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Over the past 5 years, Bougainville Copper Limited has undertaken a number of major plant expansions to the copper concen- trate production plant at Bougainville in the North Solomons Province of Papua New Guinea. These projects have scheduled three additional ball mills, three new banks of Outokumpu flotation cells, four additional tertiary screens, two additional tertiary crushers, and more recently four high capacity 24.5m dia. tailing thickeners. The value of the five separate projects totalled more than A$100 million. A requirement of commissioning and bringing on line of each of these projects has been to minimise both operational losses and copper concentrate production. The commissioning has been successfully implemented by detailed planning of the commissioning work in conjunction with the plant operation. Planning has been detailed for each man involved on an hourly basis, highlighting the work required on each commissioning task that is to be undertaken and the time expected to achieve activity Completion.

Jan 1, 1986

Within CRLÆs lifetime there have been a number of products that have proceeded through their life cycles. In each case market forces and technological advances have forced the cessation of the product. The company has then had to develop alternative outlets for its copper. Sometimes it has produced a similar product to fill the same market. In other cases the extra copper is sold as cathode. Today, CRL produces no semi-fabricated copper products and all cathode is sold. More recently, CRL has ventured into the sale of technology and manufacture of cathode motherplates. This area, whilst it is not what had been a traditional area of core business, has been found to be profitable.

Jan 1, 1998

The mining of Australia's rich and diverse mineral resources has been central to the development of the continent by "Europeans" over the past two hundred years. Mining has historically been encouraged (to varying degrees) by development-orientated state governments (the. managers of largely Crown-owned resources) and since Federation, by successive Com- monwealth governments (which have seen mineral development as a means of generating export revenue to fund predominantly social-welfare orien- tated budgets). This marriage of convenience between governments and the mining industry has to date served all parties well. However, Australia's entry to a new world economic environment at a time that community percep- tions are changing (owing to an education-inspired challenge to "old" values) is challenging the hitherto held assumption that mining develop- ment is always aligned with the well-being of the State and community. Issues such as the type and extent of State/Commonwealth government taxation, resource ownership and control, the environment, land use con- flict, the extent and desirability of secondary processing and infrastruc- ture funding are being debated in the public arena. Opponents of mining in the community are well-organised and are well funded, articulate and more importantly, they have effective communication channels with most governments, irrespective of political complexion. Apart from some television-orientated corporate image building and recent efforts by AMIC, the industry's response to this challenge has been unco-ordinated, poorly directed and arguably ineffective. Professionals working in the industry are concerned about the community's perception of themselves and their industry. Recognizing that the Australian democratic system ensures that, in the large, government at its various levels, is reflective of and responsive to the views and aspirations of people, the industry's response must be wide- ranging, equally articulate and couched in a form which is politically acceptable. New objectives in providing information to the public and its educators must be formulated. Moreover, professionals are looking for new directions from industry leaders. The Institute is well placed to facilitate this process.

Jan 1, 1988

I propose to speak today about our mineral heritage. In common usage "heritage" refers to the past. It means the discoveries, the developments, the mines and the processing plants, the benefits, the consequences, and the human experiences flowing from these. The history of the industry, inseparable from the history of the countries in which The Institute operates, is a rich background of which we can all be proud.But there is also a much wider meaning to mineral heritage. Our past has left us with the ab\lity to create and operate world scale enterprises generating wealth for the community, the ability to offer satisfying and challenging careers in a wide range of skills to our young people, and the willingness to follow adventurous and challenging vocations in remote areas, away from the big cities, at a time when the mentality of many is to get the most for the least effort and at the least inconvenience to themselves. The industry continues to be the repository of the pioneer spirit and a vital contributor to improving the life of the people in our countries.Thus, while our mineral heritage has much to do with the past, an essential part of it is how we use this rich past to build and shape our future. It is in this broader context that I am speaking today.

Jan 1, 1990

By M F. L Gibson

The issue of flyrock is very important in the operation of all mineral extraction sites that use blasting. Unlike the other environmental effects of blasting, ground vibrations and air overpressure, flyrock is (or should be) a rare event, with severe consequences which may include damage to property, injury or fatalities. These physical consequences are often matched by a loss in public confidence in the management of the operation, mistrust and bad press. In this work a deterministic analysis of flyrock was carried out using the equations of a particle in motion with drag. The solutions to these equations were used to reproduce the curves of Lundborg et al (1975) for the relationship between flyrock boulder size and maximum ejection distance. A probabilistic approach based on Monte Carlo simulation was built up with the analytical model using published data together with local case study material. A typical quarry blast situation was modelled and estimates of safe standoff distances were determined using risk assessment techniques.

