Search Documents

By B. Zongwane, A. T. Visser

In surface mining operations, ultra-heavy trucks operate on haul road networks which are typically from 10–40 km in length. Road networks for these vehicles have historically been designed and maintained empirically, relying heavily on local experience. Whilst it is possible to construct amine haul road that requires no maintenance over its service life, this would be prohibitively expensive, as would the converse but rather in terms of vehicle operating and maintenance costs. An optimal functional design will include a certain amount and frequency of road maintenance which can be planned, scheduled and optimized within the limits of required road performance and minimum vehicle operating and road maintenance costs. For existing mine haul road networks, which may not be optimally designed and maintained, the problem of identifying existing deficiencies, quantifying their impact and assigning priorities within the constraints imposed by limited capital equipment and manpower is problematic. This is reflected in the fact that most surface mine operators agree good roads are desirable, but find it difficult to translate this into an effective road maintenance system. The aim of this paper is to present a road maintenance management system which utilizes on-board truck diagnostic data in conjunction with computer-based truck dispatch systems. Through a comparative analysis of the various haul road maintenance systems available to a mine, a condition-triggered road maintenance system is introduced. System architecture, evaluation of real-time data, event trigger level determination, specific condition signatures and real-time rolling resistance calculation are discussed. Finally the event, activity, transaction and notification system is portrayed in conjunction with the determination of key productivity indicators and benchmarked road and truck performance. Keywords: Haul road, maintenance, surface mining, rolling resistance, truck haulage.

Sep 1, 2001

By T. P. Katakwa

The utilization of software is now inherent to virtually every activity along the mining value chain. However, apart from the software survey done by Gibbs in the 1990s and work on the extent of diffusion of information and communication technology (ICT) in the South African platinum sector by Mugodi and Fleming in 2003, the nature and extent of software utilization in the South African mining industry has never been evaluated. The Mine Planning, Optimisation and Valuation (MPOV) Research Group in the School of Mining Engineering, University of Witwatersrand, therefore initiated a project to collate and analyse the current utilization of software in the South African mining industry. This was done through the development of a web-based database of the relevant software. Snowball sampling was used to collect the data because the South African mining industry is diverse and software utilization is fragmented across and within the sectors of the industry. The data was then organized into distinct categories so that the information from a variety of sources could be evaluated on the same basis. A beta version of the database can be accessed online through a user-friendly front-end platform at http://db.mining.wits.ac.za. The database is expected to help at least 13 educational institutions with decisions on facilities and training that are vital to the education of mining and mining-related professionals. Exploration, mining, and consulting companies will also benefit from information in the database relating to availability and useful combinations of software solutions. The database is also strategic to software providers by providing a better understanding of their respective relative market share along the mining value chain. An analysis of the data collated in this research shows that about 77% of the software users are mining companies, 17% are consulting companies, 3% are mineral exploration companies, and the rest are software providers and educational institutions. The software used in the South African mining industry is largely provided by Gemcom Software International, MineRP Solutions, and MRM Mining Services. CAE Mining, who in 2010 acquired the Datamine Group providing Datamine software, is also widely acknowledged as a major software supplier in South Africa, but data from them had not been obtained at the time of producing the beta version of the database due to proprietary constraints. The work reported in this paper is part of an MSc research study in the School of Mining Engineering at the University of the Witwatersrand. Keywords mine planning, mining, value chain, software, database, South African mining industry, utilization.

Jun 1, 2013

When designing coal mine roof support, it is necessary to account for the uncertainties and variability that inherently exist within the rock mass and support elements. The performance of a support system is affected by these uncertainties, which are not taken into account in the current deterministic design methodologies used in South Africa. The key to the design of a roof support system is a better understanding of roof behaviour and uncertainties that can been countered during extraction. This paper sets out to develop a method that takes all uncertainties that exist within the rock mass and the mining process into account and provides a quantitative risk-based design methodology.

Jan 1, 2009

By J. Danoczi

South Africa is running out of fresh water and is looking at ways to improve water usage. This report addresses how a diamond mine in Gauteng has improved the utilization of its water resources. In the past, water from the local river was deemed the most suitable to use in the grease recovery plant but subsequent tests on the water from the slimes dam have shows that this water source is in fact more suitable for diamond recovery. Utilizing the slimes dam water provides a more stable water source than the local river while also reducing the impact of the mine on the water resources in the area.

