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By C. O. Aksoy, G. G. U. Aksoy, A. Fisne, I. Alagoz, E. Kaya

Coal produced in underground mines is transported to the surface by means of conveyor belts throughout long roadways. The combustion of belts puts a large number of employees at great risk. Underground collieries differ from other underground mines -due to the combustible nature of the product. The most prevalent cause of belt fires in underground coal mine is spontaneous combustion due to oxidation of the coal, which also enables the conveyor belt to burn over time. In 2014, a belt fire in an underground coal mine in Manisa-Soma, Turkey caused 301 fatalities. A study has been conducted on this accident for approximately 3 years, consisting of combustion tests in a purpose-built research gallery, comparison of the test results with mine records of the accident, and CFD modelling of the mine environment. The intensity of the fire was sufficient to redirect the air flow underground, causin large amounts of toxic gases to fill almost the entire mine in approximately 15 minutes. It is recommended that CFD analysis be used in planning emergency action strategies in underground mines.

Dec 13, 2023

By O. K. H. Sheff

An editorial in the April 1990 edition of Mining Magazine is worth a wider audience in South Africa, particularly as the SAIMM enters its own centenary decade and the process of change in the minerals industry world-wide makes increasing demands on the professionalism of its leaders. The editorial considers the changing status of engineers, who up to the 1880s had been held in high regard by society. Alumina and bauxite Economists forecast a slower economic growth rate in 1990, but expect continued increase in demand for aluminum at a 3 per cent annual rate during the decade. Structural and numerical analysis Struceng & Femcad (structural analysis and finiteelement method) is a conference and exhibition that is to be held in Grenoble (France) on 17th and 18th October, 1990. It is sponsored by the Institute for Industrial Technology Transfer (ITT-International).

Jan 1, 1990

By S. Annavarapu

"Fragment size distributions play an important part in the design and planning of block cave mining operations. Though several methods have been proposed for estimating fragment size distributions in advance of mining, the calibration of these estimating procedures to field measurements has been a challenge. The Block Size Estimator (BSE) program was developed for providing an assessment of primary fragmentation expected in a block cave mine using drill-core piece length data and joint characteristics from the exploration and geotechnical evaluation programmes. In order to validate the results from the BSE program, the drill-core piece length data and the joint characteristics in different rock types from the DOZ block cave mine in Indonesia were used to help generate fragment size distributions in different areas of the mine. The predicted fragment size distributions were compared with the fragmentation observed at the drawpoints during operation of the mine.This paper presents the details of the validation of the fragment size estimates by the BSE program using fragment size distribution data from the drawpoints at the extraction level at the DOZ block cave mine, and the challenges encountered in developing reasonable correlations between the estimated and measured fragment size distributions. IntroductionThe assessment of fragmentation is an important aspect of the design and planning of the block cave mining method, and forms an integral part of the design of the excavations at the extraction level and the selection of material handling systems for transporting the ore to the processing stations. Secondary blasting requirements can also be estimated based on the fragment size distributions developed for the block cave (Laubscher, 1994).Several methods of estimating fragment size distributions in block cave mines have been developed based on joint set parameters estimated from structural data from oriented core drilling campaigns and mapping of available excavations and outcrops. The BCF program (Esterhuizen, 1999) estimates the fragmentation using a combination of empirical, analytical, and rational methods to model the behaviour of materials during the primary and secondary fragmentation processes. The program JKFrag uses advanced tessellation of joint traces to create rock blocks and then generate fragment size distributions (Brown, 2002). Nickson, Coulson and Hussey (2000) presented the details of processing of the geotechnical data from the Mont Porphyre project, including an assessment of block sizes from the data collected on the core logging sheet. The distance between natural fractures was used to create distributions of block lengths, and a distribution of potential block sizes was estimated assuming that the blocks had equal dimensions in all directions. The results agreed closely with the results of the BCF program. Hadjigeorgiou, Grennon, and Nickson (2002) demonstrated the use of oriented borehole data to provide characteristic block size distributions for a mining project using a software package called Stereoblock, which generates a three-dimensional joint network for a given volume and calculates the volumes of blocks created by the intersections of these joints, simulated as circular planes. The distributions of joint orientation and joint spacing generated from statistical analysis of the oriented core data are used for the creation of the Stereoblock model. The diameter of the circular planes representing the joints is determined based on the mean and standard deviation of the joint trace length obtained from scan-line mapping."

