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By T. E. Pogue

This paper traces the co-operative initiative undertaken by South Africa?s gold mining companies through the Chamber of Mines Research Organization (COMRO) in development of hydraulic technologies. After a brief description of the structure of these technologies? development under COMRO?s stewardship, the paper turns to an overview of the structure of innovation within which these hydraulic technologies were developed. A central focus of this paper is systematic review on whether similar technologies are likely to emerge in the present system of innovation and the role played by innovation policy.

Jan 1, 2006

By R. Banda

This paper describes the decision to implement and then the implementation itself, through trials, of electronic ?Smartdets? over previously used shock tubes. It concludes that Mufulira Mine has become the first mine in Zambia to convert 100% of its stoping to ?Smartdets?, because the Mine?s management was prepared to look beyond the unit cost of product and were ready to look at the broader picture of cost effectiveness and increased productivity.

Jan 1, 2005

Changes in reductant and energy inputs which are required to adjust the slag composition in an ilmenite smelter to a higher or lower FeO content are calculated. The calculated changes are based on the assumption that solidification equilibrium with the freeze lining constrains the slag composition to follow a eutectic groove in the TiO2-FeO-TiO1.5phase diagram. Calculated equilibrium conditions along the eutectic groove are presented, and form the basis of the calculations. The inputs of energy and carbon need to deviate strongly from the steady-state values to adjust the slag composition. The inputs required at any given time depend on the desired rate of change of the slag composition, and the current slag composition. The steady-state relationship of a change in energy input of 5 kWh corresponding to a 1 kg change in carbon input also holds for the changed inputs during transient changes in FeO content. Keywords: Ilmenite smelting, freeze lining, solidification, eutectic

Jan 1, 2003

By R. M. Kear

Strategic and tactical planning are both required in the mining industry but have completely different objectives and require different environments. If these are not fully understood, then the best value for a mining operation may not be realized. This paper examines the differences in these approaches and how they interface in the mining environment. The objectives, content, skills required and the implied management issues for these two components are examined with the hope that this will assist management and the planning teams in defining their respective roles and expectations. The opinions are those of the author based on his experience on several mining operations and projects.

Jan 1, 2006

By S. Kahraman

The correlations between the modulus ratio and penetration rate of rotary and percussive drills were statistically investigated using the raw data obtained from the experimental works of different researchers. An inverse power law was found between the modulus ratio and the penetration rate of rotary and diamond drills. The penetration rate of rotary drills and diamond drills decrease with an increasing modulus ratio. The penetration rates of percussive drills increase with an increasing modulus ratio. There are significant linear correlations between the penetration rates of percussive drills and the modulus ratio. In one of the cases of percussive drilling, a strong correlation between the penetration rate and the modulus ratio was found for the rocks having a porosity value lower 1.23 %. It can be concluded that the modulus ratio might be a representative measure of rock drilling efficiency. However, further study is necessary to check the validity of the derived equations for other rock types. The effect of porosity on the correlations between the modulus ratio and penetration rate needs to be further investigated.

Jan 1, 2003

By G. Bacon

The past decade has witnessed unprecedented growth in the development and implementation of solvent extraction technology in the extractive metallurgy of nickel and cobalt. Solvent extraction is proving to be a powerful tool, opening new opportunities for simpler, more cost efficient and environmentally sound metal refining processes. These advances, however, could not have been possible without the cooperative efforts between the nickel industry and the people and organizations involved with reagents, materials and equipment development and supply as well as solvent extraction research, aided by the accumulated knowledge and practical experience from the copper and uranium solvent extraction operations. This paper provides an overview of these developments and some of the challenges ahead.

Jan 1, 2002

By M. J. Nicol, G. Cromberge, C. A. Flemming

A relatively simple rate equation for the kinetics of the absorption of gold from cyanide solutions onto activated carbon was lI5ed as the basis in the development of a model for multistage carbon-in-pulp and carbon-in-Ieach absorption circuits. The model was used in the prediction of both the steady-state and the transient behaviour of the absorption process, and the results were found to be in reasonable agreement with those observed in an extended pilot-plant campaign. A number of practical implications of the model are discussed, and an assessment is made of the economic consequences of the various process options available for the design of a carbon-in-pulp plant.

