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Lower greenschist quartzo-feldspathic schists within the N-S trending Earnslaw Synform of the Upper Wakatipu area are pervaded by late-stage quartz filled extensional and extensional shear fractures, with quartz-scheelite lodes infilling normal faults. Exposed veins/lodes mapped over at least 1000 km2 define a paleoflow system developed during late metamorphic exhumation of the schist. Both veins and lodes have consistent angular relationships to the schist foliation independent of their location on the Earnslaw synform. Unfolding the synform leads to a regional subhorizontal foliation and a systematic set of subvertical quartz veins striking NNW extending over a depth interval >5 km, striking parallel to a set of normal faults hosting the quartz-scheelite lodes. The structures define an extensional regime with s1 sub-vertical, s3 oriented WSW-ENE, a low differential stress, and suprahydrostatic fluid pressures.   The quartz-scheelite lodes (<2 m thick) occupy faults which cross-cut the quartz veins, and are traceable for a few hundred metres, at most. The lodes consist of laminated and/or massive quartz, slivers of crushed and folded schist, random and discontinuous lenses of scheelite with clay selvages separating the lode from relatively undisturbed wallrock schist. Textural evidence suggests that slip developed incrementally with total displacement on faults during lode formation on the order of a few ten's of metres.   The distribution of Glenorchy veins demonstrates broad scale hydrothermal flow through low-permeability schist, channelled within dilatant mesh style structures comprising interconnected shear and extension fractures. Flow through the lodes was likely derived from the greater surrounding area via the interlinked network of fractures and focused into the low displacement shears. Available evidence suggests the system developed together in a uniform extensional stress regime toward the bottom half of the seismogenic regime.

Jan 1, 2001

By J Merrells

Fluor, together with our clients, has yielded significant reductions in the total cost of mining projects by employing a systematic and methodical process of cost reduction. This paper outlines this structured approach to reducing the total cost of projects through the gathering of information, the evaluation of the zero base design, and the development of the execution strategy for the project in the study phase.Over the recent iron ore boom the cost of growth projects escalated rapidly due to a variety of factors including the engineering cost of re-designing facilities, construction in remote areas and an increase in the ‘perceived’ capital requirements for maintainable and operable facilities.Fluor has made strategic steps towards safely reducing the capital intensity of projects, by working with clients to develop zero base designs which utilise the minimum technical requirements in order to meet the function of the plant and then add cost for safety, maintenance and operability only where clearly justified.This paper has set forth a structured three phased approach to focus the team on reducing capital cost while maintaining a low increase in engineering effort.The initial ‘gather’ phase focuses the team on acquiring information and identifying decisions that will need to be made so that the team can prioritise and focus the attention on areas that will provide the greatest benefit. Within this phase the identification of zero base design requirements, review of lessons learnt and analysis of capital cost levers, allows the team to identify the key decisions on the project that will affect the capital cost.In the subsequent ‘evaluation’ phase the team established the zero base design, using the hierarchy of cost reduction as a guide to focusing the team’s attention on high yielding cost saving opportunities.In the final phase the team develops the execution strategy which will yield the least cost using strategies and tools such as modularisation, standardisation, replication, strategic sourcing and 3D design.CITATION:Merrells, J, 2017. Reducing total project cost in the study phase using zero base design, in Proceedings Iron Ore 2017, pp 621–626 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By Wilson G. L, Lord J. H