May 1, 2019

By K. M. Seiler

Automation in mining requires accurate maps of road networks on site. Because roads on open-cut mines are dynamic in nature and continuously changing, manually updating road maps is tedious and error-prone. This paper investigates the possibility of automatically deriving an accurate representation of the road network using GPS data available from haul trucks operating on site. We present an overview of approaches proposed in literature and test the performance of publicly available methods on GPS data collected from trucks operating on site. Based on shortcomings seen in all tested algorithms, a post-processing step is developed which geometrically analyses the created road map for artefacts typical of free-drive areas on mine sites and significantly improves the quality of the final road network graph.

Sep 1, 2021

By B. Friedrich, A. Birich

Gold has been a metal of special importance for mankind for several thousand years. Its outstanding chemical resistance is an important property of this noble metal, but becomes a disadvantage when it comes to gold recovery. The established processes are based on highly aggressive and toxic reagents. Different alternative leaching reagents with a significantly lower toxicity proved to be promising alternatives in the last decades. Major research activities in this field focused on gold ores, so that leaching of secondary resources were not described sufficiently. Based on literature research and extensive experimental investigations, a reagent assessment was conducted for hydrometallurgical gold recovery from electronic waste. It was found that besides thiourea and halides, thiosulfate in particular represents an alternative of major relevance. A variety of different electronic waste (e-waste) specimens were investigated to identify suitable leaching conditions. As a result, an almost complete and selective gold recovery in less than 48 hours from different electronic waste types and components was achieved by thiosulfate leaching. Within the experiments conducted, it was found that the leaching behaviour of cyanide alternative lixiviants differ strongly from leaching of primary ores. Keywords: Gold leaching, cyanide alternative, thiosulfate, electronic waste

Jan 1, 2020

THE THIRD INTERNATIONAL GEOCHEMICAL EXPLORATION SYMPOSIUM (Summary Account) This Symposium, co-sponsored by the Canadian Institute of Mining and Metallurgy and the Society of Economic Geologists, was held in Toronto, Canada in April, 1970. Over 700 delegates attended from 26 countries. Ninety papers were presented at the symposium and another 18 papers were read by title. The programme included: An Opening Session, Five General Sessions, a session on Remote Sensing Methods, a session on Geochemical Prospecting for Petroleum and Natural Gas, a session on Primary Halos and Lithogeochemical Methods, and a session on Statistics and Evaluation of Geochemical Data. The delegates were welcomed by Dr J. M. Harrison, President of the Canadian Institute of Mining and Metallurgy and Dr C. H. Smith, Regional Vice-President, North America of the Society of Economic Geologists. Dr D. R. Derry of Toronto delivered the opening address to the Symposium entitled 'Geochemistry-the link between ore genesis and exploration'. Dr Derry considered the various hypotheses on the origin of economic mineral deposits and expressed his belief that the next ten years will show evidence of an increased proportion of ore bodies that owe their origin, at some stage in time, to supergene agencies. He stressed that 'there are no sharp divisions between processes that form and destroy ore bodies at or near surface and those that form or destroy them at a depth of 20 kilometres in the earth's crust. The more we understand about the migration and concentration of metals the more accurately we can apply this knowledge to searching for unknown concentrations, whether at rock surface or at depth. To learn more about these processes of ore genesis we must rely on geochemical studies co-ordinated with field observations'. The five general sessions included accounts of progress in geochemical prospecting in different countries of the world, case histories describing the application of soil, stream sediment, geobotanical and biogeochemical techniques, papers on the behaviour of different elements under varied environmental conditions, discussions on analytical methods and the use of stable isotopes in mineral exploration. It is anticipated that the proceedings of the Symposium will be published late in 1970 or early in 1971 as a Special Volume of The Canadian Institute of Mining and Metallurgy. All registrants at the Symposium will receive a copy of this publication and copies will be available for purchase. At a special meeting called during the Symposium, charter members of the Association of Exploration Geochemists approved a constitution and elected an interim Council which will organize procedure and formulate policy during the coming year. The interim president of the Association is J. Alan Coope, Newmont Mining Corporation of Canada Limited, Toronto, Canada. More information on the constitution and membership in the Association will be distributed to learned societies and technical magazines in the near future. Membership will be open to exploration geochemists in all countries of the world. SOUTH AFRICAN COUNCIL FOR PROFESSIONAL ENGINEERS Report on Registration The Professional Engineers Act (Act 81 of 1968) came into force on the 14th February, 1969. At the time it was recognised that the success of the Act would depend in large measure on the extent to which engineers in South Africa would become registered professional engineers in terms of the provisions of the Act. The promulgation of the Act and its provisions relevant to registration were the subject of considerable publicity during 1969. This has resulted in a rate of application for registration far beyond the capacity of the very active committees set up for this purpose by the South African Council for Professional Engineers (SACPE). To give some idea of the task before these committees and before SACPE itself, which must ratify each case,

