Search Documents

By A M. van Niekerk, W Mey

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

Jan 1, 2006

By Burman B. C

This paper describes studies into two particular aspects of the Lochiel deposit which formed part of feasibility level geot2chnical and hydrogeological investigations for proposed open cut mine development. The two aspects were depressurisation of thick beds of silt located through the profile and the determination of characteristics and origins of soil structure and their effect on pit stability. The studies were very detailed and multi disciplinary and highlight the integration of geology, geotechnics, hydrogeology and mining that is required for mine development studies. It is considered that as more marginal deposits are developed throughout the world the demands for efficient economic mining together with in- creasing scales of operation will require simi- lar types of studies. As such the studies pre- sented herein are likely to be a forerunner to a,emerging trend for development of open pit mines in difficult ground and water conditions.

Jan 1, 1986

By J Cook, S Pike, D Pridmore

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The application of high-resolution seismic reflection to map structure and/or mineralisation in hard rock environments has progressed significantly in the last decade. Improvements in equipment, field practice, processing and understanding has seen the seismic reflection technique emerge as a cost-effective tool for high-resolution three-dimensional structural and lithology mapping to depths far greater and with superior accuracy than other more conventional geophysical techniques.This paper outlines results and preliminary interpretation of 2D and 3D seismic reflection surveys aimed at defining fault zones and locations for quartz load development in favourable host lithologies at the Cracow low-sulfidation epithermal gold system in Queensland, Australia.As this is possibly the first time that high-resolution seismic reflection data has been used to define the structurally-controlled location of low-sulfidation epithermal gold mineralisation, an important aspect of this work was the derisking or due diligence steps taken prior to commissioning the full 3D surveys at each site. This included full wave sonic logging, vertical seismic profiling and trial 2D lines. Interpretation of the 2D profiles and the drilling of interpreted structure provided the confidence to proceed with the full 3D survey.The advantage of collecting 3D data extends beyond ensuring that the received reflections are located correctly in 3D space. The final 3D data cube can potentially map the entire fault network, thus highlighting flexures and changes in orientation of the structures both vertically and along strike, which is an important aspect in the deposition of gold and for direct targeting.CITATION:Smith, R, Cook, J, Pike, S and Pridmore, D, 2015. Application of high-resolution seismic reflection surveys to exploration for blind vein systems at the Cracow low-sulfidation epithermal field, in Proceedings PACRIM 2015 Congress, pp 77–84 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By Grobler H. P, Chitombo G. R

Production blasting of Dc Beers Consolidated Mines Limited, Koffiefontein and Finsch Mines involves both uphole trough rings of 9 to I I holes and near vertical 360 degree compound rings of 42-54 holes. The rate of production from these stages is dependent upon being able to achieve a specified fragmentation size range and this has driven the derivation of blasting practices to consistently achieve this target fragmentation. At the Dutoitspan Mine, in Kimberley, where mining of the kimberlite pipe is by block caving, 100 per cent extraction of the undercut level by ring blasting is essential. If this is not achieved, pillars are formed which not only inhibit the efficient initiation of the caving process, but also concentrates load onto the extraction level, causing damage to draw points and pillars. These two case studies demonstrate the importance of achieving optimum blasting performance for downstream mining efficiency; ie fragmentation for increased productivity at Koffiefontein Mine and 100 per cent undercut extraction for efficient initiation of the caving process at the Dutoitspan Mine. The case studies also serve to highlight the long road towards blast optimisation taken by De Beers Consolidated Mines Ltd (Koffiefontein. Finsch, Premier and Kimberley Mines) since 1989.

