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By Brinkmann J. R

The relative effects of the two basic mechanisms contributing to rock breakage during blasting, shock and gas penetration, are neither well understood nor well characterized, and need further clarification. Blasthole liner (BHL) tests separate the two effects, and by enabling direct measurement of borehole expansion give insight into the shock/gas energy partitioning in rock confinement. The hydrodynamic code DYNA2D is used to simulate the shock effect of the detonation of emulsion in a stainless steel lined hole, and the predicted expansion is compared with experiment. Workers in the past have neglected near-blasthole phenomena and have calibrated models based on stress measurements remote from the blasthole. Extrapolation back to the blasthole has inherent limitations, and indeed, one of the deficiencies of these models is that they have not been able to predict correct borehole expansions, as observed in BHL experiments. DYNA2D has been enhanced by the ICI group with a detonation model which resolves the explosive reaction zone. As a preliminary step towards the ultimate goal of devising a practical damage model, simulations are used to predict the maximum expansion that would take place if the rock were to remain undamaged. Various material parameters are investigated and it is shown that calculated liner expansions are appreciably lower than measured values for high rock yield strengths, while greater than values for low yield strengths.

Jan 1, 1990

By K Biegaj

The paper describes challenges the author has encountered on Australian underground gold and nickel mines over the last eight years, when recovering high-grade gold/nickel bearing mine floor material with a mobile supersucker/giant vacuum cleaner and other equipment. Whilst for a number of years the mine floor vacuuming and other mine floor clean-down technologies have been accepted/adopted and are working well in other parts of the world and on the South Australian opal mines, regrettably, they have not yet gained acceptance of mining executives and mine managers of gold and metal mines in Australia, who still elect to leave the never to be recovered gold/metal behind or to put it plainly - waste it.For reporting purposes during the mining process, the portion of gold/metal included in calculation of ore reserves prior to obtaining capital funds for their development, continues to be camouflaged in various reconciliation and call factors. This approach, ie wasting of capitally developed and already broken ore stocks should be viewed by the shareholders as totally inappropriate to say the least, especially with the current gold and other metals prices.The author attempts to provide answers as to why the technology referred to above has not yet been accepted on Australian gold and metal mines and outlines the way forward.CITATION:Biegaj, K, 2012. Why do shareholders and mining executives allow mine managers to leave behind high-grade broken ore underground?, in Proceedings Narrow Vein Mining 2012 , pp 197-206 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012

By T J. Orr

The changing demographics of the mining industry make successful passing of knowledge and skills to the next generation critical. Training methods and technologies are being developed to meet this need. Twenty years ago classroom training was largely a one-way transfer of knowledge through instructor lectures. In contrast, instructors today can use virtual reality technologies to guide trainees as they fully participate in learning experiences. Trainees can interact with the virtual work environment, co-workers, and equipment without being exposed to workplace hazards. The speed of advancement in mine safety, health, and production training shows no sign of slowing in the next 20 years. Researchers at the National Institute for Occupational Safety and Health have studied and participated in the evolution of miner training. A look at training materials they have created in the past and those they are currently developing reveals changes in methods and technologies over time and also key characteristics which have remained constant. Possibilities for the future can be discussed in the framework of an implementation of virtual reality in new miner training sessions. The example computer-based training package teaches new miners to read mine maps and provides opportunity to practice navigation skills in a virtual mine. With this æserious gameÆ, trainees experience the look and feel of moving through an underground coal mine while in the safety of their classroom. During field-testing in 2007, trainees and instructors responded very favourably to this new way of learning. The software was usable by mine trainers with even limited computer expertise and could be installed on the affordable computers they were using for their more traditional slide presentations. The Underground Coal Mine Map Reading TrainingÆs foundation on past successful development strategies and its acceptance by todayÆs instructors and trainees provide valuable lessons for developing training materials, strategies, and technologies for miningÆs future.

