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By T P. Hynes

Submarine tailings disposal is conceptually an attractive option for managing reactive mine wastes in coastal regions by virtue of reduced sulfide oxidation under a water cover and no infrastructure to maintain after mine closure. However, the lack of detailed knowledge of metal leaching, dispersal of fine tailings and biological impacts in the marine environment has led to no operating permits currently in effect in Canada. Detailed chemical and ecotoxicological assessments at two historic copper mine sites (Little Bay and Tilt Cove) in the north coast of Newfoundland with tailings disposed in an estuarine to shallow (=100 m) marine environment have demonstrated reduced reactivity of sulfidic tailings when submerged under water. Only non-acute toxicity is detected in biota inhabiting the immediate vicinity (A review of another historic shallow marine tailings operation in the southern tip of Vancouver Island (Jordon River) with a high-energy setting also reveals problems with unconfined tailings dispersal and temporal biological impacts. Documented studies at two deeper (140 - 360 m) marine tailings disposal operations at the northern tip of Vancouver Island (Island Copper) and northwestern coast of British Columbia (Kitsault) again illustrate imperfect predictions of tailings re-suspension and dispersal. At these sites, bioaccumulation of tailings-derived metals appears to be minimal. There is evidence of rapid re-colonisation of the tailings surface by benthos but of different species than the original population. Integrating these observations with reported metal fluxes and biological diversity associated with submarine hydrothermal vents, the risks and benefits of deep-sea (>1 km) tailings disposal are discussed. To determine if submarine tailings disposal in deep, confined basins on the seafloor is environmentally friendly, detailed multi-disciplinary research incorporating physical, chemical, biological and toxicological components will be indispensable.

Jan 1, 2003

By R Balusu, P Humphries

In combination with detailed field studies and goaf gas characterisation, computational fluid dynamics (CFD) models have been used to develop optimum and effective strategies for inertisation during longwall sealing operations to achieve goaf inertisation within a few hours of panel seal-off operation. This study has combined detailed analysis of the performance of various inertisation field trials together with CFD modelling results of different inertisation operations in order to develop the optimum inertisation strategies. A number of parametric studies were conducted on the base case CFD models that had been calibrated and validated based on the information obtained from previous inertisation studies and goaf gas monitoring. These studies included changes in inert gas injection locations, inert gas flow rates, seam gradients, and different inertisation strategies to investigate their effect on goaf inertisation. Studies indicate that the strategy of inert gas injection through the MG seal was not as effective as the alternative strategy of inert gas injection at 200 m behind the face. Innovative inertisation strategies have been developed and subsequently implemented at an underground coal mine in Australia. Further investigations have been carried out in the development and demonstration of proactive inertisation strategies with the objective to suppress the occurrence of spontaneous heatings in active longwall faces, in particular under unexpected scenarios such as during slow retreat/face stoppage due to difficult geological conditions. Initial trials at two Australian longwall panels have demonstrated the great potential of this practice to contain the onset of heatings in the goaf.

Jan 1, 2005

By Rubisov DH

This paper is related to the problems of the mathematical modelling of vibrating screening process and to predicting the screening operation results. The authors propose a model of screening based on the interpretation of granular material segregation on a screen surface as an instantaneous process. Results show an agreement with laboratory and pilot plant tests. Derived formulae can be used for screen sizing and screening result estimating.

Jan 1, 1993

Improvements in mechanisation should not be considered independently of safety and of environmental hazards. The need to keep gas contents within statutory limits may make the time needed to partially drain a gassy seam the effective control on face development times. Dust levels may provide an effective control on coal extraction rates on any one face. The combination of gas and dust on high output longwall faces may make it necessary for each one to be treated as a separate mine in terms of ventilation, and the faceworkers may need special protection. Mechanisation and safety can be mutually beneficial when mechanisation combined with systematic safety assessment reduces accidents, and when a thorough study of how to reduce accidents and health risks indicates the best method to improve mechanisation.

Jan 1, 1988

The blasting of the 2190_6095 stope at Kimberley Nickel MineÆs Sally Malay operation in Western Australia is an example of what can be achieved with electronic detonating systems when a drill and blast engineering team is faced with complex blast geometry and a major pump station in close proximity to the stope. Using Dyno NobelÆs HotShotÖ system, the engineering team successfully designed and initiated the 36.5 Kt stope firing, with a powder factor of 0.35, resulting in no damage to the pump infrastructure, better fragmentation of the ore and less overbreak in what had previously been a geotechnical and geometrically challenging stoping environment. This paper will discuss the design parameters used for this stope blast as well as the benefits the operation found in using precision detonator timing in this 252 hole shot over two levels using a combination of up and down and slashing rings that were initiated in four different directions.

