Search Documents

By Ren T. X, Jozefowicz R

In many branches of engineering, there has to be an understanding of the motion of fluids in order to solve problems. Many safety and health problems in the mining industry are typical examples that involve the understanding and analysis of fluid flow, such as explosions, the spread of fires, dispersion of gas and dust, and ventilation patterns. Computational Fluid Dynamics (CFD) is concerned with the use of computers to produce information about the ways in which fluids flow in given situations. Until recently CFD has been widely applied to a variety of industrial sectors and increasingly to problems in the health and safety areas. With the arrival of more powerful computers and CFD packages, CFD techniques are no longer practised solely in a research environment, but can be used by engineers in many industrial fields. This paper introduces the basic concepts and general procedures involved in the use of CFD technology. A comparison is given as a guide to the major features of a number of widely used commercial CFD codes. Areas of potential CFD applications are identified in a range of safety and health problems in mining industry. An example is presented to illustrate the use of this technology. It is believed that the exploitation of these areas using CFD approach will contribute significantly to the solution of today's many mine health and safety problems.

Jan 1, 1995

External pressures are being exerted on busi- ness, and especially the mining and energy in- dustries, as never before. These pressures are burdensome, they emerge in unique forms, and they constitute an entirely new operating environ- ment for business. They pose one of the signi- ficant challenges to senior management today. To cope with these pressures-which we have termed the new public realities-we must deal more effectively with the media, the public, and government. However, before examining methods for improvement, it is essential to understand the nature of these new public realities and par- ticularly their determinants-the underlying eco- nomic, sociological, political, and international events and trends which have shaped them. Previously the productive element of society had only to concern itself with what might be termed `conventional realities' : the costs of labour, equipment, and land, as well as marketing and distribution factors.

Jan 1, 1978

By C Li

Removal of gangue minerals from ilmenite concentrates can beaccomplished by relatively low temperature roasting in controlled gasatmospheres to selectively enhance the magnetic separationcharacteristics of the ilmenite. At roasting temperatures below 800¦C the magnetising reactions are often not consistent with phase equilibria considerations. Metastable phases can nucleate and control the roasting products. In weathered ilmenites the phase assemblages and microstructures in the altered ilmenite grains can influence the roasting reactions. In this paper we give an overview of the phase chemistry of chemically weathered ilmenites and of metastable phases formed by low temperature roasting. We also report the results of roast experiments conducted in a neutral gas atmosphere. Major increases in magnetic properties after short roasting times at low temperatures were obtained for a range of ilmenite concentrates. For example heating a secondary ilmenite concentrate from Western Australia for 15 minutes in nitrogen at 600¦C gave an increase in the three kilogauss magnetic fraction from three to 92 wt per cent. The solid state phase changes accompanying the inert atmosphereroasts were characterised by combining elemental analyses withquantitative phase analyses of the ilmenite concentrates and their roast products. It was found that the phase reaction that is principally responsible for the increase in the magnetic properties of weathered ilmenites involves a transformation of disordered ferrous-containing pseudorutile to an ordered ilmenite-hematite solid solution containing typically ten to 35 mole per cent of the hematite component. Examples are given of the application of the inert atmosphere roast to effect separations of ilmenite from gangue minerals.

