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By E. L. Thyse, P. Bepswa

The Western Cape Mineral Processing Facility (WCMPF) is a collaborative educational initiative between the Department of Process Engineering at the University of Stellenbosch and the Chemical Engineering Departments at the University of Cape Town and the Cape Peninsula University of Technology. The primary objective of the WCMPF is to facilitate the education, development and graduation of suitably qualified engineering graduates and diplomats for the mining and mineral processing industries. In recent years the WCMPF has embarked on a number of initiatives aimed at improving the quality of mineral processing education which include, more importantly the introduction of novel ?end to end? or ?integrated? practicals. The practicals are developed around a specific mineral theme or route, which more than often includes the development of several new pilot plant practicals demonstrating key unit operations or processes in the selected mineral theme or route. The most recent mineral processing pilot plant practical programme is developed around the beneficiation of heavy mineral sands. The programme consist of the following developed pilotplant practicals: the online electrostatic separation of free flowing mineral sands using a Roche Mining Carrara high tension roll separator incorporating a Blue Cube Systems MQi in-line mineral quantifier; the production of titania-rich slag and pig iron from the smelting of ilmenite and anthracite in a 60 kW direct current (DC) plasma arc furnace as well as the mineralogical characterization of the feed and products; the continuous closed-circuit ball milling and screen classification of titania-rich slag. This paper illustrates the important role of a well-designed heavy mineral sands beneficiation pilot plant practical programme in facilitating the education and development of suitably qualified personnel for the mining and mineral process industries.

Jan 1, 2007

By S. Polansky, J. Kolacz

The new sorting system has been developed to achieve efficient separation at low mineral content levels. The system employs high resolution X-ray sensors providing multi-energy analysis, thus giving maximal information about processed materials measurable by X-ray radiography. It makes it possible to analyse the internal structure of the particles and directly detect inclusion of minerals and metals like copper or gold. The paper describes sorting application examples for zinc, lead, copper and gold ore with low metal content below 0.1% of Cu. The sorting system still allows high efficiency analysis, quantification and removal of rock particles representing waste fraction with no metal or a negligible amount being uneconomic to process. This brings a huge advantage during pre-concentration, where almost no losses of valuable minerals in the waste fraction can be achieved. The presented sorting system has been developed by Comex and X-MINE EU Project Consortium. Keywords: X-ray sorting, ore sorting, XRF analysis, XRT analysis

Jan 1, 2020

By V. M. Lovell, N. P. Finkelstein

Fundamental studies of the flotation process: The work of the National I nstitute of Metallurgy N. P. Flnkelsteln and V. M. Love Presented at the Colloquim on Flotation, March 1972, and published in the Journal, July, 1972. AUTHORS' REPLY TO DISCUSSION In his contribution to our paper Dr Lloyd makes two criticisms: The first criticism, as we interpret it, is that the agglomerate flotation process that we described is not really necessary because previously described processes effect almost the same results or could be made to give the same results by including sufficient paraffin in the reagent combination.

By J. P. Dreyer

Note: The development of AGIT AIR flotation machines by J. P. DREYER HISTORY The first AGITAIR flotation machine was developed and patented in 1932. It has a capacity of 5 ft3t and was named the No. 20. Next in line was the No. 24. Built in 1933, it had twice the capacity of the No. 20 unit. Then, in 1934 and 1939 came the No. 36 (22,5 ft3) and No. 48 (40 ft3) respectively.