Jan 1, 1983

By Antoine F. Mulaba

Introduction Copper and cobalt oxide mineral deposits formed by the atmospheric weathering of near surface sulphide deposits are commonplace in the Democratic Republic of Congo. The most common route for the extraction of these metals is a hydrometallurgical one in which the base metal oxides are dissolved in sulphuric acid and then concentrated further by solvent extraction. However, as many of these deposits are relatively low grade (i.e. 0.5-1.8%Co and 2-4% Cu) and can also contain large amounts of acid consuming gangue minerals (i.e. dolomitic, micaeous, and/or siliceous), the hydrometallurgical route becomes uneconomic due to the excessive acid leaching costs. Some means of pre-concentration ahead of leaching is then desirable to improve the process economics. Apart from the small scale mining (Pan. Afr. News Agency, 2000) handpicking, although not easy, oxide concentration by flotation has been suggested. For the flotation process, the two most common approaches are controlled potential sulphidisation (CPS) and the fatty acid flotation method. The preferred method is dictated by the nature of the mineral makeup of the gangue. Being secondary deposits, the gangue associated with these ores is often complex and can play a significant role in the overall flotation efficiency. Laboratory flotation experience gained from the testing of a number of different ores of this type has revealed that it is not possible to prescribe a set method for the flotation of various ore types. Each ore needs to be analysed very carefully before and after laboratory flotation on an individual basis in order to arrive at an acceptable flotation technique Laboratory flotation testwork was carried out on three different samples from the DRC in attempts to isolate some of the more important variables affecting the flotation of copper and cobalt oxide minerals from these weathered deposits. This paper describes some early results achieved and experiences gained with these different ores ahead of a more detailed flotation test program which will follow in the near future on receipt of a significant quantity of a more representative sample. Controlled Potential Sulphidisation (CPS) was used in an attempt to achieve acceptable recoveries of both copper and cobalt.

Jan 1, 2005

By M. L. Smith, G. Karunatillake

Lead-zinc production at MIM, Mount Isa includes three mines, a lead concentrator, zinc filter plant and lead refinery. Lead production is vertically integrated with lead-silver bullion shipped from Australia to London for refining. Zinc is sold as a concentrate. All three mines have reached varying states of maturity mining a multitude of orebodies having significant variation in grades and metallurgical recovery for three metals. Based on current levels of measured resources, the remaining project life is at least ten years. The objective is to schedule production over the life of all three mines so as to maximize the present value of the complex. Additional scheduling complexity arises out of the implementation of long-term schedules, capital expansion projects for both mining and processing, the presence of substantial inferred reserves and interactions with MIM copper production. A large-scale, time-dynamic, life-of-complex Mixed Integer Program (MIP) production schedule was formulated to optimize lead/zinc cash flow based on a detailed life of project production scheduling study. The requirements for such a study are detailed herein. The operational feasibility of the MIP solution is compared against a non-optimal approach to strategic life-of-mine scheduling. The strategic planning emphasis placed on the MIP is compared to the implementation of a life-of-mine schedules at Mount Isa using spreadsheets and other popular commercial mine schedulers.

Jan 1, 2003

By J. -Y. Jia, G. -B. Qiu, C. -G. Bai, D. -F. Chen

Due to the great importance of the smelting process, it is essential to establish a calculation model on the viscosity of the slag system containing titania. In this paper, the calculation models of mass action concentrations and viscosity for the CaO-SiO2-TiO2slag system have been established according to the coexistence theory of the slag structure, as well as the referenced viscosities ofCaO-SiO2-TiO2at different temperatures and TiO2compositions. With the two models, corresponding calculated programs are made by means of programming language Matlab5.3, and the curves of viscosity of the TiO2concentration (?TiO2/%) at 1400°C, (R=0.9~1.0) are plotted. The results show that mass action concentrations of TiO2increases with increasing percentage ofTiO2, while the viscosity of CaO-SiO2-TiO2system is decreased. The results show that the models are in good agreement with the experimental and referenced data. They also shows that the models are reasonable for the CaO-SiO2-TiO2slag system. Keywords: coexistence theory; CaO-SiO2-TiO2slag system; viscosity ; calculation models.

