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By Johnson G. D

The typical management systems used to address the issue of operating risk centre around technologies that identify, analyse and evaluate the risk factors. These logical systems such as HAZOPs, Fault Tree Analyses, etc rely heavily on technical considerations and process flow analysis. However, several research projects, across industries and countries have clearly shown that up to 80 per cent `operating risk' is determined by the actions of workers, supervisors and managers. Yet, most of the focus of risk management is on technical and procedural issues. This suggests that a significant imbalance exists in our management systems and that industries are unlikely to show significant improvement on current levels of safety performance. Effective risk management must include the intangible element of the organisation psychology towards risk. A practical and theoretically sound approach had been researched and developed in and for the mining industry. This paper describes the approach and methodologies applied at the Cosmo Howley Gold Mine in the Northern Territory, where an inclusive approach to managing financial and operating risk was followed. The Cosmo Howley Mine showed a dramatic reduction in lost time injuries and improvements in financial indices - providing conclusive evidence of the link between management effectiveness, safety and productivity. This `triangle' has often been the subject of speculation and theory. It is demonstrated in this paper how the management team of Cosmo Howley focused their practices and systems on the improvement of organisational dynamics, ensured tangible and clear focus on parameters of costs and safety and how the improvement process was managed. It is concluded that the improvement process did not require a `major re-engineering' of the organisation. The organisation culture changes that occurred were incremental, planned and effective. It entailed the implementation of sound risk management methodologies, and ensured that a significant emphasis was placed on an aspect that is defined as `organisational dynamics'.

Jan 1, 1994

The proportion of coal production from underground operations in Queensland, is likely to increase in the future. A portion of this increase will come from mines working under farming areas. The degree of compatibility between underground coal mining operations and farming is examined. Two case histories are considered in detail. These relate to farming areas in the Moura and Emerald districts. Mining the Moura, area has been undertaken for the last two and half decades, while in the Emerald area, large scale underground coal mining is currently being planned. Interference to watercourses and water harvesting programmes, damage to crops, and ponding in cultivated areas have been experienced in mining areas. With expansion of underground mining in farming areas, the principle areas of likely conflict are the effects of surface subsidence on irrigation and erosion control structures. Other potential problems that may arise in particular circumstances include reduction in availability of water for harvesting, pollution, surface cracking and damage to surface structures. Finely textured soils and erratic and violent rainfall patterns make farming in central Queensland particularly vulnerable to severe soil erosion unless strict precautions are taken. Soil erosion control is an essential part of farming. Contour banks are used to ensure that runoff velocities are suitably low. Where steep slopes are encountered, grassing is the most effective way to prevent erosion.

Jan 1, 1987

The decrepitation technique is a rapid means of measuring abundances, temperatures and to some extent the fluid compositions, of fluid inclusions in transparent and opaque minerals. The method has been used to investigate the hydrothermal fluid systems associated with gold mineralisation in the Tennant Creek, Pine Creek and Halls Creek Goldfields. At the Enterprise Mine, Pine Creek, several different stages of quartz veining are distinguished and within these, gradational changes in fluid temperatures and compositions help to define the centre and nature of the thermal system responsible for the mineralisation. In the surrounding Pine Creek region and at Tennant Creek and Halls Creek, the results were applied on a regional scale to characterize outcrops and aid in the discrimination between potentially mineral- ized and barren outcrops. The decrepitation method involves the heating of a small (lgm) sample of crushed and sized grains up to as high as 800 degrees celsius. During the heating the fluid inclu- sions within the grains develop sufficient internal pressure to physically burst, the temperature of such bursting being dependent on the type of fluid and the prevailing tem- perature at the time the inclusion was originally trapped. The resulting tabulation of the number of inclusion bursts per 10 degree temperature interval is plotted as a histogram of decrepitations versus tempera- ture and called a decrepigram. The decrepi- grams frequently show several distinct peaks at different temperatures which are caused by different populations of inclusions in the sample. The areas of the peaks indicate the abundances of inclusions in each population while the shape and mean temperature of the peak provides a guide to the type of fluids involved. Of particular importance in this study is the presence of decrepitation peaks at fairly low temperatures (around 2000 C. These are characteristic of C02 rich fluids which build up internal pressure very quickly when heated. The Enterprise Gold Mine at Pine Creek comprises a number of overlapping quartz vein systems hosted by Burrell Creek Formation sediments. The geology of this mine has been described at this conference by Dann and Delaney, who have defined several distinct stages of quartz veining based on structural, mineralogical and physical features of the veins. For this decrepitation study, 19 quartz samples from the mine and environs, including some from each stage of veining were collected. These results suggest that there are 4 major vein types, within 3 of which additional small variations can be discerned which are due to gradational changes in the temperatures and fluid compositions in the mine area.