By W. P. C. Duyvesteyn, J. R. Cutland, J. R. L. Russell

In 1970 it was decided to build a large new plant at the Chingola Division of N.C.C.M., Ltd., to treat concentrator tailings and leach residues with a low copper content by a leach-solvent extraction-electrowinning process. In order to assist in the establishment of the design parameters for the new plant, and to study the interaction of this plant with the existing leach-electrowinning plant, mathematical models, formulated as linear programs, have been developed and used extensively. The paper outlines the metallurgy of the plants and describes briefly the way in which the models have been formulated and used. The formulation involved the use of separable programming to form the products of some variables.

Jan 1, 2014

By P. Kitobo, T. Nduba, D. Mbay, J. B. Vangu, R. Ciband

The flotation plant tailings at Kamoa Copper Mine concentrator were found to contain a high proportion of extremely fine particles. The potential issues with settling these fine solids were resolved by the use of a poly-di-allyl-di-methyl ammonium chloride (DADMAC) coagulant, Flobead DB 45 VHM, in conjunction with a standard anionic polyacrylamide flocculant. This paper outlines some of the issues encountered and how they were resolved at the Kamoa concentrator. The potential to use this process and technology at other sites is also considered

Jan 1, 2023

By C. H. Wyndham, N. B. Strydom

INTRODUCTION Acclimatization of the labour force to heat is an integral aspect of gold mining in South Africa. A recent survey revealed that about 250,000 Bantu mine workers require to be acclimatized to heat each year. Until 1965 men were acclimatized by means of one of the Chamber of Mines methods (introduced by the Human Sciences Laboratory in 1953). This type of acclimatization was carried out underground where men shovelled rock in hot stopes under careful supervision. However, it has become increasingly difficult in the last few years for mines to provide underground the conditions of work and environmental heat required for adequate acclimatization to heat. In examining an alternative to acclimatization in underground hot stopes, the Human Sciences Laboratory carried out a trial in 1965 of acclimatization in an air-conditioned climatic room on the surface of a mine. The new procedures developed from this trial have been so successful that there are today 26 climatic rooms on different mines. These rooms have been built following a design proposed by Mr Hodgson of the National Mechanical Engineering Research Institute1. Approximately 85 per cent of the total number of men being acclimatized each year are put through the new procedures in these climatic rooms. This paper gives an account of the problems which arose and how they were solved, the inter-relationship between physical conditioning and climatic room acclimatization, the prodecures developed for elimination of labourers with low maximum oxygen intakes, and the advantages of climatic room acclimatization. CLIMATIC ROOMS The majority of the climatic rooms (twenty) have been built on the surface, but a number (six) of mines preferred to establish their acclimatization centres underground in order to decrease the initial costs involved in the construction of such facilities. These underground climatic rooms are usually located near shaft stations in redundant haulages and they can accommodate from 200 to 400 labourers, thus eliminating the need for multiple acclimatization shifts. Figs. 1-4 illustrate various aspects of a surface climatic room. PROBLEMS WHICH AROSE IN INTRODUCING CLIMATIC ROOM ACCLIMATISATION There were four main problems which arose in connection with the introduction of the new method. These were: (i) The type and rate of work to be used. (ii) The air conditions required to obtain optimum acclimatization. (iii) The duration of exposure to heat each day and the total number of days of acclimatization. (iv) The methods of cooling labourers with high body temperatures. Shovelling rock would have been the desirable type of physical work to employ, but the air-conditioned space required to accommodate large numbers of men and the difficulty in standardizing the work rate in shovelling led to the decision to employ instead the work procedure used by the Human Sciences Laboratory in acclimatizing men in the Laboratory. This is the lifting of the body weight against gravity when men step on and off a bench. It has the advantage that large numbers of men can work physically at the required rate in a relatively small space (120 men can be accommodated in an area of 70 ft by 21 ft) and the cost of construction and ventilation of the climatic rooms is thereby reduced. Also the work rate can be standardized by varying the height of the stepping benches in relation to the individuals' body weights. The next problem was the air condition to be used in the climatic rooms. The Laboratory's research experience in acclimatization led it to choose an air temperature of 89°F (with the air almost saturated with water vapour) and an average velocity of air movement of 100 fpm. This air condition was combined with a work rate of 1,560 ft lb/min (oxygen consumption 1.0 litre/min) on day 1, and the work rate was increased gradually over the period of acclimatization to reach a work rate of 3,120 ft lb/min (oxygen consumption 1.6 litres/min) on day 9.

