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By J. Little

It is common practice for underground mine plans to be created sequentially, where results from one planning process form the input data for another. While this is practical for manual methods, computerized optimization techniques should consider an integrated approach to creating the global mine plan. This is because optimizing an individual mine planning process, such as stope layouts, introduces a likelihood of increasing costs or decreasing revenues associated with other areas, such as production scheduling, as harmful decisions must be balanced. Considering the interaction and influence that individual underground mine planning processes have on each other during optimization will provide more profitable results than if these are ignored. Optimization techniques for stope layouts and production scheduling are reviewed. An integer programming model is proposed that allows for either integrated or isolated optimization. Both approaches are separately applied to a block model. The results demonstrate the model?s ability to produce optimal long-term sublevel stoping mine plans and the benefits of using an integrated approach. Keywords underground mine optimization, stope layouts, underground production scheduling, integer programming, mathematical programming application.

Oct 1, 2013

By John Freer

Over 200 delegates attended the SAIMM Colloquium on Flotation, which was held at Mintek on 22nd September, 1983. In introducing the programme, the Chairman of the Technical Programme Committee, Mr Eugene Fivaz, said that an attempt had been made to strike a balance between theoretical and practical papers, which he hoped would provide something for everyone. He wished to record in advance the thanks of the Institute to S.A. Cyanamid for sponsoring the lunch, and to Bateman Equipment Limited for the cocktail party to be held at the end of the day's proceedings.

Jan 1, 1983

By M. Timusk

"The working environment for ground support installation in mines has improved during the last 20–30 years, with more mechanized equipment for installation of ground support elements such as bolts, cable bolts, and screens. Ground support installation productivity has, however, not followed the same development curve, remaining more or less constant. In some cases, for example the mechanized installation of bolts, productivity has even dropped. One reason for this is that modern mechanized bolt rigs are complex. In this paper we evaluate manual and mechanized ground support systems, propose a way to measure the productivity of bolt rigs, and make relevant comparisons between different mines and equipment. Some productivity measures for rock reinforcement are suggested, using productivity results from eight case study mines.IntroductionTo improve safety for operators and equipment underground, ground support systems (bolts, screens, etc.) are installed in mines to stabilize the rock mass (Hoek, Kaiser, and Bawden, 1995). Important questions to ask when selecting a ground support system include where ground stability problems are located, why they have occurred, how problems should be addressed, and when and how the ground support system should be installed (Hadjigeorgiou and Potvin, 2011). The performance of bolting and screening operations in underground mines is important for both safety and productivity reasons. With greater mine depths and an increasing focus on safety, ground support has become a significant bottleneck in the production process of many mines.Many factors play a role in establishing safe and stable underground structures. Equally, there are several factors to consider in productivity, including the mining method, organization, logistics, mechanization level, and procedures. Today, most mines in Scandinavia have changed from manual to mechanized bolting, as this improves operator safety and arguably boosts net capacity. Internationally, however, manual installation of bolts remains common, with some claiming that manual installation is more productive (Bawden, 2011)."

Jan 1, 2016

By T. N. Huffman

Ancient mining and Zimbabwe T. N. HUFFMAN*. Ph.D. (Illinois) (Visitor) Ancient gold mining and Zimbabwe have been commonly associated for over a hundred years, either in terms of an exotic colony for gold export or as an African state based on the East Coast trade. The stratigraphy and radiocarbon dates from Zimbabwe and the known sequence for the Rhodesian Iron Age demonstrate that Zimbabwe was built after AD. 1000. A review of the evidence for ancient gold mining shows a similar antiquity, and a complementary rise in prosperity in Arab settlements on the East Coast indicates that gold was not extensively mined until the eleventh century. Large quantities of imported articles at Zimbabwe indicate the extent of trading during the fourteenth and fifteenth centuries, and the origins of Zimbabwe probably lay in an overflow of wealth from the gold trade during the twelfth and thirteenth centuries. Zimbabwe was abandoned by the sixteenth century because of environmental factors.

