Search Documents

The Bau Goldfield lies in the southwestern corner of Sarawak in East Malaysia. Evidence of past mining in the form of open pits and adits can be found over an area of 250 sq kin, centred on the township of Bau. Chinese were mining gold in the district as early as 1820. The Bau Goldfield so far has produced approximately two million ounces of gold, from alluvial deposits and over 50 hard rock mines. The largest single producer was the Tai Parit mine (700 000 oz) which was operated by the Borneo Company from 1898 to 1921 and by a local Malaysian family from 1991 to early-1997. Over the past ten years, gold resources totalling around one nullion ounces have been delineated through systematic exploration using modern techniques, with the bulk of the resource hosted in two deposits (Jugan and Pejiru).Triassic to Jurassic andesitic volcanics and coeval intrusives are the oldest rocks that crop out in the Bau Goldfield. These igneous basement rocks are unconformably overlain by 500 m of late Jurassic, massive, micritic limestone which in turn is overlain by a 1500 in thick flysch sequence, composed mainly of shale. Basement rocks and limestone are exposed along the hinge of a ENE-striking anticline that passes through the Bau district (Bau Anticline). A NNE-striking belt of Miocene granodiorite porphyry stocks and dykes also passes through the Bau Goldfield. All of the known gold deposits lie within 5 km of this zone of intnisives, with a concentration of deposits at the intersection of the intrusive hell with the Rau Anticline.

Jan 1, 1997

The Government Mining Engineer of South Africa has decided to legislate that Self Contained Self Rescuers (S.C.S.R.) become a mandatory piece of equipment for all those persons proceeding underground. It is envisaged that: * employees in underground coal mines will be fully equipped with S.C.S.R.s during 1988; * those persons employed in gold mines during 1988/89; and * personnel in all other mines by the end of 1990. It is the intention of this paper to discuss the introduction of these auxiliary life support systems, and to give an update on current market developments.

Jan 1, 1988

By R Bose, M Bovell, G Cheong

Grinding media is a major consumable in mineral processing and therefore decreasing costs associated with its consumption is regularly considered a key goal for the minerals processing industry. Grinding media manufacturers have historically developed steels with improved wear life for their products as a way of delivering incremental media quality improvement. This has included increasing carbon levels from low-to-medium carbon steels up to the eutectoid carbon composition of 0.77% where the relationship between higher carbon and better wear performance is well understood. Producers today will regularly use grades in excess of 0.8% to further improve wear performance particularly for rolled grinding media.This paper first introduces the demonstrated relationship between this increased carbon content and improved wear resistance along with metallurgical rationale behind the high carbon production process and limitations. To test the performance improvement associated with the higher carbon steel grade, a series of Marked Ball Wear Tests (MBWT) were carried out. This paper also explores the relationship between ball properties, test methodology and wear performance and concludes by correlating increased carbon grade with a reduced consumption rate of between 3.1% and 6.1% in the tests conducted.CITATION:Bovell, M, Bose, R and Cheong, G, 2018. Improved forged grinding media performance with carbon content greater than 1.0%, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 559–570 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By G Kennewell

At 11 am Monday 8 September 1997, the successful detonation of the 5/9 Mass Blast at Pasminco - Elura was signified by the subsiding of æMt KevinÆ (a 15 m high earth fill mound). The blast was in response to earlier mine subsidence, which holed through to the surface affecting future stability of underground workings. The blast was a first for Elura which fires small tonnages regularly to avoid rapid oxidation of the ore. This paper discusses the strategy and the considerable planning that went into EluraÆs first blast of this magnitude in order to succeed first time round.

