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The story of the Penjom gold mine located near Kuala Lipis on the Malay Peninsular demonstrates the valuable role successful exploration companies can play in the development of the gold mining industry. Avocet Mining PLC ('Avocet') began exploration in the area on a limited budget in 1989, securing land tenure around the Penjom alluvial workings in July 1990. The lease granted, known as Block 7, formed part of a land package offered at the time by the Pahang State Government to develop the resources of the area. Until the late-1980s, the Kuala Lipis region, situated approximately 180 km north west of Kuala Lumpur, had restricted accessibility for security reasons precluding serious exploration or mining activity. The situation has changed dramatically in the 1990s, with several foreign explorers active in the Peninsular, targeting old alluvial and underground workings adjacent to the north-south trending Raub-Bentong Suture. Deeper drilling of these prospects has shown there is potential for both small- to medium-scale open pit mining and possibly underground operations, providing companies such as Avocet with an ideal mining investment opportunity.

Jan 1, 1997

By Quilliam B, Richmond G

Aberfoyle Ltd. has utilised a variety of flotation technologies in the Hellyer concentrator in North-Western Tasmania. Hellyer ore, with its slow flotation rates and low rate differentials between values and gangue, requires the use of long residence times and low air consumption rates in the flotation circuit. The operation of the flotation circuit, with a nominal residence time of 7 hours, has necessitated the development of a control system to provide continuity through operator shift changes. Cell selections at Hellyer varied from the 54 m3 hybrid Dorf Oliver / Maxwell (DO/MX) cells, to smaller 32 m3 Maxwell cells, conventional Don-Oliver 300 (8.5 m3) and 600 (17 m3) trough cells, and a column cell. The advantages of the large cells included low specific power consumptions and a low capital cost. However, problems with mixing and the maintenance of consistent froth depth have been identified in the hybrid DO/MX cells. Short circuiting in the trough cells was apparent, causing a considerable reduction in metallurgical performance. The column cell performs to expectation, although the application is not ideal.

Jan 1, 1991

By Fisher AEJ

On Sunday morning 7th November, 1976, at approximately 2-25 a.m., smoke was discovered issuing from the 1912 m long belt drift at Appin Colliery. A Clouth steel cord rubber belt approximately 940 mm in width had been installed in the drift in 1963 on the basis that no fire resistant steel cord belt was then available to operate on a single lift at the load and on the 160 gradient of the drift. Investigation showed that the belt drift was on fire and the usually downcasting drift was upcasting. Immediate fire fighting and rescue operations were instituted and the drift was sealed off. High expansion foam was pushed into the drift from the surface and the fire was brought under control. Recovery work resulted in the fire being put out and the drift open for walking traffic by, S-P0 am., on Wednesday 10th November, 1976. lie experience gained during the fire fighting and recovery operations led to recommendations in regard to future use of high expansion foam.

Jan 1, 1981

By Gardavsky V, Gabell AR, Green AA

The I,)hyllosilicate mineral chlorite is a common constituent of altered rocks associated with volcanogenic massive sulphide deposits, and literature studies indicate that, in general, this mineral is progressively enriched in magnesium relative to iron as an orebody is approached. Studies have shown that there is a direct correlation between the Mg/Mg + Fe ratio of chlorite and its absorption spectra in the 2.7 to 3.0 um range. However, this region, which contains the fundamental 0-H stretch absorption features, is affected by intense atmospheric absorption, and therefore cannot be used for remote sensing. At shorter wavelengths (0.4 - 2.5um), there are windows where the atmosphere is sufficiently transparent and vibrational absorption bands still occur, although they are clue to overtones and combinations, and accord- ingly are much weaker than the fundamental features. Shifts to longer wavelengths with increasing iron content can still be observed in this region of the spectrum and, with better spectral resolution and sensitivity, it may be possible to monitor subtle variations in chlorite chemist by remote sensing techniques.

