Search Documents

By Twemlow GL

The accounting profession in Australia and overseas has taken up the responsibility of setting standards specifically relating to the minerals and energy industries. Australia led the way with AAS7 Accounting for the Extractive Industries. This statement was issued in 1976 and amended 1977..It largely deals with accounting for preproduction expenditure and uses the term "economically recoverable reserves". It does not require disclosure of reserve quantities or values in balance sheets or as supplementary information in financial statements. The United States accounting profession in 1982 finally resolved an accounting standard in the same area as AAS7-SFAS69 Disclosures About Oil and Gas Producing Activities. It applies only to oil and gas producers, but has extensive disclosure requirements, including proved oil and gas reserve quantities. Current developments indicate that Great Britain is about to follow the US example. At this time in Australia, AAS7 or some other statement relating to the extractive industries has not been issued as an approved accounting standard by the ASRB. Standards issued by the ASRB are binding in law.

Jan 1, 1987

INCREASE OF THE OIL CONSUMPTIONIt is of the greatest interest to study the prospects open today for the petroleum industry by looking back to the past years.The' results for the past 15,years can be said. to be- satisfying; - the develop-ment of the petroleum industry has sustained a very fast tempo and the world consumption of energy has around the years 1960-1961 - reached aòpeak figure.Undoubtedly, the petroleum industry is the principal beneficiary of the growth of world, energy demand. For the caning years a slackening of the rate of expansion is'. likely to be expected; but will. not alter the general trend. This ' slackening of expansion may be explained, partly by a better use of the energy consumed and by the increased use of new types of energy, mainly natural gas.Although.the development of world energy demands follow structural and tech-nical modifications".,-At. can be foreseen, without any doubt, that the petroleum products. consumption. vri 11 be less affected than any other type of energy by this limited reduction in the rate of increase.

Jan 1, 1962

By M Darby, B Burdett, F Lovell

The results of the process control improvement project aimed at improving the quality of Australian Bulk MineralsÆ (ABM) iron ore pellets produced by four vertical shaft furnaces are very positive. These results are achieved through process stabilisation and optimisation, improvement in process monitoring and taking early corrective actions when operating variables were outside the target ranges. A number of benefits are obtained from this project. These benefits include: More consistent and improved pellet quality. The average cold compression strength (CCS) value of pellets produced during the eight-month trial is 260 kg/pellet, which is 16 kg/pellet higher than that produced during the 12 months prior to the trial (244 kg/pellet). Reduction in the heat input by eight per cent, from 727 MJ/tonne to 668 MJ/tonne. Reduction in bentonite rate by six per cent, from 7.1 kg/tonne to 6.7 kg/tonne. Increase in the furnace throughput rate by four per cent and additional production of 10 000 tonnes per annum through process stabilisation. Better understanding of the process behaviour. This knowledge is valuable not only for setting the target operating conditions but also for developing the ABM expert system to control the process.

Jan 1, 2005

By J G. Petrie, H von Blottnitz

The selection and design of process options to deliver outcomes consistent with sustainable development requires simultaneous consideration of multiple objectives, within a climate of uncertainty û including the environmental and social aspects of technology management in addition to the technical and economic aspects of such. An issue of particular relevance in primary metal production is the deportment of minor and trace components within orebodies, products and wastes and the implications of such deportment for eco-efficiency û in particular, the long-term environmental impact of solid waste management practices. The identification of opportunities to enhance recovery of valuable by-products and simultaneously improve the environmental acceptability of final waste output requires a clear understanding of the distribution of the relevant ore components, which results from the choice of processing route and unit operation efficiency. This is challenging, given that process streams generated during primary metal production are generally poorly characterised and the behaviour and deportment of trace to minor and trace components is not well understood. This paper demonstrates how current data gaps and inconsistencies can be systematically addressed through the meaningful reconciliation of empirical plant data with a fundamental understanding of the mechanisms and parameters influencing element behaviour and deportment during the formation and subsequent beneficiation of mineral ore deposits. On this basis, quantitative distribution data and a comprehensive and comprehensible inventory of unit process inputs and outputs as a function of ore compositions and processing technology options can be generated, which is consistent with early design stage information requirements, both in terms of detail and accuracy, ie is æfirst-orderÆ in nature. This predictive approach to element distribution during primary metal production provides decision-makers with key information in the early design stages of a project (in terms of developing processes within the context of sustainability), whilst simultaneously guiding further data collection and environmental impact prediction studies.