Jan 1, 2007

By Just G. D

Performance of draglines in large scale overburden stripping operations is critical to the efficiency of a major section of the Australian Coal Mining Industry. Optimisation of dragline productivity requires an understanding of a range of operating conditions and constraints. One of the least understood of these operations is the process of bucket filling and how this may vary with respect to variable operating conditions.Studies conducted at The University of Queensland over a number of years into this problem have enabled the mechanics of excavating to be assessed for different types of fragmented rock. In relation to bucket filling, factors such as fill volume, digging time and energy consumption have been found to be significant factors in optimising bucket design, bucket rigging and operational techniques.

Jan 1, 1992

By J Rapkoch, M Cerna

As long as the tendency of Chilean copper ores continues to feature high levels of impurities, the smelters will tend to produce high-impurity mattes. The most notable impurities include As, Sb, Pb and Zn. Producing high-quality copper with such materials is a major challenge to metallurgical engineers and operators. More investigations into process optimisations and/or alternatives are needed, using both theoretical knowledge and operational skill. Converting of matte in Chile depends on the matte grade using established technologies. Mattes up to 66 per cent Cu, such as those from Outokumpu Flash furnaces, are converted in two stages, while typical Teniente Converter mattes, ranging from 70 - 74 per cent Cu are converted in one blow, directly to copper. In this paper thermodynamic data are used to evaluate possible variations in the use of traditional technologies applied to smelt copper concentrates with high impurity levels. The results of this analysis help to predict the impurity distributions between matte-slag-gas during the slag blow, and between copper-slag-gas during the copper blow. For converting high-impurity white metal, the effectiveness of volatilisation in the slag blow is analysed. In the copper blow, the type and the amount of flux (SiO2, CaO and others) are altered with the aim of optimising impurity distribution to the slag and gas.

Jan 1, 2005

Following the `Poseidon boom' of the early-1970s, there was pressure for development of a national body of company law and for the introduction and development of legislation to regulate the securities industry, including the Stock Exchange, trading in securities and securities dealers and advisers.After 20 years, the Corporations Law emerged in effect as Commonwealth legislation implemented automatically by the States.

Jan 1, 1997

Activity-composition-temperature relations for both gold and nickel have been determined for the solid and liquid states of the gold-nickel system by the application of the Margules equations. These relations are in satisfactory agreement with activity measurements of nickel in the solid state, the observed phase boundaries of the system between 700 and 1725°K, as well as being consistent with data on the enthalpy of mixing.

Jan 1, 1971

The operation of a one tonne submerged combustion pilot plant for the recovery of copper from anode furnace and converter slags is described and the effects of variables discussed. Using coal as reductant, copper levels of anode furnace slag were lowered to 1% or less, with batch times of approximately 120 minutes. Fluxing with limestone was required to produce a fluid slag at temperatures of 1200 - 1300¦C. For converter slags, reduction to 0.5% Cu or less was achieved in batch times of 35 minutes. The chemistry of the pyrometallurg- ical recovery of copper is briefly reviewed in relation.to copper recovery methods.

Jan 1, 1978

By R A. Bearman

Recent demand pressures for iron ore should not distract from the longer term view that intense competition in the industry has demanded technological innovation of a high order. There is a long track record of successful innovation underpinned by a solid base of scientific research and knowledge. By comment on recent developments in trucks, comminution and direct smelting, this paper suggests that innovation is still a key attribute of the industry. The spending of the minerals industry on underlying science, however, is not particularly high. By looking at other industries we can ascertain that for step change technologies, it is particularly advantageous to have a solid base of science and technology underpinning developments.

Jan 1, 2005

Mount Isa Mines operates Hewlett Packard 1000 computer systems for process control in its major mineral processing plants. To simplify control systems implementation, a process control software package has been developed. This package is now used at the Lead/Zinc Concentrator where the HP computer is interfaced to Foxboro Interspec/Spec 200 system and Honeywell TDC 2000 front-ends. The HP computer controls crushing, grinding, flotation and tailings disposal. This paper outlines the development of process control systems at Mount Isa Mines. The creation of the process control package is described and the reasons for its development highlighted. The application of the software package and the implementation of process control systems at the Lead/Zinc Concentrator is detailed.

Jan 1, 1978

Although the title of this paper permits a very broad scope for discussion, I propose to deal mainly with those aspects of design part- icularly related to rook filling, the'theme of this conference. The unique suitability of belt conveyors for the continuous economical delivery of materials into or out of underground workings, is well established and needs no elaboration. The facility with which conveyor units, comprised of modern modular components, can be adjusted to lengthen or shorten, their ability to be readily repositioned to suit the develop- ment of a work pattern and their virtues as low noise, reliable transport media, are already accepted by all who are involved with the mining industry.