Jan 1, 2004

By N. A. Barcza

An investigation was conducted into the reactions between the slag system MnO-CaO-MgO-SiO2(AI2O3) and the alloy system Mn-Fe-Si-(C). Synthetic slags representative of plant melts and a plant alloy were reacted in alumina crucibles at temperatures of 1400°C, 1450°C, 1550°C, and 1600°C. In similar experiments, slags were used that comprised a South African manganese ore with various amounts of lime and several synthetic alloys with various silicon contents and manganese-to-iron ratios. These experiments were conducted in a vertical molybdenum-wound resistance furnace with full temperature control. Slag-to-alloy ratios were also varied during the tests. The rate of reduction of Mn.O3 and the MnO from the slag by the silicon in the alloy was extremely rapid, most of the reaction being completed within five minutes. The strongly exothermic nature of the reaction resulted in considerable generation of heat at the slag-alloy interface, causing convectional stirring of the contents of the crucible and promoting the rate of reaction. Equilibrium was usually attained after fifteen minutes. The major limitation governing the recovery of manganese is the need for the silicon content of the alloy to meet a maximum specification of 2 per cent. Higher concentrations of silicon in the final alloy of between 8 and 12 per cent favour good recoveries of manganese from the slag, but, since such an alloy is not salable, lower recoveries must apparently be tolerated. In alloys of 2 per cent silicon, low activities of the silicon are responsible for poor recoveries of manganese. The activity of MnO in the slag can be increased by moderate additions of CaO and small amounts of MgO, i.e., by an increase in the basicity of the slag.

Jan 1, 1979

By R. C. W. Webber

Mining up to depths of 5 000 m would be a world first and, accordingly, no previous experience in the determination of acceptable heat stress limits, criteria or indices is wholly applicable. However, some South African gold mines are already operating at depths beyond 3000 m and much of the knowledge gained in reaching and working at such depths will be helpful in making adequate provision for acceptable environmental control at the greater depths being contemplated. Accordingly, it is necessary to take cognisance of the industry?s experience in deep-level mining and of standards and regulations already established in South Africa and elsewhere in order to ensure acceptable working conditions and control standards, that compare favourably and defensibly with those in other mining industries. The local and international use of heat stress limits, criteria and indices were investigated as it was necessary to determine to what extent any other indices, limits or criteria would be applicable to South African deep mine conditions. In addition, it was necessary to establish whether there was a single heat stress index that could be used for South African ultra deep mining conditions. It was found that an appropriate combination of heat stress indices would be required in planning for and ultimately controlling thermal conditions in ultra-deep mining. The depths being contemplated and the concomitant potential heat hazard present too great a risk for reliance on a single environmental component of heat stress, such as wet-bulb temperature at present in common use locally. The study recommends that a heat stress index, preferably Air Cooling Power (ACP), be used to design an ultra deep mine?s ventilation system and that wet-bulb temperature be used to monitor and control the system once it is implemented.

Jan 1, 2003

By J. Drzewiecki, J. Kabiesz

Coal mining using longwall methods of mining can lead to intense disturbances of undermined roof strata. The disturbances may extend beyond the extraction area and the resulted rock mass deformations will appear differentiated. In the case of stiff and undermined roof strata, the energy stored in these rock masses may be frequently dissipated in the form of high-energy seismic tremors. Such events can occur if these strata should fail or „free themselves” either from the constrainment of rock environment or from adjacent strata. It has also been found that the amount of the stored energy closely depends on the size and/or slenderness of these strata. Thus, it would be possible to apply specific preventive measures to reduce the energy of mining – induced seismic tremors. The methods are based on artificial disintegration of the structure of energy – storing strata. One of the most efficient methods is a method of directional hydraulic fracturing, which is regarded as an alternative solution from the traditional blasting and hydraulic methods.

