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By Whitworth NR, Fox MJ, Henley RG

The coal mass flow monitor was developed to measure the instantaneous mass flow rate of pulverised coal to the copper reverberatory furnace at Mount Isa. The instrument was calibrated with an isokinetic coal sampler which was installed immediately downstream from the coal mass flow monitor. Readings from the coal mass flow monitor were used to control the feedrate of coal to the furnace and this helped to stabilise the furnace operation.Coal samples obtained from the isokinetic coal sampler were also sized using a Leeds and Northrup Microtrac analyser. The coal size was critical to reverberatory furnace performance. These developments significantly improved the overall combustion control of the furnace and gains of ten percent were made in the furnace thermal efficiency. Testwork on an auxiliary arch coal burner is also reported.

Jan 1, 1985

With production at Olympic Dam scheduled to commence in June 1988, it has been necessary to install a complete underground ore handling system capable of removing two million tonnes of material annually from the mine. The system comprises mucking from stope drawpoints, truck haulage to underground storage, primary crushing, conveying and hoisting. On the surface, material is conveyed to stockpiles at the Metallurgical Plant. Mining of the numerous special excavations within the system was incorporated into the mine's ongoing development program prior to the underground construction phase. Utilisation of a decline from the surface enabled versatile construction equipment to operate at the underground sites as well as simplifying the transportation and delivery of construction Materials.

Jan 1, 1988

By A Buckingham, R M. Hancock

The underground Sunrise Dam gold mine commenced in October 2003 to extract ore from a series of orebodies with various dips, widths, and ore grades over a strike length of 1.5 km. To successfully operate flat stopes it was identified that a means to extract ore left behind after blasting in stopes with dips ranging from 15 to 40 degrees was needed. Various options were available, which included a bulk water cannon, hand held high-pressure water jet, remote controlled small dozer, several mini excavators and finally a specialised remote controlled excavator from the demolition industry. Trials were commenced for the bulk water cannon option in 2006 that proved that the concept worked, however, the system was too cumbersome to set up for use in cycle with production. Hand washing down using mine (low pressure) water with a two-inch bullhose proved of limited value. The small, one metre high remote controlled dozer as used in South Africa was reviewed, but the steepness of most of the stopes precluded this machine. The hand held high-pressure water jet option is still being investigated; with safety factors still being addressed. Several mini excavators were trialled to clean out the flat stopes with generally poor results, the machines being either too large to fit in the drives and pull ore down or too small with too short reach to effectively and efficiently pull ore out of the stope. In early 2007 a Brokk 330 remote controlled excavator was trialled on site with the low profile of the machine and unique arm configuration proving an effective tool for pulling ore from the footwall of short, flat stopes. A Brokk 330 remote controlled excavator was purchased in late 2007 and is currently in operation.

Jan 1, 2008

Exploring for deep shallow dipping orebodies can be very expensive and very difficult. Surface exploration is often not an option and obtaining the best location for underground drilling can cause production delays if drilling is carried out from development headings. The Otter/Juan mine has been in production for approximately 34 years. All of the production is now sourced from more than 1000 metres below the surface from an area known as the Edwards Lode. The orebody is shallow dipping and open at depth. Exploration drilling has been performed from decline stockpiles and from hangingwall drill drives. Drilling from footwall positions (eg decline stockpiles) into shallow dipping orebodies can often produce intersections which are unusually thick thus leading to optimistic resource figures. The decision to develop a dedicated hangingwall drilling position can vastly improve the quality of the data used to generate an orebody model. In 1997 a new extension to the Edwards Lode was discovered and named the æFÆ surface. In 1999 a resource calculation was performed using data obtained from drilling that was carried out from decline stockpiles. In 2002 a dedicated drill drive was developed into the hangingwall of the æFÆ surface to obtain better data to verify the previous resource calculation. For this case study obtaining more representative data reduced the resource estimate by 66 per cent. This information was obtained early enough to allow for alteration to the mine plan and without loss of capital.

