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A study is presented of the theoretically possible initiation systems for outbursts and the subsequent propagation mechanism.Previous occurrences of outbursts and their correlation to the theoretical system are described. An estimation of the energy release from two energy sources, gas strain energy and rock/coal strain energy, is presented and the relative importance of each source in the severity of outbursts. Summary: The description of mechanisms of outbursting follows the examination of these phenomena at Collinsville in Bowen No. 2 mine and at Leichhardt Colliery, Blackwater. Quantitative material contained in the paper refers to Leichhardt Colliery, Blackwater. Clearly from the work carried out to date gas release has a major part to play in the out- bursting at both of these collieries. In the case of the December 1 1978 outburst at Leichhardt Colliery energy release estimates place gas strain energy release contributing eight times the energy of that from rock/coal strain energy. Even the normal outbursts at Leichhardt Colliery appear to show this trend. Estimates of energy released are for comparative purposes between gas and rock strain energy and the values obtained may be regarded as approximate.

Jan 1, 1980

Geological information plays a significant, cost effective role, in the Mt Whaleback iron ore mining operations. The geology and structure are complex. Good communication between the Mine Planning Production Scheduling and Quality Control Sections is the key to utilisation of geological information to its full potential.Drilling and pit face mapping are the two basic sources of detailed data sets which are processed to prepare up to date geological cross sections and benchwise geological plans. This information is used directly for the blast pattern design and production scheduling. Physical ore type estimation is also undertaken. Orebody models are generated from the geological information.

Jan 1, 1990

By Schofield D

The problem of production scheduling is sufficiently complex to negate the use of many conventional optimising techniques as there are numerous and diverse factors that must be considered when trying to produce an optimal schedule. These factors include: grade distribution, orebody geometry, production rate capacity, processing constraints and market price of the minerals amongst a variety of others. In addition it may be observed that many of these factors incorporate a degree of uncertainty and any schedule produced must inevitably consider risk as a primary consideration. The very nature of the problem has limited the use of conventional optimisers. Genetic algorithms use methods based upon evolution and natural selection to produce `optimal' solutions to complex system problems. They are extremely flexible and robust in their nature and it is these characteristics that are important in this particular problem domain. A particular strength of the genetic optimisation approach is the ability to handle the multiple and non-linear constraints that are typically encountered in mine scheduling problems. This paper concentrates on the development of a prototype application of a genetic algorithm to the problem of scheduling the output from multiple production points in an underground mining operation. In particular it.describes a system (GO-SCHED) that can be customised to handle a wide variety of underground scheduling problems. GO-SCHED, a Windows-based system, can interface with a variety of databases and spreadsheets for data input and output and provides a simple intuitive approach to the solution of the scheduling problem.

Jan 1, 1995

By Bearman R. A

The majority of published material regarding the operation of crushing machinery is concerned with simulation of performance rather than design of equipment. The reason underlying the bias in published material relates to why research is carried out and who undertakes the research. Two distinct types of research can be identified: 1. Internal research by crusher manufacturers - generally related to mechanical design, value engineering and to the commercial realities attached to sales demands. Any work on basic crusher geometry or rock/machine interaction is of a sensitive nature and rarely enters the public domain. 2. Academic research - mostly confined to modelling of crusher performance and simulation. This is not because of any bias, but crusher design requires access to manufacturers data or at least an in-depth understanding of crusher design, which is rarely available. The crushing of rock is a complicated problem. It involves three aspects; the machine geometry, the material composition (type of rock/feed size distribution) and the machine/rock interaction. The machine geometry is often ignored in empirical mineral processing simulations, while the response of different feed materials is only nominally addressed in machine specifications provided by manufacturers. The manner by which the machine produces a stress field and causes different types of breakage for different rocks (or the machine/rock interaction) is sadly neglected by both groups. All three aspects must be considered collectively to successfully understand and model the entire crushing process. 1. Centre for Mining Technology and Equipment, Julius Kruttschnitt Mineral Research Centre, University of Queensland, Isles Road, Indooroopilly 4068 Qld. The importance of crushing is often underestimated. In mining and mineral processing the invisibility of the crushing process is understandable as it merely provides a coarse reduction stage prior to the intricacies of mineral extraction. However in the quarrying industry crushing and screening basically provide the finished product. A brief overview of the quarrying industry shows the importance of crushing. Figure 1 gives production figures for most of the western European countries, Australia and the USA.