Jan 1, 2003

By J. Gómez-Hernández, P. K. Kaiser

Abstract The process of stress-induced fracturing around underground excavations in brittle rock is associated with dilation or volume increase of the failed, fractured rock. Different attempts to account analytically for this dilation have been made within the framework of plasticity theory. This theory has been developed mostly for metals, strain-hardening materials or soils, but brittle failure of rock-like materials is characterized by strain-softening behaviour and the volume change is dominated by geometric factors, which may violate stability principles of plasticity. In this work a semi-empirical Rock Mass Bulking Model (RMBM) was developed, using as starting concepts: dilation angle, plastic strain rates, effective deformation modulus, effective Poisson's ratio, Griffith locus, and the definition of a bulking factor BF introduced by Kaiser et al. (1996). The model was calibrated in order to obtain bulking factors that are consistent with experimental data and case studies of measured bulking around underground excavations. Résumé La fracturation provoquée par le stress autour des excavations souterraines dans le minéral friable est associée à la dilatation ou à l’augmentation du volume de la roche en rupture. Dans le cadre de la théorie de la plasticité, différents essais ont été faits dans le but de trouver une justification analytique pour cette dilatation. Cette théorie a d’abord été élaborée pour les métaux, les matériaux ou les sols d’écrouissage, mais la rupture fragile de matériaux d’aspect rocheux est caractérisée par un comportement d’amollissement et le changement de volume est dominé par des facteurs géométriques, ce qui pourrait ne pas être conforme aux principes de stabilité de la plasticité. Dans le présent ouvrage, un Modèle semi-empirique de masse rocheuse a été élaboré, dont les concepts initiaux sont les suivants : angle de dilatation, vitesse de fluage plastique, module effectif de déformation, coefficient effectif de Poisson, locus de Griffith, et la définition d’un facteur de foisonnement FF apportée par Kaiser et al. (1996). Le modèle a été calibré afin d’obtenir des facteurs de foisonnement qui soient conformes aux données expérimentales et aux études de cas sur le foisonnement mesuré autour des excavations souterraines. Kurzfassung Der Prozess von Brüchen in unterirdischen Abgrabungen in sprödem Gestein ist mit der Ausweitung oder der Volumenzunahme des gebrochenen Gesteins verbunden. Verschiedene Versuche im Rahmen der Verformbarkeitstheorie haben versucht, diese Ausweitung analytisch festzustellen. Die Verformbarkeitstheorie wurde hauptsächlich für Metalle, kalthärtende Werkstoffe oder Böden entwickelt, da sprödes Versagen von Gestein ähnlichen Werkstoffen von kaltenhärtendem Materialverhalten gekennzeichtnet ist, und die Volumenveränderung von geometrischen Faktoren beherrscht wird, die die Stabilitätsprinzipien der Plastizität übertreten. In dieser Arbeit wurde ein halbempirisches Rock Mass Bulking Model (RMBM) (Modell für das Aufgehen der Gesteinsmasse), entwickelt, für das die folgenden Anfangsprinzipien benutzt wurden: Ausweitungswinkel, plastische Fliessensätze, wirksames Verformungsmodul, leistungsfähiges Poissons Verhältnis, die Griffith Ortskurve und die Bestimmung eines Aufgehensfaktor BF1 der von Kaiser et al. (1996) eingefürt wurde. Das Modell wurde so kalibriert, dass es die Aufgehenfaktoren erzielte, die mit den Vesuchsangaben und den Fallstudien von Aufgehensmessungen in unterirdischen Abgrabungen übereinstimmen.