Jan 1, 2008

By P. A. P. Fouché

Processing confidence for a bankable feasibility study on a green field heavy mineral deposit is inmost cases achieved only through bulk sample processing. Bulk sample is classified as a large enough concentrate sample that is processed into final products to satisfy market sample demand as well as further processing demands such as smelting. In this case study the demand was to produce 500 tons of heavy mineral concentrate from more than 5 000 tons run-of-mine on are mote location with limited to no infrastructure. The various challenges faced and lessons learned are documented as an outcome of the success of this mission.

Jan 1, 2007

By R. I. Klintworth

The multi-reef area of Cooke 3 Shaft provides a unique mining challenge on account of the very thin middlings between the pay bands and the marginal values of the reef. It is uneconomic or impractical, because of the excessive heights, to mine the middlings using conventional stoping methods. The development of suitable mining methods is discussed with particular emphasis on the control of water inflow and the policy of not jeopardizing or sterilizing other reef horizons by the mining method implemented. No definite solution is currently available, but with the aid of instrumentation, computer analyses and mechanized mining equipment, the mine continues to attempt to maximize extraction and profits.

Jan 1, 1988

By T. T. Chiweshe, L. S. Mokhahlane, M. Welman-Purchase

This study examined an alternative technique of extracting tungsten from wolframite ore using a fusion method with ammonium phosphate salt. Current techniques use alkali salts to decompose tungsten ores and use various purification methods to produce ammonium paratungstate, which is a key intermediate precursor in the extraction of tungsten. In this study, a two-step extraction process, which involves thermal decomposition of the ore using fusion and a separation stage, is examined. The novelty of this technique is the ability to completely decompose wolframite ore and form an unstable tungsten oxide phosphate (WO2(PO3)2) compound. The instability of WO2(PO3)2 in deionized water enables selective isolation of tungsten as insoluble precipitates of WO3 and WO2. The decomposition reaction of WO2(PO3)2 is influenced by the presence of oxygen and determined to be first order under ambient conditions. Scanning electron micrographs and X-ray diffraction analysis showed above 80% of the tungsten precipitated compared with the amount that remained in the filtrate solution.

Jul 10, 2024

By H. J. N. Winhoff

The tailings dam at Consolidated Murchison Limited by H. J. N. WINHOFF, Ing. Grad. (Visitor) The history of tailings dam operations at Consolidated Murchison Limited is briefly recounted, and a mechanical method of dam-wall construction is described and illustrated in some detail.

Jan 12, 1973

By M. Yavuz

Determining the most convenient plant location is one of the most commonly encountered problems in engineering applications. This paper presents a fuzzy multiple attribute decision making (FMADM) model which is developed for the selection of the optimum plant location for natural stone factories in the mining industry. The criteria affecting the decision making process in natural stone industry were determined to solve the plant location problem in the FMADM model. To determine the optimum plant location for a new natural stone factory, which is planned to be established by a mining firm located in the Eskisehir region of Turkey, an analysis was carried out by incorporating the method and the analytic hierarchy process (AHP) method. The analysis shows that the Yager?s method can easily be applied to the selection of plant location in the natural stone and mining industry when the difficulties encountered in the application process of the AHP method is taken into account. Keywords: Natural stone, plant location, decision making, Yager?s method, analytic hierarchy process (AHP).

Jan 1, 2008

Hydrometallurgical processing of complex ores and concentrates is becoming increasingly important as the mining and metallurgical industry seeks to exploit mineral deposits that are difficult to treat using conventional mineral processing and pyrometallurgical technologies. Mineral processing is often challenged by the difficulty or inability to separate valuable minerals into marketable concentrates. Hydrometallurgical processing, using selective leaching technology, can often ?chemically beneficiate? such difficult deposits. Pyrometallurgical treatment of base metal concentrates is capital intensive and subject to ever more stringent environmental control. Hydrometallurgical processing is generally lower in capital cost for an equivalent metal production rate and avoids the gas and dust issues associated with pyrometallurgical processing. The possibility of by-product recovery may also increase with hydrometallurgical treatment. Two examples of new technology or flowsheet development for treatment of complex ores and concentrates are used as illustration. These include the El Boleo process of Baja Mining for recovery of copper, cobalt, zinc and manganese from a complex clayey ore and the PLATSOL? process for recovery of copper, nickel, cobalt, platinum, palladium and gold from a bulk sulphide concentrate.