Jan 1, 2003

Anodic stripping voltammetry is an analytical technique which has established some popularity for trace analysis of metals because of its sensitivity, selectivity and capability for simultaneous analysis of some elements. The technique can be readily adapted for field use because of its relative simplicity and low power requirements. This paper describes a relatively new instrument, the Portable Digital Voltammeter, developed by CSIRO, which utilises the glassy carbon electrode in a novel cell design and provides parts per billion (ug/L) sensitivity in an instrument which can be field operated. Ten elements, Zn, Cd, Tl, Pb, Cu, Sb, Bi, Hg, As and Au can be routinely analysed. Many of these elements are of interest to the mining industry, and to exploration geochemistry in particular. Case histories where the instrument has been successfully employed for stream and stream sediment analysis of Cu and Pb, for soil surveys of Cu and Au, and for Au in stream sediments and drill chips indicate there are advantages in having on-site data, during Exploration.

Jan 1, 1987

A comparison is made between bord and pillar and longwall coal mining. Longwall mining presents a challenge to raise the level of management and engineering practice. To maintain a competitive position in the world export market, the Australian coal mining industry must continue to use and develop the most advanced, cost benefiting, safe mining systems.

Jan 1, 1987

It's my privilege to welcome you here this afternoon on behalf of the Sydney Branch of the Australasian Institute of Mining and Metallurgy. This is a most important gathering. You, the delegates, represent what is probably the most influential cross-section of the mining investment community and the oil and gas investment community to meet as a group during the last decade. We are meeting today and tomorrow to review two related issues that will have far reaching implications for the effective use of capital by the natural resources sector in the 1990's. The views which will emerge over the two days will almost certainly 'influence the availability of new capital to the companies in the natural resources sector for the decade ahead. The two principal themes of Minval '89 are, first, the valuation of mining and oil and gas assets and securities, and second, disclosure and reporting requirements in the capital markets which relate specifically to natural resources companies. This conference is taking place at a time when further consolidation and rationalisation appears likely within the mining industry. Although the base metals and other sectors of the industry are enjoying profitability not seen since the early 1980's there is caution about committing to new capacity which could bring about a return to the low prices and excess supply which prevailed during much of the last ten years. These conditions have led to increased takeover activity within the mining industry overseas, and similar trends are as evident here in Australia as they are elsewhere. Recognition of value is therefore likely to become more important than ever before in preserving shareholder wealth, for creating new wealth and for preserving the financial health of the resources industry in the future. Valuation therefore is the first theme of the conference.

Jan 1, 1989

By R W. Wilson, A R. Branch

For hot mines, the use of mechanical refrigeration machines has become an essential feature of ventilation and cooling systems. Over the last 30 years, considerable effort has been made in developing refrigeration strategies and equipment to provide cooling that is cost-effective, reliable and energy efficient. In addition to these general design requirements it is necessary to take into account project specific factors such as long term mine cooling needs, operating strategy and installation time. This paper examines a number of actual mine cooling installations which illustrate how these features have influenced the design and installations. For many mines, it is known how the cooling requirements will increase as the mine develops, based on the life of mine plan. The design of the cooling installation must cater for both short- and long-term needs. The initial installation (to meet short-term requirements) must form an integral part of the ultimate cooling installation and as additional equipment and refrigeration machines are installed, it is necessary to ensure that the system remains cost-effective, reliable and energy efficient at all stages. For many mines, refrigeration machines are installed on surface and either operated near-continuously, or for the summer months only. Different maintenance strategies and policies with regard to standby equipment are highlighted for three mine installations. In spite of developments in cooling strategy, the cost of providing refrigeration remains expensive and many mines delay the introduction of refrigeration, as long as possible. When it is finally accepted that refrigeration is absolutely necessary, it is frequently necessary to æfast trackÆ the installation. To minimise site erection time and meet installation deadlines, factory pre-assembly and standardised modular equipment are widely used.

Jan 1, 2005

Roasting of zinc concentrate at the Risdon Works of the Electrolytic Zinc Company of Australasia Limited, (E.Z.), is carried out in two fluid bed roasters capable of treating 450000 tonne/yr, or sufficient for the output of 220000 tonne of salable zinc. The furnaces were constructed by Lurgi, Australia, to the basic design developed by Vieille Montagne Company of Balen, Belgium. The advantages of fluid bed roasting include a higher metallurgical efficiency in sulphur oxidation from a feed which does not require any pre-grinding, mechanical reliabil- ity through the absence of any moving parts within the furnace and the capability of being scaled up to a large unit.

