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Callide Coalfields produces a sub-bituminous, very subhydrous, low rank, steaming coal with good combustion properties, primarily for domestic power generation. Geological input into planning of coal extraction requires expedient production of detailed structural, lithological, analytical, geophysical and geotechnical data. The CSIRO-developed SIROLOG borehole logging software and hardware system allows for detailed spectrometric analysis of coal/interburden. The gamma-gamma and neutron-gamma SIROLOG techniques both provide improved prediction of ash content over other borehole techniques. The neutron-gamma technique also predicts density and some important ash constituents (especially iron, alumina and silica). The software/hardware configuration allows for quick, easy interpretation of coal seam depth and lithology, parting thickness and ash/ash constituent contents immediately after a borehole has been logged. Within certain mine areas in the Callide Basin, the iron content of mined coal is widely variable in both vertical and lateral extent within and between seams. This variability creates problems in predicting the slagging behaviour of æas-receivedÆ coal during combustion, especially where the iron content of the ash exceeds 19 per cent. Using the SIROLOG tool in co-operation with traditional borehole sample laboratory analysis results, patterns in this variability can be determined and related to geological properties and process of formation of the coal seams. Subsequently, areas of high iron can be predicted in advance of mining. Since 1992, on-going collection and interpretation of SIROLOG downhole geophysical log data has significantly contributed to a number of research projects related to gaining a preliminary understanding of the iron distribution and formation during the Coal MeasuresÆ deposition. Because the probe was able to record variations in coal mineral matter content, it was found to complement more conventional techniques such as reflected light petrography, X-Ray Diffraction and SEM techniques that examine the mineralogy of iron species. Additionally, software has been developed to allow integration of SIROLOG data into existing geology databases, enhancing coal quality modelling and daily prediction of parameters such as raw ash, silica and iron contents that are indicators of ash fusion propensity. The correlation of SIROLOG-derived iron geophysical traces between drillholes and other sample points highlighted lithological and structural controls in the iron distribution in the sequence previously not detected. This work has allowed the development of a methodology for predicting iron in advance of mining and reconciling as-sold coal quality to that predicted. Predictions are currently being assessed at the coal face as mining progresses through high-iron zones.

Jan 1, 2000

By D V. Bright

Oroya Mining LimitedÆs Mt Gibson Gold Project, 280 km north east of Perth, is one of Western AustraliaÆs more recent discoveries of a major gold resource. Modern gold mining commenced in 1986, on a shallow laterite reserve of 6.62 million tonnes averaging 1.50 g/t gold. By the end of 1998, mining had progressed from an initial three shallow laterite pits to a series of 14 open pits with maximum depth of 100 m, on three separate trends with a combined strike length of over 10 km. The Project has yielded 868 400 ounces of gold from 16.5 million tonnes of ore at an average recovered grade of 1.64 g/t gold, from near surface laterite, supergene and primary sulfide ores. This includes a 160 m deep underground decline operation which mined 120 000 tonnes at an average grade of 9.1 g/t gold and a four million tonne Dump Leach on a synthetic base which yielded 68 900 ounces. The Project was placed on Care and Maintenance in 1999 pending drilling to refresh reserves. Hosted by strongly tectonised and altered Archaean volcanic rocks within and adjacent to a major regional shear, primary gold mineralisation occurs as structurally emplaced sulfide and quartz lodes. On the main Gibson Trend, multiple zones of mineralisation occur within a zone up to 600 m in overall width. The overall footprint of known mineralisation exceeds 20 km2 and the potentially mineralised domain exceeds 100 km2. The current estimate of a combined resource of 9.4 million tonnes averaging 2.47 g/t gold (749 500 ounces) is derived from a database of 10 500 drill holes, of which only four per cent test below 100 m vertical depth. Ore envelopes which remain open at depth and major gaps in the drilling pattern beyond the currently defined resources promise straightforward potential to define additional resources. Oroya Mining Limited and its joint venture partner Barrick Australia are targeting a major gold mining operation from this potentially world-class mineralised system. Oroya has the exclusive right to produce up to 500 000 ounces and is working toward the completion of a feasibility study into a resumption of mining using the existing 1986-built 1 Mtpa processing plant. The joint venture is in the early stages of testing the depth and lateral potential of the Mt Gibson mineralised system. Mining options currently under review include progressive open pit extension and amalgamation leading to one or more large open pits, and underground operations. It is too early in the development of the Project to offer definitive economic models of potential large-scale mining operations.