Jan 6, 1976

By C. F. Vos, J. D. Miller, J. C. Davidtz

"This work presents the potential for improving the flotation recovery of slow-floating sulphide minerals with the use of starvation dosages of a normal dodecyl (n-C12) trithiocarbonate (TTC) co-collector, together with a sodium isobutyl xanthate (SiBX) and dithiophosphate (DTP) collector mixture.At potentials below –150 mV (SHE), addition of nC12-TTC with SiBX improves the hydrophobicity of pyrrhotite, yielding captive bubble contact angles greater than those measured for SiBX or nC12-TTC alone, suggesting a low potential synergistic effect. This synergistic effect is further studied using Fourier transform infrared (FTIR) spectroscopy, the results indicating an increase in the surface concentration of the collector species when in a mixture. Thus, nC12-TTC with SiBX may act as an immobile surface anchor to which SiBX/SiBX2 molecules bond, increasing the localized concentration of collector species.Bench-scale flotation tests using mixtures of SiBX/DTP/nC12-TTC on a platinum group element (PGE)-bearing ore from the Bushveld Complex in South Africa confirm an improved metallurgical performance at very low substitutions (approx. 5 molar per cent) of SiBX. The improved recoveries for PGE, Cu, and Ni are correlated with improvements in the flotation kinetics of their slow-floating components. IntroductionShort-chain (less than C6) xanthates are very effective for the bulk flotation of sulphides (Fuerstenau, 1982), and early work (Leja, 1968; Gaudin, 1957; Plaksin and Bessonov, 1957; Taggart, Giudice, and Ziehl, 1934) indicated that the presence of oxygen in flotation slurries is necessary for the oxidation of the xanthate collector at the sulphide mineral surface to induce hydrophobicity. Fundamental research into the chemistry and adsorption mechanisms of xanthates over the years (Finkelstein and Poling, 1977; Woods, 1976; Winter and Woods, 1973) has revealed that for iron-bearing sulphide minerals, adsorption occurs predominantly through a charge transfer process. Oxidation of the adsorbed collector to the corresponding dimer takes place if the mixed potential of the system is greater than the reversible potential for dimer formation. In oxygenated slurries the rate of adsorption and oxidation of the collector depends greatly on the substrate surfaces. For chalcopyrite (Guler et al., 2005; Leppinen, 1990; Roos, Celis, and Sudrassono, 1990) and pentlandite (Hodgson and Agar, 1989) a two-step interaction with xanthate is proposed in which the chemisorbed xanthate is further oxidized to the dimer. The initial interaction of xanthate with pyrrhotite is through physisorption where xanthate physisorbs onto positive surface sites followed by oxidation to dixanthogen (Khan and Kellebek, 2004; Bozkurt, Xu, and Finch., 1998). This process is, however, slow and increased reaction time is needed to improve flotation recovery (Buswell and Nicol, 2002)."

Oct 1, 2018

By A. Brodt, I. Mezhibovsky

The traditional vertical transportation systems deliver both gangue and useful mineral. The extraction of the desired minerals requires the construction of mineral processing and waste management plants, driving production costs, and often creating a negative environmental impact. The proposed technology is an integration of mineral processing within the transportation system. The mined rock is crushed and then loaded into a vertical lifting system filled with heavy media, with an intermediate density between the mineral and the waste rock. Driven by gravity separation, the desired mineral floats to the earth's surface, while the waste sinks. Delivered minerals and sunk waste is extracted from the heavy media and is then regenerated to a dry state. The useful mineral should be suitable for further use, and the waste used for backfilling. Remained residues of the heavy media may be recycled and reused in the vertical transportation system. Trials of the proposed process in a pilot format have confirmed economic and environmental advantages over traditional methods of transportation and mineral processing technologies. Keywords: Gravitational processes of mineral processing, separation in heavy media, vertical transportation to earth's surface by floating up

Jan 1, 2020

Specifile compendium' 80. Mining and engineering. (Obtainable from Specifile, P.O. Box 7870, Johannesburg 2000.) Reviewer: J. D. Austin SKF Steel. Plasmasrnelt information brochure. Hofors (Sweden), SKF Steel, 1980. Reviewer: N. A. Barcza POTENTIAL VALUE OF COLLIERY DISCARD MATERIAL By R B MacGillivray, Pr Eng, BSc(Eng) Rand, C Eng (Fellow) Preprints of perhaps the most thought-provoking of the papers delivered at the Witbank Coal Colloquium - 'Potential value of colliery discard material' by Roy MacGillivray of Rand Mines - are available on request from the South African Institute of Mining and Metallurgy. Mr MacGillivray outlines an imaginative plan to utilize the annual nine million tons of colliery discard in the WitbankBethal areas. Two SAIMM colloquia The South African Institute of Mining and Metallurgy (SAIMM) is organizing two one-day colloquia in the State Pavilion, Milner Park showgrounds, Johannesburg, to coincide with the Electra Mining Exhibition on 16th and 17th September. Over a million rands worth of equipment will be on display, the Electra Mining Exhibition being rated among the four or five largest in the world. The 1978 Electra Mining Exhibition was attended by 24 000 visitors. "Project Management in the Metallurgical Industry", "Mine Fires" APCOM International Conference by H. W. GLEN The 17th APCOM Conference (under the auspices of the Council for the Application of Computers and Mathematics in the Mineral Industries) was to have been held in Moscow during the last week in October. South Africans have always given enthusiastic support to the APCOM series of meetings, since their inception in 1961. The conference was held in the Republic in 1972.

