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A simple and rapid method for delennining gold and silver in carbon samples is described. The method involves dissolution of carbon ash in a strong oxidising medium of aqua regia and hydrofluoric acid. Gold and silver are determined in the resultant solution using atomic absorption speetrometry (AAS). The method is efficient and reproducible. Gold results are comparable to the standard fire assay results, with agreement of results within ± 5 per cent. The co-efficients of variation for gold and silver are 0.37 and 0.39 per cent respectively for six replicate analyses. The analysis of gold and silver in a batch of ten carbon samples can be completed in approximately four hours.

Jan 1, 1992

By P Hayes, B Zhao

A range of materials are treated in zinc fuming processes to recover metal values and produce benign slag waste products. The selection of the optimum process conditions in these various technologies can be greatly assisted by the use of a chemical thermodynamic model of the system. In this paper the effects of slag chemistry on the liquidus temperatures, subliquidus phase equilibria and thermodynamic properties are described by a FACT model of the ZnO-PbO-FeO-Fe2O3-CaO-SiO2 system. In addition new experimental data on the effect of Al2O3 on the liquidus are presented. The implications of these findings for plant practice are discussed.

Jan 1, 2000

By Just J, Nguyen G, Dunn J. G, Graham J

A sample of pyritic gold concentrate was investigated by wet chemical and electron optical techniques. Sub-samples were roasted in a laboratory scale fluidized bed roaster in the temperature range 400-700¦C. The calcine was characterised, and cyanide-leached using a standard bottle rolling test. Gold extraction efficiencies varied with roasting temperature. At temperatures of 400 and 450¦C gold ex- tractions of less than 40% were achieved, but between 500-700¦C the extraction had increased to 93--98Z. The surface area of the calcine varied with roasting temperature, reaching a maximum at 500¦C. There was no correlation between the surface area of the calcine and the efficiency of gold extraction.

Jan 1, 1987

Geomorphology is one of the most basic elements in geographic enviroments. Geomorphological mapping is significant in the spatial distribution of representing land form and understanding various features of geomorphology. Geomorphological mapping began very early in China, as the map, showing conekarst(karst pinnacles) of Juiyishan, Hunan province, it was drawn in 168B.C., which was excavated from Han tomb. Mawangdui, Changsha. Its original idea of map-making is rather similar to that of modern map and could undoutedly be the oldest map of tropical karst discovered in the world.Before liberation, landform mapping was done piecemeally and only a small number of maps were prepared by a few editor as insets.

Jan 1, 1990

By Macaulay J

The recovery of gold from cyanide liquors is frequently effected by using activated carbon. Process economics however require non destructive methods of gold extraction from the carbon so that it may be recycled.Stripping at atmospheric pressure usingthe method of Zadra et al(l) suffers from the disadvantage of unfavourable kinetics with strip times of the order of 48-72 hours. Subsequent research has led to development of processes which strip the gold more rapidly namely: A.A.R.L. process, (2,3) organic solvent (4,5,6) and pressure stripping (7,8)This paper reports on a development of the pressure stripping technique in which stripping and electrowinning are carried out at elevated temperature and pressure.

Jan 1, 1984

By Swanson AR, Nicol SK

A study has been made into the influence of feed size distribution on the flotation response of coal. The results show that a full description of the flotation response of a coal must not only consider the inherent floatability of the coal, but also, the size distribution of the feed to flotation. The performances of a number of flotation circuits were compared using a coal which was "poorly floating" because of its size distribution. Split feed flotation, two stage reagent addition, and reflotation of classified tailings all gave better yields than that obtained by conventional single stage flotation. The optimum flotation circuit for the washing of the coal in question, was reflotation of classified tailings.

Jan 1, 1978

By E Kozan

The paper presents new developments of the methodology of open pit coal production scheduling optimisation. They deal with the specific features of the exploitation of single coal seam and utilisation of truck-shovel and dragline systems. A production scheduling optimisation model is developed as a linear programming problem. The objective function maximises the net present value of the mining project under the technological constraints for meeting the demand function of the coal processing plant and effective utilisation of the available production equipment. Both principles of mine planning, coal quality optimisation and waste deferment are incorporated in the model. Results of a case study are provided to illustrate the applicability of the optimisation model.