Jan 1, 2003

By Williams RE, Ralston DR

Acid mine drainage is a serious environmental and economic concern, resulting in regulation of the mining industry and significant water treatment costs. An interdisciplinary approach is needed to analyze the many aspects of a complex acid drainage problem. This paper describes the integrated application of techniques from the following fields to the characterization of acid drainage at a large underground lead-zinc mine: 1) hydrogeology, 2) surface stream analysis, 3) structural analysis of fracture distribution, 4) hydrochemistry, 5) geostatistics, and 6) multivariate statistics. The Bunker Hill Mine in northern Idaho, is developed in highly fractured and faulted quartzites and discharges 95 L/sec of water with an average pH of 2.8 and an average zinc concentration of 120 mg/L. Research has been conducted on all aspects of the acid water production and drainage problem. Recharge to the mine has been investigated using geophysical techniques and tracer studies. Fracture mapping and geostatistical analysis of the fracture data have been used to determine characteristics of inflow to the mine workings. Hydrograph analysis techniques have been applied to water flow data within the underground workings. Chemical sampling and analysis have been used to identify acid producing workings, and better understand mechanisms controlling acid water production. Multivariate statistical techniques have been applied to analyze the quality and flow data. Research results from the many subprojects of the Bunker Hill study reveal the importance of an interdisciplinary approach to the analysis of acid mine drainage problems.

Jan 1, 1988

By Cameron A

In recent years there have been significant developments in the tech- nology available for blast monitoring, analysis and simulation. Progress in these areas has been achieved through research conducted by explo- sives manufacturers and independent research groups from universities and mining companies. Miners are increasingly keen to exploit this tech- nology to help them design blasts which make optimum use of explo- sives to produce easily excavated muckpiles for the minimum possible cost. The art of blast design in the future will increasingly depend on an adequate understanding of the nature of the rock mass, the perfor- mance of explosives and the characteristics required of the muckpile to suit the chosen excavation machinery. Despite recent advances in blast simulation and the prediction of blasting performance, the best way to determine how a particular explosive will function relative to other explosives is to conduct properly designed and monitored field trials. This paper discusses recent work at Mount Thorley Colliery which demonstrates that field blasting trials can be monitored and analysed to provide quantitative data on the relative performance of bulk explosives. Techniques used in the trials included the sampling and analysis of explo- sives, insitu measurement of VOD, monitoring of near and far field vibra- tions, high speed and still photography and survey measurement of muckpiles. These techniques provided data for the analysis of throw, swell, fragmentation and burden movement together with data on the consistency and robustness of different explosive products. The blasting trials allowed both the shock and heave energy of various explosives to be observed in the field and led to the derivation of design rules for the use of differ- ent explosives at the mine.

Jan 1, 1988

By Tucker G, Clark A, Young M. F, Johnston M

Mount Isa Mines has made a huge commitment to process control in milling. Yet in lead zinc we still failed to achieve a steady operation. Comparisons with manufacturing plants showed the key difference was failure to control plant inputs. Lead