Jan 1, 2008

By Whincup P

Hilton deposit comprises en-echelon silver-lead-zinc orebodies with reserves in excess of 50 million tonnes. The host rock to the ore is a dolomitic and pyritic shale/siltstone which dips steeply west. The shale/siltstone is deeply leached and porous, particularly over the Ore Zone where the depth of leaching continues down to 440 m below surface, and constitutes an extensive permeable aquifer system containing a large volume of saline acidic groundwater. Initial production commenced at Hilton in 1987 well below the aquifer. A dedicated dewatering and monitoring programme is in place to ensure security of stoping operations and allow extraction of ore close to the leached zone in future years. Dewatering is undertaken from controlled bores from underground sites. Mine groundwater discharge is presently at the rate of 4000 kl/day with plans to increase to 8000 kl/day. An additional 2000 kl/day of fill and service water and water from secondary aquifers is also pumped from the mine daily. Although recharge rate to the aquifer is minimal, studies indicate that due to the size of the aquifer and future extensions to mine development, dewatering will be a life of mine activity. The investigations which have been undertaken to determine optimum dewatering techniques and schedules are described. These include production bore tests, mine planning constraints and computer aquifer modelling. Gravity geophysical techniques have been successful in delineating the lateral and vertical disposition of the aquifer. The mine dewatering schedule, whose principal component is underground mine drainage, is also outlined.

Jan 1, 1988

The stratigraphic sequence west of Mount Isa contains the Judenan Beds, Eastern Creek Volcanics, and May Downs gneiss. It is an incomplete sequence as major north-south faults divide the area into four separatezones containing portions of these different units. The first three zones, which occur directly to the west of the Mount Isa Fault, consist of quartzites and quartz-mica schists which are uncorrelatable between zones but have been grouped together as the Judenan Beds. The most western zone contains an incomplete section of Eastern Creek Volcanics which rests conformably on a unit believed to be equivalent to the Mount Guide Quartzite; this is again underlain by the May Downs gneiss. A detailed description of the rock types is presented, but only a broad stratigraphic correlation is possible with the very much thicker sequence to the east of Mount Isa.The age of sedimentation is believed to be Lower Proterozoic and it may not occur in the type of geosynclinal basin envisaged by previous authors.This sequence is intruded by many small basic intrusions and also the Sybella Granite with its associated microgranite and pegmatites. The Sybella Granite consists of both a massive and a foliated phase; the latteris generally restricted to the margin of the main granite mass.Four regional metamorphic zones have been identified on the basis of their pelitic mineral assemblages; these are a chlorite, biotite, biotite-cordierite, and a sillimanite zone; separating each are prominent north-south faults.This metamorphism is a regional metamorphism which accompanies the first generation folding of the area and is not associated with the emplacement of the Sybella Granite. A very localized retrogressive metamorphism is also found in some areas of second generation folding.

Jan 1, 1972

By P Gnnther, A M. van Niekerk

Coal mining operations in the Upper Olifants River Catchment in the Mpumalanga Province of South Africa are challenged with the increasing production of excess mine water that cannot be fully managed by existing practices of pollution control at source, recycling, and reuse on mining sites, storage and limited release to the natural water course. In contrast to this, the Olifants River Catchment is experiencing water stress and insufficient water is available to satisfy all water quantity and quality requirements for future industrial and municipal growth. It is estimated that the catchment has a deficit of 192 million m3 per annum if the reserve water requirements are taken into account. The future increased water requirements can be met by water transferred to the Olifants River Catchment from adjacent catchments. The cost of transferred water is likely to be substantially higher than the current cost of water supplied to local municipalities, commerce and industry. BHP Billiton and Anglo Coal Corporation are working together to jointly implement water management strategies that will contribute to the achievement of in-stream and dam water quality and aquatic objectives for the catchment. Consideration is now being given to the treatment and beneficial use of excess mine water. This will inaugurate a new era for the coal mining industry in South Africa, in which a pollution threat to the water resources in the Upper Olifants River Catchment is converted into a water source for beneficial use. Three potential mine water reclamation and reuse schemes have been identified and this paper details the technical, institutional, legal and financial considerations in the implementation of these schemes.