Jan 1, 1980

Book reviews Jones, M. J. (editor). Process engineering of pyrometallurgy. Proceedings of a joint meeting of the Institution of Mining and Metallurgy and the Institution of Chemical Engineers. London, Institution of Mining and Metallurgy, 1974. 105 pp. £6,50. Nim reports Report No. 1656 The analysis of geological samples for trace elements by direct-reading emission spectrometry. Report No. 1669 An assessment of the carbon-rod atomizer for the determination of silver.

Jan 12, 1974

By M. Bester, R. Carey, T. Russell, J. van Heerden

"In order to reach the goal of optimal and safe extraction of the mineral reserve, the mining industry is increasingly focusing on reconciliation across the mining value chain to ensure that the mining process occurs in a progressively more predictable manner. This will consequently improve the understanding of mine plans and their associated implementation risks, ultimately leading to increased investor confidence. In terms of geotechnical engineering, mine to design performance assessment is a critical aspect of mine to plan adherence focusing on the complex aspects influencing slope performance. A mine to design reconciliation process therefore needs to systematically track implementation and geotechnical aspects in order to review or update slope design criteria and pit layouts according to the mine planning cycle as the mine is developed. This paper describes the development and implementation of a standardized mine to design reconciliation system for operations utilizing laser scanning technology, analysis tools, as well as associated key performance indicators. Performance is evaluated on final pit boundaries in terms of geometry achieved as well as blast performance evaluation of face conditions. These aspects as well as the resulting catch berm capacity should be captured in an information system, enabling longer term trend analysis and detailed root cause analysis where unsatisfactory outcomes occur. Adverse outcomes should subsequently be incorporated into the mine’s risk management process informing risk mitigation measures including blast design adjustments, slope design changes, or rockfall protection measures. IntroductionIn order to reach the goal of optimal and safe extraction of the mineral reserve, the mining industry is increasingly focusing on reconciliation across the mining value chain to ensure that the mining process occurs in a progressively more predictable manner. This will consequently improve the understanding of mine plans and their associated implementation risks, ultimately leading to increased investor confidence. In terms of geotechnical engineering, mine to design performance assessment is a critical aspect of mine to plan adherence focusing on the complex aspects influencing slope performance. A mine to design reconciliation process therefore needs to systematically track implementation and geotechnical aspects in order to review or update slope design criteria and pit layouts according to the mine planning cycle as the mine is developed."

Jan 1, 2016

By G. W. Donaldson

Theoretical and engineering aspects of slimes-dam construction by G. W. DONALDSON, M.Sc. (Eng.)(U.C.T.), D.I.C. (Visitor) Tile paper reviews the recommendations made in 1959-60 as a result of research into slimes-dam construction and finds that these recommendations are still valid. The requirements for pollution control, vegetating, in situ leaching, and future development of slimes dams as building areas are considered as they affect the engineering aspects of slimes-dam construction, and it is found that these requirements can be met without any major changes to current recommended slimes-dam construction practice.

Jan 12, 1973

By S. P. Molefe

Mr Chairman, members of the executive committee, the sub-committee, distinguished speakers at this opening plenary session, delegates, affiliates, ladies and gentlemen. It is with pleasure that I have been called upon today to make these opening remarks and officially welcome you al at this auspicious assembly, the Fifteenth Congress of the Council of Mining and Metallurgical Institutions. Not only am I pleased to open the proceedings at this plenary session but for me to do so at Sun City in the North-West Province makes me doubly pleased. It is my wish that al delegates and their companions will enjoy the activities that are planned throughout the Congress and leave here with minds refreshed and stimulated by the technical sessions and memories enriched by being in such a unique and truly delightful setting as exists here at Sun City. The mix of delegates present reflects CMMI activities in many countries throughout the world-Australia, Japan, China, United Kingdom and South Africa among others. When it comes to mining and related activities, South Africa has a place at the top, a dominant role in platinum, gold, chromium, vanadium, dimension stone, coal and so forth, and here in the North-West Province we can proudly declare that some 25 per cent of the revenue from minerals in South Africa, namely R47 billion come from this area. Furthermore, we lead in the production of platinum group metals with 94 per cent of South Africa's total sales and thus hold first place in the world, 46 per cent of dimension stone sales, 32 per cent of chromate and 25 per cent of gold sales.

