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By Gillies A. D S

A device has been developed for modelling the behaviour of coal under conditions which may lead to spontaneous combustion. It is designed to model the behaviour of a stockpile of large mass. The apparatus can test coal samples taken from the flow stream from mine through washing, stockpiling and transportation to the point of utilisation. It tests samples in an as received' condition and so takes into account the effect of aspects such as particle size and moisture content on propensity for spontaneous combustion to occur. Results of the preliminary tests undertaken are given and future applications of the apparatus are Discussed.

Jan 1, 1995

The development of the Moura Coal Preparation Plant is described, commencing with the first'stage of the plant commissioned in 1963. The subsequent expansion stages are traced through to October, 1973. The plant has undergone frequent stages of expansion and modification and this process is continuing. The development programme for 1974 is described as proposed in late 1973. The characteristics of the Moura and Kianga field coal seams with respect to washability are summarised and some comment is made on the blending of these coals prior to washing, to ensure production of export grade coal within specification.

Jan 1, 1974

By Gillies A. D S

Replies to a comprehensive questionnaire on mine water resource management systems (WRMS), which were distributed to a selection of Australian mining operations in 1991, are analysed. Although the replies cannot be considered fully representative of the industry, they do provide a good qualitative indication of water resource management in the industry at that time.Within Australia's largely arid land mass, a majority of mines nonnally need to conserve water, a few need to dispose of water and a number face a seasonally varying position. An assessment of the importance of WRMS compared with management of ore extraction and processing is given. A risk assessment of failure is given; there is more acceptance of WRMS failure in the mine compared with the mill. An assessment is made of considerations in WRMS design. Managements are generally pro-active in the design of WRMS and in the setting of perfonnance standards. The operational characteristics of mine systems are examined in detail.Companies generally do not appear to allocate sufficient resources for the collection of basic WRMS monitoring data and knowledge of the water budget to efficiently manage the system. This indicates scope for considerable cost savings in most mines.

Jan 1, 1995

By Wang Xia, Zhou Aiming, Shi Shengyi

Zhangmatun Iron Mine is situated in the suburbs of Jinan city, Shandong, China. Because of surface environmental constraints, no suitable site can be selected to dispose of mill waste. The full mill tailings must be disposed of underground. This paper deals with the work conducted at Zhangmatun mine to develop a total tailings backfill system, taking advantage of a doubleshaft blade mixer and an activating agitator to prepare backfill. Cement and ground slag are added to tailings for strength development. Two stopes have been filled and the pillars have been effectively mined out during the field trial. The application of innovative total tailings backfill technology is a new concept at the mine. Detailed planning has achieved a close integration of mining, milling and backfilling. Full mill tailings, with or without rock, are disposed of underground in a continuous process to fill, totally and systematically, the cavities formed by mining. Utilisation of cemented tailings backfill solves not only the problem of disposal of mill waste, but also the resource problem of providing backfill materials to the mine. The strategy also maximises ore recovery for the mine.

Jan 1, 1998

By S Slusarczyk, Z Kozlowski

Vibration of surface caused by seismic quakes can make a risk to great mining costruction. We have to do with this risk in the Belchatow open cut mine where seismic quakes of various energy and range have occured since the end of 1970s. The seismic risk influence on the mine structure with the special attention to the slopes of an internal dump has been presented. Hydrogeological and geotechnical conditions of the lignite mining and internal dumping of overburden and ash from Belchatow power plant have been considered. Seismic activity in Belchatow open cut from 1979 to 2001 was described and the connection between mine working and seismicity of this area was investigated. The energy and approximate location of the quakes and seismological parameters of the strongest ones observed from 1995 to 2001 were presented. The mechanism of the quake focuses was determined by means of the primary-arriving wave method. Stability of the slopes was evaluated by means of the Fellenius method. It has been found that seismic events occured in Belchatow region may cause only local eboulements whereas there are not any safety risks to the stability of slopes of the internal dump in Belchatow open cut.