Jan 1, 2001

The additional information that Clarke and Taylor (1982) provide about the important but poorly documented Ardlethan deposit is, of course, very welcome. However their contention that structural considerations, in conjunction with petrology, alter the interpretation of the mineralogical and geochemical data presented previously (Scott, 1981) is not accompanied by adequate supporting evidence. Indeed characteristics of the orebodies studied invalidate their arguments.Heterogeneity between matrix and fragments is not a problem in the South Cherry and Ardwest orebodies because most samples are comprised entirely of interlocking hydrothermal assemblages with a fabric and mineralogy that is uniform through both former breccia fragments and matrix. In hand specimen, the rock superficially resembles altered granite and, as indicated by Clarke and Taylor (1982), a brecciated texture is difficult to discern. In thin section, relict brecciated textures can be observed as localized changes in the grainsize or in the distribution of minerals that outline former breccia fragments (P. J. Eadington, 1982, personal communication).Because of the intense brecciation and comminution of rocks (fragments < 10 mm are usual) in the South Cherry and Ardwest breccia bodies, hydrothermal recrystallization was complete, resulting in homogenization of fragments and matrix. Furthermore, the amount of sample analysed (-100 g for drill core and 2-3 kg for hand specimens) is sufficiently large to be representative of both former breccia fragments and matrix. The Carpathia and Stackpool orebodies, with their abundance of sedimentary fragments, have alteration superimposed on a heterogeneous fabric, and were not studied. Thus the problems of differentiating between fragments and matrix (Clarke and Taylor, 1982) are irrelevant to the particular orebodies described in my paper.Within the alteration halo, which is several hundred metres wide (Paterson, 1976), the very uniformity of the alteration assemblages implies that subsequent, postmineralization brecciation is of only minor significance.Indeed tourmaline pipes in the Ardwest pit are less than several metres across (Clarke, 1979) and produce minimal alteration in the surrounding rocks. Therefore the interpretation of the mineralogical zonation is not compromised by the recognition of several periods of brecciation.

Jan 1, 1982

In late 1989, first-pass reconnaissance exploration delineated a 4km x 6km geochem- ically anomalous area centred 10km WNW of Kainantu in the Eastern Highlands Province at 6¦13'S and 145047'E. The area, named the Basangka prospect, lies between 2 200 and 2 400m asl. Interest in the area was prompted by a 14ppm Au assay of a silica-pyrite breccia float sample taken near Henkai village. The prospect was defined after several acid-leached silica- pyrite breccia and comb textured quartz float samples returned assays above lppm Au and relatively high Ag. Very encouraging and anomalous Au values were obtained from panned concentrates, despite the absence of visible Au colours. Several pan concentrates returned greater than 1mg Au and it is believed that the Au occurs as inclusions within iron oxides which were originally pyrite. In this early stage of prospect exploration, any Au value above 0.lppm in- 150# fraction stream sediments is treated as anomalous. Rock chips, panned concentrates and -150# fraction geochemistry all vividly define the areas of interest at Basangka.

Jan 1, 1991

Despite technological improvements and better understanding of the hazards, coal dust explosions stilI occur. Experimental explosions in galleries in various countries extend knowledge with the constant aim of providing safer working conditions. The inadvertent ignition of an accumulation of methane is the traditional initiator of the coal dust explosion.There are specific parameters of coal dust explosibility and explosion propagation, including the important volatile matter in the coal, fineness and dispersibility of the dust and its concentration. Accepting that initiation cannot be absolutely prevented, it is necessary to consider explosion suppression. While both limestone dust and water are the chosen explosion suppressants, in practice water has more limitations to its efficacy when related to the degree of explosion violence. These data give rise to the criteria for explosion suppression, differences in favoured mining geometries, and using the same principles, to differences in suppression treatments.

