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By Marsham B, Baker D. C

The expansion of New Broken Hill Consolidated Limited (NBHC) concentrator necessitated the installation of hydrocyclone classifiers where rake classifiers had previously been used. Commissioning of the circuit and optimisation of circuit performance has highlighted problems related to classification of sulphide minerals. Testwork initiated to solve these problems has been used to develop cyclone models which have been incorporated in a ccnputer control strategy for the grinding circuit as a whole. The modifications to the circuit during the commissioning phase and the control philosophy are outlined.

Jan 1, 1983

The environment under discussion is that of the sandy coastal plain and adjacent offshore sandy islands. The environment is the result of natural forces of the past which moulded it. Only very recently have men and machines participated in this moulding. The future of the environment - the changes which it must undergo - is in the hands of natural forces with, presumably, man's continued participation. In essence, we are concerned with the forces operating on a mass of sand.

Jan 1, 1971

Portman Mining Pty Ltd very successfully operated the Ferro GullyNorth Mine in the Hamersley Province of Western Australia to satisfy a contract for the delivery of six million tonnes of iron ore in less than two years to the Mount Newman Mining Co Pty Ltd. The high-grade ore extracted from Ferro Gully North Mine was unusual in that, not only was it within the Joffre Member of the Brockman Formation, but it was rich in red ochreous hematite and martite and very low in phosphorus.

Jan 1, 2001

The Bowen Basin of Central Queensland covers a total area of 3 200 000 ha. The Basin has proven reserves of about 24 000 000 tonnes of coking coal and steaming coal which constitutes about 70 percent of the known coal reserves in Queensland. Large scale open cut coal mining in the Bowen Basin commenced at Moura in 1959. There are now 16 open cut mines operating in the Basin and they collectively mine through about 3000 ha of land each year. Most of the land which has been mined has previously been used for extensive grazing. No mining has yet taken place on cropping land although coal reserves underlie land which has been cropped or has potential for cropping. The primary objectives of almost all of the mining companies operating in the Bowen Basin are to rehabilitate mined land to a stable and productive form which is compatible with surrounding land use which is dominantly grazing. The acceptability of these objectives is considered against the prospect of mining of cropping land and the qualified success of the return of rehabilitated land to grazing uses.

Jan 1, 1987

All sections of our community are becoming increasingly aware of the dangers of uncontroll- ed erosion associated with modern earthworksy whether they be concerned with the protection of capital structures, reforestation of mine tailings or generally the aesthetic and ecol- ogical impact. Because of the many ecological variances and climatic conditions no single technique may be offered as the complete answer. Rather that a combination of a series of techniques is nec- essary to achieve an individual end result. These techniques may appear to be expensive initially, but when considered in relation to the overall cost, and we realise that this work represents our only insurance of the stability of our project, the cost of stabilisation is insignificant. Once erosion has commenced the cost of stabilisation escalates dramatically which highlights the definite need to include the requirement of stabilisation in early design of your projects. Stabilisation should commence during construction to ensure that control of mobile soils is gained at the earliest possible time.

Jan 1, 1976

By P G. Fuller

The Woodlawn Mine near Canberra faced the challenge of poor ground conditions from the commencement of underground operations 1987. Talcose shears bounded the dense massive sulphides on both the hangingwall and footwall side of the orebody. In another area the talc existed not only on the edges of the orebody but through out it as well. The country rock was relatively weak shales compounded by a low stress environment that allowed the wall rocks to fall apart quite easily. The challenge for the operators was to overcome the poor ground conditions. This was done by attacking the problem from three directions:technology, how technology is applied, human relations and leadership by all levels of the Management team, and by ensuring that these processes meshed together well.Woodlawn in it early days as an underground mine enlisted the assistance of BFP (Formerly Barrett Fuller and Partners) as a second set of eyes to assist with the assessment of the ground control procedures. The results are discussed in this paper. The progression to this end result included:non-contract payment systems; ground control training for the full range of mining personnel; the development and enhancement of cable bolting and shotcreting equipment; the development of Practical Standard Work Procedures by mine operators; and innovative use of shotcrete and cables bolts to control extremely poor ground conditions.