Jan 1, 2003

Two ends of a longwall face are not only concentrated locations of equipment, but also provide ventilation and access. The roof strata stability here has an important influence on mining coal and safety. Based on field obser- vations in the gateways at Zaozhuang Colliery (Shandong Province) and model tests, the author developed a structural model of the overlying strata at the ends of the longwall face - the arc triangular cantilever plate - to which the elastic theory of plates can be applied. Factors influencing the stability of the cantilever plate and its breaking character- istics are discussed. Requirements and design parameters for supports at face ends are pro- posed, based on these factors.

Jan 1, 1986

By Giannini LM, Carras S

A fundamental problem in mine planning is that of determining the "optimum pit limit" of a mine. This optimum pit limit yields information which is considered essential in the evaluation of the economic potential of a mineral deposit, and in the formulation of long -, intermediate -, and short-range mine plans. Since the mid 1960's a number of mathematical techniques based on the "block model" have been proposed for solving this problem. When applied to large ore-bodies the implementation of these techniques, especially the more elaborate ones, poses considerable computational problems. In this paper we report on our work, done jointly with Systems Research Institute of Australia (SRIA), in devising strategies for overcoming these Problems.

Jan 1, 1986

INDEX OF CONTENTSIntroductionChemical compositionsNormally Cooled MattesPort Kembla mattesMount Lyell matteMount Morgan matteGranulated MattesConclusionsIllustrationsINTRODUCTIONIn a previous paper in these Proceedings(l) an account was given of the composition of some copper-lead mattes from the Port Pirie Smelters. The research programme of the Mineragraphic Section of the Commonwealth Scientific and Industrial Research organization has since been extended to copper-iron mattes from Port Kembla (The Electrolytic Refining ana Smelting Co. of Australia), Mount Lyell (The Mount Lyell Mining and Railway Co.) and Mouilt Morgan (Mount Morga:p. Ltd.).Chemical Composition of the Mattes.The mattes examined have a considerable range in chemical composition, as is shown by their analyses (Table 1).

Jan 1, 1949

By Gomm SA

The Mount Tom Price Concentrator, which contains a heavy medium cyclone plant for beneficiation of the -6+0.5mm fraction of low grade iron ore, is described. Testwork was carried out on an opportune basis over a period exceeding twelve months, to evaluate the separation performance of the heavy medium cyclones. Plastic density tracers were used and ore samples were taken and analysed. The effect of operating medium specific gravity (S.G.) on the separation parameters, the iron grade of the sinks product, and the mass and iron recoveries were investigated. Also examined were the differences in perform- ance between particles of different size. The implications of the findings for plant oper- ation are discussed.

Jan 1, 1987

By L Reynolds, N Whetter, S C. Cox

The Reefton Goldfield has had the largest hard-rock gold production (64 t Au) on the West Coast of the South Island of New Zealand, and is currently under renewed development by Oceana Gold. The gold predominantly occurs in variably sheared quartz veins that are associated with zones of tighter, shorter wavelength folds in the host Greenland Group metasediments. The quartz veins typically occur as a series of plunging shoots that align with specific fold limbs or fold hinge zones. Shear zones containing disseminated mineralisation and quartz veins have thickness variations that relate to the angular relationship between the shear and host-rock bedding. Exploration strategies and targeting can be developed around both types of structural control.

Jan 1, 2005

Many parameters are important when considering the performance of a concentrator. These include metallurgical performance, such as throughput, metal recovery and final concentrate grade and operating costs, such as power consumption, water usage, reagents and spare parts. In most operations the objective is to maximise metallurgical performance and minimise operating costs, ideally without a large investment in new capital items. A number of projects have been carried out at Newcrest MiningÆs Cadia Valley Operations (CVO) with the aim of improving metallurgical performance and minimising operating costs. This paper focuses on the installation of newly designed flotation mechanisms in various cells in the Cadia flotation circuit and describes the effect these changes had on performance and operating costs.