Jan 1, 1988

By Millett R

In January 1989, Western Mining Corporation (WMC) acquired the Perseverance and Rocky's Reward orebodies and associated infrastructure from the Agnew Mining Company (AMC). AMC had closed the operation in August 1986 and it had been on care and maintenance since that time. To return the operation to full production as quickly as possible it was planned to mine the Rocky's Reward orebody by opencut mining and treat this ore whilst the underground Perseverance workings were rehabilitated. Removal of overburden from Rocky's Reward thus commenced immediately with a target of April 1989 for delivery of the first ore to the concentrator. Extensive rehabilitation and upgrading of the concentrator commenced in late January, and continued in stages for an 18 month period. The first stage consisted of overhauling all existing equipment and completing a crusher upgrade commenced by AMC prior to the mine closure. During this period, it was necessary to recruit a workforce and re-establish all the required support structure. In late April the plant commenced commissioning trials on mullock. The first ore was crushed on the 11th May 1989 and concentrate produced the following day. From May 1989 to June 1990 the plant was producing nickel concentrate whilst further upgrading continued. During this period, the flotation capacity was tripled by installation of a bank of eight Wemco 144L flotation cells in rougher-scavenger duties and two 12 metre by 2 metre diameter columns in cleaning duties. The existing vacuum drum filters were replaced by two Larox PF32 pressure filters, eliminating the need for solar drying and allowing the flash drier to be fed direct from the filters. These, along with a major borefield expansion and further work to the crusher increased the nominal plant capacity from 600,000 to 1,000,000 t/yr. The plant achieved the 1,000,000 t/yr rate in April 1990.

Jan 1, 1991

Both the miner and the Regional Water Board have legal obligations to ensure that all discharges of water from a mine site are free of harmful wastes, and that proper authorisation is obtained to abstract, divert, or discharge water. This requires long-term planning of water management for the whole of the mine site. Guidance is given in the paper on the issues which must be covered in water right applications.

Jan 1, 1986

THOUGH the literature on the chamber process is considerable, it mostly refers to European conditions. Owing to the demand for acid for flotation and leaching at the mine, it may be necessary to work the process under other conditions. Consequently, some results obtained during the chlorination days at Mount Morgan, within the Tropic of Capricorn, may be useful for reference when working in a similar climate. Though the chambers must be protected against tropical storms, thorough ventilation should be provided, with plenty of space between the chambers, which are almost invariably crowded together. Not only does the space assist in the cooling of the chambers, but it is very desirable during repairs, when lead andtimber have to be hoisted up. The connecting flues between the chambers, which are fairly efficient mixers and condensers, should be round, supported from above, and with the least possible timber about them. Their position and arrangement deserve careful attention. Lattice work will be sufficient protection for the sides of the chambers, and the roof should be high and well ventilated. The Mount Morgan plant, crowded and not well situated, consisted of seven chambers (four over 50 ft. in length), one Glover tower 7 ft. 2 in sq. x 20 ft. high, one Gay Lussac 9 ft. sq. x 30 ft. higb, also one 5 ft. diam. x 25 ft. high. There was one pipe column 4: ft. sq. x 14 ft. 6 in. high. The chambers were run as one unit, and were much lower than those usually constructed in Europe-less than 15 ft. high. Provided that suitable timber can be obtained, 20 ft. is quite low enough. It should be quite satisfactory to use round poles for the studs, and so admit more air space between studs andlead.

Jan 1, 1920

By M Creech

During the 1990s, wider and more productive longwall panels were being introduced into the Newcastle Coalfield. The strata of the Newcastle Coalfield incorporate numerous massive sandstones and conglomerates, some of which formed the immediate roof of the coal seams being mined. The unexpected implications of introducing wider panels into this geological environment included more variable and increased subsidence, severe periodic weighting (with associated mid-face falls) as well as windblast.Subsidence prediction at the time was based on empirically derived data essentially relating subsidence to the width/depth ratio of the panel without accounting for actual widths, nor the impacts of variable geology. This approach required modification as locally derived data was gathered and reinterpreted.The interaction of massive strata located close to the roof of the mined seam resulted in dramatic implications for some of the operations. When associated with longwall goaf geomechanics severe periodic weighting events and crippling mid-face roof falls were the consequence. When associated with narrower panels and shortwall goaf geomechanics, mines in the region experienced aggressive windblast events. The relationships between the overlying massive strata, longwall panel geometry and the various risks encountered during this period is in the author’s opinion, the most concise still documented.As the extensive coalfields of Queensland turn to underground mining operations the relevance of these experiences cannot be underestimated. This paper will discuss recent developments as well as incorporating diverse subjects such as microseismic monitoring, low frequency radio emissions and ‘electrophonics’ as they relate also to the topic.Like Moriarty, massive strata can be disguised and can offend when you least expect. This paper documents a trail of crimes committed by conglomerate in the Newcastle Coalfield that were inflicted on the general public, miners and mining equipment. Although this paper concentrates on the criminal behaviour of conglomerate, this story is also relevant to other massive units such as coarse sandstones that may be more difficult to identify and apprehend. Currently Moriarty remains at large and able to reoffend at any time, once again taking advantage of the unwary.CITATION:Creech, M, 2014. Moriarty was a conglomerate – experiences and implications of coal mining under massive strata in the Newcastle Coalfield, in Proceedings Ninth International Mining Geology Conference 2014 , pp 47–54 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By Schmidt CG