Jan 1, 1999

By Edwards A. B

Yampi Sound is a small channel in the Buccaneer Archapelago (latitude 16° 10' S.; longitude 123° 40' E.), on the northern coast of Western Australia (Fig. 1), about 90 miles north of Derby, and 200 miles north-east of Broome.The iron ore deposits of Yampi Sound occur on an approximately S.E.-N.W. trending belt of islands which form the northern boundary of the Sound (Fig. 2). From east to west they are Koolan Island, Tarrant Island, Usborne Island, Cockatoo Island, Irvine Island, Kathleen Island, Flora Island, and Bathurst Island. To the south of the Sound lie Margaret Island, which is separated from the mainland by a channel only 60 ft. wide, Dorothy Island, and Gibbings Island. Some of the channels between the...

Jan 1, 1938

By Peirong C, Pei N, Shouxi H, Hongzhong X

Indosinian (T) orogeny amalgamated the Mongolia-Xingan fold zone, the North China continent, the Yangtzi platform and the SE China fold zone into a unified continent. The early to middle Yanshanian (J-K,) orogeny created a Cordilleran type active continental margin in East Asia, reactivated the consolidated East China continent, and generated a large amount of granitoids, calc-alkaline volcanics and W, Sn, Mo, Cu, Au, and U ore deposits. The late Yanshanian (K2) orogeny began a transition to the western Pacific type continental margin. A tensional environment led to the development of peralkaline magmatism and the formation of continental basins with red beds. The Himalayan (Tr-Q) orogeny was characterised by a backarc spreading and rifting regime. The dominant magmatism was continental basaltic.

Jan 1, 1995

By Brechtel C. E

Providing adequate airflow to effectively dilute and remove diesel pollutants in large mine working headings is a little researched area. A simulated diesel mucking operation was carried out in the Exxon Colony Pilot Mine in Colorado to establish expected levels of diesel pollutants in dead-ended working headings. This heading was nominally 15.3 m (50-ft) wide by 9.2 m (30-ft) high. Two face ventilation systems were tested using sulfur hexafluoride tracer gas to represent the diesel pollutants. The results of these tests showed that conventional face ventilation systems operating at high flow rates could adequately ventilate diesel equipment in the 447-522 kW (600-700 hp) range, even in a dead heading 91.4 m (300 ft) in length.

Jan 1, 1988

By A M. van Niekerk, W Mey

Coal mining has an impact on the water management of the water scarce Upper Olifants River Catchment. A prefeasibility study was carried out by Anglo Coal and Ingwe Collieries Limited to establish the water supply and demand in the catchment. A geohydrological model was used for the coalfields to determine the stored water and excess water available. Two distinct collective and treatment systems were proposed for the Witbank and Middelburg municipalities to treat excess water from the Anglo Coal and Ingwe Collieries Limited. The Emalahleni Water Reclamation Project for Witbank was initiated first. Water management and treatment experience gained at Anglo Coal was the cornerstone to develop the collection, treatment and distribution system. A full enquiry was issued to Keyplan, Veolia, Bateman Africa and IST Technik to construct, commission, operate and maintain a 20 ML/day desalination plant to treat acidic, saline mine waters to a South African National Standard (SANS) 0241 Class 0 potable water. After the technical and financial adjudication, Keyplan were awarded the contract. An integrated regulatory process was adopted through consultation with all the relevant regional and head office staff of the Department of Minerals and Energy, Department of Water Affairs and Forestry and the Mpumalanga Department of Land Affairs via an authorityÆs steering committee. A rock engineering evaluation was done to select both the plant and waste disposal sites as all possible sites are undermined. Various contracts are required with the individual mines for water supply, the Emalahleni Local Municipality for the delivery of potable water and for the disposal of wastes.

Jan 1, 2006

We all live in professional silos û comfort zones, where we talk to like-minded people with the same training, experience and view of the world. We note in passing the existence of other disciplines, but they are tolerated rather than embraced. To the geologist, the metallurgist is a mad scientist conjuring gold out of some foul solution about which the less said the better. To the metallurgist, the geologist is a bearded, self-appointed sage who guesses what is under our feet by sniffing the air, and drives a Land Rover badly. As to the view of mining engineers held by both geologists and metallurgists, this is best left to the imagination. And of course we are all confused by the term æmetallurgistÆ. I am called a metallurgist though my skills are in mineral processing not metal processing, but I canÆt be called a mineralogist because that definition is already taken. *Please note that this is available as an extended abstract only*

