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Plenary Address Zinc is a trace element in all igneous rocks and its background geological occurrence roughly follows iron but at much lower concentration. Living matter reflects this abundance and zinc is an essential trace element for complex life forms. Thus, environmental issues include zinc deficiency in soils and/or water - and thus in local diets - and zinc toxicity evident in natural or modified ecosystems. Increased knowledge of the role of zinc in plant and animal metabolism emphasises the need to manage, within guidelines based on naturally occurring abundances, the concentrations of zinc in water, spils and in the food chain. Although recognition of the natural variability of zinc concentration provides some basis against which environmental protection standards might be set, the measure of environmental `pollution' is more commonly taken as the degree of change to natural, background levels, attributed to the particular land or water use activity. Environmental constraints on mining, processing and usages of zinc may have less to do with actual

Jan 1, 1993

By E S. Bernard

Steel fibre reinforced shotcrete (SFRS) is increasingly being used as ground support in both civil and mining applications. In recent years, methods of assessing the performance of SFRS have been developed. These include the beam test such as that prescribed by ASTM C-1018 and the panel test prescribed in the EFNARC European Shotcreting Standard. The panel test has gained popularity in recent times due to the two-way action modelled in the test. However, some difficulties have been noticed. Shear failures sometimes occur and there appears to be a rather high degree of variability in the panel test results. A new method of testing panels has been proposed. A circular panel supported on three symmetrically arranged points has been assessed at the University of Western Sydney. This paper describes the new test which may be the basis of a new specification for the testing of toughness of SFRS and summarises research work which has been carried out to-date.

Jan 1, 1999

By P Heppner, J Schell, R Newell

The effect of various methods of conditioning on subsequent flotation performance was reviewed, where complex interactions involving attrition, aggregation, dispersion and surface cleaning were discussed. The present study focussed on the influences of standard laboratory cell conditioning, ultrasonic dispersion and high intensity conditioning on copper mineral flotation characteristics. The effect of substituting demineralised water for the WMC plant water was also examined. It was found that higher copper concentrate grades were often obtained using demineralised water, however the use of high intensity conditioning in mill water gave the highest copper recovery and highest flotation rate constant. This process should be considered if copper grade and recovery in this section of the plant drops, especially if the drop is due to surface oxidation of the copper minerals. Other methods of conditioning (cell and ultrasonic techniques) improved the rate of copper flotation above that obtained in the virtual absence of conditioning, showing the importance of conditioning on subsequent flotation operations.

Jan 1, 2000

By Cortes JP

In a dynamic environment such as the Star Mountains of Papua New Guinea Geotechnical Engineering for the Ok Tedi Project must be described as both interesting and challenging. To be effective a reasonable sized team of dedicated people is required with occasional supplementation by specialist consultants and an annual review process. Ok Tedi Mining Limited's (OTML) Geotechnical Section has a vision to be recognised as the leading mine-based geotechnical engineering section in PNG and to be world class by any international standards. This paper deals with the organisational and operational duties of the Geotechnical Section at the Ok Tedi Mine. One of our major roles is in the area of safety, and in particular in the early warning of natural and mining induced geological hazards that may affect safety and/or productivity. The major activities in- clude geotechnical inspections (pit, waste dumps, tunnels, re- gional), data collection activities and database management, geotechnical design and control work.

Jan 1, 1997

By Stewart WJ

Australia's first offshsore well was spudded in on 27th December 1964 and resulted in the discovery of the Barracouta gas field. Further exploratory drilling led to the discovery of the Marlin gas field in December 1965, the Kingfish oil field in April 1967 and the Hblibut oil field in June. 1967. In September 1968, a small oil reservoir was found in a sand below the main Barracouta'gas reservoir. The Snapper gas field was discovered in May, 1968 Information on exploration activities associated with the discovery of oil and gas in the Bass Strait area may be found in the paper, "Exploration in the Gippsland, Bass and Otway Basins, Australia" by B. M. Hopkins. _ Development of the commercial fields is being undertaken on an equal participation basis by Hematite Petroleum Pty. Ltd. and Esso Exploration and Production Australia Inc. Esso Standard Oil (Australia) Ltd. is responsible for the design, construction and operation of the production facilities.