Jan 1, 1984

IT will be noticed, from the following contributed papers on the various plant, what an infinite number of parts are required to be kept in active operation in order to derive a resultant product of commercial value from the ores and materials received at the works. Crude ores and concentrates, in every degree of complex structure and resistance to treatment, are arriving daily from near and distant places, moreover their metallic contents are so varied that an outsider, unacquainted with the operations, would naturally wonder how it is possible that the rare elements are to be sorted out and classified into their true order, to meet industrial requirements.The proposition is necessarily not a simple one and owners of mining properties have naturally refrained from smelting their complex ores on account of the technical difficulties of attaining high efficiency and recovery of the metals, where limitations are imposed in procuring a variation of ores that lead to the best smelting and refinmg result. This difficulty obviously imposes many disabilities on the smelter, who is prepared to accept all such complex ores, and it may be said that were therenot available a large weekly supply of lead concentrates from the company's own mine at Broken Hill, of standard quality, much of the material being treated in the world today would certainly not be marketable.In order to sustain full efficiency, each section of the works must maintain its.true balance and synchronize with the requirements of such other departments as are dependent on its partially treated materials. This harmony of operations is not only imperative as regards tonnage output, but also relies on the condition of the resultant treatment by each plant, no large variations being permissible.The various officers are, therefore, dependent on one another to keep the order of the operations flowing regularly. This is accomplished by constant intercommunication and observation, as...

Jan 1, 1918

By Griffin P

The project is the result of a European Commission supported collaboration between Surpac Software International, the Technical University of Berlin, and the industrial partners Exploration and Bergbau GmbH (E+B) and Taylor Woodrow. The object

Jan 1, 1998

Distal rhyolitic tephras from the Taupo Volcanic Zone are widespread in the Auckland urban region. Some are primary air fall or flow deposits but most are reworked. Their presence indicates potential hazard for the Auckland urban region from future eruptions of central North Island volcanoes and associated secondary effects. Geotechnical problems occur as a result of weathering of the tephras yielding sensitive materials.

Jan 1, 1990

By Lin C, Jiaxiang D

A series of experiments were carried out with Hallimond tube in order to test the effects of different reagents. A good result has been obtained when potassium-n-butyl xanthate is used as collector for molybdenite and graphite complex are depressed by the depressor mixed with nigrosine and iron (III) chloride. The separating mechanism has been studied with help of many modem instruments.

Jan 1, 1993

This paper outlines a range of strategies for steady state optimisation of most types of concentrators. Optimisation is considered in terms of comminution performance, energy efficiency, concentrator strategy and overall mine/concentrator operating philosophies. Application becomes more complex as the range of optimisation is expanded. However, the potential gains also increase. A step by step framework for data collection and analysis is provided. This process is facilitated by powerful simulation and mass balancing programs which are now in common use. Once a sound, steady state rationale for optimisation has been developed, it may be used to provide a fine foundation for process control system development.

