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By N J. Arunakumaren

A coal mine is proposed for an area where a major river traverses the project area. There were initial concerns that inflow of groundwater from exposures of high permeability alluvium associated with the river system could pose mine dewatering problems together with adverse impacts on surface water resources in the river. The project included collation and analysis of geological and hydrogeological data collected historically over a long period of project investigation and evaluation. The project also included establishment of additional groundwater monitoring points to provide a reliable groundwater contours. The groundwater level contours were produced to allow numerical models to be calibrated to support estimation of groundwater inflow. River bed cross sections were also prepared to assist study of the effect of river flow on the inflow. Two separate MODFLOW groundwater models were produced to simulate long-term groundwater inflow to the mine with an upper model consisting of the Quaternary and Tertiary alluvium lumped together and a lower, separate model consisting of Mesozoic coal measures. Analytical solutions were used to predict initial inflow from the alluvium and from the coal measures.

Jan 1, 2003

Increasing demands on quality of metallurgical grade alumina and for lower production costs led to the development of a new fluid bed calcining process. The process, jointly developed in Germany by Vereinigte Aluminium Werke A.G. and Lurgi Gesellschaften m.b.H., takes advantage of modern chemical engineering methods such as counter-current flow of combustion air and solids, direct heat-exchange between combustion air and fine solids and near stoichiometric combustion of oil in a fluid bed. Using a two-stage Venturi-type suspension preheater for heat-recovery from combustion flue- gases, the circulating fluid bed technique with internal oil combustion at 2.2000 F for the calcining step and 'a five-stage fluidized bed cooler for heat recovery from calcines, the process gives an outstanding heat- efficiency. In a first industrial plant for 560 sh. t. alumina per day heat consumption figures of less than 1.400 BTU/lb A12O3 were achieved.

Jan 1, 1971

By Baohm C, Barker T

There have been significant changes in the Australian mineral sands industry in recent years due to changing supply and demand conditions, new product opportunities and opportunities for rationalisation of operations. Earnings within the industry have typically been volatile and this has been reflected in the share prices of listed mineral sands companies. Apart from the effects of variations in the state of the economy on the industry, share prices have also reflected the extent to which a company's earnings volatility is due to capital structure, the relative proportion of fixed costs to total costs and the nature of th'- sales mechanism. At the time of writing, the high prevailing share prices for industry participants and the current outlook for the industry would suggest that the time is opportune for raising equity capital. The immediate outlook for the industry and its various product segments appears favourable but beyond this the usual uncertainties remain. The new tax environment will cause most companies in the industry to have to rethink their dividend and capital structure policies. Most shareholders will now be concerned to maximize dividend receipts and minimise exposure to capital gains tax. Companies in the industry that have relied fairly strongly on earnings retention to help finance growth in the past will- need to look to increased equity raisings in the Future.

Jan 1, 1986

By L C. Thompson

Biomineralisation is the process by which microorganisms mediate and catalyse inorganic reactions so as to form new mineral assemblages. The goal of biomineralisation as a remediation tool is to control microbial processes and their environment so as to sequester and immobilise specific toxic metals within exceptionally strong bonds of neo-formed mineral assemblages. In this way, the bound metals are no longer mobile within a geological time-scale. Applied biomineralisation uses microorganisms, which are isolated from a metal waste environment and are selected for their ability to rapidly catalyse neo-mineral development from dissolved or leachable metals. A typical waste environment will contain microbes that contribute to the mobilisation of metal contaminants as well as microbes that possess the potential for remineralising available metals. Selection and augmenting the correct combination of bacteria and eliminating the competing mineral degrading reactions are the key to applying biomineralisation as an in situ remediation process. Applied biomineralisation harnesses the microbesÆ ability to stabilise toxic soluble metals into non-mobile mineralassemblages. This paper will discuss and demonstrate the biomineralisation process through several case studies including the Summitville mine site in Colorado, the McCoy-Cove mine in Nevada, the Argonaut mine in California, and an historic lead site in Crooksville, Ohio.

