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By H. C. Voges

The concentration of cassiterite at Iscor's Uis Mine is described, and information is given on aspects of the concentration of iron ore at Thabazimbi and Sishen Mines. At Uis, a very Iow-grade tin ore is concentrated by three-stage jigging, spiral concentration, and tabling to give a high-grade concentrate with a recovery of 80 per cent of the tin. A Iow-grade tantalite-columbite concentrate is also produced. The possibility of recovering mica, the use of sluice boxes instead of spirals, and the recovery of cassiterite from minus 45 µm material are being investigated. At the two iron-ore mines, heavy-medium separation is applied to size fractions larger than 0,5 mm. The types of ferrosilicon and the circuits used for the recovery of ferrosilicon from the various dilute-medium circuits are described. The spiral-concentration plant being installed at Thabazimbi for the treatment of the minus 0,5 mm portion of the ore is described.

Jan 1, 1982

By E. Lutz, M. Momayez, K. W. Brown Requist

As real-time air quality monitoring becomes more prevalent in US underground mines, it is important to provide the highest data reliability with the fewest possible sensors. Real-time sensors remain costly, and these costs are not exclusively financial; the time required to install, calibrate, and maintain real-time sensors poses a large barrier to widespread implementation. Current atmospheric monitoring systems typically rely on displaying point-specific values. This requires operators to infer real-time airborne contamination distributions. Monitoring and control software utilizing mine ventilation network (MVN) solvers has been implemented in limited cases because of their ability to simulate ventilation systems quickly, but these solvers use a one-dimensional representation of the mine, limiting spatial resolution of estimated distributions. Computational fluid dynamics (CFD) has likewise been considered as a means to improve spatial resolution, but processing times prevent its use as a basis for monitoring and control. For the real-time monitoring of airborne contamination distributions, we propose a spatial interpolation method that can estimate the distribution of airborne contaminants in near-real time. This method provides a middle ground between fast processing times and increased spatial resolution. With the use of a pathfinding algorithm and optimization through absolute percentage error minimization, this method outperforms spatial interpolation with a Euclidean distance. By providing contamination distribution information to operators, this method and its derivatives stand to outperform current atmospheric monitoring systems.

Apr 16, 2024

By A. Fouchee, N. Naudé, K. Schommarz

"This article presents laboratory test work conducted on an African haematite ore to determine the influence of the flotation pulp pH on the final iron grade and recovery. Results show that a combination of an isodecyl ether propylene amine/amino acetate and 1,3-propanediamine, N-(3-(C10-C16-alkyloxy)propyl)-derivatives collector is suitable for separating haematite from quartz. Higher iron grades were obtained at pH levels between neutral and pH 9. This underlines the importance of the surface charge effect of the ore on its flotation characteristics. The results serve as good baseline conditions for further optimization. IntroductionBeneficiation of iron ore by flotation is widely used in Brazil, India and China. In Africa, however, this practice is not yet commercially developed.The aim of this test work is to serve as a starting point by establishing suitable pH conditions for the development of a practically implementable reagent suite, which will then be included in a larger beneficiation circuit for producing high-grade iron ore sinter feed.In the literature, African iron ore types are graded as low-grade (60.0–62.9% Fe; 8.6– 12.5% SiO2 and insolubles), high-grade (66.0– 69.9% Fe; 0.8–4.5% SiO2 and insolubles), and meduim-grade as the remaining portion (Astrup et al., 1998). The low-grade ore used in this work contains less than 60% Fe.For Brazilian ores consisting of a combination of haematite and quartz, it is common to use corn starch as a depressant and ether amine blends as collectors with additional frothing characteristic (Araujo et al., 2005). Work by Turrer and Peres (2010) shows the possibility of using other depressants successfully as well.The main mechanism of the reverse flotation of quartz from iron ore is based on the electrostatic theory of flotation. This is due to the strong pH dependence of the zeta potential of the mineral edge planes on silicate particles (Fuerstenau and Pradip. 2005)."