A detailed analysis of faulting indicatcs that blocks of "greenstone" have been thrust beneath the southern end of the Mt. Isa orebodies.This "greenstone" basement is considered to be a major structural control in the localization of these orebodies.INTRODUCTIONThis paper is based on exploration carried out by Mining Corporation (Aust.) N.L. from 1956 to 1960 in the area immediately south of Mt. Isa, Queensland. During this period over 20,000 ft of diamond drilling was completed together with costeaning and geochemical exploration.Early in 1959, it became apparent that diamond drill information could not be correlated with the current geological concepts of this area and a detailed geological appraisal became necessary. In all, sixty square miles were mapped at a scale of 1 in. to 500 ft, using enlarged aerial photographs. All drill core was logged and sections re-interpreted.Professor K. C. Dunham of the University of Durham consulted on this project and contributed through valuable discussion. Dr. A. Day of the University of Sydney carried out a gravity survey in February 1960 and Dr. H. Wilshire of the same University undertook microscopic examination of rocks from the area. Certain sections of the area were investigated geochemically by Mr. K. K. Hughes of New Consolidated Gold Fields (Asia) Pty. Limited in 1960.In outlining a theory of ore genesis in the area the writers have drawn heavily on the invaluable data published by many previous workers on the Mt. Isa field, in particular...

Jan 1, 1963

By B Nielsen, H Lehto, J Rohleder, C Robben

Sensor-based ore sorting is being increasingly used to reduce the amount of low-grade and waste material processed in mineral concentrators. This type of preconcentration provides bottom-line benefits to users by reducing the amount of energy, water and consumables, as well as reducing capital cost. Existing operations can increase metal production, while previously uneconomic deposits and low-grade stockpiles can also be exploited. The technology can also be used to separate ore types for selective processing. The path to implementing sensor-based sorting may include:• geometallurgical evaluation• first inspection testing to investigate sensor response• bench-scale testing where sensor selection is not obvious or for difficult applications• performance testing in full scale sensor-based sorting machines• larger scale site-based piloting with a temporary semi-mobile plant installation. Sorting requires material to be suitably prepared and presented to the machines and typically this consists of crushing and screening to limit top size and optimise liberation. However, where material streams are suitably sized and prepared, additional equipment may not be required (e.g. the sorting of semi-autogenous grinding (SAG) Mill pebble streams).This paper presents a case study of economic upgrading of gold ore, by preconcentrating with sensor-based ore sorting. The case study examines sorting amenability, test work, the feasibility study through to implementation, with associated flow sheet development. The development process is analysed and evaluated with a view to rationalising the process for development of future projects. In addition, limited financial modelling based on expected results is shown to illustrate the benefit to the operation.CITATION:Nielsen, B, Rohleder, J, Lehto, H and Robben, C, 2017. Sensor-based ore sorting to maximise profit in a gold operation, in Proceedings MetPlant 2017, pp 131–146 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

Of late there have been various papers published on this subject by various authorities, in which certain definite factors influencing slime settlement have been brought forward. As the principles set forth by these writers are of great interest, and have, in most cases, been generally accepted, the author will review them in the hope that by discussion some more knowledge may be brought to bear on many points connected with the subject.The definition of slime at the present time is not a standard one, and varies according to different authorities, some defining slime as ore crushed to such a fineness that it will pass through a screen of standard size, say 150 or 200-mesh, in water (1, 2);others as that part of the finely-crushed material which is in the physical condition which causes it to remain in. suspension in water, and possesses pr?perties which render it almost unleachable (3). Authorities seem divided on this point, but of late American writers seem to prefer the former definition. On the contrary, B L Gardiner describes slime as a mixture of small particles of crushed ore of varying sizes which, when mixed with water, tend...

Jan 1, 1912

The New South Wales coal industry is a highly mechanised well organised industry which has developed from an annual production of slightly less than 13 million tons in 1950 to over 33 million tons in 1969. Although continuous miners were not introduced into the mines until 1950, by Jillle 1969 the percentage of coal won by these units was 87.3. The paper describes mining conditions in the various coalfields of the State, their complexities and problems and how these have been dealt with. The introduction of fully mechanised long wall faces has presented a challenge which has been accepted and descriptions of systems in use are discussed. Major expansion of the industry is anticipated to meet the requirements of the growing Australian steel industry, for local power generation and to meet the increasing demands of overseas markets.

