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Independent assessments of existing and projected mining operations are often required in the exchange of assets and for raising capital, requirements which are particularly prevalent where there are new mining fields, a characteristic of the Pacific Rim area. Such audits and appraisals typically consist of a geological evaluation of the ore deposits; estimates of mineral inventories and mineable reserves; assessment of mine plans and costs; assessment of ore processing methods, recoveries, and costs; assessment of infrastructure and G&A (general and administrative) requirements and costs; assessment of environmental, permitting and reclamation requirements and costs; and, finally, economic evaluation based on various discount rates and metal prices. Audits provide a challenging task for consulting engineering companies, but one well worth the effort for mine developers and those connected with financing of the mining industry.

Jan 1, 1990

A good deal of criticism has been levelled at Mines Division over the slowness of processing mining privilege applications, some of which is justified and some which is not. There are many reasons for delays in the processing of applications and not the least of these delays are caused by the applicants themselves.

Jan 1, 1982

By Z B. Rakisheva

By explosion rock mass behaviour is conditioned by preset complex of rocks natural characteristics. Very important role of blockness, which is percent (share) content at examining massif of natural separatenesses of different dimensions and configurations, separated each from other by the cracks of geological and technogene origin. Besides natural properties of massif the power, detonational characteristics of applied explosives, parameters of explosives charges disposition at massif and technology of explosion influence vastly at lumpiness (granulometric structure) of exploded rocks. The mathematical model of rock mass destruction by explosion had been elaborated and substantiated. It ties mutually the initial data (rocks properties, parameters of the charges disposition) and final results of explosion (granulometric structure of exploded rocks). The program of this complicated problem solving had been compiled. Analysing the received results of the problem solving, one can reveal contribution of each group of influence factors for lumpiness of exploded rocks. This fact creates preconditions for elimination or diminution of negative role of some controlled initial data.

Jan 1, 2003

The Geograph is a revolutionary seismic system involving special techniques in combining the use of FIT magnetic tape with shock wave echoes created by a weight dropping system.The idea of- weight dropping as a- source of seismic energy is not a new,.,oxie. Records 'indicate òa pos'sihle use of falling weights as early as .1929. 'Dr. Burton McCollum began his experiments in 1938, but it wasn't until 1951 that the method was first proven useful.The first weight dropping crew began commercial operations in Edwards and Sutton .Counties of West Texas in 1953. By 1962, more than '40 weight drop-ping.crews have come into existence with operations in the United States, Canada, Algeria, Iraq, Argent na,òSpanish West Africa, Tunisia, Qatar, Niger Morocco and Libya by most major oil companies and larger independent oil companies. .

Jan 1, 1962

The treatment meIhods selected for the concentrator at Cobar Mines Pty. Ltd. called for a high degree of automatic control of both the grinding and flotation sections.The resulting concentrator layout includes a central control room overlooking both grinding and flotation sections. The control room houses process recorders, controllers, and indicators. together with motor stopstart stations and alarms.Plant instrumentation includes load cells and variable speed hydraulic drive feeders for feed-rate control of autogenous mills, together with nuclear density gauges, differential flow transmitters, and pneumatic control valves for water and pulp density control.Flotation cell pulp levels are controlled by floats and pneumatic actuators; flotation reagent controls include magnetic flowmeters and time-operated solenoid valves.

Jan 1, 1969

By Harris R. W

Any defect activity resulting from an applied stimulus on a structure will generate a stress wave which travels in the medium under the laws of acoustics, thus the name of acoustic emission (AE). AE techniques can therefore provide information on the deformation of both surface and below ground structures. Two operating coal mines were monitored from the surface, and both mining activity and post mining microseismic activity were detected. The nature of the detected AE signals demonstrated that there were a range of deformation mechanisms in operation and that some predictive capabilities were possible with the Technique.

Jan 1, 1992

Conditional simulation is a branch of geo- statistics which allows the simulation of a mineral deposit so that predictions can be made about the variability of some particular parameter of the deposit. A summary of the general principles, advantages and limitations of conditional simulation is presented together with an example based on coal seam thickness.

Jan 1, 1981

By Corbett GJ

Epithermal gold-silver deposits occur in young volcanic terrains where post-mineral cover commonly impedes the search for mineralisation. At the Togi Project in Honshu, Japan, a complex mineralised system is largely covered by post mineral volcaniclastics. A combination of high resolution electrical resistivity surveying and detailed airphoto interpretation has, with close geological control, enabled synthesis of structural and alteration characteristics of the Togi geothermal system, in turn permitting ranking of the prospects for drill testing.