Jan 1, 1970

Australia today is one of the leading countries in the fields associated with the mineral industry, an industry which accounts for over 50% of overseas income and revenue to government. This is no accident. In order to be competitive in what was recog- nised very early in the country's history as a highly profitable busi- ness, the Australian mineral industry (mining, extractive and refining metallurgy) has traditionally been very innovation con- scious, a characteristic which has been evident from the begin- ning of the industry or very nearly so: Australia's geographic isolation and the dispersion of the mineral industry over wide distances made an exchange of ideas difficult and often impossible. One needs only to look at the inaugural address given by Sir Henry Ayers, the first president of the then Australasian Insti- tute of Mining Engineers, in Adelaide on 4th April, 1892 (1) "There is probably no other pursuit which depends more on its productive development and profitable results than in the extent and application of the scientific and mechanical knowledge possessed and exercised by its manager." and "Having in view the value of the mining industry of Austral- asians, they should be urged to apply their best skill with all the scientific and mechanical knowledge obtainable to its future development."

Jan 1, 1988

Structure is the most important control on the location of hematite deposits in the Hamersley Province in the Pilbara region of Western Australia. Unravelling the structural history of mineralised areas, however, is complex because the Province underwent three orogenic events, and three regional extension events followed the main episodes of compression. Steeply E to ENE dipping normal faults immediately predated deposition of the Beasley Quartzite of the lower Wyloo Group after the Ophthalmian Orogeny. Steeply NE and SW-S dipping normal faults predated deposition of the McGrath formation of the middle Wyloo Group, following the Panhandle Orogeny. The resulting interpreted rift was subsequently reactivated and tilted during the Capricorn Orogeny. Late NE trending normal faults are confined to the eastern half of the Province. High-grade hematite deposits occur in rocks that range from intensely folded (Mt Whaleback, Giles Mini) to rocks with less, or only little deformation (Paraburdoo, Channar), suggesting that folding had at best limited influence on ore genesis. In contrast, extensional normal faults are always associated with high-grade hematite deposits, and in particular faults that link the underlying dolomites of the Wittenoom Formation with the overlying iron formation, thus providing a pathway for mineralising alkaline fluids.

Jan 1, 2005

A good blasting result is largely achieved by putting the right amount of explosive in the right place and firing it in the right sequence. The best blast design in the world will not break the rock if the planned blast layout is not achieved in the field. One of the critical inputs into a blast design is the diameter of the blasthole. An assumption that the actual blasthole diameter is equal to the nominal drill bit size is generally made. However, a small deviation in the actual hole diameter from that assumed will have a dramatic effect on the hole's volume and, consequently, where the explosive is placed in the blasthole. Any discrepancy in actual blasthole volume from that assumed will be reflected in 'overloading' or 'underloading' of the blasthole with the calculated explosive quantity and, thus, reflect in explosive distribution and stemming lengths. When loading to a 'collar' in an oversized hole extra explosive will be used, resulting in higher than planned powder factors and explosive costs. A blasthole diameter assumed from a nominal drill bit size is an incorrect assumption. This paper will present some actual blasthole diameter measurements illustrating the variation in hole diameters seen in the field and proposes a practical method for achieving a useful blasthole diameter measurement.

Jan 1, 1990

By Player WP

The legislative operating environment, or the mineral regime, that a country has to offer is one of the key determinants that a company wanting to invest in an area takes into account in formulating its investment decision. The New Zealand Government recognises this and the importance of getting the regime right in order to provide for continuing investment in mineral exploration and mining in New Zealand. In recent years, the Government has given considerable attention to developing legislation which provides for investment to take place; for those making the investments to have a stable, fair and open investment environment with government intervention only when considered absolutely necessary because other approaches are not working; and for the people of New Zealand to know that investment must meet acceptable health and safety standards and have acceptable impact on the environment. Also of key importance is having a clearly defined mining regime which includes rules on how to obtain a permit and rules in respect of ongoing permit compliance, rights to develop a mineral resource and permit conditions (in particular, the royalty regime). In New Zealand, these matters will all be addressed in what are referred to as "minerals programmes".

