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This monograph presents a unified theory of adsorption and desorption of aurocyanide on activated carbon. This theory has proved useful for CIP/CIL carbon adsorption and Zadra and AARL elution process and equipment design; in accounting for the effects of various water qualities and process temperatures; and in the development of reagents to improve these processes. The theory presented is based on rigorous fundamentals : Classical Eyring theory links initial first order kinetics with Langmuir isotherm equilibria, and this isotherm is demonstrated for the first time to be a consequence of the activated complex postulate of Eyring theory. Simple extension to Freundlich conditions at high solution tenors is possible, but not presented. Supporting entropy data determined by the author includes practically all the pioneering CIP plants built in South Africa and Australia in the early 1980s.

Jan 1, 1991

By Harper B

The mining industry has developed a comprehensive view of the need to have production personnel well trained in the use and maintenance of mining equipment. A strong commitment from the industry to this view has been instrumental in creating an efficient, profitable and productive industry based on modem production processes, sophisticated equipment and a multi skilled workforce. As the industry continues to develop, and the skills and knowledge needed by productive workers continues to expand, the training processes adopted by the industry will need to develop in parallel, not only making use of the latest advances in learning theories, instructional design and technology, but also using these knew ideas in more efficient ways.

Jan 1, 1998

By Arit I, Adisoma G

General Limit Equilibrium Method (GLE) and Janbu's Generalised Procedure of Slices (GPS) are two limit equilibrium methods in slope stability analysis which satisfy all equilibrium conditions. Numerical difficulties associated with these metho

Jan 1, 1998

The changing characteristics of raw materials has highlighted the limitations that conventional vibrating screens have in the handling of fine wet sticky materials. These' limitations have led to the development of a totally new concept of screening, the Rotating Probability Screen. In order to illustrate the practical benefits to be gained by the extraction of fine materials ahead of subse quent processes particularly in the coal industry, the experiences gained in Ro-Pro installations in America, Australia, Europe and Britain are drawn upon.

Jan 1, 1984

By Moxon N. T

A series of low shock energy water resistant emlulsion based explosives have been developed by combining inert materials, such as Perlite P500, into the formulation. The material handling, water resistance and explosive properties of these mixtures were determined as a function of inert additive type, density, charge diameter and emulsion base. Of the emulsion bases tested Emulite produced the best and most stable low density mixtures ranging in density from 0.8 to 1.35 g/cm3 producing velocity of detonations (unconfined) ranging from 3000 to 5500 nits. The mixtures could be detonated successfully at these densities at diameters as low as 25mm. Low shock mixtures formed by combining Emulite with Perlite P500 were successfully trailed at the Cadjebut zinc mine in Western Australia. The performance of the explosive, at three densities, was monitored using both continuous and point to point VOD techniques. The fragmentation produced by the blasts were compared by photographic analysis. During this trial the low shock emulsion mixtures were shown to be as effective as the currently used explosives (packaged emulsion) at a significantly reduced cost.

Jan 1, 1990

By Misra V. N, Spottiswood D. J

In recent years the column flotation process has gained worldwide acceptance for processing various types of minerals under different circuit configurations. In an age when real prices of many mineral commodities are in decline and mining and labour costs are rising in real terms, it is more important than ever that concentration processes be not only efficient but also cost-effective. The column flotation process can give better metallurgical performance as well as involve lower capital and operating costs compared to conventional mechanical cells.This paper reviews the literature on columns and the effects of various column parameters on performance of the column flotation process. The history and principles of operation of the column flotation process are briefly discussed by way of introduction.

Jan 1, 1995

The results of a systematic geochemical survey of rare elements are applied to elucidate genetic relations in a suite of rocks and to predict the probability of mineralization. The geology, radioactivity, major element geochemistry and classification of the main intrusives are described. The distribution of a group of rare elements, their concentration trends and the bearing these have on the emplacement sequence of the rocks are considered in some detail. The guides for exploration in the Pilanesberg that emerge are listed and some areas which substantiate predictions are described briefly. It is concluded that a study of rare element trends can make a considerable contribution as an exploration tool and for clarifying relations between the members of rock suites.

Jan 1, 1986

By Marton A

The Readymix Group have a Quarry Improvement Program - 'Building in Quality (BIQ) which has many parallels to the ICI Explosives' total quality management - 'Quality Improvement Program' (QIP). Both companies have for some time recognised that the 'do it right first time' principle means less wasted effort and materials, that efficiency breeds profitability and so actively promote the quality culture. To install the principles and generate the culture requires considerable commitment and effort from the top down and invariably spreads to the suppliers and sub-contractors. Understanding the component processes involved with the quarry operation, analysis of those processes and gaining a breakdown of the cost of non conformance then allows the astute quarry operator to make the necessary changes to improve the process to realise profits. This paper outlines the steps in such a process and the profitable outcomes of the commitment to continuous improvement at the Nickol Bay Quarry.