Jan 1, 2003

By W Uhlmann, U Grnnewald, B Nixdorf

Flooding with surface water is the preferred technique for the abatement of acidification from pyrite oxidation in the lakes of abandoned Lusatian lignite mines. However, water resources of the region are limited and in addition, interruption of water inflow during the summer and the termination of the flooding process after reaching the final water level can lead to a re-acidification of the lakes. The development of three mining lakes with a surface-water flooding history of six to 28 years was analysed û in two lakes on the basis of fortnightly to monthly hydrochemical monitoring data. During summer flooding interruption, the younger lakes showed a decrease in pH from neutral down to pH 4. The degree of the pH decrease depended on the intensity of the groundwater inflow from the overburden dumps and this affected the hypolimnion more than the epilimnion. The third lake was flooded 28 years ago and up to now, interruption of the surface water inflow resulted in re-acidification. These three examples were able to show the benefits and limits of the surface water flooding technique for the abatement of Lusatian mining lake acidification.

Jan 1, 2003

By Hart J. G, Anderson J. S

The presence of platinum metals in the nickeliferous copper ore of the Thomson River Copper Mine near Walhalla, Victoria, was first revealed in 1905 by assays made in the laboratory of the Department of Mines (1).These disclosed the presence in the ore of 5 dwt. platinum metals, 1 dwt. gold and 13 dwt. silver per ton. Attempts to isolate the platinum-bearing mineral were unsuccessful, and the absence of obvious native platinum led the assayer, Mr. P. G. W. Bayley, to suspect that the platinum might be present as sperrylite. Subsequently, Mr. C. M. Lyons, then metallurgist to the Long Tunnel Gold Mining Company, Walhalla, tried to isolate the platinum mineral from samples of ore containing as much as 7 dwt. platinum metals, but again without success.In 1912, a sample of copper matte from this ore was submitted to Messrs. Johnson, Matthey and Company, Limited of London, for analysis. The analysis, which is quoted below by their courtesy, revealed tnat a large proportion of the metal pi'eviously reported as platinum was palladium, there being about two parts of palladium in the matte to one part of platinum.

Jan 1, 1942

There are countless petroleum and mineral fiscal systems throughout the world. This is because many petroleum and mineral producing countries have developed their own methods of calculating government take through fiscal evolution or individual negotiation. Those countries fortunate enough to have petroleum and mineral reserves within their national boundaries are naturally reluctant to yield this resource without a reasonable return for their population. As resource companies are perceived to be enormous conglomerates with endless amounts of cash and resources, governments and the general public demand reasonable division of production while these finite resources last. On the other hand, because companies engaged in the exploration for, and production of, minerals, oil and gas have to be large or lucky (preferably both) to sustain the great physical and commercial risks involved, the income and profit figures look so large that the general public sees them as an acceptable target for taxation. Taxation of the resource industry has been one of the industry's greatest cash flow problems through the years. Allen and Seba (1993) attribute this to the fact that the most equitable tax systems are those that affect the widest possible total of the population.

Jan 1, 1996

By Wygralk A, Hallenstein CP

On a world scale, many Mid-Proterozoic fluvial sediments are prospective for low grade, large-tonnage gold deposits. A significant area of the Northern Territory is covered by such Mid-Proterozoic sediments, the gold potential of which has been barely tested. The geological knowledge of these sediments is summarised. The Westmoreland Conglomerate, the basal Mid-Proterozoic formation of the McArthur Basin, has been subjected to detailed sedimentological studies in order to determine the paleoenvironments and to assess the possibility of paleoplacer occurrences. The results indicate that the sandstones and conglomerates of the formation were deposited by braided rivers and debris flows as an alluvial fan which originated in source areas to the north east. The formation contains several upward-fining cycles of sedimentation, which are related to repeated periods of uplift in the source areas. The formation of placer-type gold occurrences is possible in such depositional environments. Very limited heavy mineral sampling has indicated a cassiterite- wolframite-gold suite in the sediments of the Westmoreland Conglomerate. Disconformities at the base of sedimentation cycles are deemed to be the most likely sites for large-tonnage paleoplacer concentrations.