Jan 1, 1998

Although geophysical methods of prospecting have proved indispensable in the search or oil deposits elsewhere; it is only 'in recent years that they have been used to any significant extent in Australia. The increase in their use has been quite remarkable over the past two or three years, due in Sao small measure to the encouragement given by means of Commonwealth subsidy. There is no doubt that the use of' geophysical methods will coxi-tinue to increase and this increase could be greatly accelerated as and when oil is discovered in commercial quantities,This review of their use A in Australia and the remarks and statistics are confined to work on the mainland. There has been, a substantial amount of geophysical work in Papua, but as operating conditions are so very different to the mainland Papua has been regarded as a separate province.

Jan 1, 1962

By P Hayes, B Zhao

A range of materials are treated in zinc fuming processes to recover metal values and produce benign slag waste products. The selection of the optimum process conditions in these various technologies can be greatly assisted by the use of a chemical thermodynamic model of the system. In this paper the effects of slag chemistry on the liquidus temperatures, subliquidus phase equilibria and thermodynamic properties are described by a FACT model of the ZnO-PbO-FeO-Fe2O3-CaO-SiO2 system. In addition new experimental data on the effect of Al2O3 on the liquidus are presented. The implications of these findings for plant practice are discussed.

Jan 1, 2000

It is a very great pleasure indeed to participate in this interesting and important seminar. My two visits to Australia in the past have been extremely pleasant and this one is equally so. My task is to tell you what has been happening in the United States, in these past few years especially, in regard to the management of our air resources and to present in some detail the difficulties we in the copper, lead and zinc smelting industries have been experiencing. The sudden upsurge in interest in air pollution in the United States is a strange phenomenon indeed - strange because we've had air pollution a long time, just as long as there have been large cities using fossil fuels for heating purposes. And the problem has been studied for quite a long time. As early as 1919 studies by the U. S. Bureau of Mines were done in Salt Lake City, where I .live. In the winter of that year extensive measurements were made of airborne particles - dust and smoke. The average concentration of particles found was 870 micrograms per cubic meter of air. A very large number compared to levels we find today. A microgram of course is a very small unit, one twenty-eight millionth of an ounce. A fine human hair two inches long weighs about 100 Micrograms.

Jan 1, 1971

Industry can achieve best results via thorough planning, consultatiion with agencies and local communities and a 'hands on' approach to' environmental problem solvingThe Department of Energy and Minerals, through its Minerals Group, has regulatory responsibility for the mining and extractive industries in Victoria. The role of the group is to facilitate the environmentally responsible development of these industries for the benefit of Victorians. It has a wide range of contacts with other government agencies, local government and community groups.The paper is in three parts; firstly, an overview of the nature and contribution of the mining and extractive industries in Victoria; secondly, the industries' regulatory framework; and thirdly, the environmental issues facing the industries and the management of these issues.

Jan 1, 1992

In the last eight years inclined conveyor haulage systems have established themselves in the mainstream for hard rock underground mine haulage. This leaves the question; what else might be on the horizon for mine haulage and how do we address the process of selecting haulage systems for new mines? This paper considers the identification of viable haulage technologies for underground mines and explores an approach for assessing existing and potential technologies. The example of a large deep mine is considered here. The evaluation of existing haulage systems relies on precedence and the assessment of the system capacity to meet the haulage requirements envisaged for a particular mining project. The assessment of potential technologies for mine haulage relies on the capacity to deliver a viable production-scale system within the timeline envisaged for developing a mining project. The haulage technologies addressed in this paper include: shaft hoisting,conveyor haulage,truck haulage,vertical conveyors, andhydraulic hoisting. This paper does not consider rail haulage out of a mine. This is simply because Australian topography typically has insufficient relief to bring them into consideration. However, rail haulage is a widely used and effective haulage solution in situations where significant topographical relief is present. The assessment of haulage system capability focuses on the following fundamental questions: How reliable are they? What is the degree of technical risk in a business context?What levels of flexibility do they offer?How capital effective are they? What returns are indicated by the balance of capital and operating cost estimates?