Jan 1, 1993

Explosives have been an important tool for unlocking minearl wealth from the earth's crust for several countries. In'the past, innovation in explosives technology, spurred on by industry needs has assisted the Mining Industry to improve productivity and reduce costs. A symbolic relationship exists between Explosives and Mining. Australia has vast mineral wealth. Our Mining Industry is of major importance to the Economy., The value of mineral produc- tion in 1987 was $25 million or 10% of GDP. Australian Mining is a business depending on international markets. The Mining Industry is our leading export earner, generating 44% of all export income. 60% of mineral production is exported. About half of these minerals are extracted using explosives. Explosives rank as one of the top three consumable expenditures for a mine. For example: A major open-cut iron or coal mine can spend $6 million dollar per annum on explosives.

Jan 1, 1988

By George CW

Western Mining Corporation (W.M.C.)operate a 30 000 tpa nickel refinery at Kwinana, W.A. using the Sherritt Gordon Process. Following ammonia/air leaching of sulphideminerals and subsequent copper removal, nickel metal is produced as powder by hydrogen red-uction of the ammonium sulphate-rich solution. Batchwise reduction in pressure autoclaves is preceded by an oxidation/hydrolysis step to ensure nickel powder quality.The reduction process is energy intensive, requiring high temperatures and pressures. Present energy requirement is 24 GJ per tonne of nickel reduced. Of this, 95% represents steam and hydrogen consumption and 5% electric power. The design and operation of the red-uction circuit is reviewed, outlining the main areas of steam and hydrogen usage.

Jan 1, 1985

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 W Uhlmann, U Grnnewald, B Nixdorf

Flooding with surface water is the preferred technique for the abatement of acidification from pyrite oxidation in the lakes of abandoned Lusatian lignite mines. However, water resources of the region are limited and in addition, interruption of water inflow during the summer and the termination of the flooding process after reaching the final water level can lead to a re-acidification of the lakes. The development of three mining lakes with a surface-water flooding history of six to 28 years was analysed û in two lakes on the basis of fortnightly to monthly hydrochemical monitoring data. During summer flooding interruption, the younger lakes showed a decrease in pH from neutral down to pH 4. The degree of the pH decrease depended on the intensity of the groundwater inflow from the overburden dumps and this affected the hypolimnion more than the epilimnion. The third lake was flooded 28 years ago and up to now, interruption of the surface water inflow resulted in re-acidification. These three examples were able to show the benefits and limits of the surface water flooding technique for the abatement of Lusatian mining lake acidification.

Jan 1, 2003

The excessively high cost of production in underground coal mines has made the survival of many coal mines around the globe economically non-viable. The global competitive coal market speaks itself of the desirability of a lower operating cost in conjunction with a higher productivity performance, particularly in underground coal mines, and calls for an optimal production planning under a host of constraints. Such a task of optimal planning is not an easy exercise like that of traditional planning based merely on intuition, experience and subjective judgement. It essentially demands a thorough understanding of the complex interaction of mine sub-systems for judicious application of optimisation tools and techniques available with operations research. A few large mines around the globe have made an effective use of a sizeable number of operations research packaged programs for optimal decision-making (Grayson, 1989). The success of practical applications of operations research techniques made in a variety of mining problems in large mines in different parts of the world will hopefully make inroads to smaller mines in years to come. The present paper is an addition in the series of such applications of operations research tools to mining problems, particularly with reference to an underground coal mine in India. The paper is based on research work (Jawed, 1990) and deals with the development and use of a mathematical model for production planning in underground coal mines under multiple objective environment subject to a host of constraints.