Jan 1, 1995

By R M. Tosdal

Intrusion related ore deposits are widespread in the Central Peruvian Cordillera Occidental and adjacent high-plains to the east and include porphyry Cu (-Au, Mo; eg Morococha), Cu-Zn (Pb-) skarn (eg Antamina), Pb-Zn-Ag carbonate hosted vein deposits (eg Uchucchacua), cordilleran base metal (eg Cerro de Pasco) and epithermal deposits (eg Quicay). Geochronology and petrochemistry of intrusive rocks associated with mineralisation reveals that: most ore deposits were emplaced in the late middle to early late Miocene; and are related to calc-alkaline granodioritic igneous rocks with Sm/Yb >3, Sr/Y >40 and Y/Th <1.5. The largest deposits, including Antamina, Colquijirca and Cerro de Pasco are associated with intrusions with Sm/Yb >4 and which, as indicated by Pb and Sr isotopic data, have undergone relatively moderate middle and upper crustal assimilation. The chemical signature of igneous rocks related to mineralisation likely reflects melt equilibration in the lower crust at a crustal thickness of more than 45 km. Mineralisation was favoured by a change from normal to flat subduction, resulting in increased compression, crustal thickening and subsequent cessation of the magmatic arc. Premiocene ore deposits do occur, but are restricted to a broad E-W corridor between Uchucchacua and Milpo and probably were controlled by a crustal-scale structural discontinuity across the strike of theAndes. Not all igneous rocks with high Sm/Yb and Sr/Y ratios did acquire their trace element signature in the lower crust. Petrographic and Pb isotopic evidence indicates shallow crustal hornblende fractionation or assimilation of pelitic material as possible causes for high trace element ratios in some rocks. These are apparently unrelated to polymetallic mineralisation. Thus, critical evaluation of petrographic and geochemical data in metallogenetic studies, especially in areas with complex basement architecture such as Central Peru is critical and should not be reduced to simple trace element ratios. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

The fragmentation of whole rock by blasting has an influence on the subsequent loading, hauling and crushing operations. However, no method of calculating the frag- mentation has yet been developed. This paper gives a method of calculating the fragmen- tation for the simplest form of blasting, i.e. cratering. Cratering consists of the detonation of a spherical charge of explosive in a blasthole breaking to one free surface. This paper gives a method of calculating the extent of the system of radial cracks generated by the explosive in the rock. This system of radial cracks is then used to calculate the fragment size distribution curve from blasting. The calculated curves are shown to be in good agreement with experiment.

Jan 1, 1977

Depletion of shallow ore reserves is forcing the South African gold mining industry to exploit reefs at ever-increasing depths. By 2010 around 30 per cent of South African gold production probably will come from depths greater than 3 km (Johnson and Schweitzer, 1996). At such depths, virgin stresses will rise significantly, producing complex rock engineering problems (Malan and Basson, 1998). Concern over structural instability at depth has led planners to seek a technology capable of ædetection of geological structures with a displacement of 2 m or greater (or as appropriate to the mining technique) 200 m ahead of mining at an acceptable costÆ. Borehole radar probably is such a technology. Cover holes are drilled routinely ahead of development. The evaluation of its candidacy for a tactical role in ultra-deep gold mining dependsùamong other thingsùupon establishing the electromagnetic characteristics of the environment hosting significant gold reefs. The Ventersdorp Contact Reef (VCR) is one such reef. Recent borehole radar field trials, presented here, suggest that the VCRÆs overburden is a remarkably translucent, clutter-free dielectric with a Q of ~35 and that the VCR itself is the dominant radar reflector.

Jan 1, 2002

While the potential for the discovery of new high grade resources exists, it is almost inevitable that the ore resources used to provide society's ongoing demand for primary metals will deteriorate over time as the higher grade reserves are exploited first and are progressively depleted. This deterioration in quality of metallic ore resources will bring about significant interactions with other resources such as energy and water, resulting in an increase in the amount of these resources required per unit of primary metal production. In this paper it is shown that as ores deteriorate in quality, the contributions of the mining and mineral processing stages to the life cycle-based embodied energy and water of primary metal production will increase significantly. Therefore efforts to reduce the impact of deteriorating ore resources on energy and water consumption should focus on these stages.   The results from life cycle assessments of the production of various metals by a number of different processing routes, particularly copper and to a lesser extent nickel, have been used to identify a number of opportunities and technologies for reducing the energy consumption in the mining and mineral processing stages, including: comminution, eg high pressure grinding rolls, stirred mills, ore sorting, preconcentration, advanced blasting techniques, advances in diesel technology for loading and hauling, alternative processing routes, eg heap leaching, in situ leaching, water treatment and re-use, water quality 'fit for purpose', dry processing, floating modules to reduce evaporation, and paste thickeners. All the above and existing developed flotation technologies can impact on the mineralogy of the concentrate supplied to the smelter. Removal of gangue minerals early on in processing may have further downstream process implications on fuel and water requirements. The above technologies are in various stages of development, with some more advanced than others. However, all can be expected to play their part in improving the sustainability of the Australian mining industry.

