Search Documents

There is considerable variability in the level of detail incorporated in prefeasibility studies relating to mining developments. Hence, when undertaking a review or audit, it is critical to attempt to ascertain at an early juncture precisely who has compiled the various facets of the study, for what purpose it was intended and the terms of reference given to the authors. Likewise, when commissioned to undertake an audit it is preferable to have proper terms of reference and to be aware of the purpose to which the audit will be put.These factors will influence the degree of detail an auditor would expect to find in the study and consequently, the degree of effort/time required for the audit process. In most instances audits do not imply recalculation of the entire study or modifying it in anyway, but involve an overall assessment of the methodology used, combined with spot checking of detail. One of the most difficult aspects is to determine a realistic order of accuracy for the overall study when the accuracy of the individual components may differ markedly.

Jan 1, 1990

By Y Wu, F-J Ping

Today, coal production accounts for about 65 per cent of the nationÆs gross energy in China. By the year 2010, the output of coal is planned to increase to 1.65 billion tonnes and by the year 2020 to 1.9 - 2.0 billion tonnes. To meet these energy needs the Chinese coal industry is developing underground coal production on a massive scale. The new drive introduced by using direct torque control (DTC) is now proven technology for mine shaft hoisting. The drive offers unequalled speed and torque control performance as well as a low impact on the supply network by controlling the power factor to unity with a minimum of harmonics distortion.

Jan 1, 2005

By H Kundapen, J J, C Rumble, S Miller

This paper describes measures taken by Ok Tedi Mining Limited (OTML) to minimise the risk of acid rock drainage (ARD) resulting from mining operations at its Mt Fubilan porphyry copper-gold mine in the remote Star Mountains of Papua New Guinea. The risk of acid generation and metal leaching as a result of oxidation of these sulfidic deposits has long been recognised by OTML. In 1998, OTML instigated the ARD Management Program to fully evaluate these risks and to formulate, if necessary, trial and implement appropriate management strategies. In implementing the ARD Management Program, OTML has adopted a risk management approach consisting of five stages: risk identification, risk analysis, risk assessment, risk treatment, and review and monitor. Significant progress has been made in relation to risk identification, analysis and assessment. The work currently underway to put in place a comprehensive risk treatment and review process will ultimately determine the success or otherwise of this approach.

Jan 1, 2003

By Fejes G

An integral part of the Brisbane Suburban Railway Electrification involved the relining, refurbishment and track lowering in the Roma Street, Brunswick Street and Gloucester Street double track tunnels. The design and the construction procedures had to satisfy the Queensland Railways electrification clearance and track standards and the requirements of maintaining track services through the tunnels during work. Refurbishing of the tunnel linings was carried out to extend the life of the tunnels.

Jan 1, 1981

By R Dimitrakopoulos

Optimisation and mathematical formulations for open pit design and long-term production scheduling have been available since the 1960s. There are two main concerns in the application of existing mixed integer programming (MIP) models in open pit mines: a. the feasibility of generating both optimal solutions and practically mineable scheduling patterns and b. the inability to deal with in situ variability in orebodies and account for uncertainty. In dealing with these issues, a general open pit production scheduling method for multi-element deposits is presented and subsequently used to optimise the long-term production schedule in a nickel laterite deposit. The application shows the weaknesses of MIP formulations in terms of generating optimal solutions as well as practically feasible mining patterns. The application of the same formulation in the presence of in situ orebody variability and uncertainty uncovers a major reason for deviations of scheduled production from actual production, and outlines additional limits of traditional optimisation formulations as well as future needs.

Jan 1, 2003

Industrial minerals and rocks (alternat ively called non-metallic minerals) are those- which are economically important because of their desirable physical or chemical properties rather than their metal or energy content. They are divided into nine classes: structural, pig- ments, process aids, ceramics and refractories, chemical source minerals, abrasives, foundry minerals, gem stones, electrical minerals. Development of deposits is influenced by the dominance of marketing,by the required range of products, the-need for specialized process- ing, place value, and the transportation and distribution of high-bulk, low-cost commodities. Evaluation is different from that of base metals because of differences in geological occurrence, sampling methods, testing, treatment, placing a money-value on the material and the importance of export markets.

Jan 1, 1973

By Kershaw MG

At the Risdon plant of the Electrolytic Zinc Company of Australasia Limited, impurities toxic to the electrolytic production of zinc metal, notably arsenic and antimony, have traditionally been coprecipitated when precipitating iron as ferric hydroxide. With the development of a new lead/zinc mine at Elura, New South Wales, it was anticipated that the concentration of impurities, particularly arsenic, in the zinc sulphide concentrates treated at Risdon would increase. This suggested that an increase in the capacity of the iron purification step in the Risdon plant would be required to cope with the higher input of these impurities.Laboratory investigations showed that the additional capacity would be achieved, either by a massive increase in the amount of iron used as the "collector" in the process, or by a two-stage process. The latter approach was preferred as an increase in the amount of iron precipitated would lead to much higher operating costs and overloading of the existing equipment.