Jan 1, 2016

By Roger A. Blais, Michel David

"Matheron's geoslalislical method for the estimation of ore reserves has been developed to the point at which real-life problem may be handled effectively. The steps involved in the method are:(i) obtalning the variogram,(ii) fitting a model, and(iii) producing block estimates.All three steps may cause difficulty, and would-be users need a deep understanding of the theory if failure is to be avoided.To illustrate these points, specific cause are considered:(i) two almost equidimensional porpbyry deposits, one drilled randomly and the other regularly; and(ii) two iron formation, one drilled extensively and being mined, while the other is still at the stage of early estimation."

Jan 1, 2014

By Huanhuan SU, Jianqiang Zhang, Zhongyuan Liu, Junwei Ma

The high-sulfur bauxite in Henan Province was used as raw material. The grinding fineness, pH value and collector dosage on its desulfurization performance, and industrial flotation desulfurization process were studied. The best flotation desulfurization conditions were grinding fineness of 75%, pH of 8.5, and collector of 600 g/t. “One coarse, one cleaning and one sweep” closed-circuit flotation was established as the industrial flotation desulfurization process. After the closed circuit test, the sulfur content of aluminum concentrate with the yield of 93% was 0.23%, and the sulfur removal rate was 83.16%, and the sulfur content of tailings (sulfur concentrate) was 15.09%. Keywords：High-sulfur bauxite under coal mines, flotation, desulfurization

Jan 1, 2020

By C. Ndou, T. Mothupi, H. Mandende

The technological advances in efficient, rapid, and non-destructive hyperspectral core logging systems for systematic mineral mapping have led to the discovery and exploitation of new mineral deposits Hyperspectral imaging in the long-wave infrared range has been recently used successfully to identify various phosphatebearing minerals (monazite, xenotime, and britholite), with limited work on apatite associated with mafic-ultramafic layered intrusions. In this study we investigate the effectiveness of a hyperspectral imaging (HSI) system with long-wave infrared (LWIR) bandwidthsto identify apatite in the Upper Zone of the Bushveld Complex. The accuracy of the HSI results was validated by mineralogical and geochemical data. The two apatite-enriched zones detected by HSI suggesting widespread development of apatite throughout the uppermost 600 m of the Upper Zone. The lower apatite-enriched zone is approximately 40 m thick, while the upper apatite-enriched zone is about 23 m thick, consistent with previous thickness determinations by traditional logging and analytical methods. Spectral mixing observed in the response of apatite is ascribed either to the common association of apatite and olivine in these rocks, or to differences between the spatial resolution of the hyperspectral image and the size of apatite grains. The VNIR-SWIR wavelength region did not show prominent spectral features of apatite. Nonetheless, HSI in the LWIR range is effective in mapping apatite and should therefore be considered as an exploration tool. This research advances our knowledge of the reflectance spectroscopy of REE-bearing minerals, which makes it easier to detect, identify, and quantify REE-bearing silicate minerals by HSI.

Feb 6, 2023

By J. N. Van der Merwe

"Platinum is a highly valuable resource, its safe and economic extraction is paramount. The success of platinum mining by the bord and pillar method depends heavily on a comprehensive and dependable pillar design method. Pillars need to be large enough to safely support the load and small enough to avoid loss of resources. A critical evaluation of current pillar design systems used in narrow-reef platinum mining was undertaken using practical experience from a large feasibility-stage platinum exploration project, supplemented by observations from several platinum mines in Zimbabwe. An extensive literature survey was undertaken in order to determine the current status of design systems. Through this approach, the shortcomings of current pillar design systems are highlighted. Areas are proposed for further research to obtain a better understanding on how additional factors influence pillar system stability. The exploration work highlighted how rock mass classification methods can be utilized in determining the overall strength of pillars. Current pillar design systems for narrow-reef platinum mining consider width-to-heightratio (usually with different exponents for width and height) and the strength of the pillar material. However, there are many more important factors that are not considered and which have a bearing on pillar system stability. An in-depth study of these parameters with a view to establish effective narrow- reef platinum mining pillar design systems needs to be undertaken. IntroductionPillars have been used as a means of support since the early days of mining. Pillarsupported mining methods such as bord and pillar require a reliable design system for them to be successful. This paper presents an evaluation of the current hard-rock mining pillar design systems as applied to a practical large-scale narrow-reef platinum mining feasibility study. It is vital to have a dependable pillar design system for economic and sustainable mining. Using an extensive database collected from the project, the pillar strength formulae were tested and several discrepancies noted. This necessitates the establishment of more reliable pillar design systems. In narrow-reef platinum mining, large compressive stresses accompanied by geological and geotechnical factors contribute to pillar instability. A well-formulated pillar design system is required that accounts for such factors so as to minimize pillar failures."