Jan 1, 1994

Book review Burkin, A. R. (ed.) . Leaching and reduction in hydrometallurgy. London, Institution of Mining and Metallurgy, 1975. £10. hydroxide pyritearsenopyrite NIM reports Report no. 845 A n electron-microprobe study of the nickel distribution in a serpentinite from Volspruit, Potgietersrus. (22nd Oct., 1969; re-issued Dec. 1975). Report no. 1546 Pilot-plant smelting campaign on iron ores from Tete. (22nd May, 1973; re-issued Jun. 1976). Report no. 1557 Cost estimates for the production of pig iron in the Tete district of Mocambique. (18th Jun., 1973; re-issued Jun. 1976). Report no. 1600 Dilute-acid leaching of slag from Tete ore. (20th Nov., 1973; re-issued Jun. 1976). Report no. 1602 The roasting of Tete slag for the extraction of vanadium. (20th Nov., 1973; re-issued Jun. 1976). Report no. 1635 Magnetic separation tests on Tete slag and ore. (30th Apr., 1974; re-issued Jun. 1976). Report no. 1671 Pyrometallurgical retreatment of a slag for the recovery of vanadium. (11th Oct., 1974; re-issued Jun. 1976). Report no. 1785 Some thermodynamic aspects of systems relevant to the flotation of sphalerite. Report no. 1808 Spectrophotometric determination (with pyrocatechol violet as chromogenic agent) of aluminium in zirconium metal and in the residue from anodesludges. Report no. 1813 The economic potential of some pegmatites from the Kenhardt area in relation to the trace-element content of their border zones. Report no. 1817 The rapid determination by X -ray-fluorescence spectrometry of tungsten in tungsten ores and concentrates. Report no. 1820 The thermodynamics of the formation of chlorocomplexes of iron (III), cobalt (II), iron (II), manganese (II), and copper (II) in erchlorate medium.

Jan 8, 1976

Visit to the Modderfontein factory of A. E. & C. I. Ltd 23rd November, 1972 A full programme was arranged to suit both the mining and metallurgical sections of the Institute. After refreshments were taken and visitors welcomed by the factory management we were split into two groups, viz metallurgical and mining. Book review Stress-relief Heat Treatment of Vanadium Steels by Or G. O. Joy and Or A. M. Sage (21 pp, 77 references).

When a mine decides to construct surface structures close to, or on undermined ground, it is required in terms of the regulations of the Mine Health and Safety Act to obtain permission from the Department of Minerals and Energy (DME). Apart from the legal requirements, the stability of the structures is crucial as damage to the structures due to surface movements could result in loss in life, equipment and/or production. This paper deals with the rock engineering aspects of a study that was conducted on one of the chrome mines in the Bushveld Complex (BC) involving the construction of plant structures on shallow undermined ground. The paper addresses the legal requirements and guidelines regarding ground stability of surface structures placed on undermined ground and the assessment of the undermined area with regard to the following: ?sources of potentially damaging surface movements ?safe mining spans ?stability of the pillars ?effect of the loading of plant structures on underground stability. Due to the irregular layout and geometry of the pillars in conjunction with a changing surface topography, numerical analysis and not the conventional tributary area theory was used to determine the imposed loads on the pillars. In order to subject the plant structures to minimum movement, the plant should be located in areas where the pillars would remain stable, the elastic deformation of the hanging wall is minimized and hanging wall failure extending to surface is unlikely to occur. The study indicates that although the depth of undermining is shallow (between 27 m and 60 m), potential damaging surface movements are not anticipated due to the stability of the pillars, competent nature of the overlying strata and negligible effect of the plant structure loading on the underground stability.

Jan 1, 2004

By J. A. Voster

Premier Mine (a part of De Beers Consolidated Mines Ltd) which is situated 38 km to the east of Pretoria, has the largest known diamond pipe in South Africa. The mine started operations in1903. The Premier Mine kimberlite pipe is unique in that it is intersected by a 75 m thick gabbro sill at a depth of 400 m below surface. The current mining method used is mechanized panel retreat caving, which has been successfully used to extract ore from the different mining blocks. All caving at Premier Mine is below the sill and failure to exercise good draw control could cause the early ingress of gabbro waste. Draw control at Premier Mine is crucial as it aids in preventing conditions of isolated draw, which results in the early ingress of waste, compaction of the kimberlite and the loss of ore reserves. To assist, an underground vehicle monitoring and control (VMAC) system was installed to enable the effective management of the draw control function. The system has evolved graduallyin collaboration with a local developer. The data accumulated is used to decide the most effectivedraw point loading pattern in order to achieve sound draw control principles. This is achieved as each load can be related back to the draw point of origin. The VMAC data recorded also relates back to specific load-haul-dumps (LHDs), tunnels, ore passes, as well as indications of dates, times and payloads recorded. An interface exists between the VMAC and a draw control linear program. Premier Mine’s VMAC system is not a ‘dispatch’ system but rather a draw control system that caters for Premier Mine’s specific block cave requirements. Premier Mine has realized that successful automation is not dependent on technology alone but rather on the successful implementation thereof.