Jun 1, 2010

This paper covers only the energy uses of natural resources and does not deal with non- energy uses, which in 1975 were of the order of 10 per cent of the total consumption of energy resources. The United Nations `J' Series of Statistics ex- presses each of the various forms of energy in terms of its coal equivalent in metric tonnes and this basis is followed in this paper. One tonne of black coal (referred to as tce) has been taken as the equivalent of the following. 29 X 109 joules or 27.5 X 106 Btu 0.68 tonnes or 4.8 barrels of crude oil 750 cubic metres or 26.5 X 103 cubic feet of natural gas 1 ò5 to 3.3 tonnes of peat or lignite (world average 2.54; Victorian brown coal 3 0) 8055 kWh (at 3.6 X 106 joules or 3412 Btu per kWh at 100% efficiency) 2660 kWh at 33% efficiency of generation 50 grams of uranium present in natural uranium reactors (see note later under nuclear energy) 0.8 grams natural uranium in breeder reactors Nuclear and hydro electricity are expressed as the coal equivalent required to produce, at 33 per cent efficiency, the same amount of electricity. In other words, electricity produced by these sources is converted to its coal equivalent at the rate of 2660 kWh = 1 tonne coal.

Jan 1, 1978

By A W. Bewsher, T C. McCu, D B. Mapleson

The Miitel nickel sulfide deposit has been overprinted by a family of late stage structures that have acted as conduits for fluids that have contaminated the orebody with arsenic minerals. This has resulted in highly variable and unpredictable arsenic grades throughout the Miitel orebody. The ore produced from Miitel is processed under a toll-treatment agreement with Western Mining Resources Kambalda Nickel Concentrator. Part of this arrangement includes a financial penalty if monthly average arsenic grades in ore delivered exceed 800 ppm. This constraint has provided an extra challenge to the Miitel mine geologist in addition to daily underground duties. Routine development and stope mapping, close spaced sampling and cross-sectional interpretation were used in building an understanding of the structural controls of arsenic mineralisation and ore repetition at the Miitel nickel mine, and in providing maximum input to mine planning and scheduling. The distribution of structures responsible for arsenic introduction is now well understood from detailed mapping, sampling, and interpretation. By applying these insights to mine scheduling, the operation has successfully managed arsenic levels within the required specifications. Geological mapping has also improved the understanding of the structural complexity of the ore deposit, leading to the addition of ore tonnes and an increased confidence in resource modelling. Regular sampling and tight controls on data quality provided confidence in a strongly skewed arsenic data set. Multiple Indicator Kriging has been used for resource estimation of the arsenic contaminated nickel ore since it allows explicit control of the spatial influence of extreme grades in the positively skewed arsenic sample population. Both the grade control and exploration data sets are used to model the arsenic distribution.

Jan 1, 2003

The B.R.G.M., through international experience gained over many years, has become very skilled in alluvial prospection, particularly for diamonds. The research laboratories within the B.R.G.M. have also been active in creating new mineral processing equipment,. some of which is directly applicable to such prospection. One such development, the mobile prospection unit, is described and -its application in mineral exploration is demonstrated by a consider- ation of the diamond search in Australia and the general exploration of the Massif Armoricain (France). Because this latter study was fundamental in the development of the concept of "mineral-geochemistry", and its application in mineral exploration, it is also briefly described.

Jan 1, 1980

By R A. Bearman

Recent demand pressures for iron ore should not distract from the longer term view that intense competition in the industry has demanded technological innovation of a high order. There is a long track record of successful innovation underpinned by a solid base of scientific research and knowledge. By comment on recent developments in trucks, comminution and direct smelting, this paper suggests that innovation is still a key attribute of the industry. The spending of the minerals industry on underlying science, however, is not particularly high. By looking at other industries we can ascertain that for step change technologies, it is particularly advantageous to have a solid base of science and technology underpinning developments.