Jan 1, 2005

By M I. Pownceby, A Torpy, C Johnson, N C. Wilson

To extract uranium from low-grade, calcrete-hosted uranium (CHU) ore is challenging owing to the presence of carbonate and swelling clay gangue minerals that require an alkaline lixiviant to be used. Western Australia possesses ~75 000 U3O8 t in CHU resources. Improvements to alkaline leach extraction practices would improve the economic potential of these deposits.A column leach study of CHU ore was run for 105 days using an alkaline carbonate-bicarbonate lixiviant. The uranium content of the liquor plateaued after 75 days at ~275 mg U/L; the calculated maximum solution capacity was 800 mg U/L. Spiked peaks and troughs were seen in the data set beyond the 60th day, where concentrations ranged from 220 - 290 mg U/L, indicating possible cyclic uptake and loss of uranium from the solution.Pristine and leached ore samples were geochemically analysed and mineralogically characterised at high resolution using a field emission gun-electron probe micro-analyser (FEG-EPMA). Results showed that leached ore samples from the top of the column contained less carnotite than pristine ore. In contrast, leached ore samples from the column base contained regions with more carnotite than pristine ore, indicating precipitation. Three carnotite grain micro-structures were identified in the leached ore; fan-spherulite, granular and core-shell cubes, with evidence for multiple growth phases.Evidence of carnotite precipitation was seen at the edge of and in pore spaces within montmorillonite and dolomite grains. The point of zero charge of both minerals is lower than the pH of the lixiviant (pH 10.8), thus the mineral surfaces are negatively charged and would not attract UO2(CO3)34- ions out of solution. Similarly, the decrease in the uranium content of the lixiviant is not attributed to super-saturation, as this was unlikely to have been achieved. Work is ongoing to understand the reason for carnotite precipitation and the fluctuations in the lixiviant uranium concentration that are seen.CITATION:Johnson, C, Pownceby, M I, Wilson, N C and Torpy, A, 2013. Microscale characterisation of pristine and processed ore - implications for leaching calcrete-hosted uranium ore, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 303-316 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

Production implications of the introduct- ion of electric L.H.D. units in sublevel open stoping and pillar recovery at Rosebery are covered by Faulkner (1982) and Carlton (1982). The following engineering aspects associated with the decision to introduce electric L.H.D.'s are considered here: - Initial requirements for commissioning, including power reticulation at an adequate level to all operating areas. - Conversion of a manual system to radio remote control. - Maintenance backup requirement to ensure that the production potential is realised.

Jan 1, 1982

Because of the coincidental location of orebodies and population in Australia, the mineral sands industry has been subjected to numerous land use conflicts, resulting in the sterilisation of strategic ore reserves and a severe downturn of activity in the eastern states. All tiers of government of various political persuasions were responsible for the decisions leading to this sterilisation. As such, it became a community response to intense land use pressure along an attractive and popular coastline. The resultant high public exposure of the industry has placed it in the forefront of developments in rehabilitation technology. In eastern Australia, the industry has operated in a wide range of ecosystems, many with conservation values. Rehabilitation ech- niques have been developed to suit these varied conditions, and much of this technology is now widely adopted throughout the mining industry. Land use considerations in Western Australia are somewhat different to those of the eastern states. Nevertheless, the same basic principles of rehabilitation apply with modification to suit local conditions and land use objectives. The development of rehabilitation in both Eastern and Western Australia is reviewed, and the direction of future trends is indicated.