Jan 1, 1995

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

By N Kreutzman, A Moilanen, V Palosaari

Carboxymethyl cellulose, CMC, is widely used in mineral processing as a flotation depressant, mainly for the depression of carbonate and talcaceous gangue in the flotation of Cu-Ni sulfide and PGM ores. Although CMC is a common depressant that can be used in the flotation of different ores, understanding of the interaction mechanisms between CMC and mineral particles in different flotation circuits and different pulp conditions is still limited. Electrokinetic measurements, microflotation and laboratory-scale flotation tests were carried out to optimise the action of CMC depressants in the flotation of a PGM ore. Standard and new CMC brands produced and characterised by Noviant were used in the study. Pure talc and chlorite minerals and a low-grade PGM ore composite were used as test materials. A laboratory flotation test evaluation was performed using the recovery-grade relationship and double value index (DVI) calculation to estimate the effects of both valuable and harmful components on the product value. Solution conditions play an important role in the depression of gangue minerals such as talc. The most favourable conditions for MgO depression were found to be mildly acidic in which conditions the electrostatic repulsion between the CMC molecule and talc is minimised. Similar effects were obtained with electrolytes that affect the conformation of the CMC molecule and the mineral surfaces. In addition to the control of chemical conditions in the pulp, CMC molecules were modified to optimise structural variables. The new CMC brands developed in this work showed significant potential to improve flotation performance, particularly when pulp conditions are controlled.

Jan 1, 2005

Hoisting ropes are constructed of wires and strands positioned helically around the axis. This helical positioning causes that, in the rope loaded at the end with the weight Q, the longitudinal displacement u, axial force P, torsional displacement v and constant torsional moment M are generated. More over, the proper weight of the rope q gives the force acting along the axis of the rope. This force changes its value from 0 at the bottom to qL at the top. This force gives, along its length, a variable torsional moment making the rope rotate. During the movement of the conveyance downwards the falling part of the rope rotates, which makes it untwist on the section up to the half-depth of the shaft and twist on the other half-depth. As the result, the twisting lay of the rope changes increasing in the upward direction and decreasing downwards. The angle of twist of the strands changes in an apposite way. When moving upwards, the uplifted rope does not twist and retains its state of deformation up to the moment when it passes over the pulley. Next, the cycle of untwisting and twisting repeats during the movement of the other conveyance downwards. This phenomenon is known from mining practice. It was also analysed, in the works of Glushko (1966) and Popowicz (1963).

Jan 1, 1995

By R A. Medower

This paper provides a glimpse into the future of minerals processing with emphasis on æAutomation InnovationsÆ for the new millennium, particularly those involving advanced process control and innovative new applications of process control technology in 2007.

Jan 1, 2000

Oxidation or sulphidization of the surface of pyrrhotIte partIcles enhances atomic interdiffusion at elevated temperatures and provides a mechanism for interface growth between particles in contact. In a mass of pyrrhotite-rich ore or tailing, where oxidation heating is not controlled, bonding of particles by diffusional mass transport contributes significantly to the agglomeration of the mass.

Jan 1, 1976

By Chaves AP, Delboni H. Jr

Thermal comminution is an industrial process specially suited to very abrasive material, when contamination with Fe from wearing parts of conventional crushing and grinding equipment must be avoided. It involves an initial step of heating the material to be comminuted, followed by sudden cooling (quenching) and finally by a conventional mechanical process to disassemble the particle aggregates. The thermal step is, in fact, a pre-fracturing process. The heating operation causes changes in phase of the minerals and changes in volume of these minerals and other substances included in pores and cracks. The cooling operation causes thermal shock reversions or the phase transformation and consequent generation of internal stresses, high enough to fracture the solid.

Jan 1, 1993

Gold mining commenced at Telfer in Western Australia in 1977. Ore mining was carried out by owner equipment and personnel with waste stripping by a contractor. Initial ore reserves were in predominantly high grade, geologically simple reef structures. A mining method was developed using dozers to selectively mine the ore bearing horizons with a minimum of dilution. As the mine has developed the simple, high grade ore reserves have been progressively replaced by more geologically complex, lower grade reserves. In turn, mining methods have evolved to extract this ore by the most appropriate methods. On-going attention to ore mining practices will ensure that project profitability and viable mine life are optimised.

Jan 1, 1986