Jan 1, 2001

By F Baars, M Zu, C A. RosiFre, L Lobato

A genetic model for the genesis of high-grade (>65 wt per cent Fe) Proterozoic, banded iron formation (BIF)-related iron deposits such as the Tom Price, Mount Whaleback deposits in the Hamersley Province (Australia), the N4E, N4W, N5 deposits at Carajßs (Brazil), the Aguas Claras, Conceitpo, and Casa de Pedra deposits in the Iron Quadrangle (Brazil), the Donkerpoort West, Kwagas East deposit in the Thabazimbi iron ore district (South Africa), or the Saksagan ore field at Krivoy Rog (Ukraine), needs to take into account the: timing of regional metamorphism with respect to the upgrade of BIF to high-grade iron ore; significance and relationship of the proto-ore to the hydrothermal alteration minerals and zonation and the process of iron enrichment; source and oxidation state of the hydrothermal fluids that caused the iron enrichment; types of geochemical processes that caused the hydrothermal alteration and iron enrichment; and significance of the widespread carbonatisation of the host rocks as a prerequisite for high-grade BIF-related iron mineralisation.We argue that a unifying model for high-grade BIF-related iron deposits cannot, presently, adequately explain the geological and geochemical characteristics observed in these deposits and, therefore, provide two end-member models that take into account the diversity of geological and geochemical ore deposit features. Our discrete model for the genesis of high-grade, BIF-related iron deposits is based on the interpreted tectonic setting, distinct hydrothermal fluid source of, and processes observed in, major BIF-related iron deposits. We divide two end-members: Proterozoic deep fault-magmatic (Carajßs) type, and Proterozoic rift-basin (Hamersley) type.Both end-members experienced varying degrees of deep weathering episodes that effected the hypogene enrichment and, ultimately, yielded the high-grade iron ore mined in many places today.

Jan 1, 2005

Microorganisms have been used throughout history for the benefit of mankind with some of the earliest applications being in the production of fermented foods and beverages. Reactions involving inorganic substances such as metals, sulphur and sulphide compounds were hardly ever used until the early 1900s when it was discovered that Thiobacillus ferrooxidans was capable of promoting the oxidation of metal sulphides in ores. Today, it is widely recognised that biotechnology has great potential in the minerals industries, particularly in such areas as the leaching of low-grade ores of metals such as copper, gold and uranium; removal of heavy metal ions from process streams and from liquid process wastes; and in the desulphurisation of high-sulphur fuels. Although widespread commercialisation of mineral biotechnology has not yet been achieved, it is estimated that by the Year 2000 mineral biotechnology will have a significant impact on the minerals and metal industry and will probably account for tens of billions of dollars worth of annual production world-wide. This paper examines the actual and possible future applications of biotechnology in the minerals, metal refining and fossil-fuel processing industries. Firstly, the important chemical (and biochemical) principles involved in bio-dissolution of metals from ores and solid wastes, and in bio-accumulation of metals from process and waste solutions are reviewed, including leaching practices - past, present and future. Microbial desulphurisation of coal, and microbially-enhanced oil recovery are also discussed. The practical aspects of genetics and genetic engineering, the types and characteristics of those microorganisms important to mineral biotechnology, and the current research trends are reviewed as well. KEYWORDS: Biotechnology, microbial leaching, bioaccumulation, biosorption, bioleaching, biohydrometallurgy.

Jan 1, 1993

By R G Warren

Sparse geochronological data have been combined with data on felsic suites and depositional facies of rocks to provide an overview of the development of the Arunta Block. The study provides a basis for construction of a map showing the distribution of granites and associated felsic extrusive rocks in the Anmta Block. The tectonic evolution can be subdivided into a series of significant time intervals. Only in the initial stage, to about 1880 Ma, was there any subduction-related magmatism. All later felsic magmas were crustal-derived melts. The early, pre-1880 Ma arc-related units in the SE contain small showings of Cu, probably including the small Cu deposit in the Casey Bore Inlier at the edge of the Simpson Desert. The most significant time-interval for formation of mineral deposits was 1820-1760 Ma, when volcanogenic Cu-Pb-Zn deposits formed in the Strangways Metamorphic Complex and also in the Jervois district. Stratabound tungsten lodes in the hanging wall of

Jan 1, 1994

Consideration was given to the.applicab on of a solvent extraction circuit to be'included in the process'for the-recovery of a high grade product from.:-the Rum Jungle Creek.South uranium ore body.The economics of two alternative processes, firstly the Eluex process which uses an ion exchange process followed by solvent extraction.-of a.high grade sulphuric acid eluate, and secondly a process using direct solvent' extractioh of pregnant leach liquor, were studied. There was a small cost advantage favouring the Eluex process but when other factors were considered, the installation of a direct solvent extraction process appeared the better long term investment. A solvent extraction plant was installed at Rum Jungle in 1962.