Jan 1, 2004

By Lynch P

Oaky Creek Coal Pty Ltd. currently mines high quality coking coal from both underground and open cut operations at its Oaky Creek Mine. Coal is transported by rail to the Dalrymple Bay Coal Terminal south of Mackay and to the Gladstone Coal Terminal. Oaky No.1 Underground Mine, Open Cut and Highwall Mine have concentrated on seams from the German Creek Formation, one of the major productive coal measure formations in the Bowen Basin Coalfields. (Fig. 1) location map.

Jan 1, 1998

By Okura T, Hino J

Coal utilization for copper flash smelting in Japan was initiated due to the sudden upheaval in the price of oil in the last ten years. A major portion of the heavy fuel oil has already been replaced by coal resulting in a corresponding decrease in energy costs. In addition to energy cost savings, an interesting metallurgical phenomenon was observed in flash smelting operations. Unlike oil combustion, coal is not burned completely in the shaft. A considerable fraction of coal particles remain on the surface of slag and are burned at the settler. Chemical investigation has shown that oxygen potentials at the settler have consequently decreased, bringing the slag and matte phases into reducing conditions, thus oxidation and reduction can coexist in one flash smelting unit. As a result, a decrease in magnetite and copper contents in the slag, elimination of furnace hearth build-up and dissolution of intermediate layer between matte and slag have been observed. In general, these led to improvements of furnace operations. However, thermodynamic investigations have shown that some minor elements such as As, Sb, Bi and Pb concentrate from slag to matte. Results evaluated on the basis of thermodynamic data relatively agree with practical observa- tions. Consequently, for coal utilization in flash smelting operations it will be necessary to control oxygen potentials from the stand- points of copper loss in slag and minor element Distributions.

Jan 1, 1987

By Skaviniak M

Some better perspectives applying to the exploitation and dressing of polymetallic ores in the Banskfa. gtiavnica-Hod- rusea Ore District are supposed to be achieved after a suc- cessful investigation and proving there the existence of deep-seated mineralization as well as due to increasing de- mand for non-ferrous metals and consequently to higher mar- ket prices of those recently noticed. With respect to the present situation in mining and to the further technical development as well, a several times higher exploitation may be in this region expected, especially in the deeper .eated parts of the deposit. When solving the tasks of a complex economic exploitation over the whole region, consi- derable attention is paid to regional relations and impact studies (due to expected exploitation and ore dressing but also to very difficult problems of dewatering (drainage pro- blems-). It will be first of all necessary to find there an equilibrium between the consequences resulting from the re- naissance of mining industry and environmental requests un- dispensable for the city of Banska 9tiavnica and the other neighbouring towns in the vicinity of mining plants.

Jan 1, 1988

The Beaconsfield Gold Mine within the township of Beaconsfield in northern Tasmania has been established in recent years to exploit a known resource in the Tasmania Reef which was mined to a depth of 450 m below surface between 1877 and 1914 yielding 850 000 ounces of gold. Activity at Beaconsfield over the past 30 years has involved drilling to assess the resource and rehabilitation of the top 100 m of the Hart Shaft that had collapsed since the original closure. More recently the mine has been dewatered to the 375 m Level and work is well advanced establishing infrastructure aimed at recommencing production during 1998 - 99. This paper reviews geotechnical studies undertaken to-date and provides a brief overview of some practical methods of analysing ground conditions. It pursues simple observation and analysis as a tool for assessing mine design and ground support options without recourse to extensive monitoring and measurement and avoids the use of elaborate models before the basics are understood.

Jan 1, 1997

By Hoskings AD

Bolting forms a prestressed elastic layer of rock which is capable of supporting loads at right angles to the bolted surface. Investigations on rock bolting made with a number of different models give rise to empirical and theoretical prin- ciples for the formation and action of the layer. In the models, flat and arched layers of many materials were used simulating rock conditions ranging from closely interlocked blocks to fragments of various shapes. Results of observations made in the underground works of the Snowy Mountains Scheme are related to the mode of action of bolted surface layers of rock. There is abundant experimental, theoretical and practical explanation for the well-demonstrated capability of bolting as a means of rock support.