Jan 1, 1998

By Hll J. K, Zhang Y. G

The wear mechanisms of impregnated diamond drill bit matrices are complex and believed to be the key point in solving drill bit self-sharpening problems. A method has been developed to find the change in c,, the wear rate of matrices having different fracture toughness K_ at the increment of drill pressure P. The worn surfaces of specimens were placed under a scanning electron microscope to examine the wear patterns and wear mechanisms at different pressures, and were compared with the worn surface of a practical drill bit. A model is proposed that within a wide range of pressures there exist two different wear mechanisms and three wear regions for cemented car- bide matrix materials. In region one (linear region), at low pressure, the major wear mechanism is plastic deformation in which the preferential wear of the binder phase of the matrix results in the loss of WC, tung- sten carbide particles. Wear rate is controlled by hardness, H as Archard's formula predicts. Wear enters region two and three (non-linear region) simultaneously as pressure is being increased. Consequently, wear transfers to fracture mechanism in which micro-fracture occurs at the root of wear grooves and the material is removed mainly in piece and mass. It has been shown fracture toughness K,, plays a more important role than hard- ness H. It is concluded that for a specific drilling condition, the pressure on the matrix should be carefully controlled and a balance between hard- ness and toughness of the material is essential for a steady drilling Condition.

Jan 1, 1989

Most coal mines in Chongqing Area are highly gassy mines and liable to outburst of coal cnd methane. In order to harness mine environment and raise the Prodction capacity, methane predrainage is generally taken as a main preventive measure against outburst by all mines. In the recent ten years, the drainage volume per year has increased from 38.25 million m3 to mote than 100 million m3 with a volume over 12 m3 per tome of coal. In some mines, the draining rate is approaching to 50 percent, the rate in mining districts is up to 60 to 70 percent. The predrainage volume accounts for one fourth of total drainage volume. All these have effectively prevented the occurrence of coal and methane outbursts.This is the current situation of methane predrainage in coal mines in Chongqing area, the methods of predrainage to prevent outbursts and related parametres comprise:1. methods, technologies, supervision and effect of predrainage in different geological and mining conditions,2. the change of methane parametres pre-and post-drainage and the analysis of the effect of methane predrainage to prevent outbursts, and3. ways to improve the effect of methane predrainage.Thus the safety, reliability and production of Changqing Coal Mines will be enhanced.

Jan 1, 1991

For more than 15 years after the Northparkes orebodies were first discovered in 1976, the project was delayed by the need to find an economic way of mining the low-grade E26 deposit. The decision to use a low-cost block caving method to mine the orebody was made in the early-1990s; but the project's future did not solidify until 1993 when a radical new approach was adopted which sought to integrate business imperatives with technology and organisation strategies. The approach led to the establishment of a strategic vision which tied together all the components that could have a major impact on the project, to provide a framework for guiding strategic choices. The strategic vision strived to break away from the old rules of how mines are organised and operated; and involved finding imaginative new ways to radically redesign mining processes to achieve quantum leaps in performance.

Jan 1, 1997

In the general planning of this area, provision was made for the distribution over the whole area as required of the following services:(a) Power and lighting from the substation distribution boards 'located in the winder house.(b) Miscellaneous electrical indicating, control and signalling systems.(c) Telephone lines from the main internal automatic exchange located in the changehouse, the town exchange to the automatic exchange and also direct lines from the town exchange to selected offices.(d) Compressed air from the incoming 16-in. air main. (e) Water, both unfiltered and filtered; and the disposal of the following effluents:(f) Sewage from the area to the town sewage system.(g) Changehouse shower water to the regeneration area.(h) Storm water to the general mine surface drainage system leading out to the naturally drained area north of the No. 8 Shaft.

Jan 1, 1957

Conventional narrow vein mining, utilising hand held methods, is expensive and requires specialised miners who are becoming a rarity. Hand held mining techniques (shrinkage stoping, leading stoping and cut and fill) have the advantage that they can be selective. The methods allow continued sampling of the face, control of hanging wall conditions and are adaptable to changes in strike and dip. On the other hand, more productive longhole stoping methods can allow excessive dilution due to drill hole deviations and changes in orebody dip and can be subject to unexpected hanging wall or footwall failures. Development of small scale equipment (as narrow as 0.8m wide) used for drilling or bogging very smallaccess drives has been ongoing over the past decade. In this paper, types of equipment are examined and compared, particularly with respect to their produc- tivity, size, and working environment. The introduction of electric hydraulic equipment has provided a better working environment with reduced noise, exhaust fumes and heat. The concept of the "hydraulic cherry picker" may have application in mining steeply dipping orebodies. The system requires orebodies to be reasonably consistent in dip over 15 metre sub-level intervals. The system involves the basic concept and skills of machine and airleg mining, combined with the safety and productivity of a mechanized work platform. The platform or basket is stabilized between the hanging wall and foot- wall by hydraulic rams and is extended by a tilting hydraulic boom mounted to a small prime mover or trailer. Design concepts (including remote controlled charging of explosives, adaptation to the boom for rock cutting and the overall electric hydraulic mining concept) are put forward in the paper as a view as to how narrow vein mines will be mined in the future.