Jan 1, 2008

Fluid inclusions and sulfur isotopic compositions were studied in a possible extension of the Toyoha polymetallic vein deposit. The objective of this work was to gain a better understanding of the ore depositional conditions, sources of ore constituents, and distribution of mineralizing fluid in the region. Fluid inclusions in sphalerite and quartz show that most homogenization temperatures range between 190¦ and 290¦C. Most salinities range from 0.0 to 3.4 wt per cent NaCl equiv. Sulfur isotopic compositions of ore minerals (pyrite, sphalerite and galena), determined by a conventional technique, range between 1.3 and 7.7 per mil. The mineralizing fluids were characterized by relatively low and various temperatures and low to moderate salinities compared to those at the southeast region of the main ore bodies (Izumo and Shinano veins) where rare elements such as tin, tungsten and indium occurred. Obtained temperatures and salinities were attributed to the mixing of hydrothermal fluids with groundwater. Sulfur isotopic data suggest sulfide sulfur was of magmatic origin. Isotopic temperatures, estimated from the isotopic fractionation factor between sphalerite and coexisting galena, are between 195¦ and 322¦C. The temperatures are only consistent with fluid inclusion homogenization temperatures in sphalerite or coexisting quartz when sphalerite was a honey-yellow coarse crystal lacking conspicuous colored growth bands. This suggests the detailed classification of mineral pairs growth textures will be necessary for precise in situ measurements to obtain reasonable eothermometric results.

Jan 1, 2002

By L Grigorov, G J. Jame, A V. Nguyen

The dewetting kinetics between a small air-liquid interface and a silica (negatively charged in water) planar surface in solutions of dodecylammonium chloride (cationic surfactant) has been investigated using the Scheludko cell and digital high-speed video microscopy. The gas-liquid interface was created at the bottom of a small silica capillary of the cell and then was moved towards the silica planar surface. After the rupture of the liquid films between the interfaces, the expansion of the gas-liquid-solid three-phase contact (TPC) line was observed and recorded using a digital high-speed video microscope system, operating at 1000 frames per second. The surface tension of the surfactant solution was measured using the pendant drop technique. The equilibrium contact angle was measured using the Scheludko-Minings method with a silica micro-sphere. The TPC radius was determined as a function of time and compared against the available hydrodynamic and molecular-kinetic models. The experimental data are described very well by the molecular-kinetic model for the TPC line motion. The hydrodynamic model is in agreement with the experimental data only for a short time after inception of the three-phase contact expansion.

Jan 1, 2005

By S Wasi, J Tobiczyk, J Roszkowski

Methane and fire hazards have a vital effect on work safety and continuity of mining plant operation. In the 1990s, the SMP hazards monitoring and ventilation control systems, based on continuous measurement of air parameters, were put into operation at nearly 30 Polish mines. These systems provide continuous measurement of methane concentration within the range of zero to 100 per cent with automatic switching off of electrical energy immediately after detection of potentially explosive conditions. Early detection of coal spontaneous combustion and open fires is made by continuous measurements of CO, CO2, smoke and O2 content in mine air as well as temperature changes in air and rock mass. The essence of the system is intrinsic safety of all underground instrumentation and uninterrupted central power supply from the surface. All abnormal and critical states are signalled to the mine control room. These trigger alarm and emergency procedures. The computer based ventilation monitoring and control system also performs the function of an expert system for fire detection and underground fire fighting. The mine control operator (dispatcher) makes use of stored data in computer escape route schemes and procedures for the safe withdrawal of miners from hazardous areas. The operator can put in motion intrinsically safe alarm signalling units and banners with programmed messages indicating escape routes.

Jan 1, 2005

By J R. Hernandez-Aguilar, C O. Go, C Acuna

The gas dispersion properties that are the subjects of this communication include three measured parameters, gas superficial velocity (gas rate), gas holdup and bubble size, plus derived parameter, bubble surface area flux. Over the past ten years sensors to measure these parameters have been introduced and those originating from McGill University are briefly described. The sensors have seen extensive use in plant campaigns and experiences on four cell types at three sites are discussed. The impact of frother in controlling bubble size by retarding coalescence is illustrated, introducing the need to understand chemistry/machine interactions in interpreting gas dispersion results. An increase in Sauter mean bubble size (D32) with superficial gas velocity (gas rate, Jg) was found, which followed the empirical relationship where Do ~ 0.5 - 0.6 mm and C and n are fitted parameters dependent on the system (machine and chemistry). Following this trend in Db - Jg, consistent bubble surface area flux (Sb) - Jg trends are also observed. The trend in Sauter mean versus number mean (D10) is used to help interpret the nature of the distribution; as the means approach numerically, the distribution is narrowing. Analysing gas holdup versus gas rate shows both a dependence on location in the cell as well as cell position in a bank, factors which must be accounted for when comparing data from different plants and circuits. The instrumentation and methodologies being developed are presenting new opportunities for incorporating cell hydrodynamics into metallurgical diagnostics. A case study at one plant serves as illustration.