Jan 1, 1987

For the mineral industry, sustainability seems to mean socially positive and ecologically neutral mineral extraction. Mines are financed and developed in response to demand for their products. The purpose of my paper is to indicate the potential dimension of demand. As part of an unrelated study which I undertook ten years ago, it became apparent that there is a persistent relationship within communities between infant mortality and mineral use; greater mineral use corresponds to a lower rate of infant mortality. This comes as no surprise; sufficient potable water, a reliable supply of food, hygienic waste disposal, hot water and refrigeration all improve the chances of survival of the more vulnerable members of any community. The predictable provision of these facilities requires the application of minerals. This relationship is supported by a table (Appendix 1) included in the UNICEF publication, æThe State of the WorldÆs Children 2001Æ. This table lists regional infant mortality rate (IMR) statistics from around the world, including a listing for æindustrialised countriesÆ. Such countries experience an IMR lower by an order of magnitude than any other region. æIndustrialisedÆ inevitably involves the use of metallic and energy minerals. The principal use of copper is in the generation and distribution of power; it is fundamental to any industrialisation. IMR is a valuable connection because it quantifies caring for the young, a vital strategic driver of human behaviour independent of time, place, fashion or economic circumstances. I have tabulated the population, IMR and the copper demand per head of population for countries containing over 99 per cent of the population of the world in the years 1950, 1960, 1970, 1980, 1989, and 1999. These countries have been consolidated into four groups, Very High, High, Medium and Low rates of infant mortality (UNICEF has used this terminology; the Low group includes all the æindustrialised countriesÆ). The purpose of this consolidation was to reduce the volume of work, to dampen out the impact of regional wars and business cycles, and to dampen out the variable quality of information. Based on the pattern of the copper demand, population and IMR over the last 50 years, I have projected the likely copper demand in 50 years time. A dominant feature of my tabulation is the increase per decade in copper use per head and a corresponding reduction of the IMR. The word æuseÆ is preferred to æconsumptionÆ because it is estimated that over 80 per cent of all the copper ever mined is still in circulation There are two major influences at work; one is the absolute increase in population (UN estimates for 2050 are updated periodically) and the second is the movement of countries into a higher pattern of use and lower IMR. For example the Medium group in 1989 had an infant mortality rate approximating that of the Low group in 1960. With the population of the Medium group (which includes Russia and China) forecast to reach 2.6 billion in 2050, the world copper demand in that year will be significantly greater than the present figure. Nevertheless it will not be as great relatively as the increase of over 300 per cent in the last 50 years.

Jan 1, 2002

By R Markoski, P Grealish

The requirement for rapid vertical development for underground ventilation is often a factor when dealing with dynamic mine plans, with short vertical developments being used to optimise ventilation systems. In an effort to increase the safety and efficiency of the constructions, a simple and effective sinking methodology is required that is both adaptable and repeatable. A modified shaft construction methodology is proposed that attempts to minimise risk to the personnel as well as be cost-effective. Readily available equipment is used to ensure adaptability to the various environments and shaft parameters.One of the greatest risks of shaft sinking is having personnel working suspended over open cavities or underneath suspended loads. Removing this risk, by ensuring all construction is done from solid ground, allows for safer sinking operations. As the process is repeatable, familiarity and confidence in its construction sequence will increase with each successive sink.A trial sink is performed with a 3.6 m diameter, 20 m deep shaft. The shaft was excavated using a conventional strip-and-line philosophy, with the shaft then being lined from the collar via the use of large diameter corrugated steel culverts. The annulus between the steel culverts and shaft excavation is then filled with a concrete mixture to secure it in position.The new process was successful, with no personnel at any time during the process being suspended above an open excavation. The installation had relatively low capital and operational costs and was completed faster than an equivalent, conventional concrete-lined shaft construction. Therefore when compared to conventional shaft-sinking methods, this process can be considered safer, more efficient and relatively cost-effective.Further research is required to determine whether this method can be expanded to larger vertical developments.CITATION:Markoski, R and Grealish, P, 2014. A new method for rapid vertical development of underground ventilation shafts, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 603–606 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By Lewis IE

