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By R. W. O. Kersten

"The aim was to investigate stable pillar design procedures currently in use on chrome and platinum mines, subject them to a critical appraisal, and review some of the alternatives proposed in the literature. It is concluded that these pillar design methodologies suffer from drawbacks that can be detrimental to the mining industry and that an improvement is essential.It was decided that the increased availability of analytical models and failure criteria could be exploited to update the empirical to an analytical/empirical method. The proposed methodology adopted FLAC2D simulations using the Hoek-Brown failure criterion to calculate full stress-deformation curves for typical pillars. The mine stiffness concept was introduced to determine the pillar load, integrating the influence of the pillar and strata stiffness and mining geometry.The proposed methodology was calibrated by comparing experimental and predicted deformations and failure depth of pillars in one hard-rock mine. The conclusion was that the methodology is an improvement over the one currently in use. An improved factor of safety is given by the intersection point of curves for the stiffness of the system and the pillar strength. IntroductionThe paper describes part of the findings of a PhD thesis (Kersten, 2016) on an alternative stable pillar design methodology. This publication contains sufficient information to implement the method for further interpretation and testing. A detailed comparison of measured and predicted data is dealt with in the thesis, and the results show that there is promise in the methodology.The design of stable pillars in mining is of fundamental importance, not only in the Bushveld Complex mines but throughout the mining industry. Wherever mining occurs, pillars are formed at some stage and it is essential to predict their behaviour, i.e. whether they will burst, yield, or remain stable. Although of crucial importance, pillar design still suffers from major shortcomings and weaknesses."

May 1, 2019

By U. Atici, R. Comakli

"Understanding rock properties is of vital importance in mining and civil engineering. Rock properties are generally determined through laboratory tests, which require a large number of uniformly shaped samples and technicians who use indirect methods to determine rock properties. The texture coefficient (TC), which represents various textural parameters including the size, shape, orientation, and relative proportions of grains and the matrix, is an efficient means for indirectly evaluating the mechanical behaviour of rocks. In this study, 12 different rocks (ten granites, one diorite, and one gabbro) were collected and their engineering properties. including specific gravity, porosity, P- and S-wave velocities, Schmidt rebound hardness, uniaxial compressive strength, and elasticity modulus, were investigated. Relationships between TC and these measured properties were assessed. Statistically significant (at the 95% confidence level) correlations were found between the TC and compressive strength, elasticity modulus, sound velocity (both compression and shear waves for dry and saturated samples), but no significant correlation was found with Schmidt rebound hardness. The results suggest that it is possible to use the relationships between TC and the mechanical properties of rocks in rock classification. IntroductionIn every aspect of rock engineering, knowing rock properties is essential for determining and predicting the behaviour of rocks and rock masses. Mechanical properties of rocks are important parameters in mining, geology, and engineering, and they are affected by textural characteristics such as grain size, grain shape, cement type, degree of cementation, mineral content, and the ratio of the grain area to the matrix area. The effects of textural properties on the physical and mechanical properties of rocks have been investigated for a long time, and previous studies revealed close relationships between single parameters related to rock texture and mechanical properties of rocks (Akesson et al. 2001; Gunsallus and Kulhawy 1984; Merriam, Rieke, and Kim, 1970: Onodera and Kumara 1980; Prikryl 2006; Ulusay, Tureli, and Bider, 1994; Tugrul and Zarif 1998). Rock properties are usually determined using mechanical tests, which require uniformly shaped and relatively large samples. However, it is not always possible to obtain such samples. Furthermore, rocks with similar textural and structural properties may exhibit different mechanical behaviour. Howarth and Rowlands (1987) developed a texture coefficient (TC) that expresses all the main textural parameters of a rock in a single dimensionless quantity based primarily on statistical assessment. The TC makes it possible to understand the effects of a rock’s textural properties on its mechanical properties using thin sections instead of large, uniform samples. Ersoy and Waller (1995) investigated the relationship between strength and TC for limestone, sandstone, and siltstone; they also examined the effect of rock properties and TC on drilling performance. Ozturk, Nasuf, and Bilgin (2004) explored the relationship between rock quality and TC by evaluating the uniaxial compressive strength (UCS) values of limestone, basaltic andesite, and tuff. Gupta and Sharma (2012) evaluated TCs as well as the petrophysical and mechanical properties of quartzite from the lower and higher Himalayas and found a strong relationship between TC and UCS. Similarly, Ozcelik, Bayram, and Yasitli (2013) investigated the relationship between TC and various parameters in marble by applying the statistical analyses developed by Ozturk, Nasuf, and Kahraman (2014)."

