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By D Williams

Recent advances in global positioning systems (GPS), machine guidance technology and telemetry allow an unprecedented level of control of surface mining operations. GPS technology can now locate the bucket of a shovel or the blade of a dozer within 50 mm. Some of the outcomes possible are: precise selective mining û even when the ore is visually indistinguishable from waste; tracking grade and tonnage of every ore parcel through the mine; real time productivity monitoring; detailed post accident safety analysis; and tracking the movements of every piece of equipment. This paper will consider the contribution that GPS based machine control systems can make to ensuring that surface mining projects deliver the outcomes promised in the feasibility studies. Case studies of installations are presented.

Jan 1, 2003

Dewatering tailing slurries by mechanical means is often not possible and gravity and solar driven processes must be used. It has been shown previously that better use of gravity is achieved when the tailing is drained as it settles. Not only are more compact sediments obtained but also the dewatering is faster. From the results of laboratory and field tests reported here, equations were established which describe the evaporation and drainage components of the dewatering. These equations were used to calculate the effects of ponding depth, solids content of the tailing and clim- atic conditions on the time required to dewater the tailing. Since the calculations can be made with and without the drainage component, the advantages to be gained with drainage can be determined. The tailing used in the work was a clay slime from a sand washing operation. However, it is anticipated that this approach will be applicable to other similar tailing.

Jan 1, 1978

By Grace NC, Lightfoot BW

Small scale trials of the smelting of a copper concentrate in the Sirosmelt submerged lance reactor are described. Pellets of concentrate were dropped into the reactor while injecting air-rich mixtures of oil and air through a lance into a bath of matte overlain by slag. This produced a discardable slag and a matte which was converted in sequential stages in the same reactor to white metal and blister copper. Difficulties were encountered in determining the end points of the converting stages but control techniques were developed to allow successful operations producing blister copper. Deportments of minor constituents of the concentrate to slag, matte,metal and fume for the three stages are reported and possible applications are Discussed.

Jan 1, 1980

By L Ryan, S Halley

The use of a field spectrometer to systematically analyse drill samples from over 200 holes around the Permian-Carboniferous Ravenswood gold deposits in north-east Queensland has successfully identified both small and deposit-scale changes in the alteration mineral chemistry. Changes in chlorite composition within the tonalite host rocks are evident at the district scale, with Fe-rich chlorites seemingly more common in the vicinity of the deposits. Significant variations in white mica chemistry also occur, but mostly on the vein selvage scale, with no clear distinction between near-mine and distal compositions. The results indicate that chlorite compositional maps produced from regional field or airborne spectrometer data could potentially be used as a vector to ore in exploring for similar deposits in the area. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

The proponents of new mining projects always run the risk that their project is deemed to be not in the public interest. Nothing to be done here except to try and pick it earlyùit is, after all, the approvals process that is supposed to screen such projects out. But there is a second risk, about which much can be done: that inadequate or untimely information confuses the formal assessment of a project and the political context within which the decision is ultimately made. This is environmental impact assessment (EIA) process risk and it has become steadily greater in a changing world, where: miners have lost clout; public trust in institutions has declined; governments follow, as authority pyramids give way to spheres of influence; NGOs are asking the questions people want answered; and stakeholders have become the reference point. This new world deals harshly with yesterdayÆs methods. But it needs to be understood if principles and methods for managing EIA Process Risk are to be advanced.

Jan 1, 2003

By Y Zhang

Being analysed systematically, the factors influencing the production of fully-mechanised coal face have been divided into geological, mining technical, and management groups. Artificial neural network-expert systems (ANN-ES) are established to decide the influencing factorsÆ membership grade; genetic algorithm-artificial neural network (GA-ANN) are used to decide the weights; fuzzy comprehensive evaluation method is used to calculate the integration indexes. Finally, the GA-ANN model is established to forecast the production of fullymechanised coal face. It is proved that the model is reliable with higher precision. The production of fully-mechanised coal face is influenced by many factors. However, some influencing factors are neglected by the traditional forecasting methods, the results of which are not precise and hardly be used as a guide for mine production and management. The relation between the production of fully-mechanised coal face and its effecting factors is analysed, and the meta-synthetic AI approaches are used to forecast the production of fully-mechanised coal face.