Jan 1, 1971

The mining industry is facing tremendous economic challenges. Fluctuating and depressed commodity prices, the ever-increasing pressure from environmental legislation and the competing global opportunities for capital investment are placing enormous strains on every aspect of the mining business. At the same time, mines are generally becoming older and deeper with all the logistical and rock mechanics difficulties that this entails. In the face of these new challenges the industry looks to technological advances to make operations more efficient and profitable. One approach is to develop and implement highly automated and computerised equipment as part of a trend towards major reductions in the underground workforce. This approach requires more capital investment rather than less and requires a more sophisticated and well-educated workforce with skills which are generally in high demand in society as a whole. It is difficult to see how the benefit that can be gained from such technology can justify the expenditures necessary to make it operate reliably underground on a daily basis. Nor is it easy to foresee how the mining industry, based as it is often in very remote areas, will be able to hire and retain sufficient numbers of people to maintain such fleets of equipment. Another approach, and the one which I favour, is the implementation of much greater control over the whole of the mining process. Mining is essentially a very simple process - we break rock and move it. The most cost-effective means of moving and processing the mining product depends entirely on the way it is broken - it depends on primary fragmentation by blasting. I propose that the way forward for the industry in the face of our present difficulties, is not new technology but is to utilise the level of technology which currently exists in ways which have traditionally been regarded as too difficult or too inflexible - improved fragmentation and the use of conveyors. The technical success of this approach depends on the complete re-design of the ore handling system from the face or stope drawpoint to surface. The fundamental issue which determines the success of this approach is designed fragmentation.

Jan 1, 1995

The paper describes a computer model developed within the State Electricity Commis- sion of Victoria for use in open cut planning. The purpose of the model is to simulate all the typical occurrences in, and influences on, the coal supply and overburden disposal systems in order to be able to assess their performance. The model incorporates much of the long term and day-to-day operations planning logic required for the allocation of resources within an open cut. This logic takes account of power station demands, bunker stocks, plant and crew availability, the balance of reserves between dredgers, planned maintenance, etc. The perfor- mance of plant within the system is simulated using random selections from statistical distri- butions of Time to Failure and Time of Failure for each plant item. The application of the model in selecting a suitable bunker capacity in a notional open cut development is described to illustrate the potential of the model in optimising plant selection.

Jan 1, 1982

The Quioma Mine is located along the axis of the Cordillera Oriental, 130 km southeast of Cochabamba, South Central Bolivia. Silver, lead, zinc, antimony, and gold have been intermittently produced from veins in the Quioma area since Colonial times. Mineralization occurs within steeply dipping fissure veins transecting moderately folded Lower Ordovician sediments. Tectonic activity is early to mid-Tertiary and the vein system parallels the fold axis of a major northwest-southeast striking, doubly plunging anticline. Vein sets occur within a 2 km wide band over a strike distance of 13 km along the northeast limb of the anticline. Economic mineralization occupies syntectonic pre-mineral fault zones developed in more competent stratigraphis units of Lower Ordovician clastic sediments. Veins average 55 cm in width, although mineralized structures up to 3 m wide with a known strike length of several hundred meters have been mined. Mineralization consists of siderite, argentifferous galena, sphalerite, and quartz, with minor amounts of chalcopyrite, barite, and bournonite. Pyrite is rare except at the Boston vein where it occurs with stibnite that contains trace amounts of gold. A marked characteristic of veins in the district is evidence of repeated stages of movement during mineralization. Intrusive rocks are rare in the Quioma area. Narrow porphyritic dikes of Andesitic composition averaging 1 m in thickness have been observed. These dikes occasionally show a close spatial relationship to the veins and are often kaolinized and carbonitized. Vein and dike contacts are sharp and alteration does not appear to extend into the wall rock. Mineral zoning is suggested by antimony mineralization observed in peripheral areas of the anticline.