Jan 1, 1984

The New Guinea Mobile Belt is the northern zone of the Melanesian Orogeny (Dow and Sukamto, 1984), which consists of a complex zone ofupthrusted and accreted, regionally metamorphosed geosynclinal sediments and volcanics of Mesozoic to Eocene age and the overlying sediments. On the northern margin of this accreted terrane, formed an Eocene to Middle Miocene island arc. The North New Guinea Basin formed during the Upper Oligocene on the accreted margin. The depositional history of this basin is complicated by major crustal movements during the Upper Miocene to Holocene. During the Middle to Upper Miocene two magmatic arcs were emplaced. The northern magmatic arc is in part, spatically and genetically related to the Eocene to Middle Miocene island arc. The Maramuni-Utawa Magmatic Arc (southern) is a result of the Oligocene accretion and regional metamorphism. Coincident witt these magmatic arcs are belts of mineralization containing porphyry Cu-Au, epithermal/hydrothermal Au, Ag + Cu-Pb-Zn, exhalative Cu-Pb-Zn + Ag-Au, lateritic Ni-Cr-Co + PGE and alluvial Au, PGE, Cr occurrences and deposits. An intergrated tectonic model is presented for these and other data for the northern zone of the Melanesian Orogeny.

Jan 1, 1990

Supergene nickel sulphide ore mined currently by Agnew Mining Company is at times partially oxidised to sulphate. The resulting soluble nickel, and calcium and magnesium in mill water, are shown to act as depressants in flotation. The depressant effect is favourably selective in that violarite, the main nickel mineral, is less affected than pyrrhotite. Nickel recovery, however, is adversely affected, probably through reduced flotation of complex sulphides. Soda ash consumption is increased markedly by the presence of the cations as shown by operating data and pulp titration tests. A significant increase in concentrate grade, from 9% to 14% Ni, was achieved late in 1981. One of the changes in plant practice which contributed to this improvement was the addition of soda ash to mill feed rather than to flotation feed as before. It is shown by laboratory tests that this reduced the depressant effects of the cations, thereby improving recovery at the expense of rougher selectivity, or equivalently, increasing concentrate grade at constant recovery. The selective depressant effect cannot be exploited until scavenger recovery is improved and a scavenger concentrate regrind-retreat äcircuit is implemented. Development is

Jan 1, 1978

By J C. de Vries

When times are tough in the mineral industry û as they have been for some time û typical responses by mining companies are to cut costs and/ or increase production. The latter is seen to spread fixed costs, thereby also reducing unit costs per tonne mined. However, most mineral deposits respond to increased production rates by lowering ore grades, so the reduction in cost per tonne of ore does not necessarily result in a reduced cost per unit of metal produced. The authorsÆ experience is that this process often leads to a mine plan that is a long way from optimal. Producing to the point where marginal cost equals marginal revenue may work well in a manufacturing operation, but it is not necessarily the best strategy for a mining company with a depleting resource. Variations in tonnage and grade with depth, ore reserve optimism and a variety of other factors conspire to produce variations in production rates and grade that often result in suboptimal outcomes and potential mine failure. Added to this is the focus of industry analysts and senior corporate management on such measures as unit costs and ounces in reserves. This is perceived to have the perverse effect of driving the share price down when strategies are adopted that actually improve the value of the mining operation, and vice versa! Many mine failures can be prevented by a close examination of the tonnage grade curve and an understanding of how margins, net cash flows and resulting business risk change with cut-off grades and rates of production. A few relatively simple analyses early in the evaluation of a project can demonstrate the tradeoffs between the main decision parameters, leading to right-sizing of the operation. Once major commitments to major capital items have been made, and reserves have been publicly reported, optimisation of the operation becomes much more difficult than if it had been done earlier. Such investigations can also identify the upside potential and downside risks associated with factors outside the companyÆs control. Many strategies that may enhance value in the good times significantly increase the downside risk in the bad times. What is often called risk analysis typically looks at superficial issues, and does not evaluate the major factors leading to the potential for financial disaster. This paper illustrates some of these major risks, and demonstrates how they may be fully evaluated so that corporate decision makers can make fully informed decisions that take account of the real risks.