Jan 1, 1986

The Australian Constitution specifies certain powers of the Commonwealth Government to be used in its capacity as the national government. Certain of these broad powers result in the Com- monwealth having a facility to play an important part in the development of the mining industry. The State Governments, however, by virtue of their wide powers to regulate matters within the boundaries of a particular State, are more directly involved in the day to day administration and standards of activities of mining operations. In this respect the Common- wealth has something of a dual role because of its "State-like" responsibilities for the mainland Terri- tories. The components of the role that the Common- wealth Government discharges in relation to the mining industry are qualified to varying extents at particular times by the political persuasion of the Government. In absolute terms the components are as follows. 1. Economic management. The Commonwealth's fiscal and monetary policies have an important effect on industry as well as on State finances. In particular, the taxation regime employed by the Commonwealth Government is of direct importance to economic decision-makers in the mining industry. 2. International matters. International trade and commodity matters are, more and more, becoming an everyday part of the conduct of a nation's foreign affairs. 3. Exports. The Commonwealth Government, via the constitutional powers over overseas trade, have exercised varying degrees of control over mineral exports to achieve particular objectives. 4. Foreign capital and investment. Australia in general, and the mining industry in particular, is and will continue to be a net importer of capital. There appears to be bipartisan political agreement in Australia that foreign investment policy must be enunciated to ensure that investors. are in no doubt that Australia welcomes beneficial investment and technology from overseas. 5. Environment and Aborigines. Governments, both Commonwealth and State, have in recent years become more involved in these areas in response to their interpretations of community aspirations. 6. Energy. Access to assured supplies of energy is now viewed, by Governments worldwide, as a desirable asset to ensure the well-being of a nation's people and industries.

Jan 1, 1978

To solve the mining safety and health needs of the future, access to, and sharing of, timely and relevant information will be crucial. The next generation of the Web will provide tools (RDF, OWL, SPARQL, etc) to define and link content for more effective discovery, integration, and reuse across applications and organisations. A recent Gartner Research Report (Finding and exploiting value in Semantic Web technologies on the web, May 2007) predicts these technologies will begin to coalesce in ten years. Implementing this Semantic Web requires structured web content described via metadata (information about information). If an industry or enterprise bases its metadata on a common vocabulary, it becomes possible to share and reuse information. The National Institute for Occupational Safety and HealthÆs (NIOSH) Mining web site provides access to more than 1500 NIOSH-developed publications, products, and topic pages on issues as diverse as ground control, respiratory diseases, and mine emergency management. As the site has grown, locating content has become increasingly difficult. To improve the searching process, a panel of internal experts representing all major research programs was established to develop a controlled vocabulary for indexing that content. The outcome is the NIOSH Mining Safety and Health Thesaurus, a faceted, hierarchical thesaurus containing hundreds of mining safety and health terms organised into 20 facets (eg diseases, injuries and disorders; hazardous events and exposures, equipment, engineering and administrative controls). One immediate goal of this project is to reduce the complexity of locating information on the NIOSH Mining web site by implementing metadata and faceted information retrieval techniques. Another goal is to stimulate discussion in the international mining community regarding developing metadata standards so the industry is ready to adopt future Semantic Web technologies to improve access to mining safety and health information.

Jan 1, 2008

Since I first enrolled to study Mining Engineering, the idea of working with big machinery and explosives has always appealed to me. After a few courses at uni, combined with vacation work and a number of presentations at the New LeadersÆ Conferences I had attended, I began to realise that the explosives side seemed to have more appeal than the others. As I look back on the past two and a half years that I have spent with Orica Australia Pty Ltd as part of their graduate program, I would have never imagined the dynamics of explosives in mining. This I put down to the ever changing and rapid development in technology converting blasting techniques into a defined predictable science. The opportunities I have been given have delivered all the appeals from when I first started my study. As a result of my entry into a profession that uses explosives to deliver broken rock in a range of mining and construction projects, through the use of advanced blasting technology and products, my experiences have been wide and varied. These experiences have included the use of OricaÆs i-konÖ detonator technology and blast design software to allow for blasting operations to occur in a range of environmentally sensitive quarrying and construction projects throughout New Zealand, to the implementation of various Orica blast based services aimed at improving dragline dig performance and reducing coal loss thus improve overall mine sustainability in the coal mines of Central Queensland, to the advanced utilisation of Orica explosive products and technology in a number of the worlds largest copper mines in Chile. I have witnessed first hand the blasting technology available within Orica Mining Services to both deliver fundamental changes in mining results and in turn kick off my career with a bang.