Jan 1, 1971

The application of biogeochemical methods in mineral exploration in semi-arid to arid environments in Western Australia has been investigated in an area near Norseman.The study involved a comparison of trace element characteristics of rock, soil and plants in the vicinity of the Pioneer BB prospect, where nickel-iron sulphide mineralization occurs in a "greenstone" sequence of ultrabasic, basic and sedimentary rocks.Analyses of unweathered and partly weathered rock from diamond drill cores show the ultrabasic rock to be highly variable with respect to Ni, Cu, Co, Zn and Mn.Samples of weathered bedrock and overlying soil were analysed for total trace element contents and for the trace elements associated with secondary iron and manganese oxides. Approximately 30 per cent of the total nickel content of the weathered basic rock is associated with secondary iron and manganese oxides, compared with approximately 15 per cent in the weathered ultrabasic rock.The soil has a sufficient residual content to provide a reliable indication of the chemistry of the underlying rock. Total trace element analyses of the -89 mesh fraction show strong anomalies for nickel and copper over the mineralized zone. Important amounts of nickel, cobalt and, to a lesser extent, copper are apparently associated with secondary iron and manganese oxides in the soil.Melaleuca sheathiana (tea tree) has been used to study the relationship between soil and plant chemistry. No strong relationship between plant and rock type was observed. Analyses were made of leaves, twigs, wood, bark and roots, and all plant organs were found to have anomalous nickel and copper contents near the mineralized zone. Leaves were found to give the best contrast in the anomalous area and to show fewer erratic values than other organs. It is concluded that the uptake of trace elements by tea tree is low in the semi-arid to arid environment of Western Australia, but that analyses of the plants do reflect the presence of mineralization.

Jan 1, 1973

By S Kundu, J Zanganeh, D Eschebach, B Moghtaderi

The concentrations of methane and coal dust vary from one location to another in underground coalmines. In the presence of an ignition source, such as static electricity, these mixtures can initiate explosions and consequently cause massive destruction. Research data can help in understanding the level of hazards and associated risk these flammable mixtures can produce. For instance, the level of peak explosion pressure and flame speed can be well understood from experimental and numerical research data. With this aim, methane–air mixtures and methane-coal dust-air mixtures were employed in a ducted spherical vessel. According to literature, the maximum value of peak explosion pressure can be obtained in vessels of spherical geometry when compared to vessels of other geometries. Thus the values of explosion parameters generated from spherical vessels can be incorporated in understanding the highest level of hazard that can occur in a real world scenario.In this study, the duct integrated with the vessel resembles any channel or pathway connected to a methane and/or coal dust rich area in the mine. Experimental investigations emphasise that the severity of explosion in the explosion zone transmits to the channel or pathway. The length of the channel or pathway also plays an important role on the values of explosion parameters. The greater the length of the channel or pathway, the higher the explosion pressure is and therefore the higher the destruction. Ignition energy and concentrations of methane and coal dust were varied in collecting experimental data. The data of explosion parameters thus obtained can be employed in addressing hazard mitigation strategies in coalmines.CITATION:Kundu, S, Zanganeh, J, Eschebach, D and Moghtaderi, B, 2017. Incorporating research data in addressing methane and coal dust fire, and explosion hazards in coalmines, in Proceedings Australian Mine Vent Conference 2017, pp 175–180 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By D Craw

The Rise and Shine Shear Zone is a mineralised low angle deformation zone traceable for at least 7 km through biotite zone schist of the Dunstan Range, central Otago. Rocks from the shear zone obtained from recent drillholes are unweathered and facilitate paragenetic studies. There is a progression of mineral deposition from semiductile foliation-parallel shearing, to subsequent folding, and brittle fracturing. Sheared rocks are dominated by microshears containing fine grained hydrothermal muscovite and rutile that has recrystallised from metamorphic muscovite and titanite respectively. Euhedral pyrite occurs within segregations in the schist and is locally brecciated by the shears.   Arsenopyrite occurs within microshears and is intergrown with hyrothermal muscovite. Fractures within relatively undeformed schist are filled with ankerite, siderite, chalcopyrite, sphalerite and galena and these veinlets also crosscut the microshears. Locally the schist is folded and zones of brecciation, silicification and vein deposition overprint the rock. Vein quartz and albite predominate and arsenopyrite and gold infill breccia matrix and crosscutting veinlets. Sulphide deposition began in the later stages of metamorphism with pyrite deposited in quartz-albite segregations. Subsequent shearing caused brecciation of some grains and accompanied deposition of arsenopyrite ¦ gold and rare sulphides along foliation-parallel microshears. Minor amounts of chalcopyrite, sphalerite and galena were then remobilised in ankerite veins that crosscut the shears. In areas of high strain, arsenopyrite was then deposited as euhedral grains in veins and breccias. Synmineralisation deformation caused the brecciation of some grains and gold was deposited infilling fractures in the arsenopyrite. The paragenetic sequence shows gold mineralisation occurred in two distinct sets of structures (semiductile and brittle) that formed at different times in the formation of the shear zone.

