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By Beavis FC, Box JC

The important chemical and fluid flow phenomena in heap, dump and in situ leaching are summarised. Published, quantitative models of these processes are critically reviewed, and their potential applications outlined. Comparison between the independent predictions of one of the models and column leach test data reported by others confirms the potential. Some recent developments by the authors in the fields of fluid flow through unbroken ore and modelling of the more complex chemical systems are briefly Described.

Jan 1, 1981

Key blocks occur on the surface of excavations and on the walls of the ornamental stones and limestone quarries due to the formation of joint planes, fissures, microfaults and quarrying operations. Movements of these key blocks have produced numerous important failures and are responsible for routine overbreak and rock falls accounting for great costs. The thrust of this work is to demonstrate how to delimit zones of poten- tial key blocks (danger zones) in the wall of Bani-Khalid quarry of lime- stone by using the block theory technique (stereographic projection). The final result of this study indicated that, there are three potential key blocks, the most critical one has been determined. To treat the problem, we sug- gest either to provide timely support to prevent the movement of this block, or to analyze it further in hopes that available friction on the faces will hold it safely in place.

Jan 1, 1989

By R Uken G P Whitmore

The coastal dune cordon of northern KwaZulu-Natal is amongst the highest in the world reaching heights in excess of 180 m and up to 2 km in width. It comprises a complex system of Quaternary stacked dunes of various geomorphologies, types and ages. The dunes contain economic heavy minerals which are currently exploited ~20 km north of Richards Bay. Although mining of these ore sands has been in operation for the last two decades, little work has been undertken on the clay-fraction (

Jan 1, 2001

The long-term production schedule of open pit mines that maximises the net present value (NPV) of a given project relies on the proper design of phases (pushbacks) within the ultimate pit limits. There is not a phase design algorithm applied in the mining industry today that gives yearly production schedules that are optimum.The majority of phase design algorithms currently in use by the mining industry aims at grouping the blocks that fall within the ultimate pit limits into phases such that the average value of the blocks within each phase decrease as the size of the phases increase. Current phase design methods are typically based on a pit limit optimisation algorithm, originally introduced by Lerchs and Grossmann (LG) in 1965. To obtain multiple pit shells to be used for the phase design, the LG pit limit algorithm successively applied to economic block models by changing the price of the commodity or some other factor that properly parameterises the size of the pit. These modified economic block models are developed by predetermining the destination for each block in the model based on a breakeven analysis and highest economic outcome between alternative destinations. Phase designs determined by these existing algorithms may be suboptimal if a given project utilises multiple processing facilities for metal recovery and particularly if these facilities have restrictions (constraints) that require blending of attributes in the feed. To overcome these problems in obtaining phases that optimise overall production schedules, a new algorithm is developed at the Colorado School of Mines. The algorithm determines the phases of an open pit mine by taking into account multiple process options for the blocks and period by period blending requirements. This algorithm has been implemented within a software program (the software) and is being prototyped successfully in the design of improved pushbacks at a copper mine in South America and on a gold mine in Nevada. This presentation will demonstrate the shortcomings of the traditional phase design methodologies based on comparison of results coming from the new approach versus the traditional.

Dec 6, 2010

By Hannan JC

Consent to develop and operate a new coal mine in New South Wales (NSW) will be conditional upon a number of environmental controls. In NSW, applications for any new major development associated with coal mining are determined by the Minister for Planning and Environment. The environ- mental conditions placed on the development consent, the coal mining lease and the approvals, and licences under the pollution control legislation amount to a substantial component of any new project's commissioning considerations. The nature, scale and location of projects and the principles of pollution control on which conditions of State Pollution Control Commission (SPCC) approvals are based have a considerable influence on project planning. The design, construction and operation of coal mines in NSW has been progressively modified over the past 15 years, to incorporate increasingly stringent requirements for environmental management. These requirements are in turn, a reflection of a greater community demand for environmental protection.

Jan 1, 1986

By Kubik K

This paper reviews the historical data on relative height changes of landmasses with respect to sea level for Pacific Rim countries.It discusses existing theories of the Greenhouse effect, and the interaction with the vertical movements of the continental plates which leads to different effects for different places. Possible future scenarios are described and directions for future research and measurement programs are given.Relative sea levels are governed not only the increase of water from deglaciation but also by a range of other factors such as variable water storage in lakes and the atmosphere, thermal expansion of the ocean, ocean currents, and the shape of the ocean and the continents. Sea floor spreading, for example, is ultimately more significant than deglaciation in sea level control but is generally much slower.