Jan 1, 1974

By R. Haldenwang, R. Erasmus, P. T. Slatter, R. P. Chhabra

Notches are used routinely for measuring the flow rate of water with free surface flows. As far as can be ascertained, no work has been done to investigate the performance of these flow rate measurement devices for non-Newtonian suspensions. The Flow Process Research Centre at the Cape Peninsula University of Technology has investigated the flow rate of kaolin and bentonite suspensions from a tank for two notch shapes, namely rectangular and triangular, and for 3 different concentrations of each suspension. The notches were calibrated using water and then the kaolin and bentonite suspensions were tested in them. The rheological characterisation of the fluids was done with a Paar Physica MC-1 rotary viscometer fitted with a cup and roughened bob. Analysis of the results shows a significant increase in discharge coefficient with increase in concentration, and the discharge coefficient has been correlated to the yield stress. This is the first such study, and further investigation is needed to confirm and extend these findings.

Jan 1, 2007

Book Review Gold Metallurgy in South Africa, edited by R. J. Adamson and published by the Chamber of Mines of South Africa, Johannesburg, 1972. The metallurgical processes used for the recovery of gold from Witwatersrand ores were first described in A Text Book of Rand Metallurgical Practice, published in 1912 and subsequently revised in 1926. This was followed by Gold M etall1trgy on the Witwatersrand by A. King in 1949. New Publications Elements of Practical Coalmining, S. M. Cassidy (editor), New York, Society of Mining Engineers of AIME, 1973, $16.50. Future Enerey Outlook, J. A. Pederson (editor), Colorado School of Mines Quarterly, vol. 68, no. 2, April 1973, $6.00. Guide To The Preparation Of Papers For Publication In The Journal Of The South African Institute Of Mining And Metallurgy The following notes have been compiled to assist authors in the preparation of papers for presentation to the Institute and for publication in the .Journal.

By Y. Rajpal

The Hedley and Grant pillar strength formula is widely used within the South African mining industry to calculate pillar strengths in bord and pillar mining layouts, and is currently being used at Bathopele Mine. Bathopele is an operation of Anglo American Platinum near Rustenburg, mining the UG2 reef at depths ranging from 40 m to 300 m below surface. The formula includes a parameter K, which is a downrated uniaxial compressive strength value of the rock, used to calculate the strength of a pillar. At Bathopele Mine, for the shallower areas Less than 150 m the value was 33 MPa, but this was increased to 44 MPa due to the fact that rock mass conditions improved and there were no incidence of failure in the shallower areas. Underground observations showed pillars to be stable with no signs of failure, and it was questioned whether the design was not still too conservative, resulting in sub-optimal extraction ratios and consequently a loss of revenue to the mine. A trial mining section was started at the mine where the pillars were reduced from 6 m x 6 m to 5 m x 5 m and the pillar behaviour was monitored for the onset of failure. Numerical modelling was conducted using the TEXAN code to back-analyse pillar stresses in order to find a more realistic value for K. Results from the trial section indicated that the pillar design was in fact too conservative, and the value for K was adjusted to 54 MPa for future designs. This paper details the findings from underground monitoring and numerical modelling results, and includes details for further calibration of the K value in order to further optimize the extraction of the orebody.

Jan 1, 2012

By K. Koruyan

Although remote sensing technology has been available for many years, it has rarely been used for monitoring mining activity. Recent studies indicate that remote sensing is also a valuable tool for managing and planning certain aspects of the mining operation. In this paper, we examine areal expansion of marble quarries and the affected vegetation over a period of 10 years in the Mugla region in Turkey, using geographic information system (GIS) and remote sensing (RS) techniques. Images captured by ASTER Level 3A01 (3D Ortho Data Set), Landsat 5, and Landsat 7 satellites between 2001 and 2009 were used for the analysis. Changes in the natural vegetation as a function of the production level in the marble quarry were calculated using the normalized difference vegetation index. According to the study results, land cover and natural vegetation decreased by less than 3 per cent and 1 per cent respectively between 2001 and 2009, following an upsurge in mining activity in the region.