Jan 1, 2006

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

Controlled recirculation of nine ventila- tion air is becoming an acceptable practice world-wide. A brief review of operating and planned schemes is given which illustrates the various purposes for using controlled recircu- lation in different types of mines. A de- tailed description is given of the operating and proposed schemes on South African gold mines. This is followed by a description of some theoretical and experimental work which has recently been carried out into certain important aspects of controlled recircula- tion. This includes: safety systems, dust filtration, blast contaminant removal, radia- tion hazards and the development of an expert computer program for the design of controlled recirculation systems.

Jan 1, 1988

Sasol Roche Blasting Services (SRBS) has undertaken a process of trialing and evaluating the use of the SMI electronic initiating system with the specific purpose of being able to fully quantify the benefits of the system over a pyrotechnic system. After an initial trial of three shots in mid-2001, it was decided that to fully quantify the system, a complete strip would need to be fired using the system so that any losses due to ramps or end walls would be the same for both scenarios. The results have shown a significant improvement over the use of pyrotechnic initiators in several key areas including percentage cast. Through the use of survey results, the increase in cast and subsequent net improvement in blasting has been quantified. These trials have set out to compare each system in comparable situations to determine the real benefits, if any, of the electronic system over the pyrotechnic one. As the percentage cast is relatively easy to quantify using modern survey techniques, it was decided that this would be the principle method of comparison. However, while the assessment only included survey results, any improvement in fragmentation size and consistency would have flow on effects on reduced running and maintenance costs.

Jan 1, 2003

By Ramsden AR

The ability of the scanning electron microprobe to provide non-destructive qualitative and quantitative mineralogical analysis at the micrometre scale makes it a very versatile tool for the mineralogical characterisation of ore deposits and their host rocks. With the trend towards exploitation of large tonnage low grade depositsnd precious metals at the parts per million level it is becoming increasingly important to have full mineralogical characterisation and knowledge of the mineralogical residence of the valuable elements to assist formulation of a cost-effective exploration program and obtain optimum recovery in the case of exploitation. Mineralogical applications include

Jan 1, 1989

By Aziz NI, Bridgwood EW, Singh RN

One of the major impacts of using modern mechanised systems of mining is the production of large amounts of extraneous dirt intermixed with the Run of Mine output. The paper out- lines a proposed system of utilizing liquid tailings from coal mines to replace imported cementitious materials used in ground control and various other safety measures. A geotech- nical and cost assessment of the proposed system are also included. The paper concludes that it is possible to utilize processed tailings to cost effectively replace imported packing material for ground control.

Jan 1, 1986

Large scale open pit mining at Ok Tedi and Misima are described in this paper. The paper also presents the socio-political problems encountered in the construction, operation and waste disposal of high technology, high output gold and copper mines in very remote and rugged terrains. Despite these handicaps, mining companies from all over the world have established top class mining facilities including huge open pits, underground mines and mineral processing plants to extract rich mineral deposits of gold, silver and copper.Papua New Guinea is the sixth largest gold and copper producer in the world. New projects likely to come on stream before the end of this century would make it the world's third largest gold producer. The mining industry is the largest organised industry in the country employing over 10 000 persons and investing over US $1000 million on these mega projects per year.

Jan 1, 1992

Lithocaps are potentially voluminous zones of advanced argillic and associated argillic alteration located above the subvolcanic intrusive environment. They constitute exploration objectives for epithermal and porphyry-type deposits. High-sulphidation epithermal deposits may be sought within lithocaps, whereas low-sulphidation deposits may exist on their edges. Porphyry Cu-Au/Au deposits may be accessible beneath lithocaps if systems are telescoped sufficiently. Oxidation of the basal, pyritic parts of lithocaps may promote supergene sulphide enrichment under appropriate tectonic and climatic conditions.

Jan 1, 1995

The mathematical modelling of rock fragmentation by blasting is one of the most difficult and challenging problems of applied mathematics. Not only is complex mathematics required but there is incomplete understanding of the basic physics and chemistry involved. The possibility of getting the physical basis of a model correct by simple mathematical and experimental procedures is demonstrated for the novel process of fragmenting rock by high-pressure arc discharges. While the importance of obtaining the correct physical basis for a model is emphasised, high-pressure arc induced fragmentation of rock is shown to be a powerful laboratory tool for the study of blasting.