Jan 1, 1990

The Golden Plateau Mine is located at Cracow in central Queensland, 350 kilometres north west of Brisbane. The mine was operated by Golden Plateau NL as an underground mine from 1933 to 1976 with a total production of 18.5 tonnes of gold. Prod

Jan 1, 1994

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

The advancements achieved in rapid tunnelling in the 60's and 70's have been notable. It is unfortunate that shaft sinking has not enjoyed equivalent advances and there are many good reasons why this is so. Technical and commercial considerations have held back development and continue to do so despite the increasing urgency in the search for minerals and energy. By the careful selection of an appropri- ate project and the application of specialist engineering the Bdard took advantage of a unique opportunity to apply a mechanised shaft borer in field conditions.

Jan 1, 1981

By Barro L

Very large reserves of gas are contained in coal. Because of the low permeability of the coal gas flow rates are very low. Fracturing of the coal can be achieved by use of the nitrogen - foam frac techniques described but the flow rates after fracturing are not sufficient to support economic development. Fracturing of the seams in the Bowen Basin was as predicted but in the Sydney Basin no trace of the fracture could be found when development proceeded past the fractured well. Testing of coal samples has provided some insight into parameters affecting desorption Rates.

Jan 1, 1982

The word `environment' may have many different meanings but, for the purposes of this paper, I have assumed the definition included in the Environmental Protection Act 1986 (Western Australia). This Act defines `environment' as `... living things, their physical, biological and social surroundings, and interactions between all of these'. The Act further defines the `social surroundings of man' as `... his aesthetic, cultural, economic and social surroundings to the extent that those surroundings directly affect or are affected by his physical or biological surroundings'. This gives a very broad meaning to the idea of environment and environmental issues, and it is therefore understandable that the influence that environmental issues have on mining activity can vary so much from state to state, and even within states, and why the degree of influence can change so much with time.

Jan 1, 1990

Managing project exposure and risk has numerous viewpoints, including those of engineers, owners, bankers and insurers. Fewer stakeholders are involved in early stages, though with wider risk management techniques and tools available. The costs and sometimes benefits of the occurrence of risk and uncertainty have different contingent outcomes for different stakeholders. For some, the impact of risk outcomes can be mitigated or managed. Some sectors and stakeholders can manage resources project risks more completely, by choice or by externally imposed forces, opportunities and constraints. The core to resources project risk management lies in the identification and analysis of project risks, the examination of project management risk options and alternatives, and the determination of which risks are able to be controlled, managed or laid off to third parties. Without prior risk identification and knowledge, the wildcard of previously unidentified or unconsidered project risk impact has the potential for fatal impact to one or more stakeholders. A range of case studies is reviewed, from exploration projects to development and operating projects, with relevant learning experiences, from the risk management lessons available from the oil and gas sector as well as the mining sector. For many cases, the emphasis focuses on the risk analysis modus operandi and on risk management and risk mitigation techniques that can be and in some cases have recently been implemented for resources project and related debt, capital markets and equity project fundings.

Jan 1, 2003

By J M. Parr, C J. Yeats

Discovered in 1991 by combined plume detection and bottom-tow photography (Binns and Scott, 1993) and for some years thereafter the highest tenor mineral occurrence known on the ocean floor, the PACMANUS hydrothermal field has since been surveyed and sampled in great detail by CSIRO and international research agencies (Binns et al, 1995; Auzende, Urabe and Scientific Party, 1996; Binns et al, 2002; Tivey et al, 2006). Since 2005 commercial surveys employing deep-tow geophysical packages and remotely-operated vehicles (ROVs) have been conducted by Nautilus Minerals Inc and partners within Papua New Guinea-granted offshore exploration licenses (Nautilus Minerals Inc, 2008). Two academic drilling programs have been conducted, one under the international Ocean Drilling Program (ODP) directed at deep structure (Shipboard Scientific Party, 2002; Binns, Barriga and Miller, 2007), and one using a 5 m capable seafloor diamond drill to investigate the immediate subsurface at one site (Petersen et al, 2005). An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By Elber L, Whiten WJ, Cunningham KD, King GL, Bailey CW, Clay PA

The Savage River Mines concentrator treats magnetite ore at about 300 tonne/h, and produces feed for a pelletising plant. The plant incorporates two parallel grinding lines, each consisting of an autogenous mill, in closed circuit with a screen, a rougher mag- netic separator, a ball mill in closed circuit with parallel cyclones, and a finisher magnetic separator. Significant fluctuations in ore grade and grindability make it difficult to maintain pro- duct size in the narrow range desired, and to achieve maximum possible throughput at the same time, using the present largely manual control system. The present paper describes the develop- ment of a control system based on a mini- computer. It has been possible to implement a scheme of on-line estimation of product size which is sufficiently accurate for use in an automatic control system. The size estimation is essentially derived in terms of plant variables which control the ball mill cyclone cut size. Three control functions have so far been implemented and tested. These are control of the feed rate to the autogenous mill, control of water addition to the autogenous mill, and control of the ball mill sump level.