Copper-lead dross is a by-product of the refining of lead bullion produced by the Imper- ial Smelting Process. This dross contains some 27 percent copper, 50 percent lead, four percent zinc and one percent sulphur. An ammonium carb- onate leach at atmospheric temperature and pressure removed the copper from the dross while the lead zinc and precious metals remained in the leach residue for return to the smelter. The leach solution containing the copper was then purified by liquid-liquid ion exchange using LIX64N in a kerosene diluent. ("LIX" is the registered trade mark of a range of hydroxy oximes marketed by General Mills Inc.) The pilot plant had a capacity of 0.7 kg/h of CuSO4,5H20 and was operated for some fifty days on a two shift basis. Copper sulphate of excellent purity was produced, and the results obtained indicated that a copper recovery of ninety percent from the dross could be expected from a commercial installation.

Jan 1, 1975

By Martins V, Dunne R

A re-evaluation of the Hampton Boulder prospect in the early eighties resulted in a decision to proceed with mine development in December 1985. A 500 000 tpa gold treatment plant was commissioned in December 1986. The treatment facility was expanded to 1 600 000 tpa in July 1988. A tailings treatment plant to improve recoveries from harder gold bearing sulphide ores was built in December 1990. The development of an underground mine in 1991 meant that a source of sand for backfill was required. A sands plant to fulfil this requirement was commissioned during November 1991.As of June 1992 a total of 7 710 487 tonnes of ore have been treated through the New Celebration gold plant. Total gold production from inception of the new mine until June 1992 is 545 470 ounces obtained at an average recovery of 90.1 per cent from an average gold head grade of 2.4 g/t. The combined quoted ore reserves at the end of December 1991 was 14Mt grading 1.8 g/t gold

Jan 1, 1992

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

By R Lau

In recently completed road tunnel projects in Queensland, such as the Airport Link and the Clem7 tunnels, there is a smoke duct running along the roof of the carriageways to extract smoke in case of fire. In New South Wales, no road tunnels have a smoke duct. In the Melbourne City Link tunnels, there is a small smoke duct running along the roof. All of the tunnels are safe as claimed by the designers and authorities. However, there is significant cost associated with providing a full size smoke duct compared with no smoke duct. This paper is going to present a comparison of the road tunnel safety with a smoke duct and those without one from a risk perspective. It further discusses the cost-effectiveness of such provisions and whether similar levels of safety could be achieved without a smoke duct.CITATION:Lau, R, 2014. Smoke duct or no smoke duct for road tunnels, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 83–86 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By I Jabouri

There are many physical factors that can affect the self-heating rate of coal. The presence of seam gas has often been referred to as inhibiting coal self-heating due to the limited access of oxidation sites created by the presence of the gas adsorbed on the coal pores. Similarly, the presence of bed moisture in the coal also acts as an inhibitor of oxidation by blocking access of air into the pores. Gas drainage of a coal seam prior to mining removes both gas and moisture from the seam. Bulk coal self-heating tests in a two-metre column on both gassy, as-mined and gas-drained, dried high volatile bituminous coal show that removal of gas and moisture from the coal accelerates the rate of self-heating to thermal runaway from 8.5 days to 4.25 days, from a start temperature of 30¦C, with an airflow of 0.25 L/min. The corresponding gas evolution pattern for each of these situations is different. Therefore, it is necessary to take this change in coal condition into consideration when developing a spontaneous combustion management plan.