Jan 1, 1995

A non-contacting under-belt capacitance and gamma-ray backscatter technique has been developed for the on-line measurement of moisture in coal. In this technique, moisture was correlated with radio frequency susceptance and conductance determined using an under-belt capacitance sensor in which a fringing electric field Interrogates a layer of coal on the conveyor belt directly above the sensor. To compensate for variations in the density and thickness of the coal layer, an under-belt gamma-ray backscatter gauge was used to measure an equivalent volume of coal.A plant trial of the technique was conducted at Stockton Borehole Colliery, SW Australia, where the gauges were installed on the coking coal product conveyor. Product moistures, in the range 7 - 14%, were determined with r.m.s errors of 0.50 and 0.25 wt% using on-belt and static off-belt gauges, respectively. The difference in the on-belt and off-belt gauge measurement accuracy was attributed to sampling errors in the calibration of the onbelt gauge.

Jan 1, 1989

Any engineering firm hoping to do business in the modern world must understand-and take into account-the social and economic realities of client, country, culture, and community. If these considerations are ignored, any large-scale international development project is doomed to failure even before it begins. In this changing world, the distinctions between `developed', `developing', and `less developed' nations are more and more blurred. The so-called `less-developed' and `developing' nations are rapidly acquiring technology, an educated man- agerial and technical class, manufacturing capa- bilities, a growing spectrum of developed financial and raw materials resources, and a broad range of labour skills. These nations are establishing themselves as an integral part of the modern world, on an equal footing with other nations and with justifiable expectations for an ever higher standard of living and an ever better quality of Life.

Jan 1, 1978

By R K. W Merkle, E Whiteman

The anorthosite complexes and related rock types of the Indian Precambrian shield are primarily associated with either cratons or mobile belts. They were metamorphosed under amphibolite to granulite facies conditions. The major rock types are chromite-bearing meta-anorthosites, amphibolites, basic granulites, pink granites and gneisses. This study was carried out on chromitite bearing samples from Sittampundi Anorthosite Complex (SAC), Tamil Nadu, to evaluate the nature and textural settings of platinum-group minerals (PGM), using state-of-the-art technology. The structure and petrology of SAC were well studied by earlier workers (Subramanian, 1956), but only scanty data on geochemical, petrology and mineralogy of PGM are available. The mineralogy of the samples is dominated by chromite (>70 mass per cent), plagioclase (An90) and chlorite-actinolite with orthopyroxene (En85). Details of the petrological evolution of the Sittampundi complex will still have to be studied further, but indications of magma replenishment at the level of chromite formation and the elevated PGE values associated with the chromitite samples make the Sittampundi complex a promising target for future exploration activity.

Jan 1, 2008

By G D RICHMOND, Campbell J. J

Aberfoyle Limited has developed the Hellyer complex base metal sulphide deposit located in North West Tasmania. As part of exploration and feasibility study, the ore was extensively tested, including trial milling, and was found to be very fine grained and to have poor flotation selectivity. Substantial innovation was required to produce saleable concentrates at acceptable recoveries and costs. Efforts were made to reduce operating costs, to improve metallurgical performance and to improve work organisation. These efforts were pursued both in design and in subsequent plant operation. This work has resulted in a very competitive operation with production costs in the lowest quartile of the industry. Examples of the measures taken are presented and the results are evidenced by improved plant performance since commissioning.

Jan 1, 1992

The Department of Mineral Resources is the lead agency in mine site environment management and control in New South Wales. The Department introduced a Mining, Rehabilitation and Environmental Management Plan (MREMP) process several years ago in order to integrate the activities of other government agencies who may have a material interest at the mine site. The MREMP process has resulted in a spirit of trust and co-operation between agencies and between agencies and mining companies. The spirit of co-operation has been reflected in greater public confidence that mining is environmentally responsible.