Jan 1, 2019

By H. C. Van Der Merwe

In the 21st century, dynamic, accurate digital 3-D geological models are essential to the pursuit of safe, efficient and profitable mining. This is particularly true for the deep-level underground mines in South Africa. The Sirovision® solution is a collaboration project between the Australian CSIRO (Commonwealth Scientific and Industrial Research Organisation), Datamine Software Ltd. and AngloGold Ashanti Ltd (AGA). The purpose of the project is to provide a fully integrated digital rock face imaging, geological mapping and modelling system for the AGA gold mining operations. The CSIRO-developed Sirovision® Stereo Camera Rig (SCR) consists of two digital cameras, alighting system, a laser guidance system and image processing software. The imaging system works on the principles of photogrammetry, i.e. overlaying of two 2-D images with a central focus point, with mathematical algorithms extracting 3-D information from the 2-D image pair. The output from matching several image pairs is a computer-generated, full 3-D, virtual copy of the mining excavation. The image resolution and relief ares of sufficient quality to distinguish different rock types and structural contacts. Functionality within Datamine Studio3 is used to add geological intelligence to the 3-D images provided by Sirovision®. The geologist identifies and ?draws? lines representing geological features directly onto the image. By utilizing the inherent ?topography? of the 3-D image, the software is able to convert the lines into 3-D surfaces, ready for use in the 3-D geological model. Subsequent to promising underground test results from AGA?s Sunrise Dam Gold Mine (SDGM) in Australia and other mining operations worldwide, it was decided to test the Sirovision® system in the South African deep-level gold mines. The first underground tests at Moab Khotsong Mine began in January 2009. The objectives of these tests entailed the capturing of 3-D images of selected development ends, mapping of geological features onto the 3-D images and integration of the mapping data with the 3-D geological model. Some downsides have cropped up during the feasibility testing, related to practicality of the SCR for acquisition of 3-Dimagery in the deep-level underground operating environment. These constraints will have to be addressed prior to operational implementation. Facing such difficulties is not unusual when attempting to implement new technology in such a challenging working environment and testwork is still in progress at the mine in order to prove the concept of using this technology in a Witwatersrand underground gold mine. The great advantage of the Sirovision® solution is that it offers the geologist the opportunity to work remotely on a 3-D virtual copy of a mining excavation, without the heat, humidity, hazards and time constraints associated with physical mapping in an underground workplace.