Jan 1, 1977

By Gadd D. E

Since October 1972, New Zealand Steel Mining Ltd has loaded around 10 million tonnes of ironsand concentrate from single-point mooring buoys located off-shore at Taharoa on the west coast of the North Island of New Zealand. Before the first off-shore loading system was installed a considerable research effort was applied to proving the slurry loading technique. Subsequently the system has been expanded and a new buoy, pipelines and pumping system were installed in early 1978. Since then 110,000 DWT class ore carriers have been loaded at rates of around 2600 tonnes per hour through twin submarine pipelines. This paper reviews the operation of the shiploading system and attempts to answer the question: "If the Taharoa operation were to be planned in 1980, would the same research spending be necessary or have published research results since, made such practical tests unnecessary?".

Jan 1, 1980

The mining industry has had lengthy experience with risk management involving technological situations imposing risks to people and property. In such situations the relevant parameters can be fairly well defined, the outcomes can be broadly predicted and probabilities of these can be estimated. Accordingly quantitative risk assessment can be applied. In recent years there has been increased emphasis in risk management on a broader set of potential consequences. These include potential impacts on the flora and fauna of ecosystems. These are typically poorly understood and this is especially true in Australia where the vast size of the continent and sparse population make gathering a comprehensive data base on biological resources a difficult task. The resulting scientific uncertainty and ignorance regarding the potential for serious or irreversible harm to the environment mean not only that quantitative risk analysis techniques are not appropriate, but also that the precautionary principle (PP) needs to be applied as a complement to qualitative ecological risk analysis. The potential for significant impacts is particularly high in Australian ecosystems. These comprise one of the 12 æmegadiverseÆ regions of the world in terms of biodiversity and, hence, have global significance. Moving from risk management to application of the PP by the mining industry provides a significant challenge. Application of the PP has no clear guidelines to follow and, to-date, has been highly unpredictable. However, there is much to be gained for industry in embracing this challenge and taking a pro-active approach in exploring methods that will provide for clearer guidelines and hence more certainty in outcomes of environmental management decisions involving precaution. As well, there could be considerable other advantages for the mining industry in terms of reputation assurance, community acceptance and greater certainty in terms of access to resources.

Jan 1, 2000

By C Fountain

It is commonly known that copper smelter terms include penalties if the concentrations of elements, such as arsenic, mercury and fluorine, exceed stipulated limits. It is less commonly known that the behaviour of these elements in the smelters can depend on the processes used to treat the concentrate. The principle behind the penalties is to compensate the smelters and refineries for additional costs caused by the presence of the penalty elements, but these costs will vary depending on the process used and the location of the smelter.The issues caused by the minor elements include effects on the occupational health of smelter workers, increased environmental disposal costs, increased operating costs and reduced cathode copper quality.The effects of minor elements can be surprising. High levels of arsenic in concentrate are considered undesirable, but some smelters add arsenic to anode copper to improve the performance of the refinery.Excess concentrations of some elements will result in rejection of concentrates by smelters. China has blanket import bans on copper concentrates with concentrations of lead, arsenic cadmium, fluorine and mercury exceeding specified levels.This paper will review the behaviour of minor elements in smelters and refineries, explaining the deleterious effects of each of them, to provide a greater understanding for people and organisations wishing to market copper concentrates.CITATION:Fountain, C, 2013. The whys and wherefores of penalty elements in copper concentrates, in Proceedings MetPlant 2013 , pp 502-518 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

The Ausmelt Catalytic Waste Converter (CWC) has been developed for use in the treatment of industrial wastes and for the recycling of secondary materials. Ausmelt Technology uses a top submerged lance system within a versatile and efficient slag bath reactor. High temperature pyrometallurgical reactions are carefully controlled within an oxidised molten siliceous slag such that metals can be extracted from waste feedstock for recycling, with non-volatile elements reporting to the slag, usually as oxides. Modification of the slag chemistry results in a final slag product that is stable, vitrified and is able to pass standard leach tests such that it is safe to discard or be used in civil engineering applications. Toxic components in the wastes such as organohalides can be completely destroyed and are prevented from reforming. Waste to energy conversion is practiced by the addition of a heat exchanger/steam generator in the converter offgas system. The Ausmelt CWC has been used for recovering zinc from residues and slags, treating spent potliner (SPL) from the aluminium industry and a wide range of electronic and other potentially valuable waste materials. Methods of monitoring the exhaust gases at different stages in the CWC gas handling system are discussed. The assay of these gases prior to emission is used to assist in the control of the converter chemistry to ensure the complete oxidative breakdown of the feedstock.