Jan 1, 2006

Existing fluid flow techniques may be readily applied to the design of ranges for seam gas drainage. The Reynolds number characterises the flow regime within the pipe and it can be used in conjunction with data on absolute pipe surface roughness to determine the system friction factor. The application of the solution to the isothermal compressible flow equation utili- sing Moody friction factors and the concept of equivalent length of pipe for fittings and valves provides a practical method for sizing gas ranges. The physical capacity of a range can be decreased by the existence of significant quantities of water in the range and also by the ingress of air into the system at poor pipe joints etc. Both problems can be elimin- ated by adequate attention to design detail.

Jan 1, 1982

By Seeley D, Buckley N, Goodall J

Improving the performance and reducing the costs associated with export logistics chains is critical to the competitiveness of export coal mines. The fundamental practices associated with the use of export logistics chains made up of mine, trucking, rail and port operations are being challenged by the advent of third party operators on rail systems and the use of the Internet.Whilst individual mines can improve their processes to drive down their mining costs, they face major challenges in their endeavour to improve the performance of export logistics chains and reduce the significant logistics costs of moving coal from the mine to export ships, via the shared infrastructure of rail systems and ports. There is an increasing realisation that global competition is not only between mines but between coal export regions that are defined by their rail system and ports infrastructure.

Jan 1, 1998

The risks faced by organisations are part of a risk continuum. They can be evaluated in terms of hazard, uncertainty and opportunity as well as by the degree of influence they have on conformance, operating performance and strategic objectives. This paper discusses the application of risk management techniques for mitigating blasting hazards, reducing blasting output variability, and implementing blast improvement opportunities. Effective risk management practices can identify and evaluate risks across all levels of the continuum and can deliver realistic assessments of the likelihood and impact of risks on the companyÆs safety and business objectives. This paper does not attempt to present technical details about blasting, rather it aims to provide enough blasting context and examples so that the practical benefits of applying the risk management process to blasting can be fully appreciated. The topics discussed include: explosive management plan; statistical process control; quality blasting, rock-on-ground; Blast Management; Mine to Mill optimisation; and blasting information systems. The concept of a blasting risk management system employing a continuous improvement loop is also introduced. On reflection the insights presented should be extremely useful for observing and understanding which risk face has management focus at a mine site or for a blast site.

Jan 1, 2001

A real Dorothy Dix title has been selec- ted for this paper. It has the advantage, however, of being capable of being interpreted in many different ways and hence I can select my own approach. You probably are thinking that this topic would be more appropriately handled by an Accountant. I wish to make it clear at the outset that I am not skilled in the sometimes mysterious ways of Accountants - likewise that profession frequently has difficulty in pinning down economists. We have our own strange ideas about profits, marginal efficiencies, cost/benefit analysis etc. What follows is in the main a mixture of two disciplines, probably in a form that few of the purists from either side would accept. Nor do I expect the reader to accept my own prejudices. The paper is designed to stimulate thought and discussion'on the subject. Emotive words such as "profit" and "loss" make for wide differences of opinion. At the time of writing there is a surprising degree of acceptance of the viewpoint that profits in Australia are too low and one is tempted to make this point of near agreement a starting Point.

Jan 1, 1975

There are a number of different mechanisms by which wetlands can immobilise the metals in mine drainage. Here, the biogeochemistry behind four of these mechanisms (adsorption, biological uptake, precipitation as oxyhydroxides, and precipitation as sulfides) is discussed from the perspective of sustainability. Moreover, treatment wetlands are considered as part of a larger system, also taking into account the source of the drainage and various aspects of the receiving waters. The biogeochemistry of different metal immobilisation mechanisms in wetlands determines what kind of drainage can be treated with success, and it also places an upper limit on the amount of metal that can be removed from the water phase per unit of time. This has important implications for the design of treatment wetlands, perhaps particularly in colder climates. A thorough understanding of the prevailing biogeochemical processes is essential when attempting to establish treatment wetlands after the closing of a mine. If a wetland is to be used as a sustainable æwalk-awayÆ solution, the anticipated change in treatment efficiency over time (as pollutants accumulate in the system) must be considered in relation to the expected changes in drainage quality. It is also important that the total metal immobilisation capacity of the wetland is not exceeded and that the integrity of the system is maintained, in order to minimise liberation of previously immobilised metals.