Parameters affecting gold elution using the AARL process are reviewed and critically analyzed in an attempt to optimise metallurgical efficiency and minimise costs in both current and future carbon adsorption operations. Such factors as acid washing, column geometry, elution temperatures and pretreatment reagents are discussed together with eluant water quality and eluate flowrates. Hot acid washing of carbon prior to gold elution has many benefits. Besides improving elution efficiency when eluting with regional water, a hot acid treatment preheats the carbon without causing any gold leakage. Laboratory data indicated that hot acid washing reduces the mass loss of carbon during thermal regeneration. The eluate going to either zinc precipitation or electrowinning is also relatively free of troublesome impurities (organic contaminants and ferrocyanides in particular). Because of the chromatographic character of the AARL elution where an ionic strength gradient is used to inhibit the readsorption of gold, column geometry plays a significant role. While practical considerations and capital costs may restrain the length of the elution column, high length/diameter ratios are advocated in order to promote the plug flow of column eluate. From both a metallurgical and costing viewpoint, the two significant factors affect- ing the AARL gold elution are temperature and cyanide addition. High temperature and high reagent additions within prescribed limits will improve metallurgical efficiencies, but a balance between energy and reagent costs is required in order to minimise overall elution costs. As pretreatment reagents constitute a considerable portion of the total elution costs, both the addition and consumption of sodium cyanide must be carefully considered. Lower cyanide additions may be effective in certain instances, but the more practical use of 0,6 bed volume of a 2-3 per cent NaCN reagent containing 2 per cent NaOH is advocated. This is equivalent to an addition of 20-30 kg NaCN and 20 kg NaOH per ton carbon Treated.

Jan 1, 1986

By McKee DJ

Future mineral processing developments will be of two types. There will be a continuation of the advances of the last 20 years including major increases in equipment capacities, the development of reliable on-line instrumenta- tion, the use of digital computers for automatic control, and the greatly expanded use of in-situ leaching techniques. However, there will also be a need for innovations as the industry faces a different set of problems to those involved in cost and extraction efficiency considerations. These new problems include those relating to energy usage, environmental pressures, and the further development of large low grade deposits and small, high grade metallurgic- ally complex deposits. Present technology does not appear adequate to solve many of these new demands. New treat- ment concepts will be required, and the immediate outlook in this regard is not encouraging. A major research and development task in mineral processing over the next 20 years will be to seek out new ideas and develop them, and this must be pursued with imagination and determination. Both the continuation of the present research pro- grammes and the development of new methods will require a steady supply of highly qualified technical personnel. These people are not being produced in the numbers required, and this situation must be urgently rectified.

Jan 1, 1981

By Horrocks KRS, Smitham JB, Ellison JF

This paper describes the development and installation of equipment for continuously measuring separating density in the dense medium cyclone circuits of the four million tpa Port Kembla B/C plant coal washeries. Monitoring equipment consisting of magnetic coils and differential pressure cells were installed in U-tubes taking the full flow of magnetite from the drain sections of the product drain and rinse screens. The monitoring equipment measures overflow magnetics concentration and overflow density continuously and has operated since 1989. From these measurements and calibration trials, the separating density of operating cyclone modules can be inferred reliably. Variographic analyses of the data show that medium density control to +/- 0.002 RD units and separation density control to +/- 0.007 RD units are achievable. Either method for measuring separation density can be used with approximately the same accuracy, although the overflow density measurement technique suffers from the need to have regular flushing of the Dp cells which complicates the signal analysis. Data from the plant shows that separation density can be controlled by regulating medium density, but the assumption of a constant offset between medium density and separation density is erroneous.

Jan 1, 1993

By Hayward SB

The Maragorik prospect is an example of high sulphidation, Cu/Au mineralisation occurring at a high level in the hydrothermal system. As extensive ash deposits blanket the region, controlled-source audio magneto-tellurics (CSAMT), in conjunct-ion with bulldozer trenching, have been used to delineate subsurface geology. Fluid upflow has occurred along EW structures dilated by rotation on the bounding major NW lineaments. Rising hydrothermal fluids have exploited permeable horizons in contact with the upflow structures. This lithological control is evident as ledges of silicification and peripheral clay alteration, at high levels in the system. As is typical of high sulphidation systems, a two phase fluid consists of an initial rapidly moving vapour-dominated phase, followed by a liquid-dominated phase. Much of the zoned and overprinted silica to clay alteration is developed from the vapour-dominated fluid. Mineral deposition occurs as a result of brecciation of the competent silic-ification by liquid phase fluids. Such mineralisation is of restricted volume in ledges proximal to the feeder structures.The style of alteration and mineralisation are indicative of a very low temperature and hence a high level system. Thus, although high sulphid-ation systems are inferred to develop from porphyry-related magmatic fluids, such a source at Maragorik is interpreted to be very deeply buried.