Jan 1, 2009

Your Council has pleasure in submitting its report for the year ended 30th June, 1969. COUNCIL The following served as Office Bearers during the year under review: Messrs. R. C. J. Goode (President), J. K. E. Douglas and V. C. Robinson (Vice-Presidents), P. Lambooy (Immediate Past President) and D. G. Maxwell (Honorary Treasurer). Members of Council: Messrs R. J. Adamson, M. Barcza, F. P. Bath, Or J. M. Bereza, Or W. Bleloch, Messrs H. Britten, H. E. Cross, A. R. C. Fowler, A. E. Gilfillan, G. W. Holl, Prof D. D. Howat, Or J. P. Hugo, Messrs C. J. Irving, D. M. Jamieson, J. G. Kirchner, Prof J. de V. Lambrechts, Mr C. E. Mavrocordatos, Or J. T. McIntyre, Mr J. A. Nixon, Prof R. P. Plewman, Messrs J. F. Reid, H. Simon, C. G. Sowry, W. T. Stobart and P. W. J. van Rensburg. Ten Council meetings were held during the year with an average attendance of eighteen. FINANCE The annual accounts, which are attached to this report, show an excess of expenditure over income of R2,124, compared with an excess of income over expenditure of R4,218 last year. There are a number of reasons for this substantial change. There was a loss on realization of investments compared with a substantial surplus in recent years. The publication of the Journal once again resulted in a large loss in spite of a generous subvention of R2,000 from the Department of Cultural Affairs and other assistance amounting to R750. The revenue from sales of publications was down considerably. This is a figure which fluctuates considerably from year to year. The secretarial fee was considerably higher than previously. Due to pressure of work it was necessary for the Secretary to relinquish his duties with the Institute of Land Surveyors and, therefore, for this Institute to assume the additional staff costs involved. Finally there was unusual expenditure on the 75th Anniversary celebrations. There was a pleasing increase in revenue from subscriptions, due to the steadily increasing membership, but this was quite inadequate to cover the substantial increases in expenditure and losses in revenue mentioned above. The changes that have been effected in the arrangements for the publication of the Journal have been mentioned elsewhere in this report. It is expected that these will bring about substantial financial benefits in the long term. The MacArthur Forrest Memorial Fund shows an excess of income over expenditure of Rl00 and the total fund was therefore increased by this amount to R4,206. The balance sheet indicates that the market value of quoted shares and debentures increased during the year from R8,755 to R13,059, while the Accumulated Funds now amount to R22,567 as against R24,691 last year. MEMBERSHIP Fifty-six Members, fifty-five Associate Members, thirteen Graduates, twenty-two Affiliates and twenty- nine Students were elected during the year. Twelve Members were admitted to Life Membership; seven Associate Members were transferred to the grade of Member; four Graduates and two Students were transferred to the grade of Associate Member; five Students were transferred to the grade of Graduate; three Affiliates were transferred to the grade of Member; five Affiliates were transferred to the grade of Associate Member. Three Members, seven Associate Members, two Graduates, two Affiliates and six Students were removed from the Membership Roll in terms of By-Law 7.7.1. Your Council records with deep regret the death during the year of the following members: E. F. J. Bulman (Member), E. F. Chapin (Member), R. A. H. Flugge-de-Smidt (Hon. Life Member), T. S. Haldane (Member), J. M. Massie (Associate Member), S. W. Page (Student), S. R. Rabson (Member), M. Ramsay (Member), F. Wartenweiler (Hon. Life Member). A comparative statement of the membership as at 30th June, 1969, and the end of the previous year is shown in the following tabulation: 30th June 30th June 1968 1968 Honorary Life Members 12 10 Honorary Members 6 6 Life Members 176 189 Members 488 514 Associate Members 409 448 Graduates 60 68 Affiliates153 155 Students152 162 1,456 1,552 PAPERS AND JOURNAL The Institute is changing the format of the Journal from the present size to the standard international A4 size with effect from August, 1969. In making this change it will conform to more general practice today in regard to publications and this should effect certain economies and facilitate selling of advertising space. It has been arranged that in future the publication of the Journal, including advertisement sales, will be handled by Kelvin Publications (Pty.) Ltd. who are already doing this work satisfactorily for the Mechanical and Electrical Engineering Institutes. In making these changes the opportunity was taken of redesigning the outer cover of the Journal to incorporate the new coat of arms. The Presidential Address by Mr R. C. J. Goode and twelve papers which were published in the Journal during the year are listed below: August, 1968: Presidential Address: "The Institute-In retrospect and prospect." September, 1968: "Rotary mill liner practice in the South African gold mining industry," by J. H. French and O. E. Lissner.