Jan 1, 2003

By Patridge A. C

Hydrocyclones have widespread use as classifiers in applications such as mine fill preparation and coal preparation. A fundamental conflict often exists between recovery of all of the valuable material and maintaining the quality of the product. This conflict is a result of a portion of the feed material passing through the cyclone, effectively without undergoing any classification. This paper describes an investigation, undertaken as an undergraduate project in mining engineering at the University of NSW (Brook, 1994), into aspects of cyclones in which supplementary water injection is used in an attempt to reduce the amount of misplaced fine material reporting to the coarse product and hence improve the overall classification efficiency. In particular, the study concentrated on the effects of different modes of water injection. Two methods of introducing wash water into the cyclone body were investigated. A series of tests were performed on a laboratory hydrocyclone having provision for radial water injection at different levels through small orifices in the wall of the conical section, and a preliminary study was made of the performance of a novel cyclone in which the conical section had walls of a permeable polyethylene, permitting a uniform introduction of wash water over the entire surface.

Jan 1, 1995

An improved method of sample recovery for use with rotary percussion drilling has been developed. Cuttings can be recovered continuously from either dry or wet drilling, and the recovery under dry conditions is seldom below 99% of the cuttings brought to the surface by the rig. The system is designed for use with top drive drilling rigs using flush-jointed drill rods. The key feature of the system is a self-aligning mechanical seal around the drill rods. The sealing unit is removably fixed to a collar section of cas ing. the cuttings are recovered in a plastic bag attached to the bottom outlet of a cyclone. A valve at the bottom of the cyclone permits the cuttings representing various depths to I,e recovered separately for examination eind 0(iclysis. [u the Iron Monarch quarry, two percussion holes were drilled to depths if 30 metres and 28 metres using the unproved sample recovery system, and diamond drill holes bored 1 metre from each percussion hole. Samples from each hole were sectionalized over metre intervals and analysed for iron, silica, alumina and loss on

Jan 1, 1976

This paper deals briefly with three of the more controversial aspects of the geology of the Mount Isa ore deposits namely the geologic structures, the method of ore deposition and the origin of the ore.In the section on geologic structures, an outline is first given of the purely tectonic deformation advocated by the early authors. The current interpretation, which differs in the proposed order of events and causal forces, is then discussed. Other concepts, which attribute all or part of the deformation to sedimentary features or preconsolidation movement, are outlined ilnd commented on.The remaining two sections deal mainly with the better known lead-zinc orebodies. In the first of these a brief description and criticism is given of the early interpretation which was based on the deposition of successive waves of mineralisation which replacedindividual beds in the shales. The current ideas, which visualise emplacement of the ore between the beds rather than replacement of them, is then discussed. The final section develops the case for a sedimentary origin of the lead-zinc ores and broadly outlines the author's ideas concerning the evolution of the Mount Isa ore deposits.INTRODUCTIONAny consideration of the geology of Mount Isa must begin with the work of Blanchard and continue with that of Hall. Individually, or as co-authors, they published various papers on the geology of Mount Isa. Of these, the best known is their "Rock Deformation and Mineralisation at Mount Isa" (1941) which gave a comprehensive account of all aspects of Mount Isa geology.It is necessary to appreciate the limits set on geological knowledge of the mine and environs in 1941 by the extent of mine development and regional geologic studies. Underground, 7 level (897 ft.) was the lowest producing level. Development on 8 (1073 ft.) and 9 (1247 ft.) levels consisted only of exploratory drives and crosscuts in the vicinity of the Davidson Shaft. The tops of the 650 and 750...