Jan 1, 1963

At the beginning of this year it was my pleasure and responsibility to take over the Presidency of our Institute from Mr A. A. Parish who, as did his predecessors, filled the office with distinction. It is a great privilege to address you as President and it is an occasion for my wife and family, and I am most grateful for your inviting them to the buffet dinner. Our Secretary (Miss Jacka), who processes all Presidents, has told me that there are neither questions nor discussions on Presidential Addresses, and that being so, I felt free to select a controversial topic. The address I have prepared is not strictly true to label; because I intend to include also the effect on agricultural production in Australia if Britain joins the European Economic Community (i.e. the Common Market).Three points of view are1. the European, which is one of equanimity deriving from the initial brilliant success of their scheme,2. the British, which is one of anxiety not to miss the bus, coupled with a commendable wish not to inimically affect existing Commonwealth arrangements,and3. the Australian, which is one of alarm.In England all are drawing their own conclusions on the subject and views range from the extreme desirability, to the extreme undesirability, of the United Kingdom joining.No one in Britain wants Australia, or New Zealand, to...

Jan 1, 1962

By Aspinall T. O

This paper discusses the identification and assessment of risk for mining developments particularly for open pit mining. A distinction between sensitivity studies and risk analysis is developed, demonstrating the importance of geological and mining engineering judgement -as applied by experienced practitioners to the analysis and assessment of risk in such projects. Technical and financial risk analysis are discussed under: ò mineral resources and ore reserves; ò mining and processing methods; ò project construction; ò financing; and ò costs and commodity pricing predictions.

Jan 1, 1994

By Osborne V. J, Urbank W

An explosion occurred at Moura No. 4 underground coal mine in Queensland on 16 July 1986 and resulted in the loss of 12 lives. The official report of the accident concluded that the most likely source of ignition was the flame safety lamp. This paper describes an investigation of the behaviour of a flame safety lamp, similar to the one involved in the Moura explosion in atmospheres of methane, coal dust and air, carried out at the Queensland Department of Mines . Testing and Research Station. The behaviour of the lamp is described in conditions of varying methane and coal dust concentrations in air, and varying air velocity. Particular emphasis is given to the 'phenomenon of burning which occurs inside the gauze and which is capable of causing the ignition of an external explosive atmosphere.

Jan 1, 1988

Orebodies in the Mt. Charlotte - Hannans North Area N. & B. of the town of Kalgoorlie provide a marked'dontrast to the pyrite - telluride lodes of the Golden Mile, although both groups of orebodies appear to be fundamentally related. These highly siliceous telluride free orebodies N. of the Golden Mile are closely related to strong oblique faulting. The Golden Mile. lodes, while possessing an apparent over-all relationship to the oblique faults also have a close relationship to E.-dipping strike faults.

Jan 1, 1964

Trade unions are people. As organisations they exist to represent the needs and interests of their members; that is the workforce. Thus one of the underlying objectives of the trade union movement has been and will continue to be: achieving from management recog- nition that the labour input to the production process - whether that be in the factory, office or service context - is made up of individual people who can not be treated as just another factor of production. The essential difference between labour input and other factors of production such as capital and raw material is the "humanness" of the individual entities which make up a firm, company or industry's labour supply. Recognition of the "people" input to the production process has essentially two aspects: humanisation of the workplace and the treatment of labour as human beings who have a role to play both within the workplace and within broader society.

Jan 1, 1982

By Tonkin D. A

Poor performance in the several stages of the magnetite recovery circuit, coupled with poor desliming through inefficient and over- loaded desliming screens, led to excessive magnetite consumption. An accurate and reliable sampling programme was established covering all outlets of the plant. Emphasis was placed on frequency of increments in an endeavour to detect extreme conditions of short duration. Systematic checking of the entry points to these outlets than identified those sections of the recovery circuit at fault, namely magnetite recovery separators and the heavy media cyclone product rinsing screens. More product rinsing water was provided, and modifications to the rinsing screens improved the efficiency of these units. Consistency of operation through automatic control of level eliminated the sudden massive losses in the magnetic separators. Load on the recovery circuit was then reduced by improvements to the raw coal desliming screens. A 50 per cent reduction in magnetite consumption was achieved.