Jan 1, 1994

By C McIntosh, M van Dam, N Whetter, R Lane, M McCulloch

Mine geology is understood through synthesising large amounts of structural, lithological, geochemical and geophysical data derived from the original topographic surface, drilling and surfaces exposed and removed during open cut and underground excavations. Computer- generated 3D geological models of any mine environment need to incorporate large amounts of information but also should be regularly updated with typically frequent influxes of new data. Geologists with the local knowledge should also be involved in the model construction, enhancement and interpretation, placing ease-of-use functionality high on modelling software requirements. Implicit-style modelling is a fast-growing area of 3D geological software development where interpolated surfaces such as lithology boundaries and bedding orientations are defined mathematically as functions rather than explicitly through coordinate meshes. The functions are constrained only by the data and not by an artificially imposed grid; therefore, implicit 3D modelling can process a lot of information quickly and routinely operate on original data (such as observed contacts and structural data) rather than on evolved iterations and interpretations. 3D mine geology models can be readily updated with new data, which can be automatically reprocessed to test ideas in near-real time. Implicit, function-based 3D modelling software has been applied to the Globe-Progress mine in West Coast, New Zealand. This structurally- hosted gold mine has some geometrical conundrums that are in part being resolved as excavation of the open pit proceeds. The relationship of the Globe-Progress ore shoots to hanging wall and footwall structure is still not fully understood, however, and 3D geological modelling is assisting with visualisation and testing of structural hypotheses. The modelling is also capable of predicting areas of bedding defect slope failure in yet-to-be excavated parts of the mine.

Jan 1, 2009

The mineral resources of Hamersley Iron are structurally complex with fluctuations in mineral chemistry. Besides orebody charact- eristics, mineral recovery is also affected by stringent product quality demands from the competititve steel industry. Under such conditions, a geological ore reserve estimate has little meaning because it is unqualified and presupposes the defini- tion of ore. A system was developed in Hamersley - the Mine Planning Technique - to optimise recovery from available resources. This incremental planning method reduces a geological reserve statement into a simple, logical sequence of events. While there are limitations in the method used, the benefits are enormous. Among its' numerous applications, the schedule - the end product of the technique - plays an important role at Management level in decision making and policy formulation on all aspects of resource exploitation.

Jan 1, 1979

By M R. Lane, M L. Cramer, N P. Wines

Increasing attention is being focused by regulators and industry on the residual environmental liabilities associated with mining projects following site relinquishment (termed surrender in Queensland). Even sites that have been rehabilitated to a high standard and to the satisfaction of the regulator are not completely risk free and may require some degree of ongoing management. As well as ongoing monitoring and maintenance costs, considerations should include how costs associated with potential risk event occurrence can be quantified and, if considered material, how provisioning should be undertaken to minimise the risk to the state and to taxpayers. In Queensland for example, once a resource site is fully rehabilitated and meets its environmental authority conditions or rehabilitation completion criteria, the tenure and environmental authority can be surrendered. During the surrender process any ‘residual risks’ resulting from the use of the site for the resource activity must be considered, and, if requested, a payment given to the government to cover any ongoing management and risk costs. Accent Environmental, in conjunction with Lane Associates, was engaged by the Queensland Government as part of the government’s financial assurance framework reforms to develop an innovative, ‘one-size fits most’ Residual Risk Calculator for the Queensland resources industry. The calculator is an Excel-based tool that uses detailed user inputs to estimate post-surrender management requirements and liability at resource sites. If residual environmental risks associated with rehabilitated mine sites can be identified, quantified and managed through pragmatic regulatory tools and effective provisioning, site relinquishment/surrender can be achieved without compromising environmental and social outcomes or exposing the state to unreasonable financial risk. The effective management of residual risk can also help facilitate operations as well as relinquishment/surrender of sites where a ‘walkaway’ solution may not be otherwise technically feasible.

Aug 2, 2023

By James D, Dawson N

The alternate mineral dressing tech-niques for the production of ilmenite roaster feed from heavy mineral concentrate and the reasons for the selection of wet high intensity magnetic separation (WHIMS) at Richards Bay Minerals are outlined.Initial flowsheet studies were under-taken using laboratory scale equipment followed by on site pilot testing. Flowsheet development culminated with an extensive test programme conducted at Readings of Lismore in 1975.

Jan 1, 1986