Jan 1, 2003

1. Mintek reports The folowing reports are available from Mintek, Private Bag X3015, Randburg, 2125 South Africa. They are available at R25 (plus R3,25 GST) per copy to South African addressees, and US$25 per copy (including airmail postage) to addressees elsewhere. Report M91D A mineralogical investigation of samples from the Renosterkop tin prospect near Upington, by M.J. Southwood. First issued Jul. 1983, reissued May 1989. 16 pp. Report M256D The upgrading of Mamatwan manganese ores heavy-medium separation, by P. W. Overbeek. First issued Apr. 1986, reissued May 1989. Report M299D A mineralogical investigation of samples from the Eenzaamheid cobalt-molybdenum deposit, by C.D. de Nooy. First issued Jan. 1987; reissued May 1989. Report M301D The evaluation of manganese metal powder by automatic image analysis, by E.J. Oosthuyzen. First issued Feb. 1987, reissued May 1989. 13 pp. Report M311D Mineralogical and beneficiation studies of ore from Lutzputz, by R.N. Guest and C.T. Logan. First issued Mar. 1987, reissued May 1989. 13 pp. Report M314D The beneficiation of a sample of magnesium ca/crete, by L. Jonker. First issued Apr. 1987, reissued May 1989. 13pp. Report M369 The determination, by flow-injection analysis, of thiocyanate, by E.A. Jones and M-J. Hennings. Jun. 1989. 7pp. Report M389 A spectrophotometric method for the determination of zinc by flow-injection analysis, by D.E. Barnes and RA. Jones. Jul. 1989. 15 pp.2. Recent publications Pumps-principles and practice. Available from K. Myles & Associates CC, P .0. Box 2212, Northclif 2115. :200pp. R99 including GST. Standard handbook of hazardous waste treatment and disposal, edited by H.M. Freeman. Bergano Book Co., P .0. Box 190, Fairfield, CT 06430, USA. 1120 pp. US$130.Quality control handbook, by J. Juran and F. Gryna Jr. Bergano Book Co. (address as above). 4th 00. 1536pp. US$125.Refractories in the manufacture and transport of pig iron. Verlag Schmid GMBH, P.O. Box 6609, 7800 Freiburg, West Germany. DM 100. The user-computer interface in process control, byW.E. Gilmore, D.I. Gertman, and H.S. Blackman. London, Harcourt Brace Jovanovich Ltd, 1989. " 312pp. $29.Aluminum alloys-contemporary research and applications, edited by A.K. Vasudevan and R.D. Doherty. London, Harcourt Brace Jovanovich Ltd, 1989. " 676 pp. " £90.3. TMS publications issued recently The folowing publications are available from The Minerals, Metals & Materials Society, 420 Commonwealth Drive, Warendale, PA 15086, USA (Telephone: (412) 776-9000, Telex: 9103809397, Fax: 4127763770). Advances in magnesium alloys and composites, by H. Paris and W.H. Hunt (eds.). 145 pp. $65. Arsenic metallurgy-fundamentals and applications, by R. Reddy (ed.). 515 pp. $104. Casting of near net shape products, by Y. Sahai (ed.). 7oopp. $155.Continuous casting of non-ferous metals and alloys, by H.D. Merchant, D.E. Tyler, and E.H. Chia (eds.). 360 pp. $90.Dislocations and interfaces in semiconductors, by K. Rajan, D. Ast, and J. Narayan (eds.). 210pp. $75.

Jan 1, 1989

By Y. Belloa, C. Dorfling

The presence of impurities such as Se and Te in copper sulfate leach solutions can have a detrimental effect on electrowinning efficiency. These elements can be removed from the solution by precipitation; sulfurous acid is commonly used as a precipitation reagent, while studies have also reported improved precipitation with the addition of metallic copper. This paper aimed to determine the effect of conditions used during the solution purification step on the characteristics of the precipitates that formed. Precipitation tests were performed in a batch reactor with copper sulfate leach solutions obtained from the base metal refinery of a platinum group metal producer. The effects of agitation rate (250 and 500 rpm), SO2 flow rate (4.4 and 5.8 mL/min.L), temperature (65 and 95°C) and metallic copper powder addition (0, 1 and 2 g/L) on the characteristics of the precipitates formed during the tests were determined using scanning electron microscopy. The major phases detected in the precipitates formed when using SO2 as the only precipitation reagent were elemental Se and Cu2Se. The introduction of copper powder led to the production of different sulfide phases for the experiments conducted at 65°C irrespective of the values of the other reaction parameters. At 95°C, Cu crystals, Cu2O and tiny inclusions of Cu2(Se,Te) were the prominent phases noticed in the precipitates produced from all the tests conducted with copper powder as precipitation enhancing reagent. Keywords: copper, precipitation, selenium, tellurium