Jan 1, 1985

By I Grant

On the 1 June 1978, the Town and Country Planning Act 1953 was replaced by the revised and more comprehensive Town and Country Planning Act 1977. The new act brings in some substantial changes to the law affecting regional and district planning, and for the first time makes provision for maritime planning. The importance of the Town and Country Planning Act 1977 to the Mineral industry is primarily in the relationship between Regional Planning Schemes and District Schemes as the needs and resources identified in a Regional Planning Scheme will override the underlying District Schemes. The mineral extraction industry must be recognised as a regional responsibility which draws on the resources of a region to satisfy the demand of the communities within that region rather than a purely local operation within one District.

Jan 1, 1978

By Walter GW

Rock mass classification systems for stable excavation design have been studied. The parameters which are important in such a classification system and those which should be included in a classification system formulated to predict explosive fragmentation behaviour are briefly reviewed and compared. There is significant overlap in the data requirements for excavation design and explosive blast de- sign. Recently there has been a trend to ob- tain some of the data required for excavation design by the use of both field and laboratory seismic investigations. The theory of seismic techniques is summarised and the results of seismic investigations carried out for excava- tion design are reviewed. On this basis it is considered that seismic techniques have the potential to be used for data collection prior to blast design. A programme designed to de- velop such techniques and which includes both field and laboratory experimentation is Presented.

Jan 1, 1978

Since the earliest recorded prospecting of the 1860's mineral exploration and mining in Fiordland has been discouraged by the formidable physical difficulties presented by its isolation, extremely rugged relief, treacherous coastal waters and generally unfavourable weather conditions. Government assistance was often sought by the miners and prospectors but little, if any, support or encouragement was received after the initial period. During the 1840's decorative marble was quarried at Caswell and Dusky Sounds. A prospector discovered and attempted to mine copper sulphides to the north of Dusky Sound (Parks Mineral Beds) and near Mt Solitary. A small Pb, Zn, Cu, Ag, Au bearing quartz reef was discovered and driven on in the granite coast line of Preservation Inlet (Bradshaws Reef) and the ore roasted on site. Alluvial and quartz lode gold was discovered at Preservation Inlet in the 1890's and led to the recorded recovery of 11 000 oz of mainly lode gold. Falloff in grades with depth, thinning and splitting of the reefs and the high mining costs at this location led to a virtual abandonment of the field by 1906. In the late 1950's and early 1960's the geology of Fiordland was mapped by the Geological Survey at 1:250 000 scale, but field work was largely confined to the shore lines of the coast and fiords. In view of the physical difficulties it is not surprising that mineral exploration and mining up to 1970 was limited to the scant attention outlined above.

Jan 1, 1977

By G K. N Subasinghe

"In the design and operation of mineral processing plants, knowledge of the variability of ore properties and that of the expected metallurgical performance within the orebody is of great importance in order to avoid both production constraints due to inadequate design and less than expected metallurgical performance during operation. Of the many properties that determine the performance of downstream separation processes, such as flotation, gravity separation and leaching etc the liberation characteristics are of primary importance.Current methods of evaluating liberation characteristics of ores such as the use of Mineral Liberation Analyzer (MLA) and QEMSCAN techniques are expensive and suffer from the drawback that these tests are performed on comminuted particles at a given grind size and/or samples of product streams. This problem could be overcome by developing predictive models of liberation that can predict the grade distribution of comminuted products at any grind size based on texture of the parent rock. This paper discusses a procedure that has been developed to predict liberation using information obtained from a sample of the parent rock such as drill core, based on Barbery’s liberation models. The required characteristic statistical functions have been evaluated from image analysis techniques using scanning electron microscope (SEM) images of the parent rock and narrowly sized comminuted particles. Such information can then be used in a predictive model to predict or explain the variability of metallurgical performance at various grind sizes used in future operating plants. The model will predict not only the valuable mineral liberation but also gangue liberation, which will be useful to those who are looking to remove liberated gangue from comminution circuits.CITATION:Subasinghe, G K N, and Dunne, R, 2016. Predictive Model of Mineral Liberation for Geometallurgical Applications, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 347–350 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