Jan 1, 2009

By J. Abdollahisharif

Optimal cut-off grade is one of the most critical parameters in open-pit mine design because it defines the ore and waste and thus determines the maximum net present value possible from the mining operation. Although the algorithm presented by Lane (Choosing the optimum cut-off grade. Colorado school of Mines Quarterly, vol. 59, no. 4, 1964. pp. 811-829) is the most common one in the literature, it does assume constant capacities of the mine, processing, and refinery. In this paper, Lane's original algorithm has been modified to consider variable processing capacities in order to determine the optimal cut-off grade in open-pit mines. The new algorithm proposed here is compared to both Lane's original algorithm and to a previous modification that incorporated rehabilitation costs into the cut-off grade estimation. The algorithm proposed here that permits variable processing capacities is shown to be superior for the determination of optimal cut-off grade to both these previous versions. In addition, a computer-based program was developed in Microsoft Office Excel© to calculate the optimal cut-off grade as proposed here.

Jan 1, 2012

The auriferous Carbon Leader reef which is the subject of this study can be subdivided into two types of sedimentological units, each with its characteristic spatial variability. For the longwall mining method applied at Western Deep Levels gold mine, subdivision of the orebody improves the estimation of the actual error variance, but not the grade estimates themselves. This can only be achieved by choosing oreblocks of a size and shape that are maximal parallel to the longwall and minimal at right angles to it, within the limits of mining restrictions. While simple kriging is the only method that gives unbiased results, the difference between untransformed and logtransformed kriging is negligible.

Jan 1, 1987

Each year the South African Institute of Mining and Metallurgy offers a prize (or prizes should the entries warrant it) of up to RlOO for the best paper or dissertation on a topic appropriate to the interests of the Institute. The competition is open to all Student Members of the Institute. A Student Member who is in fulltime study at a university may submit the dissertation or thesis he has to write in part fulfilment of his university degree, provided that it is presented in a manner and on a topic suitable for publication in the journal. Entries for 1976 should reach the Institute by 31st December, 1976.

Jan 10, 1976

By R. J. Mostert

The role of hardenability in the development of high-strength low-alloy (HSLA) steels is discussed. The applicability of the superhardenability treatment. a steel making technique for increased hardenability, to HSLA steels is indicated, and the literature on this treatment is reviewed. Several low-carbon superhardenability HSLA steels were designed by use of published superhardenability multiplying factors. It was found that the hardenability of these low-carbon steels can be increased to the same extent as that of medium-carbon steels. The mechanical properties as determined in normalized bars indicate that the superhardenability treatment can be used successfully in the production of low-carbon hot-rolled HSLA steels.

Jan 1, 1984

By C. O. Beale

This paper is the first part of a two-part review on the subject. , , .. Here reference is made to the place of copper among the elements, Its properties, Its historical significance, and its 'end uses both in general and in South Africa. Its current market situation and its prospects are dealt with briefly. Some account is then given of the mining and metallurgical techniques employed. in South Africa in the production of copper, together with the names of the companies at present Involved and brief descriptions of their operations, ,... . .. The operations of these companies are described In greater detail In Part 11(Apn11985 Issue of the Journal).

Jan 1, 1985

By A. L. Painting

A study of the end effects in specimen cores under compression tests, with a view to the elimination of these effects by A. L. PAINTING (Student) It is well known that a cylindrical rock specimen tested under uniaxial compression in conventional fashion is subject to end effects; that is, towards the end of the core, the stress and strain distribution becomes non-uniform. The experiment described illustrates such end effects with an aluminium core between steel platens. An attempt was then made to nullifythese effects by compressing the core between pads of mercury. The resulting stress and strain distribution was significantly more uniform, but a slight over-correction was introduced.