Jan 1, 2005

By A Purchase, C Stacey

The procedure for operation of deluge systems installed in road tunnels is still a subject of debate. The work undertaken in this paper assists in the understanding of the effects of deluge in road tunnels, and thus aims to help inform the development of operational policy. Analysis was undertaken using computational fluid dynamics (CFD) simulations to help explore the deluge interaction with the tunnel ventilation (including smoke exhaust) and combustion products. It was found, for the scenarios considered, that: Deluge activation can decrease the required critical velocity for smoke backlayering, and this in turn can improve the effectiveness of a smoke exhaust system.The dominant parameter for deluge effectiveness is the vehicle configuration, with shielded scenarios (such as a fire in the passenger compartment) showing almost no water reaching the fire. The water delivery rate (5 mm/min versus 10 mm/min) has only a minor effect on the smoke duct damper inlet temperatures and downstream smoke temperatures for small fires (5 MW). For large fires (50 MW) the higher water delivery rate gives slightly improved performance (lower damper inlet temperatures and lower downstream smoke temperatures). A one-dimensional transient tunnel model incorporating different operational and deluge response policies (ie deluge activation times) was developed. It was used to examine the influence of different operational parameters on life safety risk and tunnel damage risk. It was found, for the scenarios considered, that: The life safety risk for different scenarios has a sensitivity to deluge activation policy with the case of delaying the deluge activation for a long time giving the worst outcomes. However, the most critical parameters for life safety risk are operator response time (for all response activities, not just deluge) and the type of fire (configuration, size and growth rate).There is a reduction in risk of tunnel damage when the deluge is activated earlier, although the fire configuration (ie whether or not the seat of the fire can be reached) has the greatest influence on the outcome. It is concluded that the deluge activation policy should be case-dependent. It will depend on the tunnel, the safety systems provided, and most particularly the vehicles involved. The current policy in Australian tunnels is for manual activation of the deluge by the tunnel operator as soon as practical after the fire is confirmed (see also PIARC, 2007). This is a good policy. However, future work may be helpful to improve the skills of operators to make the best judgement as to when deluge should be activated, balancing all risks. This work could include research to further the understanding of deluge and fire in road tunnels, training programs and consideration of historical fire events.

Jan 1, 2008

Western Deep Levels, a seismically active deep level gold mine, started placing backfill in their narrow tabular workings as part of the regional support strategy in 1986. Over the years the percentage of working places being backfilled has been gradually increasing. At the end of 1995 the support efficiency and the labour productiveness relating to support installation were scrutinised to determine if resources were being optimised. Owing to financial, safety and productivity constraints it was decided to redesign stope support to be less labour intensive, safer and provide an integrated stope support system. This new integrated system will thus combine the previously used temporary, permanent and back area support consisting of mechanical props, hydraulic props and backfill respectively. Backfill previously formed an integral part of the regional support in conjunction with strike stabilising pillars. To design the integrated support system the backfill placement quality has to be exceptionally good and placement must be done as close as possible to the working face. The backfill to face distance was reduced by 30 per cent and in some areas by more than 50 per cent with an increase of square metres filled to increase the effect of the backfill even more. This paper addresses the design and successful implementation of an integrated stope support system based on the optimisation of backfill to the extent where installation of mechanical and hydraulic jacks could be eliminated.