By R. Letsaole, H. Mabowa, J. Sehat, J. Tshilongo, T. Rampfumedzi, N. Ntsasa, A. Mkhohlakal1

This study explores the use of co-collectors to enhance the recovery and determination of rhodium during fire assay with lead collection, followed by acid dissolution using conventional hot plate methods. Rhodium, a critical platinum group metal, poses analytical challenges due to its low natural abundance and complex chemistry. Among the co-collectors tested, palladium and tellurium demonstrated significantly improved rhodium recoveries, ranging between 100% and 120%, whereas silver resulted in poor recovery and higher error margins. These findings highlight that co-collectors can enhance the efficiency and sensitivity of platinum group metal analysis, although their effectiveness is dependent on the chemical interaction with the target element. Acid dissolution was essential to ensure complete digestion of prills prior to analysis, enabling accurate quantification of rhodium. Overall, the findings suggest that palladium and tellurium are effective co-collectors for rhodium determination in fire assay, while silver and lead flux alone are unsuitable. This work provides important insight into optimising fire assay procedures for reliable rhodium analysis, with potential benefits for platinum group metals recovery and economic evaluation.

Mar 6, 2026

By K. Shame, H. H. Thiele

South Africa holds approximately 70% of the world’s total chrome reserves. Chromium is an important raw material for the production of stainless steel and ferrochrome alloys. Over the years, China’s ferrochrome market has been dependent on chrome ore imports from South Africa. In 2018, China imported about 75% of its chrome ore from South Africa. With the low platinum price and the rising demand for stainless steel, a growing demand to evaluate new beneficiation technologies for fine chromite was identified. Gravity separation of fine chromite (<75 μm) is inefficient, due to the limitations of the technology to upgrade fine particle size distributions. Potential for the recovery of chromite, specifically fines (<75μm), lost to UG2 PGM flotation tails, but also from MG and LG6 spiral circuit tailings exist. Flotation of podiform chromite ores from India and Kazhkhstan is successful in generating saleable product grade, following acid or alkaline flotation routes. Application to South African stratiform chromite is being evaluated, with the emphasis on evaluating reagent type, optimising dosages and the effect of pH in optimising flotation performance. Flotation can unlock additional value from chromite tailings material. The effect of ore characteristics such as gangue mineralogy, particle size distribution and headgrade are reported. The performance in terms of product quality and yield are evaluated and compared. The impact of this paper will not only prolong life of mine and increase revenue but will also alleviate environmental burdens associated with tailings dams. Keywords: Chromite, flotation, fine material, performance optimisation