Jan 1, 1990

The geological features of the destructive plate margins of the southwest Pacific favour the formation of porphyry type deposits. The major controlling factor favouring the formation of gold-rich deposits of this type is a dense crust. This results in shallow intrusion of large magma bodies beneath andesite stratovolcanoes. Where the intrusives have near vertical sides, the comparatively low temperature of transfer of volatiles from the solidifying melt favours the partitioning of gold into bubbles of volatiles. They reduce the viscosity and density of the melt, resulting in the upward movement of a mineralised melt. With the drop of pressure with upward movement the bubbles separate into a two phase mixture, triggering freezing of the mineralised melt and the formation of a gold mineralised stockwork.

Jan 1, 1995

Performance trials followed the commissioning of three large mine fans at Mount Isa in 1965. Actual performance characteristics were determined. These were in good agreement with predicted performance. Piezometer rings for volume flow and pressure measurement were calibrated, and the performance of some aerodynamic components of the installation was studied.Test equipment, preparation, and conditions are described.

Jan 1, 1967

The production of 100,000 tonnes per year of synthetic rutile from the processing of ilmenite, coal and copperas (iron sulphate) produces 200 cubic metres per hour of effluent water. A 2.0 hectare biological filter, comprising natural and man- made wetlands, has been built into the last stage of the effluent water treatment system. It is an area of shallow water (

Jan 1, 1988

By Chen B

In recent years great efforts have been made in the optimisation of ball mill operation. This paper describes a methodology developed for modelling and optimising the steady-state grinding process. Thirteen basic similarity numbers of the process are derived. Based on these similarity numbers, we build a group of mathematical models which give a full description of the relation between dependent and independent variables. The parameter estimation and multi-objective optimisation of the grinding process have been done using these models, and validated with experiments in a continuous laboratory-scale ball mill.

Jan 1, 1993

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

The production of copper by the Outokumpu direct blister process commenced in July 1988. The problems and incidents encountered in commissioning the main smelter equipment are outlined. Early difficulties were encountered in process control, hot metal handling, dust buildup in the off gas handling equipment, waste heat boiler tube failures, foam over of hot metal into the waste heat boiler and failure of ancilliary equipment.

Jan 1, 1989

Industrial minerals and rocks (alternat ively called non-metallic minerals) are those- which are economically important because of their desirable physical or chemical properties rather than their metal or energy content. They are divided into nine classes: structural, pig- ments, process aids, ceramics and refractories, chemical source minerals, abrasives, foundry minerals, gem stones, electrical minerals. Development of deposits is influenced by the dominance of marketing,by the required range of products, the-need for specialized process- ing, place value, and the transportation and distribution of high-bulk, low-cost commodities. Evaluation is different from that of base metals because of differences in geological occurrence, sampling methods, testing, treatment, placing a money-value on the material and the importance of export markets.

Jan 1, 1973

By Peng SS

This paper presents a number of mathematical models for predicting the different phases of the complete surface subsidence process associated with underground longwall mining. A computer program developed based on the mathematical models is briefly introduced.

Jan 1, 1992

Key incompatible element ratios for metabasalts from the Early Permian Croisilles and Patuki Volcanics, South Island, New Zealand, provide constraints on the tectonic environment in which their precursor ophiolitic protolith formed. Two geochemically distinct metabasalt suites are recognised among both the Croisilles and Patuki rocks. Metabasalts from one suite exhibit the geochemical signatures of depleted tholeiites from oceanic spreading ridges (N-type MORB) or spreading centres in evolved back-arc basins. These N-type tholeiites show high Zr/Nb ratios (Zr/Nb = 37-62) and are depleted in light rare earth elements (LREE)((La/Y)N

Jan 1, 1987

By Jifan X, Yongyu W, Liangjing L

Shallow interception of groundwater is a special dewa- tering form in the specific geological and hydrogeological conditions. It has an economic and technical effect. The roof of the Fankou Lead-zinc deposit is the Hutianqun aquifer made up of the limestone of the upper Carboniferous system. - A "water-bearing basin" is surrounded by the aquifuge and the aquitard below ¦0 m level at the Shiling Hill section in the Hutianqun aquifer. Based on the natural conditions, an interception gallery is excavated at -40 m level out of "the water- bearing basin", the other gallery excavated at ¦0 m level in the poor water-bearing zone of the Jinxing Hill. During 20 years of experience, the better interception effects have been gained.

Jan 1, 1988

In many metal mines in China,the 70B2 series of fans has been used for main fans for a long time.These fans generate higher static pressures than are required for the relatively high equivalent orifices of the ventilation systems of many of the mines. As a consequence, their running efficiency is common only around 30%. The loss of power is significant.

Jan 1, 1988

In epithennal deposits changes in the character of mineralization in depth and time are conspicuous and abrupt at the interface between supergene and hypogene zones. As the reaction zone migrates downward as a consequence of surface erosion, previously deposited minerals are placed in unstable chemical enviromments and dissolved. This reaction takes place at the base of the epithermal precious metal zone. Examples at Cerro de Pasco, and Casapalca, Peru; Carlin, Nevada; and porphyry copper-gold deposits are cited.

Jan 1, 1991