Jan 1, 2003

By D S. Clarke, K B. Sporli

Structure is an important control in the localisation of gold mineralisation in epithermal systems. There has been, however, only limited investigation of the structural elements involved; such a study is currently directed at the gold deposits of the Coromandel Volcanic Zone (CVZ). Here, mineralised veining and brecciation ranges up to tens of metres in thickness. Dips of veins are mostly steep, but not vertical, and there is a significant number of low angle veins. The structural control of epithermal deposits may be considered on four scales. At the mega-tectonic scale, pre-volcanism fault patterns mostly relate to separation of the New Zealand micro-continent from Gondwana. The major structural controls on mineralisation at this scale, however, are associated with the volcanic arc processes responsible for the CVZ. Post-mineralisation faulting are linked to the Hauraki Rift and the Colville Ridge-Havre Trough system. Regional scale faults controlling the distribution of gold deposits are the product of these tectonic events; much of the faulting may relate to rifting and calderas, but further work is required to demonstrate this. Detailed study is also needed on vein systems at the prospect scale to validate models of brittle deformation responsible for such systems. Evidence that a variety of structural mechanisms dominated in different deposits is found at the vein scale, with Coromandel gold deposits being classified according to their different styles of vein-fill texture.

Jan 1, 1990

By Plamer D. J, Newman O. M G

The Effluent Treatment System at Pasminco Metals - EZ (PMEZ) was commissioned in December, 1991 and has operated satisfactorily, ensuring that aqueous discharges from PMEZ comply with the Tasmanian Environment Protection Act. The system treats both spills and run-off from the Zinc Plant, and acidic liquor generated in the gas cleaning section of the Sulphuric Acid Plant. The spills and run-off from the Zinc Plant are collected in a large catchment pond. The pond liquor, after partial neutralisation with sodium hydroxide to pH 4, and removal of suspended solids, is preferentially recycled to the Zinc Plant, for example, for washing of residues. Liquor which cannot be recycled, is treated in the Lime Neutralisation Section. The other input to the Lime Neutralisation Section is the acidic liquor from the Sulphuric Acid Plant from which mercury has been removed by contact with aluminium pellets in a fluidised column. In the Lime Neutralisation Section, the liquors are blended and neutralised to pH 10 by the addition of slaked lime. The heavy metals and most of the fluorine are precipitated. The precipitated solids are removed in a thickener with part of the thickener underflow being filtered. Most of the thickener underflow is recycled to generate solids that settle rapidly and filter well. The filter cake is returned to the Zinc Plant for the recovery of contained heavy metals while the thickener overflow is discharged to the Derwent River.

Jan 1, 1993

By Clarke DS, Sporli KB

Structure is an important control in the localisation of gold mineralisation in epithermal systems. There has been, however, only limited investigation of the structural elements involved; such a study is currently directed at the gold deposits of the Coromandel Volcanic Zone (CVZ). Here, mineralised veining and brecciation ranges up to tens of metres in thickness. Dips of veins are mostly steep, but not vertical, and there is a significant number of low angle veins.The structural control of epithermal deposits may be considered on four scales. At the mega-tectonic scale, pre-volcanism fault patterns mostly relate to separation of the New Zealand micro-continent from Gondwana. The major structural controls on mineralisation at this scale, however, are associated with the volcanic arc processes responsible for the CVZ. Post-mineralisation faulting are linked to the Hauraki Rift and the Colville Ridge-Havre Trough system. Regional scale faults controlling the distribution of gold deposits are the product of these tectonic events; much of the faulting may relate to rifting and calderas, but further work is required to demonstrate this. Detailed study is also needed on vein systems at the prospect scale to validate models of brittle deformation responsible for such systems. Evidence that a variety of structural mechanisms dominated in different deposits is found at the vein scale, with Coromandel gold deposits being classified according to their different styles of vein-fill texture.