Jan 1, 1998

By N DavT

Pyritic tailings from the Quirke mine waste management area in Elliot Lake, Ontario were subjected to long-term column leaching experiments in two PVC columns measuring 122 cm in height and 15.2 cm in diameter. At the end of the leaching experiments, the columns were taken apart and sampled at 5 cm intervals for quantitative mineralogical and geochemical characterisation. Each column is represented by a total of ten samples. Polished sections, prepared from the samples, were studied by optical microscopy, scanning electron microscopy, electron microprobe and X-ray diffraction techniques. Mineral quantities were determined based on linear mixing models of whole rock and mineral compositions. Pyrite particle sizes were measured by image analysis interfaced to an electron microprobe. The tailings are coarse-grained (ie 96 per cent passing 75 ¦m) and composed of quartz, K-feldspar, muscovite and pyrite. Pyrite is homogenous and occurs as liberated particles displaying angular to subangular boundaries with strong dissolution features at the end of the leaching experiments. Based on up to 3518 particles measured in a sample, pyrite particle sizes range from 1.7 to 78.6 ¦m. Pyrite concentrations vary from 0.1 to 7.8 wt per cent, depending upon their location from the top of the columns. These correspond to pyrite losses of up to 99 per cent from their original level of 7.2 wt per cent in the upper half of the columns. Pyrite oxidation rates in terms of moles of pyrite oxidised per mole of pyrite per square metre per second were calculated from the effluent data and the measured pyrite particle sizes. The rates vary from 1.71+10-12 to 5.78+10-10 mole+m-2+s-1 within the 1.5 to 3.5 pH range for 10 ¦m particles. These results are comparable with the published oxidation rates at pH 2 where the dissolved oxygen is the only oxidant.

Jan 1, 2003

By S F. Wang, J J. Yin

Dust pollution poses a persistent challenge within mining processes, giving rise to a spectrum of concerns, including occupational diseases, mechanical degradation, diminished visibility, and the potential for dust explosion incidents. Existing dust detection and monitoring methodologies face limitations, including insufficient measurement accuracy and intricate processing procedures. Consequently, a comprehensive identification and evaluation system rooted in image processing technology is proposed to facilitate real-time measurements of dust pollution in mining worksites. The study primarily employs grey scale average and fractal dimensions to characterise particle features evident in collected dust images. As a result, the data processing platform can dynamically process data and present dust pollution conditions. Notably, this research integrates the monitoring and assessment of dust pollution with the systematic adjustment of mining parameters, ventilation parameters, and strategies for dust reduction. Through statistical analysis of dust concentration and particle size during mining processes, rock properties such as components and cuttability can inform mining parameters. This information, in turn, guides detailed excavation strategies, including cutterhead speeds, torque, and excavation speed. Similarly, analysing dust characteristics derived from images is a valuable resource for gaining deeper insights into the efficacy of implemented ventilation strategies. By harnessing vision-based information detailing dust concentration and distribution, a wealth of direct guidance becomes available for refining ventilation parameters. This encompasses crucial aspects such as the selection of appropriate ventilation systems tailored to the specific mining environment and the optimisation of operational conditions for ventilation fans. Additionally, the detailed information derived from the visual data allows for strategic decisions on factors like the spatial arrangement of ventilation outlets and the calibration of airflow rates. Moreover, precise choices for dust reduction measures and parameters can be made based on the prevailing dust conditions. Upon real-time monitoring of dust pollution using the proposed method, corresponding measures such as spraying and foaming can be promptly implemented. Crucial parameters, such as spray angles and volume, are integral to these application processes. In essence, the proposed method assumes a pivotal role in not only dust monitoring but also the formulation of preventative and control measures within mining processes.

Sep 1, 2024

By I Mason, G Turner, J Hargreaves

One of the key objectives in production from any mine is the minimisation of ore loss and dilution. This can only be achieved when the distribution of ore within the mine is known. The distribution of ore is usually evaluated from a combination of drill hole information and underground mapping data. Three-dimensional models of the ore distribution are then constructed by interpolating grades, contact locations and confirming these estimates through mapping. While the interpolation procedure can incorporate an understanding of the local geological conditions, it is an approximation and thus susceptible to some degree of ore loss or dilution. Naturally, such problems increase in areas of sparse geologic information or greater geologic complexity. Borehole radar offers an approach to decrease the interpolative aspects of modelling by providing a continuous image of some ore contacts. Borehole radar works by building a two-dimensional image of an ore contact from radio waves bounced off the contact from closely spaced positions along a borehole. This image can be imported into Datamine (or a similar design package) and incorporated into geological models of a given ore block. The results of a trial survey from the Mariners nickel mine at Kambalda are presented to illustrate the improved level of detail and accuracy that can be achieved through the incorporation of borehole radar into orebody delineation practice. Once implemented on a large-scale this technique has the potential to greatly increase the cost-effectiveness of long hole stoping at Kambalda, through increased ore recovery and reduced dilution.

Jan 1, 2000