By D. Bessinger, J. Rabe, J. Zietsman, C. Coetzee, P. H. Lamont, J. Muller

The UCAR® CHILL-KOTE? freeze lining concept combines wall cooling with carbon and graphite refractories of higher thermal conductivities to ?chill? the refractory lining by transferring heat from the refractory lining. Effective sidewall water cooling, together with the efficiency of the heat dissipating conductive refractories, lowers the temperature of the lining to below that of the molten process materials. This causes a layer of slag and process metal to solidify or ?freeze? and form a protective ?skull? which completely coats the refractory hot face. Once formed, the slag skull insulates the refractories, reducing heat loss and protect the lining from erosion, chemical attack, thermal shock, and other stresses. The result: extended life and greatly improved refractory performance. The Ilmenite smelting process depends on the presence of a solidified slag skull to protect sidewall refractory material from chemical attach by molten slag. No known refractory material is able to withstand this corrosive material. To date, UCAR has not applied their Chill Kote ? technology in the ilmenite smelting industry. This paper revolves around the results obtained from conducting an ilmenite smelting campaign on a 500kW DC open-arc furnace with a UCAR designed refractory system. The purpose of this test was to establish the effects such a lining has on refractory wear and the reduction-smelting process. Proper thermo-couple management enabled the authors to monitor lining wear for the duration of the campaign. Prior to the pilot-scale campaign, modeling work was completed to evaluate the feasibility of applying UCAR® CHILL-KOTE? technology to ilmenite smelting furnaces. The successful operation of a pilot-scale furnace equipped with the UCAR® CHILL-KOTE? lining as well as concise modeling suggest that it should be a viable option to consider for an industrial-scale furnace.

Jan 1, 2007

By J. Engelbrecht

Understanding the deportment of minerals in size fractions has already led to improvements in the flow sheets for platinum minerals beneficiation. There are, however, more potential changes in the flow sheets that may improve the recovery of platinum group metals or reduce the costs of beneficiation before refining. Based on known technology of pre-concentration, milling, gravity concentration, flotation, and magnetic separation a number of potential alterations or additions can be considered and motivated based on the mineral deportment in size fractions.

Jan 1, 2012

The following papers were presented at the colloquium* on `Mining methods and economics for improved coal extraction, and coal processing and preparation', which was held in Witbank on 3rd and 4th October, 1979. Review of Mining Methods for Improved Extraction of Coal, by P. King, of Gold Fields of South Africa, for¬merly of the Chamber of Mines of South Africa. The Application of Continuous Miners in South African Coal Mines, by J. D. Inch, Bosjesspruit Colliery, I. Brumby, South Witbank Coal Mine Ltd, J. D. Stone, Matla Coal Ltd, and C. J. Beukes, Usutu Colliers Ltd. Longwall Mining Experience at Coalbrook Collieries, by P. G. Henderson, General Mining and Finance Corporation Limited (with a contribution by C. J. Cloete, Sigma Colliery, Sasol I). Pillar Design in Coal Mines, by Dr H. Wagner, Chamber of Mines Research Laboratories. Open-cast Coal Mining at Kriel Colliery, by I. Buchan, L. F. Baars, and C. S. Northcote, Anglo Power Colliery, Kriel Division (with a contribution by M. F. Pleming, General Mining Coal Division). Richards Bay Coal Terminal, by B. Dunne, Richards Bay Coal Terminal. Coal Preparation in South Africa - a General Review,

Jan 1, 1979

By C. T. Connor, O&apos

The 10th Annual UCT -US Minerals Processing Symposium was held at the Van Riebeeck Hotel at Gordon's Bay from 31 July to 2 August 1991. The conference was attended by 133 delegates representing a broad cross-section of the mining and metallurgical industry in South Africa. For the first time the Symposium, which was celebrating its 10th anniversary, was extended to two days. A cal for papers was announced and the organizers were inundated with responses resulting in a very full technical programme which consisted of 29 oral and 15 poster presentations.

Jan 1, 1991

By I. Mc Dougall

Water-cooled copper tap-hole blocks provide an effective means of extending the life of tap-hole refractories, as the lower temperature of the refractory material inhibits wear and other damage and promotes the formation of a protective frozen slag layer. This is particularly beneficial during prolonged tapping cycles. The copper block forms an integral part of the lining, and provides mechanical support to the refractory, facilitating rapid replacement of tapping channel bricks without disturbing the surrounding lining. Safety considerations are an important design factor, and the positioning of the water channels is optimized to prevent leaks although the copper is not in direct contact with the molten fluids during normal operation. Water-cooled copper blocks designed by Tenova Pyromet have successfully been utilized on metal, matte, and slag tap-holes for a number of processes, including nickel, platinum group metals, and mineral wool.

