Search Documents

This paper reviews factors involved in the feasibility stage of underground mine project development. Emphasis is placed on the need to first select the best method of extraction and make the most accurate assessment of the expected output even with the uncertainties which may exist in structural interpretation, ground stress, geotechnical factors, and industrial conditions. The subsequent engineering planning should be undertaken from the point of view of the face requirements and is subject to constraints imposed by the method of work and nature of the deposit and, in the case of access, to surface constraints and services.

Jan 1, 1983

The design of the grinding section is discussed and details are given of the equipment installed for the autogenous grinding of ores from the C.S.A. mine at Cobar.The first section of the concentrator commenced treating ore in June, 1965 and operating experience and maintenance requirements since that time are outlined.

Jan 1, 1969

By Rokot M

In a little over three years, Chevron Niugini has built up a team of relatively young, hard working men and women, mostly Papua New Guineans, who spend most of their working days out among people in the Southern Highlands and Gulf Provinces who are directly affected by the Kutubu Petroleum Development Project. These are Land and Community Relations officers, or LACROs. They take on a huge responsibility, not only representing Chevron but also being friend, advisor and negotiator, frequently dispensers of medicines, and agricultural advice and more. When things go well, others get the praise, when things go wrong, LACROs are the martyrs. Just as the geologists who locate the oil, the drillers who find it, the engineers who design the facilities, the construction gangs who build them, the landowners who claim it, and the Government who monitor it, so are the LACROs part of a team.

Jan 1, 1991

By S Bouzalakos, W Timms, H Malli

Combining ultramafic mine tailings and acidic mine drainage via mineral carbonation to sequester carbon dioxide, presents an opportunity to minimise waste on mine sites. Low pH mine water with trace element concentrations can be effectively treated by high magnesium mine tailings, a useful source of finely ground reactive matrix. By using milled tailings for mineral carbonation, there are negligible energy requirements for communition of ore rocks to reduce particle size. This study aimed to assess the technical applicability of reacting ultramafic tailings and acidic mine water through mineral carbonation technology in the mining industry. Dissolution has been identified as the rate limiting stage in mineral carbonation; hence the study focused on identifying optimal dissolution conditions. Ultramafic tailings (particle size <100 µm) derived from serpentinite ore, were reacted with a typical mine water that was synthesised in the laboratory. Through variances in the solid to liquid ratios and temperature of dissolution, a maximum five per cent magnesium dissolution efficiency was reached at 50 g/L and 100°C. The acidic mine water was neutralised (from pH <2 to pH ~6) and iron, copper and zinc ion concentrations reduced significantly during the formation of solid precipitates. Carbonation was undertaken by injecting carbon dioxide into the magnesium-rich solution to form stable carbonates. The experimental work demonstrated proof of concept; however, dissolution efficiency and carbon dioxide sequestration was low, indicating that further research would be required before larger scale implementation.CITATION:Malli, H, Bouzalakos, S and Timms, W, 2015. Ultramafic mine tailings to treat acidic mine water and lock away carbon through mineral carbonation, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 133–136 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By Sterns UJ, Weller KR

Grinding to sizes less than 80 per cent passing 20 ¦m in both primary and regrind circuits is becoming increasingly important in processing metalliferous ores, as many of the remaining orebodies are very fine-grained and refractory. The process of very fine grinding, however, is expensive, and neither the performance nor the design criteria are well understood. This paper presents some findings from a collaborative research program, one of the objectives of which has been to better understand and improve the performance of very fine grinding circuits. Data from surveys of an industrial tower mill grinding circuit are reviewed and analysed using the population balance models of the CS]RO and 7KMRC. The performance of both models with regard to changes in feed size distribution, ball load and feedrate is assessed using these data. From comparisons between pilot and full scale tower mill operation a prototype scaling methodology is also presented which shows promise in allowing the models to be used to predict the effect of changes in mill Design.

Jan 1, 1993

Since 1975 two electric hydraulic drills, a Robbins 11ND and an Atlas Copco C0P1038, have been part of the production drilling fleet at Mount Isa Mines Limited's Isa Mine. As might be expected with innovative and technically more complex machines, breakdowns and mainten- ance problems have been greater than those experienced with pneumatic drifters. This has been especially so with the COP1038 but in co-operation with Atlas Copco, many modific- ations have been made to alleviate operating problems. The training and quality of the maintenance workforce is of great importance. The use of coloured pictorial diagrams for hydraulic trouble-shooting will aid in minimising maintenance downtime. Both machines have achieved good operator acceptance. This is the result of many factors, the major ones being the more acceptable environmental conditions, the relatively low amount of physical effort and the high degree of mechanisation. The drilling area is one in which there is great potential for cost savings and product- ivity gains. Because both machines are capable of a high drilling output, Isa Mine is confident of achieving these aims.