Sep 1, 2001

By P. J. D. Lloyd

The Witwatersrand reefs contain gold, uranium, and pyrite in the following average concentrations: 0,001 per cent, 0,02 per cent, and 1,7 per cent respectively. The paper discusses the flotation of pyrite to produce a s,ulphide concentrate, reviews work done on the production of gold concentrates, discusses attempts to produce maximum concentrates, and closes with a review of processes for the simultaneous flotation of these three species. It is concluded that high recoveries of all three species can be achieved only if a rougher concentrate of perhaps 20 per cent of the feed (by mass) IS produced, and it is suggested that reverse leaching (leaching before cyanidation) of this concentrate, followed by a cleaning flotation step for the recovery of the pyrite, would be more efficient than the routes employed at present.

Jan 1, 1981

By I. M. Wolf, S. A. Usmar, L. A. Cornish

The limiting criterion in the use of stainless steel for certain forming operations such as coining is its hardness, which determines parameters such as required striking pressure, wear on dies, and integrity of pattern detail. Attention is given here to the development of ultra-soft ferritic stainless steels for coinage. In the first instance, the influence of carbon content on the striking properties of a series of commercial and experimental 17%Cr alloys was evaluated. It was found that a lower carbon content permitted the striking of relatively highly profiled and intricate patterns, provided that the hardness did not exceed 125 HV. Hardnesses as low as 115 HV were achieved in the fully annealed condition, but these alloys required high striking pressures. In a further study, three grades of experimental 14%Cr ferritic stainless steels were produced with a view to optimizing the ductility. When the residual impurities were minimized, hardness values of about 100 HV and lower were achieved. Micro-alloying additions allowed the heat-treatment response and grain size to be controlled. Excellent tensile properties, with elongations of up to 42 per cent, were achieved in the fuly annealed condition, and highly profiled patterns were produced in coining trials.

Jan 1, 1993

By T. R. Marshall

SAMREC (The South African Code for the Reporting of Exploration Results, Mineral Resources and Mineral Reserves) Clause 7 notes that ‘Documentation detailing Exploration Results, Mineral Resources and Mineral Reserves from which a Public Report is prepared must be prepared by, or under the direction of, and signed by a Competent Person.’ Similar statements with respect to Competent Valuators (CVs) and Qualified Reserves Evaluators (QREs) are contained in the SAMVAL (South African Code for the Reporting of Mineral Asset Valuations) and SAMOG (South African Code for the Reporting of Oil & Gas Resources) codes respectively. What does it mean to be a Competent Person (CP) in the context of compiling/signing-off on SAMCODE (South African Mineral Code) compliant documents? What do the registration and experience requirements mean? Who is ultimately responsible for the report and what does such responsibility prescribe?

Sep 1, 2021

By M. Klapwijk

Ancient Metallurgy - In addition to the preceding three papers, the following three contributions were received for publication 1. An analysis of Bantu-made iron implements from the Letaba district M. KLAPWIJK INTRODUCTION It has often been stated that it is hardly possible in South Africa to classify Bantumade iron hoes according to their places of origin and manufacture. It is well known that these hoes were used for barter, and as currency in the purchase of livestock or the payment of lobolo, although reports of the value of the hoes differ widely. The difficulty in their classification has arisen from their distribution over a very wide area.

Jan 1, 1974

Metso Minerals Cisa have developed VisiofrothTM - a system which calculates parameters of the froth surface using vision from remote cameras mounted about individual flotation cells. The parameters calculated from this system can be utilised within process control strategies to achieve stabilisation or optimisation of the flotation process. As part of a JKMRC AMIRA P9 field campaign, froth vision was collected from various cells operated at different air rates and froth depths within Rio Tinto's Northparkes copper roughing and scavenging circuit. At the same time, samples were collected to determine the cell metallurgical performance at each operating condition. These froth images have been processed using the VisiofrothTM system with froth velocity, bubble size, froth collapse rate and various froth colour parameters calculated. These parameters have been compared to the measured concentrate flow and concentrate grade produced at each condition. This analysis shows that the concentrate tonnage flow is strongly correlated with froth velocity whereas the concentrate grade is best correlated using froth velocity in combination with a bubble stability parameter which affects the bubble size distribution on the top surface of the froth. This paper summarises the results from this analysis as well as an overview of the VisiofrothTM system and the parameters that are measured by the software.

Jan 1, 2007