Jan 1, 2009

By Miller JD, Ye Y

The Air-Sparged Hydrocyclone (ASH) has been developed for the fast and efficient flotation of fine mineral particles in a centrifugal field during the past decade at the University of Utah. Over the years, the air-sparged hydrocyclone unit has shown promising potential for the flotation of copper porphyry ore, low-grade placer gold and auriferous pyrite ores, various industrial minerals, and fine coal cleaning. Many fundamental studies including the X-ray computed tomography (CT) analysis have been carried out in order to understand the multiphase fluid flow phenomena associated with ASH flotation. With data available from these studies, it is now possible to construct more accurate ASH flotation models for different applications in order to analyse the behaviour of the system and to optimise design and operating variables. The ASH flotation model developed in this paper is based on the data given in `Air-Sparged Hydrocyclone/Advanced Froth Flotation Fine Coal Cleaning', Final Report, DOE Contract No DE-AC-88PC88853, submitted by Pennsylvania Electric Company (PENELEC), December 1989. Data from several hundred experiments with the two-inch ASH-2C air-sparged hydrocyclone (capacity 0.1 - 0.3 tph dry coal) are available from the report and have been used for this analysis. In the past, a preliminary model based on limited data had been developed. The current study, however, emphasises the global behaviour of the ASH system by utilising almost all the data from the report for the purpose of scale-up and industrial application. There are two parts in the current modeling and analysis effort for ASH flotation of fine coal. The first part is the modeling/analysis of dimensionless ratio of overflow opening area to underflow opening area, A*, and the dimensionless ratio of air flowrate to slurry flowrate, Q . The second part involves the modelling/analysis of all other variables in the system and an expert system for operation and control is introduced.

Jan 1, 1993

By M A. Wells

The various mechanisms by which phosphorus (P) occurs and is distributed within banded iron formations (BIF)-derived iron ore are examined. In unenriched, precursor BIF P occurs predominantly as discrete grains of primary apatite. In high-grade ores hosted mainly by the Brockman Iron Formation, P occurs in three main forms:1. as secondary apatite;2. other submicron, P-rich phases (eg Rare earth containing minerals (REE), vivianite, strengite,wavellite) present in pore networks; and3. as P occurring with iron oxides, in particular, goethite.However, the presence of secondary P-bearing phases does not contribute signifi cantly to the total P level in iron ore, and it is P associated mainly with goethite, which represents the most common occurrence of P in these ores.No direct evidence for the replacement of Fe by P within the structure of synthetic goethite has been demonstrated. Therefore, it is most likely that in iron ores P associates with goethite in occluded form as adsorbed PO4 3- species or as discrete P-bearing minerals, such as strengite, wavellite or vivianite, in ultra-fine, micro-pores or within intra-domain regions of multi-domainic goethite. Such occluded P is not easily extracted with commonly used lixiviants, such as weakly alkaline leachates. Recent development of a low temperature-alkalie/water leach extraction method has been successful in reducing not only the P content, but also amounts of Si and Al inthe initial ore. Refi nement of such a method to commercial application will have enormous benefit in realising the economic potential of large tonnages of high-P (ie >0.07 wt per cent P) bearing iron ore.

Jul 11, 2011

By Seymour K. M, Sampson D. B, Walker I. W

Ashton Mining Limited is the operator of two wholly-owned gold mine/mill complexes at Laverton and Leonora. In addition, Ashton owns 43% of the Bardoc Joint Venture mine/mill complex, which is operated by Aberfoyle Pty Limited. All three of these operations are located in the Eastern Goldfields region of Western Australia (Figure 1). At Laverton, milling capacity is in the order of 1 million tonnes per year in 3 mills (Duketon 200,000 tpa, Cork Tree Well 650,000 tpa and Craiggiemore 150,000 tpa). These mills service a distance of 80 km, from Baneygo in the north to Craiggiemore in the south. Mineral tenements cover a 150 km long stretch of a series of sub-parallel mineralised structures. At Leonora, the Harbour Lights mill is designed to treat 750,000 tpa of sulphide ore, and has treated oxide ores at an annualised rate of over 1 million tonnes/year. The mill is supported by several tenement blocks that lie within a 50 km trucking radius of the mill. The most important of these is the Mertondale tenement block, which covers approximately 25km of the Mertondale Shear Zone.