Jan 1, 2005

By T Baumgartl, R I. Maczkowiack, O White, P D. Erskine

Queensland legislation, industry codes and policies relating to mine rehabilitation and closure create the expectation of successful progressive rehabilitation and that the post-mining environment is being returned to a condition suited to a pre-agreed, beneficial end use. Yet none of the rehabilitated mined land in the Bowen Basin has been certified as successful by authorities suggesting there is a gap between current rehabilitation and the full environmental outcomes that the legislation could deliver. We tested the veracity of this perspective and reflect on where responsibility for any discrepancy lies.We first reviewed current Queensland legislation and industry codes relating to stakeholder engagement, rehabilitation, closure planning and post-mining land use. We tested the accessibility of the documentation trail for several recent coal-mining projects in the Bowen Basin and examined the level of detail in approval documentation. We then assessed the rehabilitation performance reports of these mines in relation to the contents of their approval documents. Legislation, guidelines and codes repeatedly emphasise the need to plan for closure before mine operations begin and to progressively perform rehabilitation with an agreed end-use in mind. Early stakeholder involvement in these processes and transparency of actions and outcomes are also encouraged by government publications. Overall, in terms of transparency, we found that relevant documents are generally available to the persistent enquirer. However, the rehabilitation and closure undertakings given in both mine company and regulator documentation were commonly generic and rehabilitation obligations were not explicitly incorporated into rehabilitation plans. Rehabilitation reporting was also weak in that no distinction is required between successful and unsuccessful revegetation, nor to closure objectives and mine completion criteria. Responsibility for the apparent disconnect between regulatory intent and actual performance appears to begin with the regulator too readily allowing generic information and in not requiring performance reporting to correspond with approved post-mine conditions. As a result, companies may have a much greater rehabilitation and closure risk than mine management expects. More poignantly, the checks and balances that are in the legislation are not yielding the environmental outcomes of which they are capable.CITATION:White, O, Maczkowiack, R I, Erskine, P D and Baumgartl, T, 2012. Walk or talk - Is the current mine approval process in Queensland delivering rehabilitation and closure success?, in Proceedings Life-of-Mine 2012 , pp 59-68 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

The precious metallogenic belt and its geoloqical-tectonic location in eastern China.The precious metallogenic belt of eastern China is located in the western part of the Pacific gold metallogenic belt, and occurs in the upper levels of the continent cut by a deep fault structure tending NNE and NE, and active during the Mesozoic. The precious metallogenic period ranges mainly from Late Jurassic to Early Cretaceous (160 Ma-110 Ma); subordinate mineralisation occurred during the Hercynian period, and was rare in the proterozoic.Seven precious metallogenic belts are recognised from east to west, i.e. from continent to the margin active belts, as follows:1. Au-Ag-Te metallogenic belt of East Shandong Province2. Au-Ag-Pb-Zn metallogenic belt of west Liaoning-Miyun area3. Au-Os-Ir-Cr-Cu Mo metallogenic belt of Chengde Pingquan area4. Au-Ag-Pb-Zn metallogenic belt of Zhang Xuan area5. Au-Ag-Pb-Zn metallogenic belt of Zhejiang province6. Au-Ag-Se metallogenic belt of East Qinling area7. Au-Pd-Cu-Mo metallogenic belt of Wansu area

Jan 1, 1990

By Onal G, Celik MS, Dogan MZ

Chromite tailings assaying 21.2 per cent Cr2O3 was upgraded to 48.7 per cent Cr2O3 at a recovery of 72.0 per cent using column flotation with a mixture of anionic collectors at pH 11. Electrokinetic methods were used to elucidate the mechanism of collector adsorption and correlate the findings with the optimum flotation conditions. Multivalent constituent ions such as Cr3+, A13+, Fe2+ and Mg2+ were found to adsorb on chromite surface and shift the zpc of chromite in the direction of oxide form of the mineral. The anionic collectors also imparted a negative charge to chromite in the entire pH region. The higher zeta potentials obtained upon adding the anionic collectors is ascribed to the adsorption of anionic surfactant onto the positively charged chromite surface. The positive sites are generated through formation of significant amount of hydroxy complexes of magnesium at pH 11. Complementary infrared data reveal the absence of a shift in the spectra indicating the possibility of physical adsorption in the system.