Jan 1, 1978

By Haslam C. O, Taylor S

Four historical periods of Australian lead-zinc-silver exploration and development are identified.In the first period, 1841-1900, Australia's deeply weathered surface yielded bonanza deposits. The outcrops of easily worked secondary ores, enriched in silver and lead, were discovered by prospectors with the incentive of production at times of high silver price. Districts discovered in this period still contributed, in 1982, 60 per cent of Australia's lead-zinc production, mainly from Broken Hill.The second period 1901-1944, was one of strong mine development but stagnant lead-zinc-silver exploration. Mount Isa was discovered and developed, but otherwise effort was devoted mainly to the mining of deposit extensions and to the metallurgical flotation of zinc. The deposit discovery rate was low but the discovery of Mount Isa was so significant that discoveries of this period contributed, in 1982, 30 per cent of Australia's lead-zinc production.The third period 1945-1972 was one of re-invigorated exploration.New geological and geophysical surveys, developing concepts of ore genesis, and worldwide comparisons of orebody settings improved target area selection. Evolving remote sensing methods, and rapid analytical techniques, assisted detection of lead-zinc deposits. Initiation of exploration led to discovery:1. in regions of previously unsuspected lead-zinc-silver potential (Sorby Hills, Mons Cupri, Golden Grove).2. of poorly exposed deposits in recognized mineral districts (Hilton, H.Y.C., Woodlawn, Elura, Que River).3. during active exploration for another commodity (Brown's, Woodcutters, Mary River, Beltana, Lady Loretla and Pegmont).The period saw a sustained growth in lead-zinc-silver production mainly from established operations. Mines discovered during the third period contributed, in 1982, 7 per cent of Australia's lead-zinc production.In the fourth period from 1973 to the present, exploration initiatives became fewer but resulted in continued discovery of poorly exposed deposits at Teutonic Bore, Thalanga, Benambra, Scuddles, Hellyer, and Jillawarra. Development initiatives strengthened in the period and production commenced at Woodlawn, Teutonic Bore, Que River and Elura; pre-feasibility work commenced at Scuddles, Hilton, Lady Loretta and Thalanga.

Jan 1, 1984

By G R. Dickens, N H. S Oliver

Deformed regions of the Hamersley Province, Western Australia, contain several major iron ore deposits where banded iron-formation (BIF) of the Dales Gorge Member was converted to martite-microplaty hematite. The genesis of these ores remains controversial, in part because no study has systematically documented how stratigraphically equivalent rocks change chemically from undeformed regions into the deposits. Profound chemical and mineralogical differences do occur between rocks in the undeformed north and mineralised south. BIF and shale can be classified into three types: BIF, altered BIF and iron ore, and black shale, altered black shale and red shale. A series of low temperature (20 to 250¦C) chemical reactions can explain the observed differences in chemistry and mineralogy. The inferred reaction paths indicate that no single process could have produced all of the altered rocks at Mt Whaleback. Recently described carbonate-rich, silica-poor rocks at Mt Tom Price (Taylor et al, 2001) suggest this alteration sequence is even more complex. Our favoured explanation for the genesis of hematite ores is one that can explain deposits at Mt Whaleback and Mt Tom Price: following regional metamorphism, hydrothermal fluids locally formed carbonate-rich, silica-poor BIF with magnetite and carbonate-rich altered black shale. Subsequent surface derived fluids oxidised this magnetite, crystallised microplaty hematite (mpl) and eventually dissolved carbonates and silicates leaving high-grade ore. Either during or sometime after mineralisation, acidic, oxygenated fluids converted altered black shale to red shale and unaltered BIF to martite-rich BIF without carbonates across the southeast of the province.

Jan 1, 2002

The types of risk to mining projects using environmental protection as justification are examined. In Australia, Governments, whether Federal or State, enforce environmental legislation. The way they do This has an impact on the risk to a project. This is discussed and examples are taken from the Northern Territory uranium industry. Special reference is made to mine closures where the roles are not yet entrenched.