Jan 1, 2017

By F. Botha

South Africa is amongst the 40 driest counties in the world, with extreme weather conditions and beset by both droughts and floods. Coupled with economic growth is an increased demand on water resources and, as with all other industrial developments, mining requires large volumes of water, which is likely to have an impact on the environment. Further to this, the mining industry also realizes that minerals are a non-renewable resource and the contribution to wealth creation from mineral extraction is not everlasting. It serves as an economic boost and careful planning is required to ensure that the legacy of mining is sustainable, and that some of the returns from mining provide continual economic and social prosperity.

Jan 1, 2012

Zincor operates four Lurgi fluidized-bed roasters at its roast-leach-electrowin refinery in Springs, South Africa. In 2006, Zincor?s four roasters had reached ages ranging between 26 and 38 years, while the expected life of this type of roaster is generally 20 to 25 years. Roaster 3 was the first to be rebuilt in 2006 because its condition had deteriorated the most. Roaster 4 is being rebuilt in 2007 and the last two roasters will be rebuilt over the next few years as necessary. The main damage to Roaster 3 was caused by buckling of the roaster steel shell. This caused the freeboard and dome areas to shift, resulting in cracks in the dome brick lining and crumbling of the bricks lining the freeboard. The steel shell buckled owing to the combined effects of excessively high operating temperatures and corrosion. These were caused by the following two main factors: ?Thicker external insulation was installed during a previous maintenance shut, which resulted in an increased steel shell temperature and exacerbated the normal metal fatigue ?SO2/SO3 containing gas that had permeated the brick lining passed through its dew point during frequent planned and unplanned shuts over the life of the roaster. This caused acid formation between the refractory brick lining and steel shell, resulting in corrosion of the shell. The initial plan was to replace only the damaged areas of Roaster 3, but when it was dismantled more damage was found, and the roaster was rebuilding from the tuyeres upwards. During there building the opportunity was taken to modify the design of some of the brickwork to extend its life and make future repairs easier. This paper discusses the mode of failure of Roaster 3 and the lessons learnt during its dismantling and rebuilding.

Jan 1, 2007

By J. S. C. Joubert

The Koidu Kimberlite Project is situated in the Kono District of Sierra Leone, approximately 330 km east of the capital city, Freetown. The mining lease area is 4 km2 and comprises 2 kimberlite pipes, 4 dyke zones and a number of blows off the dykes. Koidu Holdings established on the property and began dewatering and the removal of silt from the existing 30 m excavation of the No.1 Pipe in 2003. While the original planning for the pipes included conventional open pit operations, mitigating factors such as the proximity of the town, the presence of houses close to the perimeter of the pipe, the size of the pipe and the planned open pit depth with relevant stripping ratios, as well as uncertainties on the grades in respect of an underground operation, lent itself to the vertical pit concept. The vertical pit was established using an A-frame headgear for the hoisting arrangement, with sidewall support comprising a combination of 20 m and 40 m long cable anchors, rock bolts, wire mesh and pneumatically applied concrete. The pit reached steady state production in January 2007 and produced some 26,000 tonnes of head feed per month until August 2007 when mining reached a depth of 74 m below the pit collar (approximately 126 m below surface). Mining was suspended following a sidewall failure that disrupted operations. Now that the grades in No.1 Pipe have been validated, focus has been switched to an underground operation taking account of both No. 1 Pipe and No. 2 Pipe. While the mining costs for the vertical pit have been higher than for a conventional open pit, the concept did circumvent the social implications, the issue of grade consistency and diamond value at depth, as well as providing the time frame to carry out a full underground mining study.