Jan 1, 2014

The April General Meeting of the Institute was held in Kelvin House, Johannesburg, on 16th April, 1969, at 4.30 p.m. Mr R. C. J. Goode (president) was in the Chair. There were also present nineteen Members, including Messrs R. J. Adamson, F. P. Bath, J. K. E. Douglas, A. R. C. Fowler, P. Lambooy, D. G. Maxwell and J. A. Nixon, (Council Members), Messrs E. L. Atkinson, I. R. Chaston, J. L. Edwards, J. S. Hall, S. A. Hancox, A. F. Lee, W. K. B. Loftus, H. S. Simpson, A. N. Shand, R. A. Wilson, H. J. Wright and J. E. Van Leeuwen. Nine Associate Members, including Messrs O. Davel, G. Douglas, P. R. Garcia, D. J. Murphy, D. Rankin, G. Schwartz, H. N. Singer, S. Thompson and D. A. Viljoen. One Graduate Mr D. Bosley. Ten Visitors, including Messrs S. Adler, C. E. Alvey, B. J. Botha, K. Chant, L. W. Davis, R. N. Guest, R. V. Keet, E. G. Keown, M. D. Lourie and S. McMurray. Secretary Mr D. C. Visser. Total present: Fourty-one. MINUTES The President requested that confirmation of the minutes of the previous meeting be held over as they would only be appearing in the Journal of the following month. Agreed. MEMBERSHIP The President: "I have much pleasure in announcing that the names of the under-mentioned candidates, having been published in accordance with By-law 5.2.2, Council has elected them to membership of the Institute in the following grades: Members: Kenneth Sinc1air Rae, Ian Robert Malcolm Chaston. Associate Members: Norman Isaac Thomas, Ian Connell Robinson. Graduates: Simon Richard Jeremy Perkins, Bleddyn Reginald Lear, David Williams. Affiliate: Richard Robert Will. Students: Angus David McElwee, Clive Renard Archer, Peter Andrew Locke. MEMBER TRANSFERRED TO A HIGHER GRADE From Graduate to Associate Member: Patrick James Burns. I welcome the newly elected members to the Institute and congratulate the member who has been transferred to a higher grade." (Applause). GENERAL BUSINESS The President reminded members that a buffet supper at a cost of 55c would be available after the meeting. PAPER FOR PRESENTATION The President noted with pleasure that a strong contingent from De Beers and the Finsch Mine were present. He expressed gratitude to Mr Loftus for coming

By O. T. Konina, V. A. Masloboev, A. V. Svetlov, E. A. Krasavtseva, D. V. Makarov, A. A. Goryachev

Dusting phenomena have been examined at the tailings storage facility of Apatit JSC Kirovsk, a mining operation located in the far north of the Russian Federation. The material composition of the tailings was identified. Existing dust suppression methods were examined. Field observations were undertaken and official data was obtained from the Murmansk Administration for Hydrometeorology and Environmental Monitoring, and analysed. A database was built for forecasting dusting according to critical scenarios in order to estimate the peak MPCs of suspended solids in the atmospheric air. Mitigation measures were formulated and recommended to the mining operation. Keywords: Mineral dust particles, apatite-nepheline ore concentration tailings, suspended solids MPC, climate change