Jan 1, 2006

The paper considers Aboriginal responses to large-scale mining, including Indigenous attitudes towards land access for exploration and project development. The core question, in which I have been interested for some time (Trigger 1997a; 2000; 2001), is: what are the significant factors affecting responses among Indigenous communities to mining exploration and development project proposals?

Jan 1, 2002

The study of gas emitted from face coal samples at the coal face is part of an investigation of instantaneous outbursts of coal and gas. Normally, seam gas essentially comprises methane of which the origin in the metamorphism of coal is undoubted. The origin of other gases sometimes occurring in high proportion in seam gas, particularly carbon dioxide, is more controversial. A simple meter for rapidly assessing gas in coal was developed. Tests with the meter enabled comparisons of seam gas in face coal at some outbursting and nonoutbursting mines, and under various working conditions. The varying results of widespread testing suggest certain trends, including some prospect of recognising outbursting potential at the coal face.INTRODUCTIONThe aim of this work is identification of differences in gas condition between coals subject to instantaneous outbursts and coals which have not outburst, and between faces of coals which will and which will not subsequently outburst. Any comparative test should be conducted right at the coal face on coal about to be worked and the results of testing should be available after a short period. Moreover, the method and the comparison of results should require no special skill, and be well within the capacity of junior mine officials. Any consistent relation between gas condition and subsequent mining conditions - outbursting or not might be valuable in prediction of outbursts.INSTANTANEOUS OUTBURSTSInstantaneous outbursts (Hargraves, 1958) , are largely unpredictable and unaccountable ejections of coal (up to 5,000 tons) and gas (up to 5,000,000 cu.ft.) from a standing coal face. Usually the gas is essentially methane (CH4 ) but may be essentially carbon dioxide (C02 ), or an intermediatemixture...

Jan 1, 1962

By S Smit, P J. J Strobo

ZINIFEX Century Mine is a zinc, lead and silver concentrate producer. Flotation is the primary method of minerals separation in this circuit. The flotation circuit is quite large with 79 flotation cells. The levels in each of these interconnected cells are controlled at more than 45 level control stations. Due to the multivariable interaction throughout the circuit, good level control was found to be difficult to achieve by just using normal Proportional-Integral-Derivative (PID) control. As a first step in advanced process control, the FloatStar Level Stabiliser, a multivariable controller developed specifically for flotation circuits, has been commissioned at Century mine to solve the level control problems. The first section of this paper therefore discusses and shows the results and improvements obtained by using the FloatStar level stabiliser. The results and benefits of the FloatStar Flow Optimiser are discussed in the second section of this paper.

