the organic and the aqueous phases flow countercurrently in a horizontal vessel, and the emulsion between the two liquid phases is generated by high-velocity gas jets injected at the bottom. The gas jets are located at certain intervals along the bottom of the vessel with phase disengagement zones on either side of the plume zone created by the gas jet. The system is simple, having no mechanical moving parts or complex internal structures, and yet provides good contact between the phases with minimal backmixing. Tests have shown that emulsions with a wide range of specific interfacial area, including that typically encountered in mixer-settlers, can be generated in this process. It has significant built-in flexibility of operation including the control of the flowrate and hold-up of each liquid phase. The SOHNEX process overcomes the difficulties in the operation of conventional solvent extraction equipment such as mixer-settlers and column extractors. A major advantage of the SOHNEX process is that the energy of mixing can be closely controlled by adjusting the strength of the gas jet. This allows an optimal control of the drop-size distribution of the dispersed phase and thus the specific interfacial area. The process is continuous, and any number of extraction and separation stages may be built into a single vessel. The gas can be recirculated in a closed loop, thus eliminating solvent loss and mist problems, especially for high-temperature operations. The SOHNEX problem can handle solutions that contain suspended solids and that form third phases. The simplicity of the equipment and operation with low maintenance will mean much reduced capital and operating costs as well as low environmental risks and improved safety. The SOHNEX process has been tested for continuous copper extraction from a dilute solution. Calculations also showed that uranium and other radioactive elements can readily be extracted in a small unit of the SOHNEX extractor while satisfying the nuclear criticality condition.

Jan 1, 2000