Jan 1, 1978

By J M TORLACH

Learning is an iterative process, and we might reasonably expect that after more than a century of mining during an era of sustained technological development, (following a millenium or two of unrelieved hard physical graft), that the more obvious physical hazards could by now be competently managed. It is perhaps a reflection on the perversity of human nature that we have not fully learned our lessons in this exacting environment, and that worse, we have still too often failed to profit by the experience of those lessons. The more obvious underlying factors which impact on this situation are examined briefly, as a prelude to consideration of some outstanding examples of recurrent problems experienced in recent years. Reasons for the continued existence of sub-standard practices are outlined, with a focus on the human element, and finally proposals for appropriate remedial strategies are summarised. This paper therefore seeks to examine and discuss some of our deficiences and to suggest some directions for the way ahead.

Jan 1, 1992

By Silitonga M

Generally, the acceptable parameter for predicting the intensity of ground vibration due to a blast is the amount of explo ive u ed and the distance from the explo ion. A eries of closely controlled tests were carried out and it was observed that the degree of confinement or burden of an explosive charge play an important role in the variation of the transmitted magnitude of the shock wave through the ground.The intensity of the shock wave increases with burial depth or with greater confinement of an explosion until a critical depth is reached.Beyond this critical depth, the magnitude of ground vibration remain constant. This is an important finding, which explains the anomalies between the expected level and the monitored ground vibration in a particular situation.

Jan 1, 1984

By L Yang, L Chen, E Hu, D Tang

Online monitoring of particles cumulative percent passing (PCPP) for a target size at hydrocyclone overflow, compared with traditional offline methods, provides PCPP feedback in real time, and is advantageous in enabling energy-efficient comminution, increasing downstream flotation efficiency, and improving upstream resource knowledge. However, existing online approaches are generally costly and bespoke, and some are sensitive to operational changes. Therefore, this study proposes a new low-cost alternative based on accelerometer measurement for online PCPP monitoring in the overflow of hydrocyclones and provides a preliminary experimental investigation under dry condition. The proposed method uses a sensing probe inserted into the overflow pipe of a hydrocyclone to receive particle impact from the incoming slurry, with accelerometers attached to the probe and mounting frame outside the pipe for particle-probe impact detection. As a preliminary investigation before studying particle-probe impact events in slurry, tests under dry condition without fluids were conducted using dry sand particles in free fall from a fixed height. Accelerometer measurements are analysed in both time and frequency domains through root-mean-square (RMS) and fast Fourier transform (FFT). Results show that accelerometer measurements are useful in estimating mass flow rates, which are correlated to the accelerometer output amplitude RMS values in time domain, in a non-linear mapping. Different particle size classes can be identified by examining the accelerometer output amplitude at a known mass flow rate. Different particle size classes feature their distinct signature frequencies (SFs) that can be examined via FFT and the SF is found to be independent of the mass flow rate. The results imply that any PCPP changes can be detected by the change in the accelerometer output amplitude as well as a shift in SF, which demonstrates the effectiveness of using accelerometers to gauge changes in PCPP. Based on the current findings in dry condition, future work will investigate particle-probe impact events in slurry.

Aug 24, 2022

Most of the world' s continental' shelves are .primarily . esozoic-Tertiary phexicmena. Those ,of south,eap- ern Australia are' no exception, although cam-plicated by possible TTmelon-seed" type block upthrusts in the region of the Bass Strait (e.g. King Island, Wilson's Promontory etc.) These terraces represent the progressive infilling and seaward. outgrowth of enormous volumes of tern g_enous sediments into the marine environment. Asa consequence they constitute the preferred habitats, of, petroleum.The Gambier ,sub-basin forms part of the southern Australian-continental terrace where it opposes the (3000 fathom), Jeffrey deep. The'purpose of'this paper is to discuss its nature, structure,_ and developmental history in re-lation to its oil prospects.

Jan 1, 1962

Underground mines in Australia and worldwide are extending to greater depths. The effect of depth brings a number of challenges to mining engineers including geotechnical, ventilation, haulage and selection of mining method. The main effects of depth from a ventilation perspective are increased heat and humidity leading to reductions in productivity, occupational safety and health issues and the potential for fatalities. Numerous approaches have been undertaken over the years to mitigate against these effects. In this paper a review of various approaches to improving climatic conditions at a number of mine sites worldwide is undertaken. From these case studies it is argued that for mines at depth with the potential for a climate problem perhaps an alternative design philosophy to the established design philosophy should be utilised. In conclusion, the paper proposes some simple rules of thumb for use in mines with climate problems or the potential for climate problems.