Jan 4, 1974

By R. G. B. Pickering, B. Ebner

The hard rock gold and platinum mines in South Africa have seen little development in the technology of mining. Holes are still drilled in the rock—though the latest water hydraulic rockdrills will complete that task in two minutes compared with the eight hours for hand drilling. Charging up is with far safer explosives and with available initiation systems it is no longer necessary to run up the face lighting each fuse. Movement of rock in the stope is predominantly by means of scraper buckets and scraper winches — these were first introduced in the 1920s.Support is still mainly rock, either in sit pillars or backfill, or alternatively wood. Just as themining process has changed very little it is hardly surprising that the productivity of mining is also relatively unchanged. Major efforts have been made to mechanize the mining process. However, most of the narrow reef mines where ‘trackless mechanized mining’ was introduced in the early 1980s have reverted to conventional mining. In the wider reefs mechanized mining is the option of choice, unfortunately most of the gold and platinum mines have very narrow reefs that are not suitable to’ off the shelf’ equipment. The move to introduce room-and-pillar mining into the narrow UG2reefs is at the expense of mining more waste with the reef, fortunately it appears that appropriate waste and reef separation processes are available. Room-and-pillar mining followed by long holedrilling and blasting of a narrow slot of reef out of the pillars currently appears to offer the best of both worlds—maximum reef recovery with minimum waste dilution. All these mining methods are still dependent on blasting to break the rock. The cyclic nature of mining by blasting places severe constraints on the rate of face advance that can be achieved and consequently the utilization of the invested capital. For narrow reef hard rock mining to break out of these constraints and to really make progress in the 21st century it is necessary to follow the lead of the soft rock mining industry and change the technology of mining. In the underground coal mining industry, coal cutting has been proved to be the most cost-effective solution. In narrow reef hard rock mining the future must be based on the development of non-explosive methods of rock breaking that in turn are integrated into continuous mining systems. Non-explosive so that the mining operation can be conducted on a continuous basis, with nodelays for the removal of blasting fumes. Continuous mining also maximizes the return on the capital invested in developing the mine. Rock cutting will define the stope width and that in turn will be designed to minimize waste dilution; it will also minimize damage to the hanging and create a safer environment. Mechanization makes it possible to automate the mining process and further improve safety by positioning the operators in a safer environment. This paper defines the work to evaluate cutting processes carried out by Sandvik TamrockVoest Alpine. The evaluation was in the UG2 and the pyroxenite and norite typical of the Merensky Platinum Reefs. A novel form of mining machine is proposed that will utilize existing technology. Finally the paper describes the interaction between Sandvik Tamrock Voest Alpineand Lonmin Platinum and the initiation of an agreement to develop and trial a prototype hard rock narrow reef mining machine.

Sep 1, 2001

By K. Levin, P. Lloyd

During the commissioning phase, which is usually the most exciting part of a project involving the design and construction of metallurgical plant, the commissioning engineers interact between the client and the project management. The client wants to see whether all the equipment that he has bought and that, in his opinion, has taken far too long to erect will actually work. Project management expects the commissioning people to con¬vince the client that this is the best design ever developed and that never before have time and money been spent so well. The commissioning team has to fulfil these expectations. Commissioning work is a `shirt sleeve' function, with little of the glamour that is normally associated with fields such as engineering and operations. The team usually works in a partially completed plant with more temporary than permanent services and little (if any) office accommodation, normal working hours do not apply, and the demands made on the team change suddenly and dramatically. This article outlines the activities of the commissioning group and the systems used to smooth the commissioning path.

Jan 1, 1981

By R. R. Mankowski

The work described in this paper is an attempt to increase present-day knowledge of fatigue in mine hoisting cables, particularly the internal energy loss arising from interwire/strand friction in a cable undergoing periodic non-planar transverse vibration. Such frictional energy loss is known to be one of the major influences limiting useful working life of hoisting cables in use today, and is responsible for the large capital outlay required to maintain the high safety factors prescribed by the mining industry. The experimental method employed identifies two mechanical characteristics of cables that are independent of amplitude and frequency, and are primarily attributed to the type of cable construction. Interest is focused the time rate of change of curvature as the major parameter influencing the internal damping mechanism. Empirical results confirm that amplitude and mode number play an important role in quantifying the internal losses, and also reveal that a critical radius of curvature exists below which damage due to vibration fatigue rises exponentialy to potentially high levels.

Jan 1, 1988

By D. G. Hulbert, I. K. Craig, S. P. Moult

This paper describes the application of a throughput-optimization strategy to a run-of-mine (ROM) mining circuit that is controlled by a multivariable controller. The objective of the optimization strategy is to maximize the ROM throughput at a specific product size. Results from long-term tests, which indicated how 'steady-state' optimization can be achieved, were used for the throughput optimization. This strategy increased the ROM throughput by 11,4 per cent. A mathematical relationship relating residue to grind can be used to calculate the economic benefits of stabilizing control. It was estimated that the throughput optimizer could result in an increase in gold production worth Rl,4 million per annum when waste rock is treated, and that stabilizing control could increase the treatment plants annual revenue by R150 000. If the extra milling capacity brought about by the optimizer is interpreted as a capital cost saving of 10 per cent on the price of a new mil, then a capital cost saving of RI million could result.

Jan 1, 1992