Jan 1, 2008

Professor R.F. Sandenbergh matriculated at Germiston Afrikaans High School, and then he obtained the degrees of B.Eng. (Chem.) in 1972, M.Eng. (Chem.) in 1975, and D.Eng. (Met.) in 1983-all from the University of Pretoria. Mr J.A.D. Britz matriculated in 1958 at the Roodepoort Hoerskool, and joined the mining industry in 1959 as a student mine official at the Rand Mines Training Centre. Mr J.A. Cruise matriculated at Durban High School and joined Union Corporation as a Learner Official in 1962. He was awarded a scholarship to read for B.Sc. and M.Sc. degrees in mining engineering at the University of the Witwatersrand

Jan 1, 1990

By M. Steyn

The coordination compound tetrakis(1,3-diphenyl-1,3-propanediona to)zirconium(IV), [Zr(DBM)4], (DBM = dibenzoyl methane/1,3- diphenyl-1,3-propanedionol) was synthesized and characterized by single-crystal X-ray diffraction. [Zr(DBM)4] crystallizes in the monoclinic space group P21/c (a = 24.769(4) Å, b = 10.216(5) Å, c = 19.314(4) Å, and = 101.541(5)°). The coordination geometry around the zirconium atom, formed by the eight O-donating atoms of the four -diketonates, is found to be a near-perfect square antiprism. Crystal packing is stabilized by C?H... interactions throughout the crystal lattice. This structure is a noteworthy example of the application of ambient condition synthesis of zirconium compounds in N,N'-dimethylformamide (DMF) as reaction and crystallization solvent, highlighting the possibilities of aerobic condition metal purification through chelation.

Jan 1, 2014

By R. Kuyvenhoven, A. Parbhakar-Fox, X. Prieto, J. Quevedo, L. V. Danyushevsky

This paper presents the results of a study focussed on determining the distribution of cobalt in different types of pyrite of the La Estrella IOCG deposit in Chile. In the IOCG mineral deposits, where copper is the main product, the quantification and distribution of cobalt is required to correctly define the technical and economic viability of recovering cobalt as a by-product. In the La Estrella mineral deposit, seven alteration and mineralisation events were recognised through both optical and automated electronic mineralogical analysis. Of these seven events, five different types of pyrites were identified, each with unique characteristics of the pyrite crystals. Through advanced elemental analysis of these five types of pyrites, it was determined that the concentration and distribution of cobalt within the pyrite crystal is dependent on the mineralisation event. The results indicate high cobalt concentrations in the early pyrite mineralisation events, associated with relatively fine pyrite grains, and cobalt generally occurring in a solid form in the pyrite core. The late pyrite mineralisation event exhibits the lowest concentrations of cobalt, with cobalt predominantly present along the outer periphery of the pyrite. These results are relevant from a metallurgical point of view because the preferential location of cobalt within the pyrite crystal will influence the maximum metallurgical recovery of cobalt. For this, a cobaltiferous pyrite concentrate must be formed which, according to the characteristics of pyrite, must be processed with the optimal solubilisation method. The overall objective is to ensure both good cobalt recovery and a high concentration of cobalt in the leach solution resulting from pyrite leaching. Keywords: Cobalt, pyrite, IOCG, copper, metallurgical recovery, solubilisation, Chile

Jan 1, 2020

By J. Hadjigeorgiou, G. Knox

Since their introduction in 2010, paddled energy-absorbing rockbolts have been widely used in seismically active hard rock mines. This paper provides new data and reviews previous work to quantify the performance of paddled energy-absorbing rockbolts under controlled laboratory conditions. Of significance is the realization that the typical split location in impact tests, at the centre between two paddle anchor points can at best provide an upper limit value. This inherent variability in performance under different testing configurations should be acknowledged and taken into consideration in the design of ground support in seismic conditions. This paper discusses the reduction in capacity of paddled rockbolts as a function of loading angle from a maximum value during axial tests (0° loading angle) to the lowest value during pure shear (loading angle of 90°). A significant reduction in displacement capacity is observed as the loading angle changes between axial (0°) and 40°. Beyond a 40° loading angle up to shear (90°) loading the reduction in displacement capacity is less significant. Due to the variances in the capacity observed through the variance of the testing configuration: loading mechanism, direction of loading, location / presence of a discontinuity, it must be recognized that results from laboratory-based testing are not independent of the testing configuration. This should be acknowledged when extrapolating anticipated performance in the field.