Jan 1, 1993

By M Spiteri, S Woth, J Caratti, K Henley

Blasting is an essentially violent process aimed to disrupt and loosen rock for productive excavation and downstream processing. Dilution of the orebody to some extent is the inevitable result, particularly in narrow vein gold mines. A small change in gold recovery is usually a strong lever on revenue generation. As a result blast designs are carefully engineered to both minimise and control the direction of rock movement. Traditionally blast designs in gold mines have used the minimum powder factor that will still permit rock excavation. This now conflicts with the recent industry trend to optimise the total process flowsheet from the mine to the mill. Numerous mines have achieved success in reducing total mining cost by increasing powder factors. Not only is explosive energy cheaper than mechanical comminution energy requirements, the increased blasting effect may deliver benefits across all downstream processes of digging, hauling, crushing and milling. Kalgoorlie Consolidated Gold Mines (KCGM) Fimiston operation is the largest gold mine in Australia, located in the heart of the Kalgoorlie Goldfields. Blast dilution has been reduced at KCGM by managing location of blast boundaries and by firing along strike to choked faces. Significant economies of scale have resulted from application of a bulk mining methods. The bench height of 10 m is the largest in the Western Australian Goldfields, and is typically mined in a single pass with large face shovels. Recent increases in production rates in both the mine and mill has been partly attributed to a 30 per cent increase in powder factor. KCGM then examined the benefit of a further 18 per cent increase in powder factor to 1.0 kg/BCM. A concern though was the impact of very high powder factors resulting in excessive blast movement and subsequently ore dilution. This was the subject of a project conducted with Orica Explosives. OricaÆsDMC(Distinct Motion Code) blast model was applied to understand the effect of not just further increases in powder factor but also blast geometry and explosive type. The modeling work demonstrated that high powder factors may be applied with minimal increase in ore dilution provided the combination of blast geometry and explosive type is optimised. These results are currently being implemented to achieve further reductions in total mining costs without a significant impact on recovery.

Jan 1, 2001

As has been the case since the early Phoenician traders, the minerals used by modern man come from deposits scattered around the globe. The price received is more and more being set by worldwide supply and demand. Thus the price component in the profit equation:Profits = Material sold (units)x(Price/unit û Cost/unit) is largely determined by others. The recent price history for two of the major metals, copper and iron, are given in Figures 1 and 2, respectively. As can be seen there has been a steady decline in the prices (when expressed in constant dollars) over the 20 years which have lapsed since the first of the International Conferences on Mass Mining, æDesign and Operation of Caving and Sublevel Stoping MinesÆ was held. If one would look back over the entire 20th century this would also be the trend. Cost containment/reduction through efficient, safe and environmentally responsive mining practices is serious business today and will be even more important in the future with increasing mining depths and more stringent regulations. A failure to keep up is expressed very simply as: Profit This, needless to say, is unfavourable for all concerned (the employees, the company, and the country or nation). The mining companies have had to look at ways of reducing the expense part of the profit equation while maintaining safe, environmentally conscious operations. Table 1 summarises the rules for working in todayÆs economy.

Jan 1, 2000

By O S. Maluleke

In some deposits valuable heavy mineral quality is poor due to increased mineral surface coatings from higher slimes and more competent sand orebodies. Mineral surface coating can include silica or aluminium rich clay minerals and iron based minerals that render the final product quality off-specification, in this case specifically ilmenite and zircon. Conventional physical beneficiation processes such as magnetic separation, electrostatic separation and gravity separation are not able to remove these surface coatings. Surface dependent separation techniques such as electrostatic separators are affected by these coatings which hinders the rejection of non-valuable mineral from product. Attrition scrubbing is the most commonly used technique to reduce surface coatings, using mechanically induced particle to particle interaction, abrasion and shearing.In many cases it is a challenge to measure the surface removal efficiency of these scrubbing units. Elemental analysis techniques (ie X-ray flourescence) (XRF) in a multi mineral environment are unable to measure surface impurity reduction with enough precision. Mineralogical analysis (in this case Qemscan®) has constraints in terms of sample preparation with highly coated particles being plucked out during block polishing. This paper suggests a combination of laboratory separation techniques coupled with elemental analysis to evaluate the surface removal efficiency. Three different types of feed materials were used to analyse the efficiency of surface removal using production attritioner scrubbers. This approach relates the downstream beneficiation plant’s expected performance with that of the attrition scrubber’s scrubbing efficiency.