Jan 1, 1995

By Riley S. J

The basic aim of mine planning is to design mine layouts and schedules that achieve optimisation of operations, minimum cost and maximum resource recovery. Successful accomplishment of this aim is facilitated by timely and comprehensive rehabilitation planning commencing at the pre-feasibility stage and continuing until the end of mining. Incorporation of a final landfomt design for waste rock dumps in a mine plan requires a prediction of surface stability, which may be achieved through erosion modelling. Erosion prediction models can be placed in two broad categories: soil loss prediction models eg USLE and CREAMS, and geomorphic models such as SIBERIA. A waste rock dump landform design based on selected slope form and grade and drainage systems should be developed as part of planning. A digital terrain model (DTM) of the landfonn should then be produced which can be modelled for long-term erosional stability using pre-determined parameter values. If acceptable standards of stability are not achieved, the landform should be redesigned and remodelled until the desired result is obtained. The planning process incorporating models requires knowledge of spoil or waste rock properties and model parameter values. This information is site specific and can be obtained from drill cores or costeans at the pre-mining stage and from spoil or waste rock during the mining stage. Realistic model parameter values are critical in post-mining landfonn design and can be obtained by several methods, including rainfall simulation, monitoring, geochemical analyses and grain size analysis.

Jan 1, 1994

By J A. Meadows, M G. Annandale, G Castelain

Bauxite mining on Cape York Peninsula (CYP) commenced in the early 1960s in the region surrounding the town of Weipa. Rio Tinto Alcan (RTA) operates its bauxite mines on the homelands of 11 Indigenous Traditional Owner groups. The mining activity currently operates under three Aboriginal Agreements including an Indigenous Land Use Agreement – the Western Cape Communities Coexistence Agreement (WCCCA) – which provides RTA with access to the land in return for a range of benefits to the Traditional Owners, including employment, training, royalty payments and future relinquishment of the land (Klimenko and Evans, 2009). Despite reports of some ‘good progress’ in meeting the terms of the WCCCA (Klimenko and Evans, 2009, p 5), many of the region’s Traditional Owners remain dissatisfied. Two key areas of Indigenous community concern are the current premining management practices and the outcomes of post-mining landscape rehabilitation efforts.CITATION:Annandale, M G, Castelain, G and Meadows, J A, 2016. Sustainable mining – indigenous community benefit, in Proceedings Life-of-Mine 2016 Conference, pp 173–175 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By J A. Shonhardt, I Porter

All types of coal are liable to spontaneous combustion to a variable degree according to the inherent characteristics of the coal and also extrinsic factors. In order to successfully extract coal from highly capital-intensive longwall mining operations it is necessary to evaluate and manage any risks that may be present due to spontaneous combustion. A spontaneous combustion risk management plan for longwall mining is described in this paper. This risk management system comprises identification of conditions promoting spontaneous combustion risk, a laboratory or empirical risk classification system, determination of gas ladder, adoption of adequate ventilation plans and gas monitoring systems that will lead to the development of the spontaneous combustion action plan. The risk management system was applied to a greenfield site in NSW in 1992 when prediction of a high-risk category for the coal seam was made. After commencement of production a spontaneous heating problem emerged as predicted. Description of the case history of spontaneous combustion risk management for a longwall operation in this coal seam is included in this paper.