Jan 1, 1994

The nickel operations at Kambalda consist of mining thin massive to disseminated Ni sulphide orebodies from 10 individual mines of variable grade.Daily sampling involves visual estimation of the grade of working faces based on geological parameters. This system of grade estimation is used as a guide for daily grade control only.Nickel metal allocation is based on an external sampling system. As all ore sources are blended at the primary crusher, only one calculated mill head grade is available. Therefore all sources are sampled prior to crushing. This system historically consisted of mechanically grab sampling ore from trucks as they passed over a weighbridge on arrival at the concentrator. Currently the system involves diverting one out of every ten trucks to its mine sample stockpile, which is crushed through the primary, secondary and tertiary crushing system fortnightly. The individual mine grades are re-combined to create a total sample grade. This is reconciled against the calculated mill head grade. The reconciliation factor is applied uniformly to all individual mine sample grades to calculate mill reconciled mine grades.

Jan 1, 1990

Gold mineralisation at Wapolu lies within an exposed arcuate zone at the decollement contact between a basement dome of high grade metamorphics and an overlying ophiolite sequence. This contact was originally a thrust fault which has since become a decollement zone for gravity sliding in association with basement doming. Hydrothermal models for the gold mineralisation postulate an epithermal system in which fluids were channelled up the decollement with boiling of those fluids causing hydrothermal brecciation and subsequent gold deposition. The alteration assemblages, fluid inclusion data and geochemistry indicate that the upper levels of the system are exposed.

Jan 1, 1987

Mining is an intensive resource development industry, where operations are often of relatively short duration and can result in dramatic impacts on the natural environment during the operational period and for many years post mining. An integral component of all mining operations is water û through exploration, resource definition, mine development and operation, rehabilitation and the long-term post-mining land use. Water is a basic requirement in the provision of worker amenities, in drilling, as a means of dust suppression, as a medium for washing or processing the mine product, and as an aid in establishing vegetation on post-mining landforms. Water also plays an important role in mobilising environmental contaminants and is the primary medium for the transport of contaminants off the mine or processing site into the wider environment. It is for this second reason that the mining industry considers water management as a key component of mine management. Cost-effective water management relies on planning that incorporates a total mine system approach commencing prior to exploration and continuing through to rehabilitation and decommissioning. One of the primary considerations that will provide confidence to both government and community at the time of mine closure and lease relinquishment, will be the evidence that any water originating from, or passing through, the mine site is of a quality that will not have any negative impact on the surrounding environs into the future. The role of vegetation in stabilising disturbances to a landscape is well known, as is the recognition of vegetation being a fundamental component of the water cycle through the physiological processes resulting in the transfer of water back to the atmosphere through transpiration. In terms of water management at a mine site, the two crucial issues are the æquantityÆ and æqualityÆ of water that enters a receiving æoff-leaseÆ catchment. In terms of tolerances of the receiving environment, the total load of potential contaminants becomes critical, a reduction in which can be achieved through reduced volumes of water discharged, reduced chemical and physical concentrations of contaminants in that water, and ideally, both. This paper examines the potential role of vegetation in reducing the quantity of water released from a site, and secondly considers vegetation in the role of influencing the quality of that water.

Jan 1, 2003

By Anievas JB, Sevillano AC

This paper describes the acquisition, exploration, development, initial operation and subsequent financing of the Bulawan mine by means of a listing on the Toronto Stock Exchange of a subsidiary of the parent company, Philex Mining Corporation.Located on the island of Negros in the Philippines the property is unique on at least two counts: it is a disseminated gold deposit that occurs in a region of predominantly porphyry copper mineralisation; and it is a gold deposit that is mined by a bulk method of extraction (front and block cave) instead of the normal selective mining methods.

Jan 1, 1997

Most text books on rock blasting claim that the relationship between burden and borehole diameter is linear. The statistical calculation presented here with real values from one hundred open pit and underground mines indicates that the relationship is exponential. For underground mines the burdens are consistently lower than those for open pit mines because of higher ore densities, greater confinement in blasting, and finally greater demand for well fragmented rock. The results shown in this paper are recommended to be considered in basic teaching of rock blasting technique. The formulas can be used for a first rough estimation of practical burden and spacing. The formulas do not however give any information about the fragmentation. For that purpose it is necessary to use other formulas not described in this paper.