Jan 1, 2004

By G J. Massoth, K Faure, A G, R G. Ditchburn, I J. Graham

From modest beginnings in 1996, research into the mineral potential of New ZealandÆs Exclusive Economic Zone has progressed into a major multidisciplinary component of GNSÆs recently funded 6-year æMineral Wealth of NZ and its EEZÆ Programme. In excess of $7.5 M of research funding has been expended, plus $10 M leveraged via collaborations with NIWA (NZ), NOAA (USA), JAMSTEC (Japan), U. Kiel (Germany) and ANU (Australia), whose scientists have contributed hugely to research cruises, as well as subsequent analysis and publication. The 1999 NZAPLUME I cruise was the first research expedition to systematically locate, and chemically characterise, submarine hydrothermal venting associated with arc volcanoes of the southern part the Kermadec intra oceanic arc system. This was followed by the 2002 NZAPLUME II and 2004 NZAPLUME III cruises to the mid- and northern-sections of the Kermadec arc, respectively. Combined, these cruises have surveyed 1300 km of the volcanic chain (from Whakatane to Monowai), including 34 major volcanic centres. Together with concurrent surveys in the Tonga arc, this is now the longest continuous stretch of intra oceanic arc to be surveyed for hydrothermal emissions. Most of the volcanic centres are characterised by simple cones although 30 per cent contain caldera complexes, and compositions range from basalt through to rhyolite. Massive sulphide mineralisation has been recovered from several volcanic centres in the southern Kermadecs (Clark, Rumble II West and Brothers), suggesting the existence of significant Au and base metal bearing deposits along the arc front.

Jan 1, 2005

By D J. Corp

The Halmahera Contract of Work is a sixth generation contract held 82.5 per cent by Newcrest Mining Limited and 17.5 per cent by PT Aneka Tambang and takes in the Gosowong Project area. In 1991 Newcrest Mining Limited established a small exploration office in Jakarta and proceeded to seek exploration opportunities. The Halmahera area was identified as a substantial prospective ground position in a relatively unexplored area. In late-1991 Newcrest Mining Limited and PT Aneka Tambang agreed to explore in Halmahera. Initial field work commenced in July 1992. A vigorous ground reconnaissance programme led to the discovery of the Gosowong deposit a little over 12 months later in September 1993. In April 1997 the Contract of Work was approved covering much of the island of Halmahera. Between September 1997 and November 1998 activities were directed principally towards obtaining the necessary permits required to commence construction activities. Some particularly ambitious targets were set for achieving this outcome. An aggressive construction programme commenced in late-1998. Construction took place during a period of unseasonally high rainfall, which in itself presented additional challenges to the construction team. A key milestone for the project was achieved on 1 July 1999 when wet commissioning of the process plant commenced. Construction of the Gosowong Mine was achieved on time and within budget. A period of some six years elapsed from the initial discovery of the Gosowong deposit to the time of the first gold pour. Much of the permitting, construction and commissioning activity took place between September 1997 and July 1999. This coincided with a period of significant social, economic and political upheaval in Indonesia. During the construction period a high level of importance was placed on the structured recruitment and training of local people, as well as fostering appropriate community and local business development programmes in the communities nearby the project. Emphasis was also placed on environmental management with detailed long-term planning and progressive rehabilitation commencing during the construction phase. The permitting and subsequent development of the Gosowong Project has demonstrated that even during the difficult times, with commitment, it is possible for mining and exploration companies to conduct business in Indonesia.

Jan 1, 1999

By M Wilson, D Whiteman, P Kuiper, S Talu, G Watt, A van As

Once the draw process has begun in a block cave, it is very difficult to identify which regions of the cave have successfully propagated, where the caved material is flowing from and where it is flowing to. The uncertainty around cave flow increases as the cave is drawn and can be further compounded by poor draw control practices. These uncertainties make it difficult to plan effective draw strategies to control dilution, as flow model predictions tend to gradually diverge from the actual state of the cave. There have been documented occasions where observed caving phenomena, such as muck pile surface rilling, could not be reproduced with the cave flow models of the time. The ultimate consequence of cave flow uncertainty is generally manifest as higher dilution and lower grades.In order to measure the real-time flow of caved material within an active block cave, CRC Mining and Elexon have developed, together with Rio Tinto, a cave flow monitoring system called Cave Tracker, which is being trialled at Argyle Diamond Mine (ADM) in Western Australia. The Cave Tracker system at ADM comprises electronic ‘beacons’ that have been installed down long HQ diameter drill holes located above the extraction level. As the cave-back propagates and the rock mass fragments, beacons are released into the muck pile and flow along with the caved material to the drawpoints below. At Argyle, the beacons are configured to emit a signal every three days. These signals are picked up by detectors installed on the extraction and undercut levels, allowing the positions of the beacons to be determined.By examining the real-time material flow in different regions of the cave, flow mechanisms can be better defined. Draw control strategies can then be actively tailored to manage the current state of the cave. Thus, previously undetectable indications of excessive rilling, rapid cave propagation, cave stall, air gaps and dilution entry can now be identified early and assessed continuously as the cave progresses. For the first time it is possible to amend draw strategies based on measurements from inside and outside of the fractured zones, allowing caves to be managed more effectively.CITATION:Whiteman, D, Talu, S, Wilson, M, Watt, G, Van As, A and Kuiper, P, 2016. Cave Tracker flow monitoring system installation at Argyle Diamond Mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 479–488 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