Jan 1, 1987

By Nye P. B, Fisher N. H

At the second Empire Mining and Metallurgical Congress held in 1927, the Empire Council of Mining and Metallurgical Institutions was formed and it was proposed that the Council take steps to prepare a "Review of the Mineral Resources and Industries of the Empire." At the third congress in 1930, it was resolved that the proposal to institute the review should be submitted to the Imperial Conference held in 1930. This was done, and the Minerals Committee, of the Imperial Economic Committee compiled, an interimreport which was based on statistics of imports and exports, and did not consider resources and consumption.In 1942 the Institution of Mining and Metallurgy, London, wrote to the Empire Council and stated that it was desirable that the Council should be in a position to take part in decisions affecting the future of the mining and metallurgical industries. The Council communicated with the constituent Institutions regarding the nominations of two members then in England. Subsequently the Mining, Geological and Metallurgical ,Institute of India prepared a review of the mineral resources and industries of India and their post-war development, and the Empire Council forwarded a copy to the Australasian Institute of Mining and Metallurgy and asked if that Institute would submit a review on simjIar lines for Australia. The Australasian Institute arranged that the Australian review should be prepared by...

Jan 1, 1946

By Toro HCH, Von Borries GH

A brief description of the semi-autogenous grinding (SAG;) facilities of Compania Minera Disputada de Las Condes is given. A data-logging and computer system was connected to the plant inter facing the existing analog control system in a supervisory s, control philosophy. The development of a control straiov,v t,) maintain maximum power of the SAG mill atsubjected to process restrictions is shownThe present control scheme is discussed inalgorithm was designed based on correlations onLween vartaoles. Associated with this, a direct level of control was developed be, on classical control algorithms, process inter-active tuning has been included. Also, an algorithm to prevent overloading of the is discussed. Control scheme tests are presented in comparison t manual operator control under the same conditions. It is shown t the control strategy gives a more stable operation and a higher plant throughput.

Jan 1, 1985

By J S. Laskowski

Froth flotation process requires the use of frothers. These important flotation agents are commonly characterised as either æselectiveÆ or æpowerfulÆ and are chosen following general guidelines and verification by laboratory and/or pilot plant tests. Fundamental properties of the flotation frothers have been extensively studied over the last few years. These studies have led to the development of standardised procedures to characterise frothers in terms of their ability to reduce bubble size and to increase foam stability. In this research project, the performance of five frothers in flotation of coal is evaluated and related to the fundamental properties of these agents. Since the recovery of water in the concentrate is closely related to the non-selective transport of solid particles by entrainment, the tested frothers are also assessed in terms of their ability to promote the transport of water towards the froth collection zone, both in absence and in presence of solids.

Jan 1, 2005

By Valenta R. K

A technique is presented for the integrated forward modelling of the three-dimensional structure and the geophysical response of multiply deformed terrains. This technique allows information collected by field geologists and geophysicist to be reconciled by the development of a simplified kinematic structural history of the area. The structural modelling simulates the deformation history of the area in terms of a succession of structural events, such as folds, shear zones and intrusions. The interaction of these events with a starting stratigraphy results in the prediction of the geometry of the structures. By specifying geophysical rock properties for the units in the initial stratigraphy predictions are possible for the potential field anomalies for gravity and magnetics. This approach is suited to a range of applications, and its uses in the modelling of regional structures, testing of geophysical data processing, volume balancing, multiply constrained inversion and training are discussed.