Jan 1, 2020

By Ravichandar. D., K. B. Nagashanmugam, M. S. Pillai

"Blast furnace performance depends strongly on the coke reactivity index(CRI) and coke strength after reaction (CSR) properties. An innovative and cost-effective method, known as the Salem Box Test, has been developed to prevent the mass production of inferior coke unsuitable for blast furnace use. This method consists of coal carbonization on a micro-scale and involves charging approximately 18 kg of coal blend in a stainless steel box, carbonizing it together with coal cake in the plant coke ovens, and testing the coke produced for CRI and CSR to determine its suitability for blast furnace use. Only coal blends that yield coke with CRI <25% and CSR >64% are permitted for mass production, and other coal blends are either rejected or the blending ratios adjusted in an attempt to upgrade them. The experimental results reveal that, for a given coal blend, the quality of coke produced by the Salem Box Test is comparable with that produced by bulk production, indicating that the test is acceptable as a screening tool for regular use. The present paper describes the methodology and application of Salem Box Test to predict the suitability of coke for blast furnace use at JSW Steel Limited, Salem Works (JSWSL), and illustrates its advantages in adjusting the coal blending ratio to produce superior coke, in detecting coal contamination, and in preventing bulk production of inferior coke."

Jan 1, 2015

By A. W. Breed

The bioleaching of arsenopyrite, the oxidation of arsenate and the precipitation of ferric arsenate are competing reactions, hence their rates depend on the relative concentrations of the respective species, and the activity of the bacterial culture. Bacterial arsenic resistance may be attributed to the Pst+Pit-mutation and an energy dependent efflux pump. Pst+Pit-mutations result in a reduced uptake of arsenate. This enables the bacteria to survive in solutions in which the arsenate concentration is significantly higher than the arsenite concentration. However, the excretion of arsenate requires energy. Therefore, in the absence of an energy source or during periods of reduced bacterial activity, the inhibitory effect of arsenate may manifest at concentrations to which the culture has been adapted. The chemical ferric leaching rate of pyrite and arsenopyrite decrease with a decrease in the solution redox and may be described using a modified Butler-Volmer equation. The bacterial ferrous-iron oxidation kinetics of L. ferrooxidans also depend on the redox potential, and can be described using a Michaelis-Mententype model modified to account for both temperature and pH. A model developed using the independently determined ferric leaching, and ferrous-iron oxidizing kinetics, has been shown to compare well with the experimental data for the continuous bioleaching of pyrite. Keywords: Leptospirillum ferrooxidans, arsenopyrite, bioleaching, sulphide minerals ferrous-iron oxidation kinetics, ferric leaching kinetics, redox potential

Jan 1, 2000

By P. O. Akinseye, F. T. Cawood

Mineral royalties are one of the oldest forms of mining taxation, and were initially introduced to extract economic rents from mining. Over time, the royalty regime has become more complex as it was identified as an important policy instrument that can achieve more multi-faceted outcomes. Such a multi-tiered approach in the use of the royalty instrument is also the case with South Africa. With South Africa’s new mineral royalty regime now in place for ten years, it is perhaps time to assess its impact and effectiveness. To carry out this assessment, an econometric evaluative study was undertaken using four major commodities in South Africa, namely gold, platinum, iron ore, and coal. The study explored five different policy options for government to consider and tested them to determine the most favourable one that will realize the regime’s policy objectives. After the assessment, two major options stood out. Hence, this paper seeks to highlight which of the two options is the most favourable for consideration by policymakers. Based on that study, we find that the current structure is effective, but also recommend that the factors in the formula for refined minerals be ‘modified’ to reduce the capped profitability ratio from the current 60% to 30% and the maximum royalty rate for refined minerals from 5% to 3%. The minimum rate of 0.5% during times of depressed mineral prices and no or low profitability will not be affected.

Dec 1, 2021

By M. Tangstad, B. Monsen, H. Midtgaard

The increased attention towards reducing emissions of fossil CO2 due to its potential global warming effect has resulted in a focus on renewable resources, as charcoal. Since charcoal is produced from growing wood it does not contribute to global warming. This paper gives a brief review of consequences of and reasons for using charcoal in the silicomanganese (SiMn) production. Results are presented from practical SiMn smelting experiments, on a pilot scale, using charcoal as reduction material and comparing with coke. As slag- and CO2-reactivity are important for furnace performance these features have also been measured.

Jan 1, 2004