Jan 1, 1987

High resolution seismic profiling has proved a cost effective tool for defining the structure and seam geometry of Late Cretaceous-Late Miocene age lignite deposits in the South Island of New Zealand since 1981.In 1985 a total of 45 km of Mini Sosie seismic reflection was carried out in the Benhar, Hawkdun and Ashers-Waituna deposits as part of a major multidisciplinary resource investigation funded by the Liquid Fuels Trust Board. For each deposit the seismic programme involved integrating four or more intersecting Mini Sosie traverses with a grid of 1000 m spaced geophysically logged drillholes. The objective was to detect faults, with displacements ranging 30 - 100 m, which might impede mining using bucket wheel excavator systems at depths down to 300 m below surface.In general the quality of processed seismic data was high and with the assistance of ynthetic seismograms and other geological information, it was possible to identify a number of significant previously unknown faults. The success of this seismic programme ha shown that high resolution seismic profiling, used in conjunction with relatively low density drilling, can produce valuable structural and tratigraphic information at an early stage of open pit mining investigation.

Jan 1, 1989

By Peng S. S

Measurement of pressure distribution under the base plate of the Hemscheidt 2-leg 800-ton shield was performed underground for two shifts using 12 pressure cells installed in two rows, one each under each split base plate. Pressure distribution was uneven depending on contact condition. In general the highest base pressure occurred at 1/3 of the base plate contact length from the rear edge. The resultant was near vertical, and the pressure under the tail side split base plate was always higher than the head side. For comparison, pressure distribution on the canopy and under the base plate was also measured under controlled conditions at the USBM's Mine Simulator Testing Facilities in Pittsburgh, PA. A total of 45 tests were conducted under several simulated contact conditions. The results showed that the actual contact area is highly dependent on the compliance of the immediate roof and floor due to the sloped canopy tip and a base lifting device under the base tip. The loading distribution tends to change in magnitude and profile as the leg pressure increases. The base lifting device exaggerates the high toe loading on the base plate characteristics of this type of shield support.

Jan 1, 1992

By C Menzies

Hydraulic Monitor mining at Solid EnergyÆs Spring Creek Mine has proven to be a safe and effective method of extracting steeply dipping thick seams at production capabilities approaching one million tonnes per annum.   This paper traces the development of Hydraulic Monitor mining from its initial introduction into old workings at Strongman Mine, its refinement at Strongman 2 in shallow, thick and steep workings, through to its introduction into the deep, very thick seams at Spring Creek Mine. This last step of the progression came with all the added complications that come with depth, particularly flammable gas.   This paper will describe the various changes in mining conditions that dictated the performance of the monitor, how the mine layouts were changed to adapt, and the various operational systems that were put in place, to allow a safe and productive operation.

Jan 1, 2007

By Fowler T. J

Examples are provided of discontinuity analysis at selected sites in central Victoria. Discontinuities are rock fractures of low tensile strength, including bedding, foliations and joints, which are analysed during rock excavation design, to quantitatively determine the defect orientations, spacing and lengths. Their analysis can reduce the cost of mining operation and improve safety. Extrapolation beyond the exposed face is required, although difficult without an understanding of the regional geology. For rock engineering purposes assumptions are commonly made that discontinuity characteristics are uniform throughout the rock mass, however this is often invalid, as rock masses have usually undergone large-scale deformation, exhibit anisotropy and inhomogeneity. Structural geologists are able to interpret large-scale deformation responses for the purposes of structural correlation and extrapolation. Examples of discontinuity analysis linked to regional geological assesment from sites in central Victoria, reveal that discontinuities exhibit similar characteristics in a range of rock types of different ages and composition. Spacing variations between individual sites are believed to be a result of local rock type differences.