Jan 1, 2012

By K. Koruyan

Although remote sensing technology has been available for many years, it has rarely been used for monitoring mining activity. Recent studies indicate that remote sensing is also a valuable tool for managing and planning certain aspects of the mining operation. In this paper, we examine areal expansion of marble quarries and the affected vegetation over a period of 10 years in the Mugla region in Turkey, using geographic information system (GIS) and remote sensing (RS) techniques. Images captured by ASTER Level 3A01 (3D Ortho Data Set), Landsat 5, and Landsat 7 satellites between 2001 and 2009 were used for the analysis. Changes in the natural vegetation as a function of the production level in the marble quarry were calculated using the normalized difference vegetation index. According to the study results, land cover and natural vegetation decreased by less than 3 per cent and 1 per cent respectively between 2001 and 2009, following an upsurge in mining activity in the region.

Jan 1, 2012

Mine wide, underground wireless communications are possible with the use of Ultra Low Frequency (ULF) technology. Due to the propagation through rock of ULF radio signals a relatively small antenna can provide communications coverage over a complete mining operation. Starting as a Personal Emergency Device (PED) for emergency messaging to miners under all circumstances, the ULF communications system has grown to include capabilities of remote control of underground equipment such as pumps and fans and centralised blasting initiation. This technology is now in use on 5 continents having lately made it onto the African mining scene. The paper and presentation will provide the audience with the benefit from international mining know-how in this technology as well as local African experiences. A recent commissioning exercise for example, is expected to pay for itself in electricity savings within a few months. These and other results from practical demonstrations and usage will be covered. This novel technology becomes an integral part of the daily operating infrastructure of a mine with immediate safety and business benefits. It is able to reduce capital expenditure and is designed for ease of routine operational use. The paper will conclude with insights into current R&D for further development of this technology.

Jan 1, 2007

By Phillip J. Mackey, Rodney T. Jones

"Copper and copper alloys remain key materials for society today, with important uses found in the electrical, transportation, and construction industries. Copper demand is rising, with projections indicating that by 2025 global refined copper demand will increase to 29.5 million tons, up from the 22.4 million tons anticipated for 2015. This will require the opening up of dozens of new mines and numerous new smelters over this time period. Fortunately, Africa has significant reserves of copper, and African copper can once again play a key role in contributing to meeting the rising global demand for copper. This paper provides a brief overview of the current copper smelting operations in Southern Africa. INTRODUCTION Copper and copper alloys are essential materials for today’s modern world. The familiar green copper patina colour seen on buildings and other structures sometimes belies its true “green” characteristic – copper is essential for key emerging technologies such as wind turbines, tidal generating systems, solar energy systems, electric cars and the like. Consequently, it is believed that there will be continued growth in copper demand in the years ahead. Projections indicate that by 2025, as an example, global refined copper demand will increase to 29.5 million metric tons, up from the 22.4 million ton level anticipated for 2015. This will require dozens of new mines, and of the order of the equivalent of 10 to 12 new 0.5 million tons of copper/year-sized copper smelters (after factoring projected copper produced by electrowinning (EW))—overall, a huge undertaking. Fortunately, Africa has significant reserves of copper, and African copper can once again play a key role in supplying this rising global demand for copper. Africa’s share of global mined copper production was about 10% in 2014; however this will increase significantly in future if announced new projects eventuate. Southern Africa has an important role to play in this process. The present paper provides a brief overview of copper smelting in Southern Africa."

Jan 1, 2015

By C. Nangolo

Mineral commodity prices comprise one of the key criteria in the selection of mining stocks. We contend that of the three principal elements of mineral commodity prices, spot price, forward price and long-term price, one has a greater impact on the share valuation processes used by investors. This research paper examines the extent to which each of these elements influences the valuation process. The intention is to provide investors in mining stocks with a greater understanding of how fluctuations of commodity prices over time affect the prices of the mining stocks they hold, or intend to sell or buy. Three mineral commodities, gold, silver, and copper, were used as case studies, since market data on these commodities is readily available in the public domain. Nine market indices covering all three mineral commodities were selected. These are based on clearly defined criteria with the intention of eliminating ambiguity and to test for correlation with the three sets of mineral commodity prices. Nine mining companies, which were not the primary drivers of the relevant indices employed in the study, were used to validate the results obtained from the indices in order to avoid duplication of the same correlation during cross-checking. Each commodity price was adjusted for operating costs. For each market index, an average operating cost was calculated from the companies comprising its basket, while each company?s annual operating costs were used for the stocks of the individual companies examined. The data was collected for the period January 2004 to October 2010. This period was further split up into three sub-periods to account for the Global Financial Crisis (GFC) period that started in mid-2008. We conclude that mining stock prices are correlated with mineral commodity prices, but with spot and forward prices exhibiting stronger correlations than long-term price. This finding should be useful for evaluation purposes. Where cash flow methodologies such as discounted cash flow or earnings per share are used to value ordinary shares and commodity prices are required to estimate future cash flows, the findings suggest that spot prices should be used as opposed to long-term prices. The work reported in this paper is part of a current MSc research study at the University of the Witwatersrand.