Jan 1, 1995

Standards in the public reporting of resources and reserves in Australia have dramatically improved since the implementation of the Australasian Code for Reporting of Mineral Resources and Ore Reserves (The JORC Code) in 1989. Whilst the JORC Code states clearly that Mineral Resources and Ore Reserves are imprecise calculations and should be treated as estimates, there is strong evidence that many people regard them as fact, including some accountants, directors, auditors and investors. Mineral Resources and Ore Reserves are key inputs in the valuation of a mining company and the determination of financial performance. Geological knowledge is the foundation upon which Mineral Resources, Ore Reserves and investment decisions are made, however this information carries with it substantial uncertainty. Case studies and company reports have established that errors derived from inadequate geological inputs have led to reduced profitability in operating mines and in extreme cases the premature closure of mine operations. Whilst there are many causes of mine closure and reduced profitability, including commodity prices and exchange rates, the cumulative effect of all geological uncertainty contributes significantly to the erosion of the credibility of mining within the investment community. There are a number of methods used to characterise and model uncertainty in Mineral Resource and Ore Reserve estimation. Empirical mining indexes, sensitivity analyses, Monte Carlo simulations and Conditional simulations are used to identify and estimate geological uncertainty, notably the quantification of uncertainty in grade and tonnage estimates. These techniques have not generally been applied to estimating geological uncertainty associated with key Ore Reserve inputs such as appropriate mining technique, equipment selection, production rate, mining dilution, stability requirements, materials handling, metallurgical processing, product quality and waste storage. New software tools are needed to model the entire mining process with all its geological and other interdependencies, enabling all uncertainties to be separately identified and estimated. By its very nature, mining involves the assumption of significant technical, financial, political, environmental and social risk. Success comes by understanding and managing these risks and consequently the mining industry will never choose to reduce the level of geological uncertainty to nil. The ultimate aim of improved identification and estimation of geological uncertainty is to quantify inputs into the Ore Reserve process, allowing a company to assess the risks and manage these accordingly. This approach is relevant to feasibility studies for new projects as well as life-of-mine planning through to the weekly schedule at existing mines.

Jan 1, 2003

By Schon RW, Stephens CJ

The Whitsunday Volcanics occupy most of the offshore islands from the Whitsunday Group, southeastwards through the Cumberland and Northumberland Groups, possibly extending to the mainland adjacent to Shoalwater Bay, a distance of 370 km. Some of the islands of this group are granitic, but preliminary Rb-Sr data indicate these to represent Permo-Triassic basement. Cretaceous volcanism is interpreted to have occurred during initial rifting prior to the continental breakup of northeastern Australia and subsequent development of the Tasman Basin.The volcanics comprise mainly lithic ignimbrites, with local development of inter-bedded surge and bedded tuff, accretionary lapilli tuffs, lithic concentration zones, and lag deposits. Isolated fluidual rhyolite and dacite domes occur. The deposits are considered subaerially emplaced. A Rb-Sr isochron age for volcanism of 110 Ma is determined from new data. The total thickness of the volcanics is unknown, but a minimum thickness of 4-5 km on Whitsunday Is. is suggested. Eruptive centres are inferred to be distributed throughout the volcanic zone. The volcanics are cut by numerous, dominantly near N-S, dykes ranging from dolerite through to rhyolite in composition.Chemically, the volcanics and dykes exhibit a continuous range of compositions from basaltic andesite, through andesite, dacite, to rhyolite, with minor more alkalic compositions. Phenocryst mineralogy in the silicic rocks is mainly plagioclase, augite, and Fe-Ti oxides, with less frequent quartz and hornblende occurrence. Sr and Nd isoptic compositions for volcanics and dykes are close to mantle values. These data are tentatively interpreted in terms of a lower crustal magma arc source separated from the mantle only a geologically short time prior to Cretaceous magmatism.