Jan 1, 1990

By M Stewart, J Vann, A Bu, D Frederickson

The Golden Gift is a recently discovered deep deposit below the main operating areas of the Stawell Gold Mine. At an early stage of the project, diamond drilling was used to define the mineralisation on sections approximately 100 - 150 m apart. The project economics were sensitive to both grade and tonnage. There were consequently two significant risks on resource quantification: risk on tonnage (ægeological riskÆ); and risk on grade (ægrade riskÆ). The degrees of freedom inherent in the geological model were considered to be potentially high because of wide drill spacing and likely structural complexity. To quantify geological risk three geologists familiar with Stawell mineralisation independently interpreted the deposit. This generated three plausible, different geological volume models. Conditional simulation was then used to quantify grade risk. Conditional simulation requires the user to define input statistics (histogram and variogram model) and a geological envelope. Based on global mean grade of an ordered set of simulations, æpessimisticÆ, æmedianÆ and æoptimisticÆ simulation cases were defined. The result was a 3 x 3 risk matrix with geological risk (the three interpretations) on one axis and grade risk (also three cases) on the other axis. An interesting result was that geological and grade risks were of a similar order of magnitude. Therefore a risk analysis of grade by geostatistical methods within a fixed geological model is of limited value, especially if the drill spacing is wide. After completion of this study, with additional drilling, the geological degrees of freedom at Golden Gift reduced substantially. A second Golden Gift risk study used a refined geological model to build a set of simulations to be used in preliminary mine design. A third simulation study in the deeper parts of the Magdala ore deposit, a well-drilled part of the mine with production history, demonstrates that the geostatistical simulation method used at Golden Gift is a robust and useful tool to quantify grade risk.

Jan 1, 2003

By M Xu and, P F. Wells, A N. Kerr, Y Shields

Triethylene tetramine (TETA) has been used in combination with sodium sulfite (sulfite) for pyrrhotite depression at Clarabelle Mill since 1998. This combination has been highly successful at reducing pyrrhotite levels in the bulk (Ni/Cu) concentrate. Although highly effective, the roles of TETA and sulfite are not well understood. Treating bulk samples of the circuit feeds through the miniplant enabled the effects of circuit configuration on the performance of the pyrrhotite rejection circuits at Clarabelle to be determined. Reasons for the different performance of the non-magnetic pyrrhotite rejection circuit in the miniplant were investigated and tested in the laboratory. The effect of different grinding environments in the laboratory was examined to better understand the depressing mechanisms of TETA/sulfite. Modification of the grinding chemistry improved the selectivity of pentlandite over pyrrhotite in the presence of TETA/sulfite at current plant dosages.

Jan 1, 2005

Although mining, particularly of gold and coal, played a significant role in the development of New Zealand, from the time of the spectacular gold rushes of the 1860s its economic importance to the country as a whole has decreased substantially since that time. Gold, coal and non-metallic agricultural and industrial minerals have been found in economically significant quantities, however, the search for base metals has not been successful.

Jan 1, 1982

Low-grade, porphyry copper type mineralization at the Moonmera prospect is related to the intrusion of a granodiorite porphyry mass into the Upper Permian "Gracemere granodiorite". Significant copper mineraliza- tion appears to be associated with the alteration assemblage quartz-sericite- kaolinite. The ore shell is surrounded by a zone where montmorillonite and kaolinite are in greater abundance and this assemblage is over- lapped, mainly at depth, by potassium feldspar alteration. Secondary biotite is abundant throughout the mineralized zone. Preliminary sulphur isotope results on the sulphide mineralization are compatible with a magmatic origin for the sulphur.