Jan 1, 2002

As an environmental "pollutant", noise is different. For one thing, it is localised (as opposed to transfrontier) and, for another, relatively low levels can trigger very strong human reaction. The reactions, which are annoyance-based, range from mild to violent and do not always correlate well with the levels experienced. This paper draws on technical aspects of noise to consider control and control principles and balances them with the subjective nature of the perceptions and reactions. It is critical to bear in mind that health effects resulting from noise are secondary to the primary human reaction. It is also important to appreciate that annoying noise levels are usually well below those which cause hearing loss. Large mines tend to be remote from cities and towns and the country surrounding such mine sites is often inhospitable. In general, residences near large mines are committed for use by mine personnel and annoyance from mining noise would be rare. Noise problems at long term operations are often a result of secondary activity or land use. As a pioneer mining community develops, secondary and service industries may be established and a township created. With changes in way of life, the perception of problems also changes. Therefore, it is never too early to plan for noise abatement, particularly because noise is only one of a number of environmental and community concerns. Ihny environmental problems are associat- ed with development or expansion of smaller open cut facilities such as hardrock quarries. There is an ever-present need to reduce product cost by mining or quarrying deposits close to the end user and many local authorities have to operate quarries for undertaking their civil engineering responsibilities.

Jan 1, 1987

By J S. Moema, R Paton, J Zimba

Today, most organisations are familiar with the pressure to increase their effectiveness and efficiency, regardless of the nature of their business. Cost cutting and increased productivity are the main themes of many initiatives to ensure the profitability of operations and, ultimately, shareholder satisfaction. It is well known that the cost of comminution to liberate minerals such as gold from their respective ores is a major expense for mines. Comminution costs consist predominantly of grinding balls and electricity. However, there are no national or international standard specifications for grinding balls û on which a single mine may spend several million dollars per month. In addition, in the past mines generally did not specify the minimum requirements when purchasing grinding balls from suppliers. The result is that every supplier has its own grinding ball recipe (regarding chemistry and heat treatment), and is under no pressure to implement a quality assurance plan to ensure that a consistent product is delivered. The resulting variation in the quality of grinding balls leads to increased steel consumption rates and hence increased milling costs. A more stringent quality plan will generally not be welcomed by suppliers since this may entail further investments and/or reduce the production rate. In a sense, suppliers benefit from poor quality grinding balls as this leads to increased sales. Perhaps the main problem is a lack of understanding of the factors that influence grinding ball performance. This paper will describe the factors that influence the wear rate of grinding balls from both a microstructural perspective and a mill perspective. In addition, some insights are provided on the different grinding balls available and ways that users can verify their quality.

Jan 1, 2007

By Teague JK, Read HW

The relationship between the maceral composition of coal and the strength of the coke produced from that coal has received a great deal of attention in recent years. Studies using two Bulli Seam coals, and blends of Bulli and Wongawilli Seam coals, from the Illawarra Measures of the Southern Coalfield of New South Wales were carried out. The optimum range of vitrinite was found to lie between 45% and 60% (mineral matter free). Above and below this vitrinite range coke strength deteriorated. I Coke strength indices increased with rank and the optimum vitrinite content increased with an increase in rank. These changes will require confirmation as trends by testing a third level of rank. It was noted that vitrinite content decreased with an increase in the specific gravity of separation of the coal. . T Use of- petrographic analyses will increase confidence in choosing coals for coking, provided the coals are well known. Such analyses offer the possibility of greater flexibility in coal purchases and the possibility of producing a marketable blend from coals, which have limited market potential. Critical base coals for blends can be conserved. Significantly more work is required before coal reserves can be utilised to optimum advantage. This work would require extension of-the studies discussed in this paper and, in particular, the testing of a wider range of rank.