Jan 1, 2005

By Large RR

Underlying the 15 million tonne, high grade Hellyer volcanogenic massive sulphide deposit of western Tasmania is an extensive, well developed, and well preserved stringer system. Pervasive alteration of the footwall mafic volcanics occurred as the hydrothermal system initiated. Mineralogical zoning exists within the footwall alteration pipe, with a central siliceous core giving way to zones of chlorite, chlorite-carbonate, sericite-chlorite, and finally sericite-quartz on the margins (stringer envelope zone). However, the alteration morphology and zonation is not symmetrical around the central siliceous core; eastward the alteration zones are steeply dipping and terminate abruptly under the massive sulphide, while westward they extend out under the ore body in a blanket fashion. Geologic evidence indicates that the pervasive alteration started with the development of sericite-quartz which was subsequently overprinted by chlorite and finally quartz-sericite as the hydrothermal system became focused towards the centre of the stringer system.

Jan 1, 1990

By Brumley J

The development of the SECV brown coal open cut at Loy Yang will require depressurisation of aquifers both within and below the coal seam sequence in order to maintain open cut stability. Prediction of future open cut dewatering requirements at Loy Yang Open Cut and evaluation of the regional consequences of dewatering has required development of a detailed hydrogeological model of the Loy Yang area. The complex stratigraphy of the coal seam and aquifer/aquitard sequences at Loy Yang have been analysed and integrated with the hydrogeological concepts developed from regional groundwater studies to formulate a realistic hydrogeological model as a basis for finite-element flow modelling.

Jan 1, 1988

Over the past five years, dedicated tertiary mining engineering programs have become financially unsustainable in Australia on the basis of undergraduate enrolments alone. The situation is worse in other minerals related disciplines and extends to the technical minerals education sector. This paper reviews the causes for the current situation. Indicators are presented which suggest that enrolment trends can no longer be attributed only to business cycles in the minerals industry but are also reflective of a fundamental shift in student interest in the sciences and resources based engineering disciplines. Reactive responses to changing trends are diluting and compromising the quality of mining engineering education. It is unlikely that the trends can be reversed or resisted. Tertiary minerals educators need to position themselves so that they can be responsive to on-going change. Two proposals are offered which aim to anchor mining engineering in a long-term sustainable manner. The proposals have a common educational component which is concerned with restructuring how mining engineering programs are presented and providing more flexible access to such programs. However, the two proposals have significantly different commercial components. The commercial component of first proposal is concerned with working within the traditional education framework of universities to endow a critical number of core staff positions. It effectively equates to fund raising. The second proposal is concerned with developing a stand-alone commercial operation around the education and research advantages of the global and multi-disciplinary university system. As a shareholder in this business, a university department would earn dividends that it could then use to support its education initiatives. This proposal provides a performance-based mechanism for supporting university minerals programs and has the potential to be cost-neutral. Both proposals are suited to resource sharing with a select number of international mining schools and to the incorporation of the other tertiary minerals disciplines under threat.

Jan 1, 2000

By J Barnes

During September 2000, Nabalco management identified the need for a corporate system to deliver its key performance indicators (KPIs). In June 2001, a need was also identified to replace the existing metallurgical accounting system. After a review of the technologies available, the decision was made to develop the systems in-house, in preference to purchasing commercial software packages. This would allow much greater control over the structure, and provide for an iterative, concurrent development process between software and key business developers. This has proven invaluable in the development process. The purpose of the KPI system is to provide a unified reporting tool for all performance indicators. These indicators include production, safety, health and environment, personnel, costs, continuous improvement initiatives and opportunity losses. All of these disparate measurements are brought together into the KPI system and used to determine the performance for each department or area. The general principles of the balanced scorecard business approach (Kaplan and Norton, 1996) are applied to achieve a performance measurement for each area within Nabalco. The new metallurgical accounting system (MA) is a SQLServer database with web page and Excel interfaces. The database is structured around daily inputs of all measurements and calculations. The data is stored and adjustments and reconciliations can be made to this data as required. The focus is on accounting rigour, with all adjustments recorded in the database to allow for full auditing. The structure of the data focuses on the five input/output streams (bauxite in, caustic soda in, fuel oil in, residue out, and alumina out). In-circuit inventory provides a secondary measurement on which to check and calibrate the MA system. The KPI and MA systems were developed using Web technologies and are available to any internet-enabled device with Internet Explorer installed. This removes the need for software rollouts and user training. This will promote the wide use of the systems throughout Nabalco and Alcan.