Jan 1, 1995

By Y Mita, T Iwama, R Inoue, S Ueda

In the iron and steel manufacturing industries, efforts are being made to achieve carbon neutrality by 2050, and the transition from a coal-based steelmaking process to that utilising renewable energy is being pursued. An alternative process in which directly hydrogen-reduced iron is melted in an electric furnace is being investigated. It is known that foaming slag reduces heat loss from the steel bath in electric arc furnace, but iron loss due to the suspension of steel particles in the slag is indispensable. To improve the separation of steel particles from the slag, the control of the slag viscosity is important. Although the slag viscosity has been extensively studied, in those studies the slag was considered to be a simple liquid. However, in actual operations, slag is a multiphase fluid consisting of solid, gas and liquid phases. Therefore, in this study, by measuring the sedimentation velocity of titanium, stainless steel and glass spheres in an aqueous glycerin solution containing bubbles generated by the reaction between NaHCO3 and C2H2O4, the apparent viscosity of the gas-liquid fluid was evaluated based on Stoke’s law. It was found that the apparent viscosity of the gas-liquid fluid is larger than the viscosity of liquid phase and depends on both the bubble volume ratio in solution and the density of the falling solid sphere, and the apparent viscosity was different from that previously obtained by the rotation method. The apparent viscosity derived from the sedimentation velocity of solid spheres changed depending on the specific gravity of the ball. This is because the apparent viscosity is derived from the velocity of a ball falling in a static bubble in this method, whereas that is derived from the force applied by a stationary flow in the rotational method.

Aug 21, 2024

By McKendry J. B

Gretley Colliery is situated at Wallsend, a suburb of Newcastle in New South Wales and is owned and operated by the Newcastle Wallsend Coal Ccnpany, a wholly owned subsidiary of Peko Wallsend Limited. The mine has been an efficient bord and pillar producer by industry standards. However, its continued economic viability was threatened because the bulk of remaining reserves lie in more difficult mining conditions and are of poorer quality. Alternatives were examined to improve productivity and allow Gretley to become more competitive in the current difficult market Environment.

Jan 1, 1988

The capabilities of the three 61R and one 81R Robbins Raiseborers currently in use at Mount Isa are defined. Their applications in the development of ventilation and hoisting shafts, orepasses, escape routes, fill passes etc. are described and possible future uses of these and newer raiseborers at Mount Isa are examined. Problems associated with the use of raiseborers, together with ways of overcoming them are discussed. The impact of raiseborers on the mining operation is assessed in terms of new approaches to design and development, safety, cost and manpower efficiencies.

Jan 1, 1974

By G Steward

Gravity Leaching of high-grade gravity gold concentrates, such as Knelson Concentrates, with the ACACIA Reactor represents a new generation of concentrate treatment methods. The ACACIA Reactor is a complete packaged plant for the maximising of gold recoveries from gravity gold concentrates. This paper will introduce the process technology and provide process results from the Porgera ACACIA Reactor installation. The advantages of the ACACIA Reactor are many, and justification for installation has been varied. The typical advantages of the process include: increased recovery of gold from the Knelson Concentrate; no return of high-grade table tails, often grading several thousand g/t, into the mill circuit; reduction in tails grades of slow leaching gold; reduction in the requirement for operating staff by the removal of the manual tabling process and replacing with a fully automated treatment system; improved security by removing the tabling step where operating staff come into direct contact with visible gold; improved health and safety, by the removal of the treatment steps for the table concentrate, which often include operators handling corrosive chemicals and the production of sulphur and arsenic compound fumes; and improved metallurgical accounting, by allowing daily head grade calculations. The ACACIA Reactor was developed by Anglogold for Union ReefÆs Gold Plant and has been in production for over two years, and has proven to be a low cost, high recovery, mechanically reliable method for the processing of gold concentrates. Such has been the success of the plant, there are now four full installations of the processing plant, including Anglogold Union ReefÆs, Anglogold Sunrise Dam, PACMIN Carosue Dam and Porgera Joint Venture.