Jan 1, 1991

By Kendall W. T C

This paper provides a brief overview of the history of the Chaffers Dewatering Project which was successfully commissioned in August 1993. Until the end of 1992 the `Superpit' and the deep mines of the Golden Mile had all been dewatered by a staged pumping system from the 28 level in the Lake View Shaft, which was removed at that time when the Lake View Mine was absorbed into the Superpit. Feasibility analysis had indicated that adaptation of oil industry technology offered the greatest potential for a low cost solution to the problem of dewatering the open pit and deep mines. A KCGM engineer and one of the authors visited the Jackson oilfields to look at the deep well pumping technology in use there in early-1991. In the final analysis a new dewatering station was established in the 23 level crushing station of the Chaffers Shaft using conventional plunger pumps, but the rising main was screwed 178 mm OD (7 inch) casing the suspended from the surface to a depth of 686 metres, and was installed using oilfield personnel and methods. Only the second installation of its kind in Australia, the project achieved the dewatering objective at about half of the capital cost of the more conventional approach and at lower operating costs as well.

Jan 1, 1995

By M Zhu, J Safarian

Understanding the slag composition-structure-property relationship remains challenging due to the amorphous nature of slag melts and the difficulty of high-temperature experimental investigations. Since the CaO-Al2O3-SiO2 slag system is maybe the most important slag system for various hightemperature metallurgical process, the present research employed high-throughput molecular dynamics (MD) simulations on the entire composition region of the CaO-Al2O3-SiO2 slag system to determine physical properties like molar volume, density and diffusivity, structural properties such as distribution of different oxygen types for each simulated slag melt. The obtained slag properties result from the simulations displayed good consistency with experimental data, underscoring the reliability of the MD simulation as a novel tool to predict reasonable slag properties and to study slag behaviour from atomistic insight. The simulated results demonstrate a near-linear relationship between molar volume changes and composition, highlighting the predominant role of oxygen atoms, which is attributed to the significantly larger size of oxygen compared to other cations in the slag melts. This disparity in size leads to oxygen ions occupying most of the space in slags, thereby playing a major role in determining the overall molar volume. The simulation results of slag density revealed a decreasing trend with increased SiO2 content and identified a local minimum at constant SiO2 when Al2O3 content increases, also consistent with established slag density models. Furthermore, the simulated oxygen self-diffusion coefficients reveal a strong composition-structureproperty relationship, where an increase in CaO content enhances slag diffusivity, while a minimum in diffusivity is observed near a CaO/Al2O3 ratio of unity. The diffusivity minimum also corresponding to the local viscosity maxima, indicating effective simulation of charge compensation effects and dynamic characteristics of slag melts. The simulated distribution of oxygen types in slag — bridging oxygen (BOs), non-bridging oxygen (NBOs), free oxygen (FOs) and tricluster oxygen (TOs) — reveals a composition-dependent pattern: BOs peak near CaO/Al2O3 = 1, NBOs and FOs are abundant in CaO-rich areas with NBOs peaking near the Ca3SiO5 composition, FOs in the CaO corner, and TOs predominantly in the Al2O3 corner, highlighting the complex interplay of network formers and modifiers for the charge compensation effects on the slag’s structural properties. The successful application of MD simulations in this study paves the way for a powerful approach to explore the complex relationships in multicomponent slag systems and bridges the gap between mathematics modelling and experimental observations in high-temperature metallurgical processes.

Aug 21, 2024