Jan 1, 1990

By Wauchope AMH

Arsenic residues from BHAS Refinery operations are currently treated to form a calcium arsenic compound and stored in lined dams on site. Laboratory and large scale work on these residues has resulted in the development of a hydrometallurgical process for production of arsenic trioxide. The process also recovers the material from the storage dams. The residues are hot water leached to produce an alkaline arsenic liquor. This liquor is mixed with material from the storage dams and lime to form a calcium arsenic precipitate. The precipitate is then reacted with sulphuric acid to form gypsum for return to the main plant, and an acidic arsenical solution. Metallurgical gas containing 3-6% sulphur dioxide is bubbled through the solution and on cooling arsenic trioxide is precipitated. The product contains in excess of 95% arsenic trioxide. Installation of a plant at Port Pirie based on this process is being evaluated by BRAS.

Jan 1, 1984

To grow a mining company today is seen to be challenged by the reduced interest in resources companies by the financial markets, the complexity of native title and a somewhat depressed commodity cycle. However, the opportunity to grow production and sales in a mining company are as numerous as they have ever been. It is the challenge of growing significant shareholder value that is difficult. The distinction between growth in æcompany sizeÆ and growth in æshareholder valueÆ is an important distinction upon which some resource companies are now firmly focussed. The equity market/commodity market cycle can provide windows of opportunity to consolidate and expand a company for the benefit of shareholders. These benefits may not be reflected until more buoyant equity markets return but, as the cycle turns, as it surely will, those with the foresight to position themselves may be richly rewarded.

Jan 1, 2000

By Martin CH

Over the past forty years colliery management has coped with intensive mechanisation and other rationalisation of traditional conditions to accomplish increases to outputs by miners, mines and nationally. The basic managerial function of planning, organising, directing and controlling have adjusted and expanded to current management demands, including the detail of achieving the highest possible efficiency, particularly in forward planning. Although industrial aspects have vastly improved, there are lingering problems. Safety is not necessarily the basic ingredient of any industrial events-which occur but is always paramount. Likewise some legislative changes may have elements of political and particular vested interests and conservation of technical expertise may be threatened by such frustrations. Not only technical excellence is required, but particular attributes of the individual are required in management evolving from "simple owner management to the complete corporate approach required for the multidisciplined operations of to-day".

Jan 1, 1988

By Young JA, Rogers G, Bannister S, Edwards SA

Many coal mine operators have responded to economic pressures by massive investment in machinery to reduce unit costs. To sustain the increased production which must justify the expenditure it is essential to know the resource in great detail months or even years in advance of its extraction. The required detail includes variations in composition and any lateral disruptions to the seam which night affect production. As Wilson (1985) has pointed out, a day's production loss can mean half a million dollars income forgone, and an unexpected major fault can mean a shutdown of weeks. Traditionally, seams were probed by surface drilling on (typically) 250 or 500m centres, and by horizontal drilling from sithin'the seam. Core was analysed chemically. The new generation machinery cannot tolerate the risk attendant on such widely spaced sampling, but the costs of much closer sampling rapidly become prohibitive.

Jan 1, 1987

The Prospero orebody is a part of the Helene mine at Cosmos and was scheduled to begin production in March 2008 after the exhaustion of the Tapinos orebody in the same mine. Treatment of the Tapinos orebody was challenging and it was envisaged that Prospero would have similar properties given that it was also anomalous in deleterious elements and would be of a similar mineral hosting. It was deemed necessary to undertake a metallurgical test work program to identify any potential processing issues, complex mineralogy or significant metallurgical domains. The paper discusses the processes which were employed to undertake the metallurgical test work program and describes the aspects that can be employed by other developers to quickly and effectively assess potential future orebodies. It will demonstrate that the work was successful at determining expected metallurgical behaviour, providing direction for mining operations and highlighting areas for more extensive research.

Jan 1, 2009