Jan 1, 2002

Around 35 Mt of industrial clays were produced in 1994 under the broad classifications kaolin (25 Mt), bentonite (8 Mt) and attapulgite/sepiolite (2 Mt). A brief review of world sources and markets is given as background to Australia's small production (0.5 Mt) but developing interest in industrial clays. Clay markets have changed significantly over the past 30 years resulting initially in consolidation and expanded production from traditional high-grade clay sources but also creating opportunities for development of new discoveries. Decline in the use of clay-based refractories has come at a time of strong growth in demand for refined kaolin for the paper industry. Traditional markets for bentonite as oil drilling muds, iron ore pelletising and foundry bond sands are mature and in overall decline. Today, bentonite has a significant share of the growth market in pet litter which a few years ago was dominated by attapulgite/sepiolite clays. Both bentonite and attapulgite/sepiolite have good prospects for increased demand in environmental markets both in containment of hazardous wastes and sorption of toxic substances. In common with all industrial minerals, markets for clay minerals will demand continuous improvement in product quality and consistency. Development of new and improved products will be increasingly the responsibility of the raw material supplier. In order to remain competitive, this will require a substantial commitment to quality assurance and research and development. Increase in market share will come for those producers able to translate developments in their products to cost savings or increased competitiveness for the industries that they Supply.

Jan 1, 1997

By P Allum

This paper presents a case study to reduce the operational cost on the secondary ball mill circuit in the Lead/Zinc Concentrator at Mount Isa Mines. The circuit includes two five-metre diameter ball mills each closed with a cluster of ten 15-inch cyclones. The operating cost for both ball mills is about six million Australian dollars per annum.The concentrator achieves 75 per cent of the plant design capacity with one ball mill operating, but will have to use two ball mills when 100 per cent plant capacity is required. The optimisation study on the circuit identified a new flowsheet that enabled the concentrator to reach 100 per cent of the capacity by using one of the two secondary ball mills. The success of the project utilised the existing equipment rationally and saved the operational cost for one ball mill at full concentrator capacity. A further simplified secondary circuit is proposed using the IsaMill for the secondary grinding duty. Performance of the IsaMill circuit and the potential cost savings are predicted.

Jan 1, 2002

By J Lyons, S Baker, D MacHunter, D Pepper

Mineral processing plants require a storage buffer to bridge differences in production rates between mining and processing. Where coarse ores are processed, such as coal or hard rock, this buffer may be an ore stockpile or silo. For wet-mining processes, eg dredging or hydraulic mining, or where fine ores are slurried close to the mining face, a surge-bin is used to contain the plant feed and smooth out the variations in mining rates. These bins have gradually evolved from simple storage vessels to units that are now frequently part of the mineral separation process itself, such as providing a desliming function to remove deleterious ultrafine gangue. This feed conditioning is often essential to achieve the levels of plant performance required in times of declining ore grades and or where inherent ore characteristics make separations harder to achieve. To achieve these dual roles requires careful consideration of bin design factors such as geometry and lining selection and increased use of instrumentation and advanced, or remotely supervised, control systems. All this ensures they provide capacity to smooth out variations in mining rates and guarantees that when conditioning ores or adjusting slurry densities ahead of the plant it is achieved without loss of valuable minerals. This paper examines the evolution of the modern surge-bin from a simple, so called, constant density tank with its inherent mass-flow compromises, limited feed preparation and beneficiation abilities, and footprint penalty, to a current state-of-the-art surge-bin, the LFCU, with a control system which provides demonstrable steady outputs, while conditioning and in some cases beneficiating the ROM material and all from a highly compact unit. It further discusses their use in other applications around the world, for example providing the necessary security for long distant high-density pumping systems; constant high density, low water usage, tailings disposal pipelines and high capacity ultrafine iron ore beneficiation.

Aug 24, 2022

Prior to 1972, Peko Mines Limited at Tennant Creek used a central mill at Peko, which consisted of a gravity circuit, flotation and cyanidation of tailings, to treat their gold ore from surrounding mines. The Warrego concentrator, 60km to the west, was built to handle the Warrego and Gecko copper orebodies, which were being developed concurrently with the concentrator construction The Warrego concentrator consisted of a flotation circuit, using autogenous grinding at 100 - 120 tph, compared to the more elaborate Peko circuit employing rod mill - ball mill grinding capable of treating only 18 - 26 tph. During development of the Warrego copper mine a gold rich ore pod was located, because of which the mining plans were adjusted to allow simultaneous, separate extraction of the copper and gold ores. However, the plans for the concentrator were not affected as the gold ore could be carted 60km to the Peko central mill for processing.

Jan 1, 1978