Jan 1, 2020

By G. A. Bezuidenhout, S. Bradshaw, W. Malan

"Currently, the matted-based collection process is most widely used for platinum group metal (PGM) recovery. However, because PGM-containing concentrates are becoming more enriched with UG2 (Upper Group 2) low-grade concentrates, this is expected to be integrated or replaced with an alloy collection process.The reduction LG (low-grade) concentrates with silicon carbide (SiC) was investigated. The purpose of the study was to ascertain the feasibility of using SiC as reductant with regard to metal fall, PGM grade in the alloy, slag composition, and overall PGM recovery, and if possible, the integration of such a process in the current matte-based collection process. Rowland and Easterns LG concentrate samples from Lonmin were analysed by Xray diffraction (XRD), X-ray fluorescence (XRF), and inductively coupled plasma mass spectrometry (ICP-MS). It was found that SiO2 and MgO are the most abundant oxides and Pd is the most abundant of the PGMs. Sulphide-bearing minerals such as chalcopyrite were detected in low concentrations (below 1%), and Cr2O3 concentrations are between 2-4%. SiC reduction of Rowland and Easterns concentrate were conducted at 1600°C with reductant to concentrate ratios ranging from 2.5 to 3.5 kg SiC per 100 kg concentrate.The reduction experiments revealed that PGM recoveries from Rowland concentrate were poor. SEM images showed entrained metal prills in the slag phase. The slag viscosity at the end of the melt was calculated by using FactSage, and the results indicated that the viscosity was higher than 4 poise, which is above that of Easterns slag. PGM recoveries for Easterns concentrate were significantly better. More than 85% of the Ir and Pd and almost 60% of the Pt were recovered in a test with a reductant to concentrate ratio of 3.5 kg SiC per 100 kg Easterns concentrate. At this reductant to concentrate ratio, Fe recovery was also the highest, at 66%. SEM imaging of a slag sample revealed few or no metal prills entrained. The FeO content in the initial concentrate charge was then increased by adding Peirce-Smith converter slag in order to decrease the slag viscosity and further increase PGM recovery. A test was conducted with the addition of 10 kg converter slag per 100 kg Easterns concentrate. The reductant to concentrate ratio was kept at 3.5 kg SiC per 100 kg Easterns concentrate. The Ir and Pd recoveries were more than 95%, while Pt recovery was almost 70%. Fe recovery increased to 76%. On the basis of these results an optimum feed ratio between Easterns and Rowland concentrates and Peirce-Smith converter slag were calculated. FactSage predicted that the concentrate charge should consist of 70-80% Easterns concentrate with 20-30 kg converter slag per 100 kg LG concentrate. SiC reduction of this optimum LG concentrate charge is expected to recover more than 90% of all PGMs. Cr and Si concentrations in the alloy will be below 1% in total.The effectiveness of SiC as reductant was also compared to carbon reduction. Carbon reduction of an optimum concentrate charge at the same reductant to concentrate ratio resulted in a marginally higher metal fall than SiC reduction. However, gas emissions and energy requirements are higher for carbon reduction.The study has shown that base metals and PGMs can be recovered in an iron alloy by SiC reduction of LG concentrate with converter slag additions. Integration of such a process into the matte-based collection process could be considered as a future alternative for smelting UG2 LG concentrates."

Jan 1, 2014

By R. A. H. Lycett, P. R. Jochens, D. D. Howat

The crystallization of rutile from titaniferous slags by R. A. H. LYCETT, M.Se. (Eng.),"A.M.I.M.M. (Visitor), P. R. JOCHENS, Pr. Eng., M.Se. (Eng.) (Rand), Ph.D. (Member), and D. D. HOWAT, B.Se., Ph.D., F.R.I.C., F.I.M. (Fellow) Factors affecting the precipitation of rutile from smelter slags were investigated, with particular reference to the effect of additions of phosphorus pentoxide to the slag. The phases were identified and the phase boundaries determined for slags having phosphorus pentoxide additions of 0 to 50 per cent. The liquidus temperatures of these slags were determined, and a pseudo-binary phase diagram was constructed. Rutile crystallized as the primary phase from melts having a phosphorus pentoxide content of more than IS,S per cent. Prismatic rutile crystals whose TiO. content was more than 97 per cent were grown from melts that had a phosphorus pentoxide addition of 30 per cent. However, the morphology of the precipitated rutile was such as to make subsequent separation impracticable.

Jan 9, 1975

By W. J. Van Den Berg, J. G. Taylor

The paper discusses the introduction of blindhole boring on the South African gold mines of Anglo American Corporation. It covers the boring trials conducted, and outlines the progress made in the development of blindhole borers. The operating costs, and performances, of the latest 1,52 m diameter borer are given. Future trends and requirements In the application and design of blindhole borers are discussed, as well as factors that are of importance in the design of future machines.