Jan 1, 2011

Book review Proceedings of the Symposium on Mining Methods. London, Institution of Mining and Metallurgy, 1974. 160 pp. The Symposium was held from 30th October to 1st November, 1974, and the papers include an interesting range of subjects in coal-mining operations, covering the improvements achieved to date, current practice, and required development for the future. Salamon, M.D.G., and Oravecz, K. 1. Rock Mechanics in Coal Mining. 119 pp. NIM reports Report no. 1822 Stability constants and linear free-energy relations for the platimtm-group metals. (22nd Oct., 1976). Report no. 1852 A revised method for the dissolution of platiniferous materials by the sealed-tube technique. (18th Oct., 1976). Report no. 1828 y-picoline adducts of the nickel, copper, and zinc chelates of 2-thenoyltrifluoroacetone. (26th Nov., 1976) Report no. 1847 A pilot-plant investigation of a kinetic model for flotation.(19th Nov., 1976)

Jan 2, 1977

By N. Steven

Published parameters from the Mufulira copper in situ leach (ISL) in Zambia are used for order-of-magnitude flow-rate calculations for an envisaged gold ISL in back-filled Witwatersrand stopes. A successful leach operation requires that the porous medium, usually a sand, has a hydraulic conductivity in excess of 5 x10-7m/second (i.e. a permeability >50 millidarcies).Empirical evidence suggests that average linear velocities would be of the order of 60 m/day if the backfill has the grain size of a fine sand. The proposed gold lixiviant would probably be an alkaline or ammonium thiosulphate, not cyanide. The resultant sulphate-rich ground and drainage waters could probably be processed using existing purification techniques to produce gypsum and magnesium/calcium carbonate. Within the next 100 years it is inevitable that solution mining will find widespread application on the Witwatersrand, if not for gold extraction, then certainly for water remediation purposes.

Jan 1, 2009

By M. Görnerup, A. Kapilashrami, Seetharaman. S., A. K. Lahiri

Simultaneous reduction and foaming of chromium-rich slag have been studied in a laboratory furnace equipped with X-ray image analysis. Reduction of the metal oxides by graphite generated CO, which caused the melt to foam. The slag composition continuously changed due to reactions and dissolution of lining. Gas generation rate, foam height, and gas bubble size were studied and correlated to slag composition. Viscosity increased significantly during the experiments due to a change in slag composition. Bubble sizes varied little during the progress of reactions but differed considerably for different slags. Bubble sizes were largest for V2O5 containing slag, which is contrary to the general understanding that the presence of strong surface active agents reduces the bubble size. The foaming index did not follow expected trends for bubble size and viscosity, suggesting that foaming index is not a suitable parameter for discussion of foams under dynamic conditions. Keywords: slag, foaming, dynamic conditions

Jan 1, 2004

By L. A. Vermeulen, D. D. Howat

The use of pebbles as the medium in the grinding of quartz gravel in a laboratory mil provided experimental data that were used to quantify the relationships between the feed rate of ore to the mil, the fineness of grind of the product, and the wear rate and consumption of the grinding medium. Fineness of grind is expressed as the inverse of the harmonic mean size, a quantity that is calculated from data obtained by sieve analyses. The commonly used criterion for fineness of grind (the percentage of material smaller than 75 µm in the mil product) is shown to corelate approximately linearly with the inverse of the harmonic mean size. An increase in the feed rate was found to cause the harmonic mean size of the product to increase linearly, Le. the relationship previously found for metalic grinding media is applicable to al grinding media, irespective of shape or composition. Simple expressions for the consumption and wear rate of pebbles are derived from the experimental data, and are shown to be functions of the feed rate. The expression for wear rate is a monotonicaly increasing function, while that for consumption is a hyperbolicaly decreasing function of the feed rate. In contrast, a linear relationship was found between the rate of wear of the grinding medium and the rate production of fines. The expressions that were previously developed in relation to the use of metalic grinding media are shown to be equally applicable to pebble milling.