Jan 1, 2008

By Jena P. K

Smaller deposits of high grade chalcopyrite or the concentrates of low grade and complex copper bearing ores, can be subjected to extraction processes other than smelting and converting. Low temperature chlorination and segregation processes are among those mentioned in the literature. In the present work, extraction of copper from a Brazilian chalcopyrite concentrate by slurry chlorination with chlorine gas at room temperature, dry chlorination by chlorine gas in the temperature range of 350 to 450¦C and segregation roasting of the calcined concentrate in the temperature range of 650 to 800¦C have been carried out. The effect of several experimental variables on the extraction of copper has been discussed in all these cases. Under optimum experimental conditions, 100 per cent Cu extraction was possible by either slurry or dry chlorination processes and around 86 per cent Cu by segregation roasting. For all the three cases, possible methods have been suggested to trial the studies on a pilot scale to assess their technoeconomic viability.

Jan 1, 1992

By E Villaescusa, C Drover

The stability of access tunnels is one of the main engineering challenges in deep underground mine construction. Many underground hard rock mining operations are now reaching depths where the induced stresses are such that sudden and violent failure of the excavations can occur very soon after construction. The loading conditions on the installed ground support schemes are often underestimated by conventional engineering design methods. Therefore, the actual loading conditions often exceed the installed ground support capacity. This can result in failure of the excavations and, in extreme cases, potentially closure of mining operations amounting to hundreds of millions of dollars in lost production. More frequently, violent excavation instability at great depth causes operational delays, costly and unplanned rehabilitation, as well as risks to worker safety. In order to address this challenge, this paper briefly summarises a modern, innovative approach to the design and construction of mine development at great depth. The process follows seven main steps. The first step is to characterise the rock mass strength, structure and stress. The second step is a stability assessment, which identifies the plausible modes of excavation failure, based on the rock mass characterisation. The third step is the definition of an excavation geometry which is harmonic to the high stress conditions. The fourth step is to prepare a site-specific face destressing drill and blast design which will reduce the potential for rock mass instability during the development construction cycle. The fifth step is to accurately quantify the expected loading conditions on the installed ground support. The method of doing so is uniquely analytical and probabilistic. It is based on the natural mechanical relationships between rock strength, structure, induced stress and the physical characteristics of the instability, including its mass and ejection velocity. The sixth step of the design process is to specify a ground support scheme arrangement with sufficient strength and displacement capacity to exceed the rock mass demand by a safe margin. The final stage is to install the complete ground support scheme using mechanised technologies which minimise the exposure of the equipment operators to unsupported ground at the tunnel face.

Nov 29, 2022

By V Salamakha, K Tang, G Si, J Oh, X Wu, Z Yu

The development of machine learning (ML) algorithms has led to promising advances in lithology classification from geophysical logs, which is indispensable in various underground engineering applications. Due to the resolution and availability of logging data, ML models can recognise lithology change in a definitive form at a fine scale (0.01 m). While the results from previous models indicated promising performance in the classification, the robust capability of generalising lithology prediction to unseen data may not be true for those models due to: (1) data bias caused by borehole selections, and (2) logging data mismatches among boreholes. To this end, this paper aims to investigate the generalisability of ML models and seek potential improvements. Four ML models were selected to be trained on single reference boreholes to test the other (as unseen) in the same region, which includes Support Vector Classifier (SVC), Random Forest (RF), eXtreme Gradient Boosting (XGBoost) and Residual Neural Network (ResNet10). The data set involves 11 boreholes from a coalmine in north-western Bowen Basin (Queensland, Australia): density, gamma ray, neutron, and sonic logs are selected as inputs. Additionally, a data adaptation method is applied for better generalisability. The results show that there is an accuracy trade-off between the same borehole and unseen boreholes across the models. It also indicates a 16–43 per cent reduction in model performance when generalising the predictions (in marco-F1 score), while the adapted data sets can contribute to a around 12 per cent improvement. This study provides a fundamental understanding of the model generalisability when using a single borehole, essential for further correlating boreholes for regional lithology classification; the adaptation method can improve the generalised accuracy, and reduces the labour to label lithology, which facilitates the identification of gas storage mechanisms, geological/geophysical modelling, and stratigraphic analysis.