Oct 9, 2024

By M. Izadi Yazdan-Abadi, S. H. Amiri, M. Ramezanizadeh, M. Bazmandeh

Iron ore concentrate is used as the fresh feed of pelletising plants. The green pellet properties depend on iron concentrate characteristics such as particle size distribution (PSD), specific surface area (Blaine value), iron grade, moisture content and grinding methods. The grinding methods affects particle size distribution and Blaine value. To find out the effects of grinding methods on pelletising process, green pellets were produced with concentrates that were reground by means of HPGR (high pressure grinding rolls) and ball mill. The Blaine values of ground concentrates in both types of milling were approximately 1400, 1600 and 1800 cm2/gr. The results of green pelletising tests on a pilot plant scale showed that at the same Blaine values, drop numbers of green pellets produced by ground concentrate inside HPGR were higher than the green pellets produced by ground concentrate inside a ball mill. Also, reground concentrates by means of HPGR, in comparison with ball mill, caused the production of green pellets, at higher wet and dry compression strengths. As a result, it was found that preparing the pelletising feed by means of HPGR led to more positive effects on the properties of green pellets. Keywords: Ball mill, HPGR, green pellet, drop number, wet and dry compression strengths

Jan 1, 2020

By S. Ling, T. Liu, Y. Shang

A new copper-molybdenum flotation technology developed for a certain coppermolybdenum ore is introduced. We achieved copper-molybdenum bulk flotation in lowalkali conditions. Locked-circuit test results showed that the bulk concentrate contained 21.05% Cu and 1.10% Mo, with copper recovery of 87.37% and molybdenum recovery of 77.07%. For the copper–molybdenum separation process of the bulk concentrate, we use a new depressant, BK511, to replace the traditional sodium hydrosulfide. We achieved copper–molybdenum separation through one rougher, nine cleaner, and two scavenger processes. The results of locked-circuit tests showed that the molybdenum concentrate contained 46.19% Mo and 0.75% Cu, with molybdenum recovery of 93.80%; the copper concentrate contained 21.50% Cu and 0.069% Mo, with copper recovery of 99.92%. This new technology overcomes disadvantages of using large amounts of lime, sodium hydrosulfide, and other reagents in traditional copper–molybdenum flotation.

Jan 1, 2023

By L. Petzold

The demand for stainless steel is ever-increasing. As an essential element in stainless steel-making process, so is the demand of chromite concentrate. At the same time, the industry proven technologies for beneficiation of chromite are limited. Chromite is only crushed, screened and jigged to produce a concentrate. However, for ultrafine and low-grade material, no satisfactory beneficiation methods for the enrichment of chromite fines exist in industrial operation. This poses a clear challenge for the industry, which Primetals Technologies has addressed with the development of a new beneficiation process. The aim of this process was to enrich low grade chromite tailings to a quality suitable for the smelting process. Required concentrate grades are different over the world, concentrate grades of Cr2O3=40% and lower are found at the Bushveld Complex, South Africa. The target for the present study was a Cr2O3-grade in the area of 49%. Three different chromite tailings with Cr2O3 grades between 16 % and 29 % were part of a study, executed by Primetals Technologies. All three tailing materials were characterised by Mineral Liberation Analysis (MLA). Based on the physical, chemical and mineralogical findings, process flowsheets were developed. The process flowsheets included grinding to ensure a full liberation of the chromite. The liberated material was classified at a cut size of 63 μm to a coarse and fine fraction. Gravity separation and flotation processes were tested with the coarse particle fraction. Due to the limitations of gravity separation with fine particles, only the flotation process is suitable and was tested with the fine fraction < 63 μm. A Design of Experiment (DoE) with six factors, each three levels, was conducted to identify optimal parameters for the fine chromite flotation. Two different collectors were tested: a phosphoric acid ester and a fatty acid type collector. In small scale test work a chromite concentration suitable for the smelting process was achieved. On this basis Primetals Technologies will develop a pilot-scale test program to research recirculation effects and upscale potential of the process. Keywords: Mineral processing, tailings beneficiation, flotation, density separation, process development, chromite