Jan 1, 1997

By Moy A. D

The Esperanza deposit is located 120 kin N of Mount Isa, Queensland at approximately lat 19¦20'S, long 139¦22'E on the Camooweal (SE 54-13) 1:250 000 scale map sheet. It is one of several structurally controlled copper ¦ cobalt deposits developed along the Mount Gordon Fault zone and related faults, within the Western Fold Belt of the Mount Isa Inlier (Figure 1). Together with the nearby Mammoth orebodies it forms the basis of the Gunpowder operation of Aberfoyle Limited. Until recently ore was mined from the Mammoth orebodies by open stoping with decline haulage to surface leach pads. Leaching of in situ broken ore (in place) and surface heaps, followed by solvent extraction and electro-winning (SX-EW), produced copper metal on-site. In March 1997, mining was suspended at Mammoth and the focus of the Gunpowder operation switched to development of the Esperanza orebody, which is expected to begin open cut production in mid 1998. SX-EW methods will produce 44 000 tpa of copper from an expanded plant. The pre-mining mineral resource at Esperanza (measured, indicated and inferred) is estimated at 4.6 Mt averaging 7.7 per cent copper.

Jan 1, 1997

Water retention, water loss and delay in tailings storage rehabilitation are major challenges for many Coal Mines. Work by Stewart, Backer and Busch in the early 1980s suggested that there were improvements to be made in tailings dewatering and density by the addition of flocculant. This prompted ACARP, in cooperation with Bulga Coal Management (Xstrata), to initiate a research project investigating the impact of flocculant addition on tailings deposition density, water retention and the tendency for tailings to form surface crusts suitable for subsequent rehabilitation. A polyacrylamide-based flocculant (200 - 250 g/tds) was injected into the tailings line immediately prior to disposal into the impoundment area. The flocculated slurry rapidly released clear water and created a beach due to the immediate increase in deposition density. The deposition density increased from 35 per cent w/w to 61 per cent w/w solids within 24 hours and continued to increase to 75 per cent, seven days after treatment. The water capture at the tailings storage facility improved by more than 90 per cent; water which would otherwise be lost from the circuit through retention and evaporation. The impoundment capacity had nearly tripled due to the improvement in initial deposition density from 420 kg/m3 up to 1163 kg/m3. Four weeks after disposal surface crusts were forming on the storage facility, suggesting that there would be less delay between cessation and tailings storage rehabilitation.

Jan 1, 2008

Cores of pre-Tertiary basement from ten oil exploration wells are related petrologically to the "axial", "marginal" and "shelf" facies of the New Zealand Geosyncline.A NW. Nelson-type basement is inferred beneath peninsular Taranaki and the western continental shelf. The terms Taranaki Basin and Wanganui Basin are re-defined and the terms North Wanganui Basin, South Wanganui Basin, Pipiriki High, Taranaki Fault, and Turakina Fault are proposed. Major faults are interpreted as of mainly transcurrent type and appear to form the western part of a splay at the northern end of the Alpine Fault. Evidence for a major Cook Strait Fault is reviewed.

Jan 1, 1967

By Gibson G, Jaques L

The Broken Hill Exploration Initiative (BHEI) is a collaborative venture between the Australian Geological Survey Organisation (AGSO), Mines and Energy South Australia (MESA) and the New South Wales Department of Mineral Resources (NSWDMR) to provide a new generation of geoscientific information to promote and enhance the exploration for, and discovery of, new deposits in the Broken Hill region. The area under investigation (Figure 1) exceeds 150 000 square kilometres on either side of the NSW-SA border and is centred on the city of Broken Hill. N.T. I I OL n. WA 8A I Maw. AC,7 !ii oFCU vlc~ ~T. Fia I - Nlap showing the 150 000 square kilometre regwa,. i.i lcr investigation by the Broken HiII Exploration Initiauvr highlighted on the map of Australia. A major impediment to the exploration for, and to the understanding of, the genesis of the world-class Broken Hill Pb-Ag-Zn deposit is the structural and metamorphic complexit\ of the region. Important objectives of the BHEI are therefore: I. the definition of the three-dimensional structure of the province, 2. the deformation history, and 3. the stratigraphic and age relationships of the rock units. Early discussions between the BHEI partners and industry scientists revealed that new geophysical surveys would be a key requirement to help advance the understanding of the province, especially a contiguous high resolution airborne geophysical dataset covering both outcrop and areas of shallow surficial cover. The purpose of this paper is to draw attention to the new high resolution airborne geophysical data and to discuss their interpretation and potential for enhancing the knowledge of the Willyama Supergroup geology.

Jan 1, 1997