Jan 1, 2003

It is now 32 years since Walsh's classic publication (1) heralded the beginning of atomic absorption spectrophotometry (AA) as we know it today. During this time, AA has developed into the most widely used analytical techniques for the determination of the metallic elements. The years have seen progressive changes in instrumentation so that today it is a highly sophisticated technique. One area of development in AA that is experiencing renewed attention is in the area of electrothermal excitation. In this technique a flame is not used by the analyte solution is atomised by an electrically heated graphite furnace. For a large number of elements the graphite furnace atomic absorption spectrophotometer (GFAA) is considerably more sensitive than flame work. It is common to be able to detect concentrations one hundred times smaller than those possible by flame. Today's geochemists are finding that they can gain valuable information out of very low limits of detection. Electrothermal atomic absorption spectrophotometry (or GFAA) allows for low limits of detection and can be seen to be a valuable aid to geochemical prospecting Analysis.

Jan 1, 1987

By J Kelly, C Kelsey

The Autogenous Kelsey Axial Displacement (KAD) mill is essentially a short retention time centrifugal mill, designed to effectively harness extraordinarily high concentrations of input energy for efficient particle size reduction. The mill which has an operating duty band extending from primary to ultra-fine also has the unique capacity to generate fine and ultra-fine products from single stage size reductions of either coarse or fine mineral feeds, in both wet or dry operating modes. This paper covers developments following a recent optimisation programme which confirmed that mill shell speed and the velocity differential between the shell and the rotating internal disc assembly tips could be optimised in relation to specific energy for a given feed rate and feed size providing the product size remains constant. Subsequent test-work further demonstrated the versatility of the mill with duties ranging from the removal of surface contamination associated with heavy mineral concentrate particles to the production of premium ultra-fine talc, from a single stage of size reduction. Open circuit grinding of a rougher gravity concentrate to liberate gold ahead of leaching also highlighted the scope for the application of low cost KAD milling for a range of hydrometallurgical feed preparation duties, which involve fine and ultra-fine grinding.CITATION:Kelly, J and Kelsey, C, 2013. Advanced media-free fine and ultra-fine grinding - The Kelsey axial displacement mill, in Proceedings MetPlant 2013 , pp 152-161 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By Roberts T. J, Thomson I. A

Mill scale, which contains a high proportion of magnetite and wustite, was added to the feed to the Whyalla grate kiln pellet plant during the production of acid pellets for domestic consumption. Its addition resulted in increased production -rates together with reduced consumptions of bentonite, fireclay and fuel. Mill scale was particularly beneficial when treating feed containing difficult to process, earthy, high ignition loss iron ores. Test work in the laboratory and subsequent plant experience showed that the magnetite and wustite oxidised in the drying and preheat sections of the travelling grate. The additional heat reduced gas flows through the grate kiln system, aided the drying of green balls containing earthy ores and increased the preheat strength of the balls. These advantages were offset to some extent by higher power consumptions to grind the harder mill scale and process difficulties caused by the contamination of mill scale with oil and coke.

Jan 1, 1974

By Welch B. J

Results obtained from linear sweep voltammetry at a graphite anode in cryolite-alumina melts are presented, together with those obtained from a chronopotentiometric investigation of the influence of dissolved metal. The results, consistent with both production information and other fundamental studies, showed that the following two reactions occur at the anode.Equation 1Al (dissolved) ? Al3+ + 3eThe latter accounted for some of the loss in currentefficiency.The rate of the former reaction is limited by the slow desorption of the CO from the electrode surface. Mass transfer conditions, and hence cell design, influence the importance of the second reaction.

Jan 1, 1976

By Braaksma M, Dudley K

The Girilambone Copper Mine is located in central New South Wales and has been operational since May 1993. Girilambone is operated by the Girilambone Copper Company (GCC) which is a joint venture between Straits Resources (60 per cent) and Nord Resources (40 per cent). The mine complex consists of an open cut pit, ore crushing and stacking, heap leaching, solvent extraction (SX) and electrowinning (EW) allowing for the recovery of 14 600 tpa of LME grade A cathode copper. The leaching and SX-EW plant have been described previously by Rear, Taylor and Busby (1994) and Miller (1994).