The Australian minerals sector has a shortage of skilled professionals to satisfy an industry that is experiencing renewed vitality. Graduate numbers are low throughout Australia and the world, while economic rationalisation is seeing many educational institutions downsize, or even close, their minerals-related programs. In addition to requiring more entry-level graduates, minerals producers are looking to update the skills of their current workforce to keep up with the industryÆs continuing technological revolution. To address the issue the Minerals Council of Australia (MCA) endorsed collaboration between several Australian minerals producers and a team of universities to generate the Mineral Tertiary Education Council, or MTEC. MTEC recently initiated a venture to increase the availability of professionals with relevant skills to the minerals industry. Primarily aimed at delivering postgraduate programs, the initiative will allow graduates from other disciplines to æconvertÆ to the minerals sector as well as provide professional development training to an existing work force. This venture represents a novel approach in that courses will be delivered by more than one institution and will employ innovative teaching materials with flexible and remote delivery formats. The programs will cater specially for professional development in the minerals sector, which generally requires high flexibility due to the nature of work conditions and locations.

Jan 1, 2004

By Palmer DJ, Bain JH, Pullen JB

Over the last ten years at Risdon, zinc production capacity has almost doubled. This has resulted in modifications, many of which have affected zinc deposition operating conditions in the cells. Some of these changes appeared to have affected average current efficiency to such an extent that a special investigation was initiated, using multiple regression analysis to assess historic cell unit operating para- meters. The study highlighted the importance of certain parameters in maintaining maximum current efficiency for zinc deposition from !Risdon purified solutions under conditions of !changing current density, acidity and zinc con- centrations. Maximum current efficiency was obtained only within a zinc to acid ratio in cell electrolyte of 0.45 - 0.55 and a residual zinc concentration greater than 48 g.1-1, irrespective of actual zinc concentration or The investigation also established: ieters giving minimum power consumption at termined current density; the effect of ntration changes in common impurities on nt efficiency; the existence of high s of some impurities in solids precipit- in the cells and pure solution tanks.

Jan 1, 1975

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

Jan 1, 1981

By Williams RJ

This paper presents an overview of the design and development , application to date and potential of a real-time return gas monitoring system.Initially developed as an ACARP/Industry funded project, whose prime aim was to create a `turn-key', prototype, stand alone, real-time, Return Gas Monitoring System (RGMS) capable of providing quantitative assessments of gassiness levels on a shift by shift basis, enabling unusual gas emission patterns to be readily flagged.

Jan 1, 1998

By D J. Clark, S Hewson, T Li

Cadia Hill Pit is a gold copper porphyry deposit hosted in monzonite. The pit slope design is primarily based on structural controls related to faults and shears with largely massive rock masses between the structures. The slope design attempts to achieve an optimum configuration at a bench to overall scale, considering economics and safety implications against the geotechnical and structural conditions. To date the slopes have been mined at interramp angles of up to 60¦ over heights of 120 m. Limited slope and batter failures that have occurred are structurally controlled and occur rapidly. The pit-mining schedule requires concurrent mining of part of the final pit walls and the progressive interim cutbacks. Engineering and operational solutions to hazard reduction and risk management issues have been implemented wherever viable to æengineerÆ out the hazard and mitigate the risks. However, comprehensive management plans and operating procedures have also played a vital role. This paper details the management plan and the operating procedures that have been developed and implemented to mitigate the risks associated with rock falls.

Jan 1, 2003

By Russell J

A sustained drop in the grade of Mount Isa lead-zinc-silver ore occurred in mid 1980. It was decided to increase concentrator throughput from 200 000 to 240 000 tonnes/four week period to maintain budget metal production. To achieve this increase whilst maintaining acceptable grinding and flotation performance, crushing plant final product size had to be reduced from 100%-13mm to 1000-11.2mm. The goal in the crushing plant was to achieve a 20% increase in throughput with a 20% decrease in the top size of the product. This was achieved by operational changes to improve plant availability and optimisation of the existing crushing and screening equipment Performance.

Jan 1, 1978

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

Rock bolting provides a supplement or alternative to conventional timber and steel supports. The tensile strength of the bolts lies within a range established by manufacturing quality control. Rock bolt testing determines the ability of the rock, anchor and individual bolt as an assembly to accept load. The.test is performed to the yield strength of the bolt or anchor and deflection is observed. The anchorage index, inches deflection per 1000 lb load increment, is a measure of anchorage quality. This allows comparison with anchorages under ideal conditions. It also permits comparative assessment of roof bolt anchors in a particular environment.

Jan 1, 1971

By Woodcock JT

Successful chemical control of flotation requires practical solutions to many problems. A brief discussion is first given of those para- meters which can be controlled and those which it would be desirable to control. Suitable analytical methods for application to flowing pulp and to clear solution from pulp are out- lined in relation to on-line and off-line control. Practical problems of deciding where a measurement is to be made or a sample is to be taken and how the sample is to be prepared and presented to the measuring device are then considered. Equipment calibration and maintenance are considered in relation to the above factors.

Jan 1, 1978