Jan 1, 2020

By R. G. Diale, H. R. Chauke, T. M. Ledwaba, P. E. Ngoepe

FeCo alloys play an important role in soft magnetic materials with a wide range of technological applications due to their high saturation magnetization and Curie temperature. However, these alloys have low ductility at room temperature. The ductility can be improved by the ternary addition of elements such as V. A density functional theory supercell approach was used to generate B2 Fe50Co50-xVx (0 ≤ x ≤ 50) structures and the properties were evaluated at different atomic percentage compositions to determine the ductility at room temperature. The structures were fully optimized to obtain better equilibrium ground-state properties such as lattice parameters and thermodynamic properties for both binary and ternary systems. The stability of Fe50Co50- xVx was evaluated from the heats of formation, elastic properties, and phonon dispersion curves. Furthermore, magnetic strength was evaluated from magnetic moments. It was found that all structures are thermodynamically stable due to the negative heats of formation. The calculated Pugh’s ratio and Poisson’s ratio confirm that alloying with V effectively improved the ductility. It was also found that Fe50Co50-xVx showed a positive shear modulus for the entire concentration range investigated, in agreement with phonon dispersion curves. The ternary addition of V to the FeCo system resulted in reduced magnetic strength due to a decrease in magnetic moments. These findings reveal that B2 FeCo-V alloys can be used as components and actuators for the automotive industry.