Jan 1, 1973

By R West

The Olympic Dam smelter facility processes copper concentrate feed using direct-to-blister smelting technology to support the current site production rate of 225 000 t/a copper. The metallurgical control of the Olympic Dam smelter is largely managed from a single central control room. Control room operation and management is therefore a key function in ensuring safe and reliable operation of the smelter, including identifying and initiating control of abnormal events. As part of a consolidated smelter reliability improvement program, a team consisting of process and control system engineers was formed. The teamÆs charter was to address and resolve the alarm flooding issues being faced by the control room technicians and the lack of an up-to-date base of supporting functional documentation. The project was successfully resourced with WorleyParsons metallurgists, Citect PLC technicians and the on-site technical team. Implementation was conducted over a 12 month period with the goal of achieving best practice alarm levels. The goal was achieved through a systematic process of alarm design review that analysed every configured alarm versus best practice design standards. Innovative concepts such as group-based alarms, first-up interlock displays, graphic only alarming, alarm help and alarm shelving were developed and implemented in conjunction with improved alarm masking. Total configured alarms were reduced from 20 000 to 5000 while the alarm rates were reduced from in excess of 200 alarms per hour per controlling technician to best practice levels of less than 12 alarms per hour per controlling technician. Completion of this program has provided a firm foundation for implementing further control optimisation and was a key activity in supporting sustained smelter reliability levels.

Jan 1, 2005

In both exploration and mining, the laboratory is often seen as a cost rather than a profit centre. The aim in most mining companies is to increase profits by reducing costs, so the budget for the laboratory is under constant pressure.There is another option; to see the laboratory as the brain of the operation. By lifting the status of the laboratory and treating it as a profit centre, mine costs may be reduced in other ways, e.g. reduction in milling costs. This change of status will require investing more capital in better equipment, more training for employees and more employees to carry out project research.There are many examples of major costs being incurred because of inadequate laboratory work. Conversely, by spending more money on laboratories and their activities, overall costs can be reduced or profits enhanced.

Jan 1, 2002

The Cooperative Research Centres (CRC) Program was established and is supported by the Australian Government at a total cost of $140 million per year. Six of these centres have been established to help Australia's mineral industry: three in exploration, one in mining and mineral processing and two in extractive metallurgy. Since the CRC Program has now been in operation for five years, it is a good time to ask whether the minerals industry is being served adequately by these centres. In this paper, the performance of one CRC, namely the A J Parker Cooperative Research Centre for Hydrometallurgy, will be discussed in terms of the objectives of the CRC Program. As will be shown, the Parker Centre has made considerable progress since its establishment in 1992.

Jan 1, 1996

By Summers DA

Faculty at the University of Missouri-Rolla have carried out research on the application of high pressure water jets as a means of excavat- ing coal for over 15 years. During the course of this time, a number of different concepts have been explored--the most recent of which has been to use high pressure water jets as a means of extinguishing an underground coal seam fire. This paper will examine the use of some of these technologies and will consider the results as a basis for discussion of further applications of water jets in the future. The structural pro- perties of coal which distinguish it from other adjacent geotechnical material and provide a considerable advantage to water jet cutting, will also be presented and the advantages of using this tool will be discussed.

Jan 1, 1986

By V S. Svinin, V V. Rybin, V A. Maltsev

In large-scale mining, large-sized intermediate pillars, or block-pillars, are generated on the horizon or between closely located mines. These pillars are mined under high rock pressure that results from the stress concentration zones superposition from closely located working excavations. This problem becomes much more complicated if high tectonic stresses occur in the rock mass inducing a rock-burst risk situation. Mining experience gained in mining seven block-pillars at three Khibiny mines in Russia under the geomechanical situation like that described aboveÆ is discussed in detail. It has been shown how safe mine of block-pillars depends on their width, location relative to significant geological failures and uncaved rocks of the hanging wall, the order of pillar recovery, and application of special measures for rock mass stress relieving. Basing on the analysis of the mining experience and special scientific researches, the basic principles are worked-out for safe block-pillar mining under rock-burst prone conditions.

Jan 1, 2000

Mining and metals projects have tended to increase in both scope and cost to a point where many projects are Droperly designated as superprojects. Specialist engineer- constructors have developed organisations and systems to provide project management services during the design and construct phase of large projects. However, the engineer-constructor is also required to provide a wide spectrum of services during the evolution of large projects prior to the construction phase. Some common phases of pre-construction evolution are identified together with the associated types of specialised services which may be required. A project management team approach is described which has been developed for the design and construct phase. It is suggested that a modified matrix organisation could be adapted to the provision of special- ised services as well as to project management for ore-construction phases of the project.

Jan 1, 1980

The history of the discovery. and successful development of the offshore Gippsland Basin oil and gas fields has been well docu- mented in contemporarary and more recent industry and profes- sional literature. The various articles, papers and books record fairly balanced views and comments as to the nature and results of the explora- tion effort, and factual data concerning the subsequent develop- ment of the fields and facilities concerned with petroleum production in the Bass Strait and Gippsland environment. Recommended reading for those interested in the scientific and technical aspects of the Gippsland Basin developments and the search for petroleum in the Bass and Alway Basins includes the available library contained in the publications of The Australasian Institute of Mining & Metallurgy The Commonwealth Mining Congres since 1960 The Australian Petroleum Exploration Association The Geological Society of Australia The American Association of Petroleum Geologists Various Commonwealth and Victorian Government instrumentalities Trade Journals

Jan 1, 1988