Jan 1, 1961

By Khosia NK, Ravishankar SA, Sankar TAP

Alumina reduction in Rajhara iron ore slimes essentially involves separation of hematite from gibbsite in relatively coarser fraction and from kaolinite in the finer fraction. Selective dispersion flocculation studies on synthetic mixtures clearly indicated that while it was possible to achieve almost perfect separation of hematite from kaolinite using starch and PAMX (modified polyacrylamide containing hydroxamate functional groups) flocculants, no selectivity was observed in iron oxide-alumina system. A schematic flowsheet suggested on the basis of this work for the beneficiation of Indian ore slimes thus consists of classification in a hydrocyclone, followed by selective dispersion of coarse fraction (underflow) and selective flocculation of the overflow fraction. Starting with a feed assaying 46 per cent Fe and 11.6 per cent A1203, a concentrate assaying 60 per cent Fe and 4.7 per cent A1203 could be produced at an overall iron recovery of 60 per cent using conventional Reagents.

Jan 1, 1993

Around no subject of technical )uterest have prejudice and wrong-thinking in the past so wrapped a web of obscurity as that of the corrosion of metals.It is a matter which has primarily concerned the engineer, but the paucity of his training in chemistry and electrochemistry has been the stumbling block to a better understanding of its mechanism.Now that the more important conditions controlling corrosion have been scientifically.established, it can be seen that, with the exception of but a few of the minor points, the electrochemical laws enunciated by Faraday, Helmholtz; Nernst, and others, are sufficient to include all the facts of the process.The word corrosion (derived from the Latin rodere-to gnaw) is so often wrongly applied that a definition at this stage would be useful. As now understood, it means the dispersion and waste of the useful solid metal by conversion into a useless compound which mayor may not be retained on or near the metal remaining.Commonly the presence of these compounds is regarded as evidence of corrosion, but the converse is not necessarily true; the lack of visible corrosion products on a clean surface of metal is no criterion of the absence of this change. It may be difficult to prove that the erosion of such a surface has been caused by chemical and not by mechanical effects alone.

Jan 1, 1932

Today the application of computer programs for planning of mine-ventilation and for safety- analysis of ventilation systems is widespread practice in German mining. The computer program for network calculat- ion, developed at the "Mine Ventilation Testing Centre of the Westfalische Berggewerkschaft- skasse" allows the distribution of airflow and pressure in mines to be calculated. In a physically well founded manner it takes into account the natural ventilation as well as changes of volume-flow in the mine, which both are dependent on pressure and temperature. Compared to an incompressible treatment of the mine air these circumstances are of increasing importance with the increase of depth, air temperatures and fan-pressures'. This especial- ly holds for the calculation of airflows during failures of fans or for assessing the influence of open mine-fires on ventilation. The application of the program is very easy and its structure is made to fit the requirements of practice. For instance it takes into account the fan characteristics of all fans. For each planning calculated air- flows in all mine workings are compared to those of an eligible basic calculation or to measured airflows. In addition for the

Jan 1, 1983

The Mineral Research Centre is located at Perth in the suburb of Waterford, adjacent to Curtin University of Technology and within a Technology Precinct which includes Technology Park. The Centre, constructed by the WA Government at a cost of $16 million and occupied in late-1994, comprises three separate buildings housing the CSIRO Division of Minerals, Curtin University's School of Chemical Engineering and the Mineral Processing Laboratory of the Department of Minerals and Energy. The emphasis on R&D at the Centre is primarily in hydrometallurgy as a result of staff expertise, extensive bench and pilot-scale facilities, track record with the industry and, very importantly, two of the occupiers being partners in the AJ Parker Cooperative Research Centre for Hydrometallurgy. Staff in the Centre have a long involvement with R&D agencies such as AMIRA and MERIWA. The hydrometallurgical focus of the Centre complements that of pyrometallurgy at the GK Williams CRC in Melbourne and the Centre for Mining Technology and Equipment in Brisbane, to ensure that the mineral processing industry in Australia has access to a complete range of expertise and facilities to serve its needs.