Jan 1, 1974

The underwater test is now being used routinely to characterise explosives and initiators. However, several outstanding issues regarding the role of confinement and the usefulness of the test results in predicting expected blasting performance require further elucidation. This paper reviews the underlying principles governing the test, and highlights its relative advantages and disadvantages in product development and applications. It deals with topics of energy release, energy partitioning, confinement and efficiency, supported by illustrative examples from tests with various products and geometries. The results are analysed in terms of both the detonation parameters measured and their extension to predicting blasting performance in the field. It is emphasised, that just as with other performance tests, the results and conclusions are only valid under the particular test conditions employed, and over-generalisation of these results can lead to erroneous conclusions.

Jan 1, 1999

The purpose, basic data requirements and various analysis/modelling tools employed for geomechanical evaluation of mine-site conditions are overviewed. The impact and application of computer technology are dis- cussed. Broad guidelines and criteria are presented for establishment of a practical geomechanics data-base system to yield infor- mation suitable for mine design purposes. Future needs of the Australian mining in- dustry are examined.

Jan 1, 1983

For decades strip mining with discon tinuously operating 'draglines and shovels has been the most economical operation method in the shallow hard coal opencast mines of Aust- ralia, North-America and some other countries. Continuously operating equipment such as bucket chain excavators and bucket wheel excavators in combination with conveyor belt systems, conveyor bridges and stackers had been deve- loped in Germany; during the last 25 years this type of equipment has been further developed in order to allow a high degree of rationaliza= tion as to opencast mines in unconsolidated overburden in Germany, in many European couh- tries, in India and in Victoria. The differing compactness of the layers to be mined, the increasing mining depth, the adverse over- burden to coal ratio and geotechnical con- ditions account for the combined use of con- tinuously and discontinuously operating equip- ment and systems. This paper is to demonstrate some projects showing the combination of continuously and discontinuously operating equipment which aims at optimizing opencast mine operations. It will be reported on the following combinations: - combined use of bucket wheel excavator/

Jan 1, 1981

Agglomeration Drum Selection and Design A model has been developed by for drum agglomeration which allows selection of geometry and power input. Specific aspects considered are: calculation of total operating volume, solids residence time based on drum geometry and operating parameters, selection of the drum aspect ratio, selection of proportion of critical speed, calculation of rotating power requirements. The model uses solids total residence time to calculate the required operating volume. The burden density is calculated from the solids bulk density, agglomerate packing and the fluid density. Power is calculated using a modified Liddell and Moys correlation for burden position and shape, and the operating drum speed. A further power allowance is made to allow for accretion drop off during drum rotation. Results from the model (especially power and per cent operating fill) have been verified from industrial installations of significant size. Predicted and observed power draws are within five per cent when burden slip and bypassing are not significant. When these are significant (at fills above 15 per cent) the actual power draw will be less than the model prediction. Under these circumstances the quality of the agglomerates will be poor.

Sep 13, 2010

By Ruffles B. R

A computer simulation has been developed to model the flow of copper ore in Isa Mine. It simulates extraction of copper ore from the 1100 orebody by load-haul-dump (LHD) units to ore passes, haulage from chutes on 19 level by Rockflo trains to crusher bins, crushing and hoisting. It can assess in terms of the tonnage and head grade of ore hoisted, the effect of varying operating strategies, as well as measur- ing shortfalls in required capacities of any of the operations (extraction, hauling, crushing and hoisting). The simulation was designed as a modular, deterministic, steady-state model with parameter input allowing complete flexibility in its use. Queuing theory is used extensively to evaluate the effect of interference at potential bottlenecks. The model has been used to determine the effect on production of varying train sizes, maintenance policies on the haulage circuit, orepass capacities, and extraction operations.

Jan 1, 1974

By Wright G. N

Curragh Queensland Mining Limited, a co-venture of Australian and overseas interests, operates an open cut coal mine 13 km north of the township of Blackwater in Central Queensland, refer attached location map.

Jan 1, 1992

By Skinner J, Brackenbury K

The AuPlus" Systems have been applied in the gold mining industry to achieve improved gold recoveries, faster leach kinetics and reduced cyanide consumptions. Calcium or hydrogen peroxide, collectively known as peroxygens, can be used. The choice depending on plant design and the nature of the ore. Laboratory test work and plant trials are included in this paper to illustrate the benefits of peroxygen usage in extractive gold metal- lurgy.

Jan 1, 1991