Jan 1, 2003

The twin iron ore islands of Cockatoo and Koolan are located in the spectacular setting of Buccaneer Archipelago off the Kimberley coastline of WA.Cessation of ore shipments from Koolan in 1993 ended 42 years of continuous mining activity which began with the first shipment of ore from Cockatoo in 1951.

Jan 1, 1993

Mine geologists have access to an economic mineral deposit, production parameters and secure exploitation title. They are well placed to understand ore formation and should contribute to the effective exploration of company mine property. Application of their special skills has been curbed by pre-occupation with production duties and by company re-engineering, including staff reductions. Contributions to exploration have been diminished and personal development inhibited. Modified management is required. Participation in mineral system studies and in exploration research comprise part of the basis for the re-emergence of mine geologists on the exploration scene. Changes in investment strategies in the minerals industry may create new employment opportunities. With regard to estimation of resources and reserves, the competence of practitioners who are incapable of disclosing their methods in transparent terms is under question. Ethical standards are also under public scrutiny because of some notable malpractice. Independent auditing may hecome more intrusive. While understandable in a market context, it reflects poorly on the profession. More substantial effort in public communications can improve the credihility ofthe industry and equip practising mine ceolouists for snider responsihility.

Jan 1, 1997

By Glatthar J. W, Lauder D. W, Manlapig E. V, Mackinnon I. R

The Ok Tedi copper orebody consists of porphyry and skarn orebodies. The skarn orebodies, identified by different mineralogies, are the source of high intermittent fluorine levels in the mill concentrates. This paper discusses the results of t

Jan 1, 1998

By E S. Bernard

Steel fibre reinforced shotcrete (SFRS) is increasingly being used as ground support in both civil and mining applications. In recent years, methods of assessing the performance of SFRS have been developed. These include the beam test such as that prescribed by ASTM C-1018 and the panel test prescribed in the EFNARC European Shotcreting Standard. The panel test has gained popularity in recent times due to the two-way action modelled in the test. However, some difficulties have been noticed. Shear failures sometimes occur and there appears to be a rather high degree of variability in the panel test results. A new method of testing panels has been proposed. A circular panel supported on three symmetrically arranged points has been assessed at the University of Western Sydney. This paper describes the new test which may be the basis of a new specification for the testing of toughness of SFRS and summarises research work which has been carried out to-date.

Jan 1, 1999

By Richmond GD

The Hellyer concentrator of Aberfoyle Limited commenced production in 1989 processing a fine grained, massive sulphide ore containing Zn, Pb, Ag, Cu and Au as values. Four concentrates are produced - copper/silver, lead, zinc and bulk (Pb/Zn) - with overall payable recoveries (1991) of 80 per cent Zn, 55 per cent Pb, 50 per cent Ag, 30 per cent Cu and ten per cent Au. Metallurgical development work commenced immediately after plant commissioning, and continues. The flotation response and liberation analysis on a size basis highlighted reagent balance problems associated with tower mill regrinding of sphalerite, poor conditioning of flotation pulps, poor selectivity for fine galena, and insufficient liberation. These were the main causes of values lost to tailings, values reporting to the 'wrong' concentrates and of impurities in the concentrates. Modifications to tower mill regrind circuit operation, and the use of improved conditioning techniques have greatly improved concentrator performance, particularly in the finer (-5 micron) size fractions. Studies of concentrator and laboratory flotation by size and liberation analysis are the basis of diagnostic metallurgy. The techniques used to evaluate the improved concentrator performance are discussed.