Jan 1, 2009

By Baguley PJ, Napier-Munn TJ

This paper presents preliminary resu]ts from field studies which were conducted to establish, among other things. the influence of medium viscosity on the partitioning behaviour of dense medium cyclones and drums in mineral applications, using frrrosilicon- ba_sed media. The medium vicoosit.y- was measured on-line, and partitioning behaviour was determined using ore sampling and density t r acers . The results demonstrate that viscosity is an important. operating variable, influencing ,eparat.ing density and efficiency under certain conditions. The implication is that metallurgical performance can be optimised by manipulating viscosity, either by appropriate selection of medium' characteristics or by automatic alarming and/or "ontroi using signals from the on- 1. i ne viscometer.

Jan 1, 1987

Norway, a country large in area but small in population, has put large effort in protect- ion of its inhabitants in case of war. The Civil Defence has provided shelters for more than 50% of the population. Some of these shelters are put into rock. Since rock installations give large resis- tance against weapon effects and also by advan- tage can be used for several purposes in peace- time, an interesting development has taken place the last decades. In towns and cities you will find sport halls, swimming pools, bowling and shooting ranges etc in rock, which easely can be conver- ted to civil defence shelters. Some typical installations are highlighted in the following.

Jan 1, 1987

In 1972, with the West Lyell Open Pit winding down, mining operations transferred underground. All development tunnelling until the end of the decade was carried out by a fleet of ten pneumatic Jumbos.A decision was made in 1980 to purchase an electric-hydraulic Jumbo and a second was purchased in 1982. Their introduction changed the face of development at Mount Lyell. Significant new demands were placed on main-tenance sections, particularly on electrical reticulation.Subsequently, two further electric-hydraulic Jumbos were purchased from Agnew Mining in 1984, and successfully overhauled and commissioned. As well, two electric-nydraulic production drilling rigs have been purchased. Only one of the original pneumatic Jumbos remains in service.

Jan 1, 1985

By Pathan AG

This research work is concerned with an investigation of the fracture toughness of sandstone, siltstone, and coal. Tensile failure trades have been examined with three different specimen geonetries, i.e; rectangular bar, round bar (in three point bending), and diametral compression discs. The Stress intensity approach, and J-integral methods were used to evaluate fracture toughness. Results from both approaches are discussed. True crack length was determined after pre-cracking, using the compliance calibration technique. Fracture toughness results of sandstone are independent of crack length and the size of the specimen. Fracture toughness may hence be regarded as a material property for sandstone. In cxnntrast fracture toughness values for !siltstone and coal are dependent on crack Length.

Jan 1, 1986

By Mould G. R

The paper presents a general background to the subsidence research programme being undertaken by the Department of Mineral Resources and Development in New South Wales. The results of the studies undertaken over the last ten years are summarised. The differences between these results and those obtained by the National Coal Board are discussed. The results of a study carried out on the effect of total extraction beneath a freeway in the southern coalfields are discussed in some detail. The procedures developed for the const- ruction of a 500 mm diameter natural gas pipe- line crossing a number of collieries in the northern coalfields are also outlined. The future direction of the Department's subsidence research programme is discussed.

Jan 1, 1980

By Leach T

The Tolukuma Gold Deposit is hosted by metamorphic and volcanic rocks, and igneous intrusions. Dilatant structures for the main veining appear to be provided by post-metamorphic flexure/faulting; syn-mineralisation tectonics is recognised from the en-echelon patterns of much of the veining. A SSE trending structure containing high grade mineralisation has acted as a major dilational zone within or at the contacts of porphyry intrusions. An ESE trend has controlled numerous dilational structures splaying eastward from the SSE vein structure and containing medium grade mineralisation.Early hydrothermal activity (Stage I) is represented by unmineralised, pyrite-rich brecciation and fracturing. Associated chloritic veining is indicative of single phase neutral-chloride fluids upwelling in relatively low fracture controlled nenneahility

Jan 1, 1993

The B.R.G.M., through international experience gained over many years, has become very skilled in alluvial prospection, particularly for diamonds. The research laboratories within the B.R.G.M. have also been active in creating new mineral processing equipment,. some of which is directly applicable to such prospection. One such development, the mobile prospection unit, is described and -its application in mineral exploration is demonstrated by a consider- ation of the diamond search in Australia and the general exploration of the Massif Armoricain (France). Because this latter study was fundamental in the development of the concept of "mineral-geochemistry", and its application in mineral exploration, it is also briefly described.

Jan 1, 1980