Jan 1, 1990

By Singh T, Singh D. P

India has limited resources of coking coal. Most of the coking coal seams are located in Jharia Coalfield. These seams were worked in the past by the bord and pillar system in a haphazard manner, which has resulted in honeycombs of old working. Most of such areas are under fire. In order to meet the demand of coking coal in the 21st century, it is essential that the coal locked due to old underground workings is recovered fully by conducting opencast mining to an ultimate depth of 500 m. The major problem envisaged in conducting opencast mining in such areas will be the stability of pit slopes over voids and the behaviour of subsided material in the pit slopes. An attempt has been made to simulate this complex situation from a specific section of the rockmass of a mine in an equivalent material (EM) model. The old workings existing in upper coal seam (V) were simulated by developing staggered bord and pillar workings in two sections and depillaring them. Opencast mining was conducted for recovery of coal locked due to irregular working in coal seam V. The slope instability caused by intersection of the slope with the void, during frontal working (by shovel-dumper combination) was observed in various situations. In this paper, the technique adopted for simulation of a 125 m thick section of rockmass in an EM model is outlined. Adverse effects of staggered workings and

Jan 1, 1988

By Short KC

The Hunter Region, with a major part of the coal resources of New South Wales and a long history of coal mining, has experienced a rapid expansion of coal resource development in recent years. While there are inevitable conflicts between mining, urban development and related infrastructure, and between mining and other resources, the application of sound planning practices, and improved co-operation and co-ordination among the various parties, helps to reduce such conflicts. The planning process involves consideration of factors such as transport- ation (including port facilities), mine subsidence, provision for surface facilities, a,iC the need for buffer 'ones. In addition, provision must be made for urban expansion, often co-existing or in close proximity to present or future coal mining development. Approval of coal mining developments takes place within the legislative framework of the Environmental Planning and Assessment Act, 1979 (EPA Act), the Coal Mining Act, 1973 (CM Act) and the Mining Act, 1973. Considerable effort has gone into stream- lining and co-ordinating the procedures under these Acts. The EPA Act provides for regional and local environmental plans, as well as a linked process of development control and environmental impact assessment. The CM Act provides for the grant of exploration and coal mining titles and mechanisms for the responsible management of Mining.

Jan 1, 1987

By Mason D. O, Tuckwell K. D

Whole rock geodhemical analyses from samples of Potosi gneiss within the Willyama Supergroup have been utilised to identify geochemical trends towards Pb/Zn ore positions. Although the analyses come from disparate sources they have been incorporated in the data base only if locational, sampling, analytical, lithological and stratigraphic descriptors were reliable. These data have been statistically analysed using programmes of the GASP software package. A discriminant function has been derived which permits Potosi gneiss associated with the Pb/Zn lode horizons in the Broken Hill domain to be distinguished from Potosi gneiss in a similar stratigraphic position in the Maybell Domain. In the "near ore" position the Potosi gneiss has significantly lower mean Na2O and significantly higher mean MnO. Also mean Rb, CaO and K20 are higher and mean Sr lower. This discriminant function serves to identify areas prospective for Pb/Zn mineralisation. A second discriminant function based on MnO, Si02 and K20/Na20 gives a semi- quantitative indication of proximity to ore.

Jan 1, 1983

Over the past 15 years many world-class gold discoveries have been made in the region. Some deposits, such as Lihir and Porgera in P.N.G., have a contained gold resource that places them among the top dozen deposits ever found on a worldwide basis. Can we see any pattern to these discoveries, or are they the result of good luck or chance by geologists and prospectors who struck it rich? Whilst such discoveries were a feature of the gold rushes of the 1850s and the 1900s, the present boom is now scientifically based. This paper develops an argument that long-tent, multi-disciplinary exploration by experienced geoscience teams underlie the successes achieved. Dis- coveries nearly always reflect a combination of skills, drawn from the areas of geology, geochemistry, geophysics and remote sensing, and a team approach. They do not represent the chance finds of a prospector's pick or such as the Norseman discovery where the gold reef was first noted by the prospector when his horse fell over the outcrop. The following deposits provide major examples of exploration successes within the Australian-Pacific region, it is not an exhaustive list and I have noted other significant producers at the end of this paper. For the Australian mines listed and based on our estimates for 1990 gold production, they represent about 20 per cent of the Australian production total.

Jan 1, 1991