Enterprise Optimisation is a methodology for increasing the value of mining and mineral processing operations through better long-term planning decisions. It involves a combination of ten mechanisms which deal with decisions at different stages of the value chain. A decision made at any point in the chain potentially affects the decision for all other points in the chain. The key, therefore, is to optimise them simultaneously. The Enterprise Optimisation approach can be shown to produce increases of five per cent to 35 per cent or more in net present value (NPV), even when several optimisation methods have already been applied. This paper steps through an example case study, illustrating the effect of each mechanism and how they can work together to develop greatly improved results. This example results in a series of counter-intuitive outcomes, which challenges conventional management practices and typical organisational objectives based on organisational silos.

Dec 6, 2010

Although the Diamond that is cut and polished and made up into an article of jewellery, is so well known, there are, comparatively speaking, very few outside the industry who know this beautiful crystal in the crude state, as turned out ofNature's laboratory, and the means employed in winning this precious stone.This article is written with the endeavour to give the reader some idea of the geological formations in which the Diamond occurs, and as it is reported that Diamonds have been found in Western Australia, as well as in other parts of the Australian Colonies, a few hints as to the means employed in working the ground in South Africa may be of use to those intending to prqsecute the search in this country. The general geological formation of the South African Diamond Fields is Lacustrine shales and sandstones, intersected by dykes of various eruptive rocks, varying considerably in their character. and in places vesicular in texture, the vesicules being more or less filled in with zeolites by permeating waters.

The Performance of Benzyl Arsonic Acid as a Collector in the Flotation of Wolframite and Cassiterite Slime

Sep 13, 2010

By S Moradi

The aim of this study was to investigate the possibility of leaching zinc from the tailing (-2 mm) of Angouran flotation plant using sulphuric acid. The tails were first calcined at 800¦C for one hour. The effect of factors such as stirring rate, temperature, initial acid concentration and solid/liquid ratio, on zinc extraction were studied. The results obtained show that at the best conditions, about 91 per cent of zinc were leached using a stirring rate of 800 rpm, a reaction temperature of 50¦C, a 30 minute reaction time, a 100 g/L initial sulphuric acid concentration and solid:liquid ratio 1:6 g/ml. The P85 of the feed material was about 150 ¦m and acid consumption was 600 kg/t.

Jan 1, 2002

Over recent years the trend in Australia has been towards the definitions of sustainable development which emerged from the 1992 Rio Summit of retaining a commitment to ecological integrity, but also incorporating social and economic dimensions of sustainability. Sustainable development may be seen as maintaining and enhancing:natural capital: defined as all natural resources, both environmental and those of traditional economic value; manufactured capital: made by human kind; including produced goods, infrastructure and built environment; human capital: defined as the health, well-being, intellectual capabilities and spiritual welfare of individuals; and social capital: defined as social relations and institutions within and between societies, their norms and functionality (Ameef, 2002). This paper will endeavour to assess the challenges and opportunities facing the professionals and their Institute in the minerals industry in Australia because the MMSD Global and Regional Australia Reports do not, in the authorÆs opinion, adequately address the æhuman capitalÆ input into the current or future development of the minerals industry, in particular, the sustainability of the professionalsÆ skills, knowledge and experiences in a global context.

Jan 1, 2002