Jan 1, 1988

Careful monitoring of the position of the cave front is essential for well-managed block cave mining. Seismic monitoring systems yield 3-D information about the location of fracturing ahead of the cave. However, because the a seismic gap between cave surface and seismogenic zone is of unknown extent, the cluster of micro-seismicity can only yield an upper bound for the cave height. The large velocity contrast between the fractured rock in the aseismic gap and the broken loose material within the cave can be used by an inversion procedure to find a few simple geometric parameters (such as height of the top of the cave) if a simple 3-D shape?for example a paraboloid?is assumed for the cave. Ray-tracing must be used as the large velocity contrasts cause seismic waves to bend around the cave, but the inversion takes the form of a minimization problem in only a few dimensions and so the computational time is feasible. This technique has been successfully tested on realistic synthetic data.

Jan 1, 2007

Dr Andrew Cosgarea, Jr, Associate Director of Opera¬tions of the U.S. Mint, and Chairman of the Awards Committee of the International Precious Metals Institute, announced the IPMI award recipients for 1985. The awards were presented at the Institute's Annual Banquet in New York City on 11th June, 1985. The Distinguished Achievement Award was presented posthumously to Dr E.M. Savitsky, of the A.A. Baikow Institute of Metallurgy of the U.S.S.R., for a life-time career devoted to investigations on the properties of the platinum-group metals. Dr Savitsky investigated over 300 phase diagrams, which became the basis for the selection of alloys and the prediction of properties. He published over 300 technical papers during his career. Dr Savitsky died during the summer of 1984 while being considered for the IPMI Award. The Engelhard Henry J. Albert Award was presented to Dr Stephen J. Lippard, Professor of Chemistry, MIT, in recognition of his research contributions in platinum chemistry and its application to nucleic acids. This prize

Jan 1, 1985

By Y. Chen, D. He, J. H. Potgieter

The demand for rare earth elements (REE) is increasing rapidly owing to the emergence of new cleanenergy and defense-related technologies. China’s dominates the world production of REE. In this paper, we review the ore characteristics of four typical REE deposits in China and discuss the conventional beneficiation techniques, including gravity and magnetic separation, flotation, and hydrometallurgical processing of these ores. Some of the latest laboratory findings and industrial applications, as well as the development of novel reagents for REE processing in China are presented. The REE beneficiation technologies developed and employed in China could constitute a good case study for many other emerging projects being explored around the world.

Mar 2, 2022

By P. Horrell, K. Rhodes, G. Harrison, J. Dean, D. Sammons, M. Stander

Anglo Platinum have perceived a need to increase the rate of reef development both for new mechanised stoping technology and on conventional new developing mines. The Research and Development Division of Anglo Platinum therefore initiated an experimental reef raise project with a tunnel boring machine (TBM) at Bafokeng Rasimone Platinum Mine (BRPM). The scope of the trial was for the boring of a reef raise 340 metres in length on the Merensky Reef. The boring phase of the trial took place over six months and the average rate of penetration of the TBM was 0,47 metres/hour. TBM utilisation was 22%. The TBM used in the trial was a Jarva MK6 manufactured in 1972 and its design with its backup system was not considered to be an ideal machine for reef development. However it was the intention of the trial to prove the concept of developing with a TBM on reef. In this respect the trial was unequivocally a success. There were many problems and long delays did occur during the boring phase. Nevertheless there is every confidence that a new TBM can be designed specifically for this type of work that will achieve high rates of advance up to (say) 400metres/month and with a more flexible steering system in order to negotiate reef changes. It can therefore be expected that TBMs will be used in the future for reef development on South African platinum mines.

Sep 1, 2001