Oct 5, 2011

By G M. Evans, C M. Phan

This paper presents an analysis on the dynamic adsorption of frothers and collectors onto air bubbles in flotation. The analysis was carried out using the theory on the surfactant transfer by diffusion and adsorption. The bubble size was considered when solving the diffusion equation for the dynamic surface excess. The adsorption kinetics was modelled employing the Langmuir adsorption isotherm and its extension with the inclusion of the lateral interaction of the adsorbed molecules (the Frumkin adsorption isotherm). The numerical computation was applied to solve the governing equations. The dynamic adsorption of the surfactants was measured in terms of the dynamic surface tension for sodium dodecylbenzene sulfonate (SDBS) and Dowfroth 250, using pendant bubble tensiometry. The results show that for air bubbles with diameter of the order of 1 mm, the bubble size effect on the dynamic surface tension is small and the solution of the diffusion equation for a planar gas-liquid surface can be used to describe the dynamic adsorption onto the air bubbles. The experimental data obtained with SDBS were well described by the Frumkin adsorption isotherm and the molecular diffusion. The model description for the experimental data obtained with Dowfroth 250 required the kinetic equations. The paper is relevant for further analysis of the role of the adsorbed surfactants in the particle collection.

Jan 1, 2005

By Jankola W. A, Delong O. J

Historically, the silica content of zinc concentrates treated at Cominco's Trail Operations has been low. Silica in the roaster calcine seldom exceeded 1.5 per cent because of the low silica content of concentrate from Cominco's Pine Point mine. With the shutdown of Pine Point, alternate sources of concentrate were required and it was anticipated that calcines containing greater than two per cent silica (with excursions above three per cent) would have to be treated. Previous experience indicated that the existing leaching circuit could not tolerate such high levels. Therefore, a research program was undertaken to identify the key factors affecting silica precipitation; to compare different process alternatives; and to make recommendations for modifications to the existing plant. A project to modify and upgrade the leaching circuit has now been completed. Calcines with higher silica contents are successfully treated, but the upper limit of the circuit is unknown. The results of the research work will be discussed and the new leaching plant will be described. Recent operating results will also be presented.

Jan 1, 1993

By R Brake

The Enterprise Mine (EM) is located at Mount Isa and is wholly owned by Mount Isa Mines Limited (MIM). This high-grade copper mine extends from about 1000 m below surface to almost 2000 m below surface. A recent $400 million upgrade has taken the operation from a production rate of 1.3 Mtpa to a capacity of 3.5 Mtpa. The effects of high surface ambient temperatures in summer, combined with the depth of the mine and high virgin rock temperatures results in heat stress in the working place that, without intervention, would exceed the levels that human physiology can withstand. It would also result in significant decreases in productivity and high accident rates even where work is possible. Moreover, with a very hot and deep mine, the needs of æegressÆ and entrapment of workers during a mine emergency must be carefully considered. Enterprise Mine has taken a æsystems approachÆ to the issue of working productively, healthily and safely in heat. This involves setting limits of thermal stress for workers, understanding productivity decrements when working in heat, establishing productive and healthy environmental targets, developing engineering solutions to meet these targets, creating a well-educated workforce with respect to working in heat and then developing health protocols to ensure workersÆ health is protected. Refrigeration must be added to the mine to provide acceptable and productive conditions underground. By the time the mine is commissioned in 2000, Enterprise mine will have an installed refrigeration capacity of in excess of 40 MW(R). The ventilation engineering principles proven over many years at the other Isa underground mines are tailored to æfloodingÆ the mine with air to remove the heat, which is the main contaminant. This principle will not work at the Enterprise Mine, for reasons discussed below. With the underlying ventilation principle no longer satisfactory, a complete review of the entire ventilation principles and engineering solutions was required for the Enterprise Mine.

Jan 1, 2000