Jan 1, 1993

The mineral sands deposit of Australia pose a number of unique, and quite unusual problems for the explorationist. Most concentrations of heavy minerals have been found in the unconsolidated sediments of the east and west coasts. Mineral sands mines open larger areas per tonne of concentrate than most other mines. This is because of the shallow depth of the sands containing the heavy mineral concentrations. Obtaining tenure can, by mining industry norms, be a massive operation due to the large areas to be examined and, particularly on the east coast, the large number of land holders encountered. A commercial development can still emanate from anything ranging from a small high grade body to a massive low grade deposit, the prices currently being obtained for rutile, zircon, ilmenite and monazite, although still modest when the remarkable properties and applications of these minerals are considered, is nevertheless attractive when compared to the prices being obtained for the base metals with the exception of gold. The current interest in the location and definition of new reserves of heavy minerals reflects this relative price attractiveness. The discovery of heavy mineral concentrates does not necessarily ensure the early establishment of a mine. Because of the cyclical nature of market prices, the average returns likely over the life of the mine permit the employment of only relatively simple, low cost, mining, concentration, and separation processes. If difficult mining conditions are encountered or the removal of small contaminants by complex metallurgical processes are required, then higher market prices must be obtained. Until the market is prepared to pay more for the commodities so produced, the resource will not be economic and lower cost reserves will be mined in preference. The Australian mineral sands industry has seen many closed mines because of past failures to properly assess the data base collected during the exploration and development phases of the failed projects.

Jan 1, 1987

Nearly eighteen months ago Newmont Waihi Operations joined with the local district council and members of the Waihi community in the initiation and running of a community liaison forum.   This forum û the Waihi Community Consultative Committee (WCCC) û was set up with the objective of improving communication, providing a forum for discussion and ultimately working through a range of issues relating to the future of the town and district after the projected closure of Martha Mine in late-2006.   After 18 months of meetings where all represented groups have presented their views, the challenge now is to work together to investigate likely options, seek sources of funding, produce business proposals and plan for the future of Waihi in what we call the Golden Legacy Project.   This paper backgrounds the companyÆs experiences to date, the issues the group has addressed and its proposals for the future. Methods employed to set up an effective community liaison forum are considered, drawing on specific examples from the WCCC. The actions and structures required to ensure effective and ongoing community æbuy inÆ at all levels are also discussed.   This paper develops themes addressed in Taking it to the Streets presented in 2003.

Jan 1, 2004

By E J. Gardiner, C M. Hogan

Acidic drainage has long been recognised as the largest environmental liability facing the mining industry, and to a lesser extent, the public, through abandoned mines. The Canadian Mine Environment Neutral Drainage (MEND) initiative was the first international multi-stakeholder program to develop scientifically based technologies to reduce the effect of acidic drainage. The original MEND Program extended over a nine-year time frame ending in 1997, with technology transfer activities continuing to the end of year 2000 under the MEND 2000 program. Both programs have contributed enormously to the understanding of acidic drainage and how to prevent it. MEND3, launched in 2001, intends to further this effort with a strong, research-driven program. The successes of the MEND initiative have come through the collaborative efforts of the partners, the sharing of experiences, the thorough evaluation of technologies and their incremental improvements. As a result, the knowledge base on acidic drainage has grown considerably. An international model of alliance between the various worldwide initiative involved in acidic drainage is being formalised at this conference. This global alliance will enhance technology transfer capabilities and will lead to improved environmental performance for the industry. It is through collaboration that we have achieved the most progress in environmental performance, and this formal relationship will further expand these benefits.