Jan 1, 1996

By P J. A Lever

This paper presents details of CRC MiningÆs work with waterjet assisted blasthole drilling. The objective of this work was to investigate techniques that reduce the cost and increase the productivity of blasthole drilling. The focus is on a technology that uses a high pressure waterjet to assist the conventional rotary rock cutting action of a tricone drill bit. The potential benefits of this technique are increased productivity, reduced drill bit wear and reduced hole deviation and hence improved quality of drilling. This paper describes the results of a laboratory based experimental program comparing conventional tri-cone drilling performance to the proposed waterjet assisted approach. Additionally, work has been completed looking at the more practical issues around the collection and sampling of drill cuttings and water recovery (recycling) when drilling with a waterjet. These studies have demonstrated that waterjet assisted drilling can significantly increase the rate of penetration over conventional rotary drilling. For the best-case experimental result, the relative improvement was over 40 per cent. More importantly, it is a starting point for examining alternative uses of the additional drill productivity obtained from waterjet assisted drilling. For example, increased drill productivity could be used to improve rock fragmentation by drilling a tighter blasthole pattern in the same time period. an existing drill fleet, then the drill fleet size could be reduced, or improved rock fragmentation could be achieved by drilling a tighter blasthole pattern within the same time period.

Jan 1, 2004

By Meyer C. F

The increasing use of continuous miners in the extraction of high coal seams has amplified the need for enhanced ventilation systems in the headings. Owing to larger face dimensions and higher production rates, more ventilating air is required to effectively dilute liberated methane to acceptable concentrations. However, the increased air quantities raise and entrain greater amounts of dust, to which the operator is subjected. Various methods (eg sprayfans, on-board scrubbers and jet fans) are used in various configurations and combinations to ventilate the headings. These arrangements generally result in a complex air flow pattern, which complicates achieving an optimum balance between diluting methane and minimising dust capture. In order to cost effectively investigate and propose solutions to this problem for the South African coal mining industry, the Division of Mining Technology has embarked on an extensive work program to evaluate various ventilation methods presently in use. Four currently generic ventilation patterns in various heading scenarios have been simulated using the Computational Fluid Dynamics (CFD) computer program. Evaluating these outputs against a predetermined set of criteria allows the best system for a particular situation to be chosen. The program also facilitates fine-tuning of an adopted system without incurring the cost and inconvenience of doing such tests in situ. This process not only provides solutions at significantly reduced costs, but also yields deeper insights into the factors affecting heading ventilation than hitherto possible.

Jan 1, 1995

Coal slurry pumping was introduced into the U.K. in 1973. Gateside packs were prepared in areas of containment using R.O.M. coal and a special fast setting cement. The packs restricted roadway convergence and moderated spontaneous combustion risks, but costs were high and alternptives were sought. A similar system using OPC and an accelerator had limited success. Much more successful was the Aquapack process which used dilute slurries of a special OPC based cement and an accelerator based on sodium carbonate and bentonite pumped simultaneously into la fabric packbag. The Tekpak system using HAC and a much modified calcium sulphate mixture superceded Aquapack on the grounds of improved cement pumping life lower alkalinity and lower costs. A further modification of this system gave a cement with a 24 hour pumping life thus obviating flushing out pipe ranges except at the week-ends, improved packbags also increased the efficiency of the process. The hazard of spontaneous combustion can be inhibited if air supply channels across the waste can be located and plugged. Using gas samples from pack pipes to locate the heating and injecting a special grout, formulated from bentonite, sodium silicate and thixotroping agents. into the waste on the intake road has proved a successful method of controlling heatings. Mine' roadway and face cavities are being safely and successfully filled with cementitious foams produced in a novel placer machine. The foams are based on fast setting cements with specialised foaming agents. Up to 13 cu. metres per hour of fast setting thixotropic foams can be produced and their use is now widespread throughout U.K. coal mines.

Jan 1, 1986