Jan 1, 2002

Determining the environmental consequences of green field projects is becoming an increasingly important component of new projects. Feasibility studies are regarded by potential investors as incomplete if a comprehensive Environmental Impact Assessment (EIA) has not been completed. These EIAÆs need to meet various local and international requirements in order to achieve bankability. Heavy mineral mining projects are often located in ecological sensitive coastal zones, and bring with them a suite of social impacts in the mainly developing countries within which they are usually located. This paper draws on experience gained in undertaking EIAÆs for heavy mineral mining projects in Kenya, Mozambique and South Africa, and uses these case studies to identify potential pitfalls. Important lessons include the need to initiate the EIA process as early as possible in the project, in order to develop management systems to mitigate the environmental impacts of exploration. Close and on-going consultation with affected communities is also seen to be critical to the success of the EIA. Proactive participation on the part of the environmental consultants with the project team and all interested and affected parties (IAPs) is important. An EIA commissioned later in project planning makes it difficult for the EIA to contribute in a positive manner to the project. Early engagement with environmental consultants allows the environmental assessment to develop from a report to an actual process, and to become fully integrated with project planning. The proviso is that an initial æfatal flawÆ assessment is required to identify any potential æshow stoppersÆ, in order to meet one of the important objectives of EIA, namely an assessment of whether or not the proposed project is the preferred development intervention in the study area. For more controversial proposals this may require the commissioning of a Strategic Environmental Assessment (SEA), which circumvents some of the limitations of the project level EIA. Whilst confidentiality is a constraint to full disclosure, an open participatory approach to public consultation is essential to add credibility to the EIA process and to gain, at least, the acceptance of the process from the majority of IAPs. Full disclosure is encouraged by organisations such as the International Finance Corporation, who acknowledge that good public consultation costs a lot of money, but bad public consultation costs a lot more! An open approach to disclosure presents understandable difficulties for proponents, as they are required to give up some of their control over the project, and to trust the social scientists engaged in the process. However, independence in the EIA process is critical to its success. This paper will highlight these and other issues by drawing on five case studies to identify lessons learnt, and explore the above themes in more detail.

Jan 1, 2001

By Hunter TC

Metals Refining Operations Pty. Ltd. (NMO), PNG's only gold and silver refinery is operated by Golden West Refining Corporation Ltd (GWR), a member of the Rothschilds group and has a strong PNG ownership link through statutory shareholders. Located in Waigani, MRO has been successful in substantially increasing production through toll refining for Porgera, Misima, Tolukuma, Wapolu and, more recently, at Lihir as well as treatment of alluvial gold from smaller operations. This increased throughput has resulted in the need to constantly upgrade equipment, techniques and practices, particularly to continue quality improvements and meet market demands. The evolution of these changes are documented and discussed and the probable future development plans are detailed.

Jan 1, 1997

Epithermal deposits have been defined as the lower temperature end of a spectrum of hydrothermal mineral deposits and are inferred to have formed near the EarthÆs surface. The preservation of an epithermal gold deposit in an Archaean craton is rather problematic, especially when such deposits form clusters or groups as reported for the Pilbara and Yilgarn cratons. For two of the better studied examples of epithermal gold deposits in these cratons, Becher and Wiluna, the evidence that they formed near the Earth surface is non-diagnostic, and the epithermal origin appears uncertain. Despite the simplicity of the original definition, there have been numerous errors in classifying epithermal gold deposits. It is suggested that these errors are primarily due to poor criteria defining the group as there is limited evidence of poor observational science being the cause. The criteria being used to recognise epithermal gold deposits include tectonic setting, ore element suite and quartz vein textures. None of these are diagnostic of epithermal deposits and their link back to the original low pressure-temperature definition of the class is tenuous. There has been definition creep over time as new observations on potential epithermal gold deposits become accommodated within a flexible definition. There is some urgency establishing and then using criteria to reliably identify epithermal deposits. Distinction of epithermal gold from weathered gold deposits is an important step. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

Wheal Gawler was Australia's first metal mine. This leader was followed by an army of other metalliferous underground mines and surface operations in Australia. As a mine it was not highly significant economically because its small total production of nearly pure galena had low multiplier effects on the economy of South Aus- tralia. Its importance lay in its symbolism: here was a silver-lead mine close to the new town of Adelaide posing the question of what other min- erals lay in the Mount Lofty ranges and in the fields beyond.