Jun 10, 2024

By J. H. Viljoen, C. H. Graan, N. B. Strydom, J. S. Greyson

M J Martinson (Fellow) There is everywhere a lamentable dearth of quantitative information on occupational factors affecting the health and safety of mineworkers, and as the authors point out in their introduction underground lighting is one of the factors which has received little attention in South Africa prior to this welcome paper. Since the authors are to some extent pioneering, it is perhaps inevitable that the paper should raise more questions than it answers, but nevertheless it provides a provisional yardstick against which the need for, and success of, remedial action may be judged. Before commenting in detail on a few aspects of the paper it may be worthwhile to summarize the statutory provisions relating to underground lighting, contained in Chapter 15 of the Regulations promulgated in terms of the Mines and Works Act 27 of 1956. Chapter 15 is entitled `Lighting, Safety Lamps and Contraband&apos;, but in the context of the present paper only four simple regulations need be noted: firstly, no person shall work or travel in an unilluminated part of a mine unless he carries a light ; secondly, adequate stationary lights shall be provided at stations and certain other localities in shafts, winzes and places used for winding; thirdly, mechanically propelled conveyances shall be provided with an effective bright light shining in the direction of travel; and fourthly, moving machinery to which personnel have access shall be illuminated so as to be clearly visible. In all four regulations the standard of lighting to be provided is wholly subjective, and under these circumstances the wide inter- and intra-mine variations in light intensity disclosed by the study are hardly unexpected. Nevertheless the data presented in the authors&apos; Table I raise three points (1) Is there any evidence that the 19 mines visited during the survey are representative of the 45-50 large gold mines in South Africa, or that the shafts selected are representative of the respective mines? Mine managers would scarcely be human were they not to offer better lit working places for the survey; perhaps the use of a scaling factor (e.g. tonnes or transit mineworkers per shift, kilowatts, etc.) for each working place might have helped to put the figures in perspective. (2) Looking at two of the more numerous - and probably important - of the ten working places included in the survey, i.e. stations and tips, one is struck by the marked. skewness of both intensity distributions (with higher frequencies at the lower intensities) and the abrupt cut-off in both cases just short of pitch darkness. Thus, of the 45 meaned readings recorded at 26 tips no less than 19 fall in the lowest range of 0,1-0,9 1m/ft2, with but one tip in total darkness; of 46 readings on 26 stations, 7 fall in the lowest range and none is in total dark-&apos;1 ness. Although a light with an intensity in the range 0,1-0,9 1m/ft2 may satisfy the regulations, it is certainly arguable that in some situations it may be safer to have no light at all. (3) In view of the skewness referred to above, one wonders how meaningful are the `total average light intensities for (the gold mining) industry&apos; quoted in Table I, which the authors compare with illumina¬tion levels found in other countries. Looking at tips again, one notes that 34 out of 45 meaned intensity readings fall below the `total average&apos; for tips, and only 10 exceed it. From this it may be concluded that a few well-lit working places included in a `total average&apos; may conceal a plethora in Stygian gloom. In their discussion the authors make fleeting reference to the effect of underground lighting on productivity and accident rates, without however quoting any South African experience in this regard. Intuitively it seems highly likely that better lighting (in the widest sense) would improve productivity and reduce accidents, and of course it is in these areas that the mining industry might seek economic justification for providing better lighting. It is all the more regrettable therefore that these factors were not studied simultaneously with the present investigation, especially at the Psychological Division of the Human Sciences Laboratory has recently published a study on underground accidents in the gold mining industry without making any reference whatsoever to lighting as a causal factor. In the event neither of the two studies enables us to make an economic appreciation of the situation, and this seems to be a classic example of a situation where some dovetailing of research effort would have greatly increased the useful return. On the effect of lighting on accidents, it may be noted that in 1939 Mickel presented some very interesting statistics to the Mine Managers Association of the Transvaal2, on the improvement in accident rates which followed the random issue of electric cap lamps to native mineworkers in the Hercules Section of E.R.P.M. the previous year. Based on a 12 month trial period in which 250 000 shifts were worked with carbide lamps and (contemporaneously) 307 000 shifts with cap lamps, the incidence of major accidents (at least one day in hospital among men using carbide lamps was 1,15 accidents per 1000 shifts, while the incidence of minor accidents (requiring dressing only) was 11,52 per 1 000 shifts. The corresponding figures for men using cap lamps were 0,79 and 7,31 accidents per 1 000 shifts respectively, representing a reduction of over 30 per cent in both major and minor accidents. While these figures are obviously dated - only men using cap lamps were issued with hard hats, for instance - they do indicate a need for similar research today.

Jan 1, 1971

By J. Petersen, M. Reuter, E. Asselin, M. Becker, N. Uys

In order to meet society’s ever-increasing demand for metals and address the numerous technical, economic and environmental challenges within the current mining context, a holistic approach to process design, which is grounded in mineralogy, is needed. This would ensure that the impact of varying process mineralogy (and associated chemistry) on technical considerations and the associated economic implications and environmental consequences are taken into account upfront. This investigation focuses on the commodity zinc due to its strategic value coupled with limited resource availability and the wide variety of substantially different process technologies in existence. As the most commonly processed zinc ores contain zinc sulphides, the mineralogy/chemistry of these ores and their associated process routes will be discussed. The findings have been generated through the analysis of two case studies, Teck’s Trail Operations (British Columbia, Canada) and Hudbay Minerals’ Flin Flon Operations (Manitoba, Canada). The flotation of zinc sulphide ores to produce concentrates with varying mineralogy, represents the starting point for both case studies. The hydrometallurgical process routes for the further refining of zinc and other valuable metals include roast-leach-electrowinning (RLE), and zinc pressure leaching (ZPL). The effect of process route choices on primary metal recovery (Zn), coproduction of other base metals (Cu, Pb), potential for other valuable metal production (Ag, Au) including less well known, but increasingly important trace elements (In, Ge), and the production of other by-products (H2SO4, S0) are discussed. The economic and environmental implications of these aspects will also be considered. It is concluded that a quantitative modelling approach must be taken where waste management is integrated into process system design and simulation as a key unit operation. Keywords: Zinc Sulphide Processing; Design Decisions; Mineralogy

Jan 1, 2020