Jan 1, 1978

The January General Meeting of the Institute was held in Kelvin House, Johannesburg, on 15th January, 1969 at 4.30 p.m. Mr R. C. J. Goode (President) was in the Chair. There were also present eighteen Members, including Messrs F. P. Bath, H. Britten, J. K. E. Douglas, P. Lambooy, V. C. Robinson, W. T. Stobart and P. W. J. van Rensburg (Council Members), Messrs J. C. Hall, P. C. Pirow, Dr D. I. Legge, Messrs E. R. Rudolph, H. R. Reid, Dr N. Stutterheim, Messrs B. F. van der Merwe, L. W. P. van den Bosch, D. T. Watt, M. Youngworth and T. Zadkin. Two Associate Members, Dr P. R. Jochens and Mr D. A. Viljoen. Two Students, Messrs R. P. W. Henrard and D. Ossin. Sixteen Visitors, including Messrs I. Barnes, B. F. Bath, S. Botha, P. A. du Plessis, K. Edwards, Dr F. S. Fulton, Messrs H. Grant, B. Havenga, L. Kok, Dr D. Lasar, R. Sandler, C. W. Wolhuter and J. D. Young. Secretary, Mr D. C. Visser. Total present: Forty. MINUTES The President: "May we confirm the minutes of the meeting held on the 20th November, 1968, as published in the December, 1968, issue of the Journal?" Agreed. MEMBERSHIP The President: "I have much pleasure in announcing that the names of the under-mentioned candidates, having been published in accordance with By-Law 5.2.2, Council has elected them to membership of the Institute in the following grades: Members: Basil James Jackson and James Petrie Archibald. Associate Members: Ronald Creasy, Hugh Angus McCallum and John Barton Cunliff. Graduate: Hermanus Isak Johannes van der Merwe. Affiliate: Edgar Ramsay. Student: Petrus Daniel Wolmarans. MEMBERS TRANSFERRED TO A HIGHER GRADE From Affiliate to Associate Member: Neil Bradfield and Mervyn Bayard Allman. "I welcome the newly elected members to the Institute and congratulate those members who have been transferred to a higher grade." (Applause). GENERAL BUSINESS The President: "Are there any matters to raise under this heading? If not, we will proceed to the next item on the agenda which is the presentation of today's paper."

By J. A. Theron

"This paper provides guidelines on performing mass and energy balance modelling involving coal and coal derivatives. Usually, the inputs to a pyrometallurgical process would be specified in terms of elements and compounds. Reliable thermochemical data is more widely available for species involving uniquely defined, relatively smaller molecules. However, in the case of coal, the molecules are extremely large and not uniquely defined. Consequently, modelling processes involving coal and its derivatives have several potential pitfalls. These are outlined in the present paper. The main findings are as follows:•,Coal proximate analysis should not be regarded as absolute; it could vary with several parameters, including heating rate •,For modelling, the use of ultimate analyses should be considered a preferable option to proximate analyses, where, ‘fixed carbon’ and ‘volatiles’ are not defined in terms of chemical composition •,Significant errors could be made if the larger molecules are neglected during calculation of the calorific value (CV) of coal gas (the gas liberated when coal is heated in the absence of oxygen) •,For elemental analyses, the oxygen content (which is calculated by balance) should be checked to ensure it is within the expected range •,For representation of sulphur in coal, double-counting due to SO3 in the ash analysis should be avoided •,Potentially, oxygen in coal could be represented as O2, H2O, CO, or CO2; however, use of some of these species without considering the experimentally determined gross CV results in significant errors in the energy balance. If coal enthalpy is calculated from elemental analyses without correction, representation of coal oxygen as H2O(l) gives reasonable accuracy (up to 6.9% error for a set of South African coals). Coal volatiles could be represented by a complex mixture of compounds, even using different oxygen-containing species than the abovementioned four, provided the enthalpy is corrected •,It is recommended that an ‘enthalpy correction value’ is incorporated in energy balances involving combustion, devolatilization, or conversion of coal and coal derivatives, e.g. coke, char, or tar. That would imply that proximate analysis, elemental analysis, as well as the gross CV would be required for all solid or liquid coal-derived substances being modelled. No other correction due to the form of carbon being different than graphite should be used, as that would imply doublecounting some effects."