Sep 1, 2024

By J Tsiklieris, O Turner

Suppliers of products and services have a pivotal role in sustainable development in the mining and minerals industry. Reputable suppliers know their products and services, and the industry, and have unique knowledge of these in relation to their customerÆs needs. Petroleum hydrocarbon suppliers, in particular, impact upon a mineÆs sustainability because of the extensive reach of petroleum hydrocarbons into the mining and minerals life-cycle. The petroleum hydrocarbon life-cycle is a useful framework to enable engagement between supplier and customer on the issue of sustainability. The life-cycle starts with supply of fuels, lubricants and services at the mine, through to plant operation and maintenance, transport of mined products, ship loading, and finally through to mineral processing and other downstream value-adding. There are barriers to leveraging supplierÆs capabilities which have to be overcome before the industry will gain the potential benefits from such supplier engagement.

Jan 1, 2004

By B Hooper

Deep cuts in CO2 emissions will be required to stabilise and, in the long term, decrease CO2 concentrations in the atmosphere. Technologies for capturing CO2 from major stationary sources (power stations, industrial plants, etc) and storing that CO2 for long periods of time is one of few near term options for decreasing CO2 emissions. This transition to low carbon intensity energy and possibly the hydrogen economy through renewables and in the long-term technological developments such as artificial photosynthesis.Capture of CO2 from post combustion emissions can be done using a range of technologies though costs are currently high and dependent on the concentration of CO2 in the emissions. Techniques include solvents, pressure swing adsorption and the use of membranes. Options for decreasing capture costs by increasing the concentration of CO2 in the emission stream include the use of oxyfuels (in pulverized fuel types boilers) and by moving to integrated gasification combined cycle (IGCC) operations either simply for power generation or for poly-generation opportunities. Once the CO2 has been captured it can be stored using a variety of methods. Storage in the ocean has been suggested but is considered an unlikely option because of environmental uncertainties and political opposition. Mineral storage is a niche opportunity. The greatest potential lies in geological storage of CO2 and this option is commanding increased attention from the Australian and international community.In Australia, the Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC) is an important new initiative that will support energy companies and energy intensive industries in meeting challenges posed by greenhouse gas issues and assist them in their efforts to reduce their emissions profile.The progress of geo-sequestration and the challenges in the capture and separation of CO2 in the process industries are discussed.

Jan 1, 2004

Seam gases are the most important atmos- phere contaminants in Australian collieries, their importance increasing with depth; C02 as well as CH4 may be important in intruded envir- onments. The generally high rank of the coal, with low moisture content, makes for abnormal dust production. The other contaminants are introduced and subject to better control, in- cluding products of spontaneous combustion. Due to market situations the generally lower rank and higher sulphur coals more prone to self heating are mined less. Future mining at greater depths should see greater problems with atmosphere contaminants.

Jan 1, 1983

By Berglin IK

Since 1962, ferro alloy production in Australia has been concentrated at Bell Bay, Tasmania with a major expansion occurring in 1976. This concentration was based originally on the perceived requirements of the expanding Australian steel industry, but recent stagnation within this industry has seen Temco become progressively more export oriented.In 1984, approval was given for a $47 million uprating of facilities which will allow for the introduction of the latest technology to ensure high quality, low cost production in a highly competitive export market.

Jan 1, 1985

By Lott JB, Scuffham JB

Until very recently the application of solvent extraction to. the recovery of metals has been considered only for ithose operations where no other process was available. In general, .these operations, have involved metals such as 'f uranium or the rare earths, where the value of metal recovered has been very high. As a result, the tendency has been to consider solvent extraction as a very specialised, high cost technique with minimal application in the base metal industry. Since the mid-1960's this attitude has had to be changed drastically with the development of solvents specifically designed for the selective extraction of individual metals such.ascopper. The result is that solvent extraction must now be regarded as a proven hydrometallurgical technique for the recovery of base metals, and in particular copper. The first significant event in the application of solvent extraction to base metals was the production by General M. Inc. of a compound, designated LIX-63 (R)(1), which was a specific extractant for copper from ammoniacal sns. This did not find a wide application, however, because copper solutions with a pH in the applicable range we more readily treated by conventional techniques.

Jan 1, 1970

Degussa's PAL-system (peroxide assisted leach) has been proven to be more economical than the conventional cyanidation technique. Significant in- creases in the gold recovery have been reported, accompanied by savings in cyanide. Accelerated extraction kinetics and modified reagent demands necessitate a redesign of the conventional cyanidation plant. The South African Osprey Mine is presented as an example of a successful PAL-application. Based on the plant and laboratory data it is shown that the redesign of the flowsheet can be an important factor for the effectiveness of a metallurgical plant. In the case of the Osprey Mine, the PAL-technology all ows a modification of the current preoxidation-ClPcircuit to two separate CIL-plants to treat run-of-mine ore and old tailings dumps. A doubling of the throughput is possible without enlargement of the plant. This innovation in the field of gold extraction, the combination of the PAL-process with a redesign of the metallurgical plant, can be considered as a basis for a more profitable gold mine.

Jan 1, 1991