Jan 1, 1996

By Y Peng, D J. Bradshaw, X Chen

At NewcrestÆs Telfer gold mine, a strategy of regrinding pyrite rougher flotation concentrates has been proposed to increase gold recovery and reduce cyanide consumption in the CIL circuit. The regrinding will be followed by an additional copper/gold flotation stage, where copper minerals need to be separated from pyrite. However, although the minerals are well liberated, the separation of chalcopyrite from pyrite in the cleaner stage is not always straightforward. The surfaces of the fine particles, produced during regrinding, are more easily oxidised and contaminated than coarse particles, directly influencing the particle floatability. The depression of pyrite is difficult in the cleaner stage as well due to copper activation, a process which is also highly dependent on the grinding environment. In this study, different grinding media, including mild steel and stainless steel, was used in the regrinding to produce different regrinding chemistry, such as, pH, Eh, and iron hydroxide contamination. The effects of regrinding conditions on chalcopyrite flotation and its separation from pyrite were studied. It was found that the stainless steel grinding media, which produced an oxidising environment, was more beneficial for the separation of chalcopyrite from pyrite after regrinding. The mild steel grinding media had a detrimental effect on both chalcopyrite and pyrite flotation. This study addresses the importance of choosing suitable regrinding conditions in the pyrite and copper flotation circuit.CITATION:Chen, X, Peng, Y and Bradshaw, D J, 2012. Effect of regrinding conditions on the flotation of chalcopyrite and its separation from pyrite in the cleaner stage, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 279-286 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By Sneddon A

Expansion of central production facilities at the Kutubu Petroleum Development Project in Papua New Guinea (PNG) required excavation of a steep hillside overlooking operating crude oil processing, storage and pumping facilities. Drilling and blasting were used to remove a large volume of rock which varied from hard limestone to soft sandstone, with zones of soft clay and many underground caverns. Similar ground conditions had made it very difficult to predict and control blast-ing results during previous excavation in this area.Special conditions of the project included restrictions on ground vibration levels at a high pressure oil pipeline and pump station within 100m of the blasting area, and a prohibition on any flyrock. As work progressed, some blasting was necessary with 20m of installations being constructed on the levelled project site. Thus blast design, drilling and charging were carefully controlled to avoid any incidents which could interfere with oil production or progress of the construction project.

Jan 1, 1994

The first 12 m diameter rakeless thickener in the Australian gold mining industry was installed to treat plant tailings at the St Ives gold plant in April 2000. The plant processes approximately 3.2 M tonnes of ore producing about 430 000 oz of gold per annum using conventional crushing, grinding, gravity and carbon in pulp processing methods.The main benefit sought from the thickener was to improve water recovery in the plant and provide water for a 55 000 oz per annum heap leach operation. The thickener design indicated that more than 128 m3/h of overflow water could be returned directly into the plantÆs water circuit, relieving the demand on the borefields. The resultant surplus in the water circuit would then be available for the heap leach project. Based on laboratory and pilot plant scale tests conducted by EIMCO the thickener was designed to handle up to 700 m3/h of tailings slurry (450 tph of solids) with a 40 per cent oxide component in the ore blend. The normal plant throughput is 565 m3/h of slurry (400 tph of solids). Gold mineralisation in most areas at St Ives comprises quartz-sulphide vein and breccia lodes with common albite-biotite-chlorite alteration assemblages. There are well developed supergene gold horizons in the clay-oxide profile above most of the deposits (Osborne, 2002). This results in a wide variety of ore types being treated. At times 40 - 50 per cent of the ore may be oxide in nature. After some commissioning difficulties associated with instrumentation, the thickener has performed satisfactorily although it has not reached its design capacity. The maximum density achieved under normal operating conditions with 20 per cent oxide ore is about two per cent below the design. The thickenerÆs performance deteriorates further with increasing amounts of oxide ore in the blend. The thickener has provided sufficient water for the successful operation of the heap leach and has also provided some down stream benefits for the gold plant by way of pH and cyanide conditioned thickener overflow water.

Jan 1, 2002

Peko Mines N.L. has considerable experience in the treatment of a wide range of comparatively small orebodies.Gold-silver, bismuth, and sulphide and oxide copper ores are treated under difficult geographical conditions.Treatment of these ores is complicated by some unusual metallurgical factors.Metallurgical operations are described, including the treatment of the gold-bismuth-copper ore from Juno. The new Warrego mine is to have a highly instrumented concentrator by December 1971. Autogenous grinding is being considered.

Jan 1, 1969