Jan 1, 2014

By M. M. Makhofane

Anhydrous zirconium tetrafluoride can be used as a precursor for the manufacturing of nuclear-grade zirconium metal. This can be done by fluorinating plasma-dissociated zircon with ammonium bifluoride in a batch reactor. This paper describes the batch process. It was proved that anhydrous zirconium tetrafluoride can be manufactured by this route as confirmed by X-ray diffraction. The process shows potential for scaling up to the kilogram scale and possibly the tonnage scale.

Jan 1, 2012

NIM Reports Report No. 1563 Neutron activation analysis of samples from the Kimberley Reef Conglomerate. Report No. 1569 The use of DDTU as an analytical reagent for the noble metals. Special general meeting A Special General Meeting of the Institute was held in Kelvin House, Johannesburg, on Wednesday, 14th November, 1973. The President, Mr P. W. J. van Rensburg, opened the meeting at 9 a.m. and read the notice of the meeting, which was as follows: Colloquium and general meeting CONSTRUCTION OF SLIMES DAMS A General Meeting and Colloiquum on the above topic was held on November 14th and 15th, 1973, at Kelvin House, Johannesburg. Mr P. W. J. van Rensburg (President) was in the chair. The Colloquium was attended by 135 delegates and was opened by the President at 9.10 a.m. Orange Free State Branch PROCEEDINGS OF THE ANNUAL GENERAL MEETING The Annual General Meeting of the Branch was held in the Western Holdings Cant,een on Tuesday, 11th September, 1973, at 7.00 p.m. Book Review Westwood, W., and Cooper, B. S. Analytical methods in use in non-ferrous minin~ and metallur~ y: a selective review. London, Institute of Mining and Metallurgy, July 1973. 54 pp. £3.50.

Jan 12, 1973

By O. Dahl, B. Musuku, N. Schreithofer

Recovery of fine pentlandite is proving to be a challenging task in the Kevitsa sequential flotation operations, with over 60% of the nickel losses reporting into the -25μm size fraction. Since commissioning, the Kevitsa process has undergone major changes to address throughput and flotation performance. Major changes were implemented in the configuration of the milling and flotation circuits as well as in the operating conditions and reagent regime. Some of these changes improved nickel flotation while others deteriorated flotation performance. Most of the changes have had a direct impact on nickel flotation. This paper reviews the systematic analysis, laboratory testing and salient changes done to the process with special focus on the impact on the fine pentlandite flotation. Keywords: Blending, Flotation, Chalcopyrite, Pentlandite, Fines

Jan 1, 2020

By J. Petersen, A. E. Lewis, J. Chivavava

Rare earth elements (REEs) have special properties that prompted their extensive use in high-tech applications. The demand for REE has, therefore, increased over the past years, resulting in the supply risk of the materials. Extraction from non-conventional low-grade ores, like easy-to-mine ion adsorption clays (IACs), by hydrometallurgical methods is being explored to supplement the supply of REEs. The extraction of REEs from low tenor IAC leach solutions requires enrichment using cost-effective methods such as precipitation. Therefore, the aim of this study was to understand the recovery of REEs from IAC leach solutions using various reagents for precipitation. In the first part of the study, recoveries of REEs from IAC leach solutions through direct precipitation using H2C2O4 and NH4HCO3, as well as antisolvent crystallization using C2H5OH, were predicted via thermodynamic modelling using OLI Stream Analyzer. Verification experiments were then conducted through the use of an agitated reactor. Simulation results showed that high yields of REEs were possible using each of the reagents, but large quantities of C2H5OH were required. Experimental results confirmed the high yields predicted from simulations. Precipitation with H2C2O4 was found to selectively recover REEs while rejecting Al. However, utilization of NH4HCO3 and C2H5OH resulted in the co-precipitation of Al. Furthermore, the yield of Y from antisolvent crystallization was significantly lower than the theoretical value. The product recovered from antisolvent crystallization consisted of well faceted, large crystalline particles, which filtered faster than the fine, amorphous REE carbonates recovered using NH4HCO3. REE oxalates were crystalline, larger than the REE carbonates and, overall, showed the highest filtration rate.

Dec 11, 2024