Jan 1, 2003

Some thirty ore minerals occur in the Mount Morgan orebody. Pyrite is the dominant mineral with chalcopyrite, magnetite and pyrrhotite major components. Gold and gold tellurides, in accessory amounts, are economic- ally important. The prevalence of volcanic rocks in the mine area and the presence of trace amounts of such minerals as cassiterite, gold, native bismuth and rutile suggest a voicanogenetic origin for the ore. The ore occurs in a breccia pipe which cuts through the volcanic and associated strata but the former existence of a syngenetic stratiform ore bed is evidenced by the presence of occasional masses of perfectly banded sulphide ore including a barite-rich "black shale" with sulphide layers exhibiting slump structures. Mineralization is thus both _ syngenetic and epigenetic. The orebody (breccia pipe) is intruded by small stock-like bodies of quartz latite which is believed to have been the upward rising magma invading the orebody of which it is the parent. This has resulted in the annealing recrystallization of the ore minerals and the quartzose gangue with a low strain rate due to magma drag and dilation during intrusion.

Jan 1, 1974

By Silitonga M

Generally, the acceptable parameter for predicting the intensity of ground vibration due to a blast is the amount of explo ive u ed and the distance from the explo ion. A eries of closely controlled tests were carried out and it was observed that the degree of confinement or burden of an explosive charge play an important role in the variation of the transmitted magnitude of the shock wave through the ground.The intensity of the shock wave increases with burial depth or with greater confinement of an explosion until a critical depth is reached.Beyond this critical depth, the magnitude of ground vibration remain constant. This is an important finding, which explains the anomalies between the expected level and the monitored ground vibration in a particular situation.

Jan 1, 1984

The Central Extended Orebody is located within the Cracow Goldfield approximately 360 km northwest of Brisbane and approximately 220 km west of Bundaberg. It is an epithermal gold deposit hosted by the Late Carboniferous to Early Permian Camboon Andesite. The lode was mined by open cut methods and produced 170 458 tonnes of ore at 5.62 g/t gold.The geology of the rit is relatively simple, comprising two rock types, trachyandesite and rhyolite which have been sub-divided into several units. The trachyandesite is sub-divided into three rock types: brecciated trachyandesite which is the most widespread, hydraulically fractured trachyandesite hosts the mineralisation and the third sub-unit is chloritised hydraulically fractured trachyandesite and has no associated mineralisation. The mineralisation is confined to quartz veins in hydraulically fractured trachyandesite. Several phases of brecciation and subsequent quartz and quartz/adularia vein injection are evident although not all phases are mineralised. Two rhyolite dykes intrude the trachyandesite one is monolithic, the other is sub-divided into hydraulically fractured rhyolite (barren), silicified rhyolite and auto-brecciated rhyolite.

Jan 1, 1993

By King ND

This paper presents an economic study comparing two gold recovery processes, zinc precipitation (Merrill-Crowe) and carbon-in-pulp (CIP). Capital, operating, and gold losses costs from an actual CIP plant study are compared to costs developed from a hypothetical Merrill-Crowe process flowsheet. ' Results indicate an overall economic advantage to CIP over Merrill-Crowe for plants processing slurries within the range of the five gold solution grades selected for this study.

Jan 1, 1982

Bureau of Medical Inspection, Broken Hill, New South Wales.INTRODUCTIONFor a considerable time it has be3n realised that the pathological changes produced in human lungs by the inhalation of free silica varied, not only according to the amount of silica inhaled, its particle size and the period during which it was inhaled, but also according to other mineral elements which might be admixed with the fine silica dust and inhaled along with it, or inhaled subsequently to the silica containing dust. It was observed that, in many instances, these admixed dusts tended to inhibit the action of the free silica in causing injury to the lungs, as well as the development of certain complications, whilst in other cases it was felt that certain substances could actually accelerate the tissue damage caused by the silica.A fresh impetus to the problem of the prevention of the development of silicosis was given when, in 1937 and 1939, Denny, Robson and Irwin published papers entitled "The Prevention of Silicosis by Metallic Aluminum." Working at the same time at the Saranac La.boratory, and quite independently, and using a colloidal aluminum hydroxide, Gardner arrived at the same conclusions as Denny, Robson and Irwin, namely, that in experimental animals the development of silicotic changes could be prevented if eithertogether with the silica, or subsequent to its inhalation...

Jan 1, 1946

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

Jan 1, 2003