Jan 1, 1987

By N G. Corner

A sea bed sampling programme by CRA Exploration Pty Limited over an area of 12 000 km offshore from Westland, Southland and Otago, New Zealand, led to the discovery of the Harvester Prospect, an area of some 67 km2 which averaged 189 mg/m3 gold in surface samples. This area was in water depths of 70 to 106 m and contained a high grade core of 33 km2 which averaged 283 mg/m3 gold. The gold recovered was fine grained, averaging 124 microns, and indicated a potential resource of approximately 10 t of gold per metre of thickness. Interpretation of existing seismic and geological data suggested that the gold anomaly may be associated with a unit of sediments 10 - 40 m thick, probably deposited during a lower sea level stand. Two initial attempts at vibrocoring the anomaly produced inconclusive results. In 1989 a much more powerful vibrocorer with scaled up support facilities and a dedicated 24 h turnaround laboratory were employed. The final results clearly showed that the gold was from an uneconomic surface enrichment.

Jan 1, 1990

By F Pavloudakis

The installation of on-line analysis systems in the open-pit mines of the Public Power Corporation SA (PPC, the state-owned electricity entity of Greece) is considered to be the key-parameter for performing improved quality control and blending/homogenisation of the produced lignite. In order to investigate the accuracy of these systems under the site-specific conditions of the Greek lignite deposits, a research project was carried out. This was necessary since there is lack of experience in using on-line analysers in mines that produce a fuel of such a poor and largely fluctuating quality. After thorough market research, a dual energy gamma ray transmission on-line ash analyser was installed in Kardia mine of Ptolemais û Amynteon Lignite Centre, which is located in West Macedonia, Greece. The initial results obtained after the realisation of a series of dual-comparison trials (ie using two series of reference values that allow three-way comparisons) pointed out several problems that obstacle the achievement of high accuracy on-line measurements. More specifically, the measurements obtained by the analyser were higher than the concentrations determined by the two laboratories when the ash content was lower than 12 per cent (in wet basis). On the contrary, when the ash content was higher than 12 per cent, the measurements of the on-line analyser were lower than the concentrations determined by the laboratories. In other words, the range of the measurements obtained by the analyser was narrower than that corresponding to the lab analyses results. Therefore, the use of this on-line analysis system under the site-specific operating conditions of Kardia mine does not guarantee improved quality control of the lignite fed to the mine-mouth located power plant. Most probable reasons that explain the above-mentioned problems are the following: The frequent and widely ranging fluctuations of the chemical and mineralogical composition of the lignite transported by the conveyor belt, especially as far as its calcium content is concerned. This result from the nature and the origin of the mineral matter co-excavated with the lignite, which varies from calcareous marls to sands and clays rich in aluminium and silica minerals. The fluctuations of the lignite quantity transported by the conveyor belt. The change of the linear concentration of iron contained in the fabric of different belt parts.

Jan 1, 2003

By K Bojarska

Examination of wastes aimed at evaluation of their usefulness for utilisation needs applying modern chemical testing methods. The XRD-XRF-ICP-GC/MS set of test methods constitutes an integrated testing system enabling ecochemical examination of wastes. As far as the problem of time-consuming operations is concerned, the offered system fits in a market-oriented field of activity of accredited chemical laboratories. Within a reasonable period of time, it allows to obtain information about mineralogical and chemical properties of wastes. It provides full range of information beginning from mineral composition (XRD) through chemical composition including the number of elements and organic compounds (XRF-ICP-GC/MS) up to the contents relating to the amounts of ingredients, both organic and inorganic in the leaching tests (ICP-GC/MS). The XRD-XRF-ICP-GC/MS testing system proves to be of particular importance in obtaining reliable results enabling to perform precise assessment (from ecochemical point of view) of wastes to evaluate their usefulness for utilisation in building materials, in civil engineering and reclamation works.

Jan 1, 2003