Jan 1, 1974

By J Benn, V Kuznetsov, G Timms, A Spain

Earthen covers are now widely used in the mining industry to control the generation rate and/or release rate of low quality drainage from piles of sulfidic minewastes. Covers are usually designed to reduce the water infiltration rate and in some cases may also reduce the oxygen flux to the underlying sulfides. Engineered covers have only been used since the 1980s, however, and there is very little field data on their performance in the longer term. This lack of information has implications for the degree of confidence that can be placed on the predictions of the environmental impacts of sulfidic minewastes, for the acceptance of close-out criteria by regulatory authorities and for the financial liability of the mining industry. Covers were placed on sulfidic waste rock dumps at the abandoned Rum Jungle uranium mine during 1984 - 1985. These covers were designed to reduce the water infiltration to less than five per cent of incident rainfall by both water shedding and storage-release mechanisms. Regular monitoring by the Australian Nuclear Science and Technology Organisation (ANSTO) demonstrated that the covers performed better than the design criterion for around ten years, but infiltration rates have subsequently increased. There is a 66 per cent probability that the infiltration rate now exceeds five per cent of incident rainfall. The cover on the largest pile, WhiteÆs heap, was sampled in pits dug at eight locations. Sampling was carried out at the end of the monsoonal wet season and again at the end of the ædryÆ season. This, together with laboratory testing, enabled cover performance to be assessed against five criteria: design, construction, cover material characteristics, physico-chemical characteristics and biological characteristics. We are of the opinion that the design of the cover was suitable to achieve the objectives of stability, water shedding, storage-release, and provision of a substrate for vegetation growth. Over most of the surface of the heap, the construction of the covers, drains and erosion prevention structures was in accordance with design specifications. However, several small and localised bare patches on the upper surface of WhiteÆs heap coincide with a reduced cover thickness, which is likely to have been due to poor construction in those patches. The construction of covers on minewastes is dependent on an adequate source of material meeting design specifications. From our limited examination, it appears that there was shortage of material for each of the three zones û a lower impervious clay layer, the moisture storage-release layer and the upper erosion-resistant layer for vegetative growth. An indication of this was that the upper layers in some areas were observed to be thinner than specified. We are of the opinion that this shortage of suitable material has been responsible for some of the changes observed ten years after emplacement. Physical and geotechnical testing indicated that the cover materials no longer meet the original specifications. In particular, the permeability at the 8 locations was found to be greater than specified, by up to several orders of magnitude. The higher permeability may explain the higher observed rainfall infiltration and moisture content of the waste rock. This increased permeability appears to be due to a combination of biological and physical processes û galleries formed by termites and ants and an extensive system of shrinkage/desiccation cracks formed by the development of a polygonal blocky structure involving the entire lower clay layer. The desiccation cracks may fill with coarser illuviated materials and form a conduit through which roots access the underlying waste rock. Measurements were made of oxygen flux into the heap as cover layers were excavated in the pits. They indicated that the full cover currently reduces the oxygen flux to 20 - 23 per cent of that into bare waste and that this reduction seems to be proportional to the cover thickness. It was also found that the oxygen flux into the cover is about four times higher at the end of the dry season than at the end of the wet season and that the difference is due primarily to the difference in moisture content of the cover. Recommendations are made for the design and construction of covers.

Jan 1, 2003

By J E. Everett

When ore is being selected from a regularised block model, a common procedure is to accept as ore any block whose iron content exceeds a cut-off value, and whose content in each contaminant analyte is below an appropriate cut-off value. This method defines a quadrant within the multidimensional analyte space, such that any block lying within the quadrant is accepted as ore and any block lying outside the quadrant is rejected as waste. The cut-off levels can be adjusted to maximise ore tonnage at a target grade (or analyte vector). When the method is applied to a project comprising multiple pits with systematically differing grades, it is found that ore tonnage at target grade is maximised if different cut-off quadrants are used for the different pits. This is apparently illogical, because it implies that an ore block from one pit may be accepted as ore, but an identical block from another pit is rejected as waste, even when ore from both pits is to be blended into the same product and there are no production cost differences between the pits. The paradox is an example of the ætheory of the second bestÆ: if there are multiple conditions for optimality and one condition is broken, then obeying the other conditions may not be the best policy. The problem lies with the quadrant cut-off method, which is shown to be inconsistent even for selecting ore from a single pit. A criterion that is inconsistent cannot be optimal. It is shown that a linear composite cut-off function provides maximum ore tonnage, and that a single composite cut-off criterion is consistent and optimal over multiple pits. Further, it is shown that a composite cut-off function not only maximises ore tonnage at a specified composition, but also can be used to select ore so as to maximise project value, if marginal costs and values are available.CITATION:Everett, J E, 2013. Selection of ore from multiple pits, in Proceedings Iron Ore 2013 , pp 185-192 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

Comparatively recent Tasmanian legisla tion established a series of rigid control standards for environmental protection just as ma spectacular expansion of the mining industry was nearing completion. Upgrading existing protection to obtain the necessary licence to operate under these new regulations required further major works and involved a considerable outlay of non- productive capital at a time when escalating costs and falling metal prices were straining economic efficiencies to the limit. Late in 1974 a major environmental protection scheme was commissioned by the Electrolytic Zinc Company of Australasia Limited at Rosebery on the West Coast of Tasmania. This 4 million dollar project was specifically developed by the Company ahead of and to meet the new standards for control of total effluents discharged from its zinc-lead -copper-pyrites mine and concentrator.

Jan 1, 1977