Jan 1, 1970

By Yokozawa K, Yamamoto T, Kameoka Y

Japan Construction Method and Machinery Research Institute has been conducting various field surveys of tunnel works and other excavation works, and the cost and efficiency of these two excavation methods have been studied. Based on these data, the costs of blasting excavation and mechanical excavation represented by roadheaders were calculated. The costs were calculated and compared for rocks of various hardness. When the total construction cost is considered, the degree of overbreak becomes one of the most influencial factors, because the overbreak area must be filled up with expensive shotcrete in NATM. So, in the next step, the relation between the excavation costs considering overbreak and the rock hardness was studied using the data on overbreak obtained by the field survey.

Jan 1, 1987

By J J. Cilliers, E Ventura-Medina

Mineral froth flotation is used to separate particles of valuable mineral from its associated gangue. It involves the selective separation of the hydrophobic particles from the slurry into the froth. As air is blown into the slurry, the hydrophobic particles attach to the air bubbles, while the waste particles remain in suspension. While the froth rises up, bubbles start to coalesce and burst, allowing the entrained liquid surrounding the bubbles to drain and return part of the gangue to the pulp. Mineral separation is therefore a function of the amount of valuable material loaded on the bubble shells, as well as the amount of gangue material entrained in the liquid channels separating the bubbles (Plateau borders). As a result, the separation performance of the process is affected by mineral attachment and drainage or bursting in the froth. This study aims to establish the relationship between solids loading, froth stability and separation performance. For this purpose, a series of industrial experiments were carried out to measure mineral attachment as well as bubble bursting by combining direct sampling of the bubble films and video image analysis of the froth surface. This work suggests that the solids loading on bubbles strongly affects the separation performance. The results generally showed that solids loading and concentrate grade are closely related, while froth bursting rate can be linked to the drainage of gangue from the Plateau borders and also to the overall recovery of valuable mineral. It was shown in particular that higher loadings, usually associated with higher froth bursting rates, are indicative of more selectivity in attachment and therefore a higher mineral grade in the concentrate. Additionally, this work suggests that bubble solids loading and froth stability are essential parameters to include in froth flotation models as they allow control and optimisation of the flotation performance.

Jan 1, 2005

Experimentation with new methods, materials and machines to improve primary drilling and blasting is a continuing practice in the hard rock quarry operations of the BMI Group. These experiments will continue in the remote hope that one day we may produce a perfect feed for the primary crusher. As this day is still a long way off, the necessity to break oversize boulders will be a problem to be faced for the foreseeable future. To gauge the efficiency of primary blasting from this point of view, BMI monitor the tonnes of material crushed in the primary crusher for each boulder requiring secondary breaking. Over a period of about 10 years, this figure has improved from 30 tonnes througi the primary crusher per boulder, to 100 tonnes per boulder at our largest operation, which produces in excess of 2 million tonnes per year. Evan with this improvement, 25,000 boulders require secondary breaking each year This paper does not provide the solution to this problem, as like primary blasting, it will have to be constantly reviewed as new products and techniques become available. The paper sets out all of the methods tested or considered for test by BMI and our nnnn1iicinnq nn Chair PffPr.tivPness . Economic

Jan 1, 1978

In a previous paper in these Proceedings(l) it was shown from a study of the bore'logs and analyses then available, that the brown coal seams of the Latrobe Valley areas show progressive changes in composition with increase of stratigraphic depth, equivalent to a rise in rank: These changes appear as:(i) An increase in ultimate carbon and hydrogen, calculated on a dry, ash-free basis, and(ii) An increase in calorific value, calculated on the, same basis, each of the order of 1% per 100 ft. of depth, and(iii) A decrease in moisture content of the order of 0.5% to 1.0% per 100 ft. of depth. The decrease in moisture content was found to be less regular than the other changes. In some bores the moisture content remained more or less constant throughout a single seam, or fluctuated slightly, decreasing stepwise on passage to the seam below.It was noted that individual analyses within a bore showed irregular fluctuations, tending to mask the general trend in composition change. This was particularly so for the moisture content, which had been determined for 10 ft. lengths of core, whereas the other components were determined for 50 ft. lengths of core. Averaging of the moisture contents over 50 ft. lengths reduced the masking effects of these irregularities. The suggestion was made that these irregularities arose from variations in the relative proportions of pollen, resin, wood (lignite) and woody attritus composing the core. Such variation in the coal seams has since been established in some detail for the...

Jan 1, 1948