Jan 1, 1990

By Beeforth C. G

The use of Non-Linear Programming to obtain improved schedules of future activity in two specific cases of mining and treatment of minerals is described. The two cases were (i) reclamation of gold, uranium and sulphur from old surface tailings dams and, (ii) underground mining of gold. The method used an augmented Lagrangian device to reduce a constrained Non-Linear Programme to a sequence of unconstrained hill- climbing procedures. The main advantages of the method appear to be those of (a)flexibility of modelling of industrial characteristics and constraints and, (b) reasonably modest computation times.

Jan 1, 1977

By Wilson PH

A research programme sponsored through the Australian Mineral Industries Research Association investigated two aspects of mine aerodynamics on model scale. These were aero- dynamic losses in (a) shaft/airway intersections and (b) losses created by mine cages moving in a combined haulage/ventilation shaft. The shaft/airway intersections studied included base and intermediate levels for both upcast and downcast. shafts, with one to four rectangular airways intersecting a circular shaft. Changes in intersection geometry were limited to the installation of 45¦ conical brow cutoffs of varying size and the addition of simple flow control devices. The relative air- flows between the airways and the downstream shaft were varied over a range employed in Australian mining practice. In general, experiments revealed that a small brow cutoff was significantly better than none at all, and a simple device such as a cone can reduce losses and improve flow stability at an intersection. The mine cage studies determined the effect on aerodynamic loss of cage area blockage, height/length ratio, openings in cage walls and surface roughness due to external structural members. The results show that in a combined haul- age/ventilation shaft, when the relative air

Jan 1, 1978

By Waters CA, Happ JV

The debismuthising plant, commissioned in 1980, is based on the Kroll-Betterton process for preliminary bismuth removal with subsequent antimony treatment for fine debismuthising. Bullion flowrate is continuous and the plant was designed to achieve low bismuth lead product at rates of up to 20 tonne/h.Development of the first stage of the operation has enabled reliable operations at 25 tonne/h to be achieved. Thesedevelopments also introduced the opportunity to treat higher bismuth bullion at up to 35 tonne/h when operating the first stage only to produce product lead of 0.029 per cent Bi, meeting the ASTM B29-55 Corroding Lead Standard.

Jan 1, 1985

By Fee DJ

Some four hundred million tonnes of low rank sub-bituminous coal occurs in four separ rate lobes at Leigh Creek. These deposits are in a sparsely populated pastoral area remote from industrial centres. Early development was retarded because of high mining and haul- age costs and the availability of other fuels. The search for additional fuels after the second world war led to thorough investigations into the burning characte-,istics of the coal and the discovery of shallow coal suitable for open out mining. The development of the field included the establishment of water supply, improved rail facilities and a town.

Jan 1, 1975

The Bureau of Mines, with a history of mining research since 1910, still seeks improvement in safety and health along with improvement and competitiveness in the mining industry. Much promise of such improvements lies in new technology, and this is particularly the case in the still growing coal mine sector, although much Bureau research is long term, high risk, aimed at new concepts.The miner's environment is a primary concern, involving technologies of contaminant monitoring and control in high production scenarios. Contaminants arising from diesel use, alternatives to high speed rotary cutting and more efficient dust removal are being addressed, and drilling efficiencies, better monitoring through unitising operations and insitu rock dust monitoring are particular features.

Jan 1, 1991

Tyre cost at Mount Morgan Limited had been 24% of the truck operating cost. Comprehensive tyre testing resulted in a reduction in tyre costs of about one third. A record of the evaluation techniques may enable the selection of tyres that are most suited to particular conditions. Rubber characteristics, rubber quantity, tyre design, road conditions, dump conditions and inflation pressure were found to be sig- nificant variables. Measurements of tyre temperatures at the breaker strip were used to select the tyre design and inflation pressure required for Mount Morgan Limited's conditions. Relugging of tyres was discontinued as a result of tyre testing.

Jan 1, 1974