Jan 1, 1994

By D Wardiman, R Benton, D Sims, T Carr, V Singh

The Kencana underground gold mine comprises two world-class epithermal vein deposits located in the North Maluku province of Indonesia on Halmahera Island. The K1 deposit has a recent extensive mining history, whilst development of the K2 deposit is in progress. Kencana epithermal vein zones have a relatively simple planar geometry dipping 25 to 45¦ towards the East and extend 400 to 600 m along strike and down dip. True width ranges from 1 m to 20 m. Economic gold grades are generally associated with two distinct mineralisation styles: Main Zone û continuous material characterised by classic epithermal vein textures including crustiform/colloform chalky white quartz- adularia sulfide banded and brecciated veining typically grading 10 to 40 g/t Au. Bonanza Zone û semi-continuous identifiable zones within the Main Zone. Characterised by brecciated quartz-adularia sulfide banded vein æginguroÆ material typically grading 80 to 200 g/t Au. Associated with this æBonanzaÆ zone are gold grades averaging around ten times higher than the surrounding Main Zone. At the resource evaluation stage, these deposits are typically drilled on approximately 25 m by 25 m spacing. This drilling density is usually adequate to allow robust estimation of global resources, including the lateral definition of æBonanzaÆ style mineralisation. It appears intuitive at the resource definition stage to separately model the æBonanza ZoneÆ using deterministic methods such as manual interpretation and wireframing. Inevitably, however, such deterministic methods result in a simplified version of reality. Whilst the geologistÆs interpretation of the overall vein volume and lateral extent of æBonanzaÆ mineralisation has proven to be remarkably accurate, close-spaced sampling and mapping of the K1 orebody has shown that this style of mineralisation exhibits extreme short-scale geometric and spatial variability. A consequence of this short-scale geometric and grade variability is the significant uncertainty with reporting these Resources and Reserves at relatively small reporting time periods such as monthly production periods. The mining method employed at Kencana often involves extracting the full width of the mineralised vein with multiple mining passes over several months. In the past it has proven difficult to achieve accurate production budgets and forecasts at Kencana as any given mining schedule based on the resource model is acutely sensitive to the quantity and location of æBonanzaÆ material. Moreover, the degree of uncertainty or risk associated with a mining schedule significantly increases as the reporting time period becomes smaller. A further deficiency of deterministic methods for geometric modelling is the inherent lack of ability to derive confidence intervals for quantifying uncertainty and risk. The use of conditional simulation techniques can help overcome this deficiency. Geostatistical conditional simulation techniques have been applied at Kencana in an attempt to model and quantify geological and grade variability in the upcoming K2 orebody based on the experience to date with mining the K1 orebody. At Kencana, conditional simulation has provided a successful means to quantify uncertainties and risks associated with various data densities and reporting time periods. The results of this project have provided managers and planners with a clearer understanding of the likely variances and risks associated with predicting gold metal production at key reporting time periods based on data at the resource model level of resolution. With corporate requirements to adhere to mining budgets/quarterly schedules, this type of analysis allows a more scientific approach to estimating grade uncertainty in the mining schedule. Until now this has been difficult to quantify due to the extreme gold metal variability. The availability of this type of analysis allows a time-efficient rationalisation on redesigns of the mining shapes and effective communication of the likely uncertainties involved.

Jan 1, 2009

Not so many years ago the reason for an inadequate result from a geophysical survey was insufficient data or poor quality data. In many instances such as gravity, magnetic and radiometric surveys, both these constraints are vanishing or have vanished. High quality sensors, improved data storage, accurate differential GPS and top quality interpretive software now enable the interpreter to understand not just the cause of the anomaly but the host environment in which it resides. Examples of potential field data and also data provided by the more complex electromagnetic systems, from Australia Ghana, West Africa, are used as illustrations.

Jan 1, 1997

By M Chappell

This paper describes the design of the steel fibre reinforced precast concrete (SFRC) segmental lining for the intake and discharge tunnels for the Gold Coast desalination plant in Queensland. In addition, the key design requirements and design methods for the lining of these 2 km long, 2.8 m internal diameter tunnels, including structural, durability and maintenance requirements are discussed. Details of the segment configuration and erection process are presented along with information on the manufacture and trial testing of the concrete for the segments. The paper also gives a brief introduction to steel fibre reinforced concrete behaviour. Construction of the tunnels commenced in April 2007, and the authors believe this is the first application of this technology in Australia.

Jan 1, 2008