Jan 1, 2020

By T. Bhambhani, J. Jankolovits

Sphalerite flotation using copper sulfate has been performed in the industry for decades and the mechanism of Cu activation is well established. Despite its ubiquity, many practical questions surrounding copper sulfate persist. It is not clear how iron selectivity is achieved in zinc circuits given the propensity of iron sulfides to be activated by copper. Also, the large variation in copper sulfate dosages across different plants and ore types cannot be explained. Lastly, Zn flotation with greatly reduced copper sulfate dosages attracts significant interest and has been demonstrated in certain laboratory settings, but no information is available on why those laboratory solutions have not been adopted in plant practice. Flotation studies are presented that demonstrate that Zn flotation with very low copper sulfate dosages is possible when using certain novel collectors that are not practised in the industry. However, these reagent schemes are impractical because of a heretofore unappreciated and critical role that copper sulfate plays in Fe rejection. With both very low and standard copper sulfate dosages, copper sulfate influences both Zn flotation and Fe rejection. The results highlight the multifaceted role of copper sulfate in zinc flotation and the need to holistically consider complex systems’ behaviour to understand flotation reagent mechanisms and optimise plant performance. Keywords: Sphalerite flotation, metal activation, copper sulfate, iron rejection

Jan 1, 2020

"Chairman: Dr W. S. RAPSON Rapporteur: Mr J. W. WILSONPapers:Computer applications in rock mechanics by F. H. Deist, E. Georgiadis and J. P. E. Moris Rock mechanics in the design of mine layouts by K. Hodgson and N. G. W. Cook Automated regulation of mine ventilation by P. NiskanenThe rock mechanics papers, because of their complementary nature, were presented in succession and discussion on both followed directly. The paper on automated ventilation control at a mine in Finland was then presented and the session was closed with several contributions to this paper.By and large the papers and discussions which followed in this session showed how a classic tie-up had developed between the use of computing techniques in important fields of mining, and their practical application. In fact, the dis-cussion following the rock mechanics papers showed clearly that without the aid of high-speed digital computers the rate of progress in applied research in deep-level hard-rock mines, would have been severely hindered. Furthermore, it became apparent from the comments made by several contributors that the rock mechanics techniques and computer progress described in Deist&apos;s and Cook&apos;s papers could be used to provide useful data in the solving of rock mechanics and design problems on mines other than flat dipping deep tabular deposits.The paper by Niskanen, which described an automated ventilation control system at a mine in Finland, showed how effective computers could be in areas where the reversal of mine ventilation occurs due to severe seasonal temperature ranges. Although the system described in the paper could not be introduced easily in complex underground mines, several contributors gave examples of similar ventilation problems that could be solved mechanically,In introducing his paper, Dr Deist said that the purpose of the paper was to give a brief account of some of the programs designed by himself and his co-authors to aid in the solution of rock mechanics problems,The first system presented by Dr Deist was known as MINSIM in the South African mining circles. This system was designed specifically to aid in the solution of rock mechanics problems in the South African gold mining industry. It was particularly designed to handle tabular deposits at great depth but it has been used satisfactorily on a number of occasions to obtain at least approximate solutions in other mining situations. Dr Deist said that the principles embodied in the programs were easily extended and, in fact, there was a project in progress at that time which was aimed to do this. He said that the principles could easily be extended to shallow-depth mining at steep or very steep inclinations."

Jan 1, 2014

By D. D. Aksenova, V. A. Ignatkina, L. A. Samatova, A. V. Lygach, E. D. Shepeta

Calcium minerals such as scheelite, phosphate, apatite are valuable minerals, which have similar flotation properties to the calcium gangue minerals. An additional problem is the fine dispersion and close mineral association of valuable and other minerals. Low polar compounds (non-ionic surfactant), such as fatty iso alcohols, neonol and phosphol, and their combinations with sodium oleate have been studied using flotation of monominerals and ore flotation; ATR IR spectroscopy and TEM for study surface of minerals; UV spectroscopy for control solubility, aggregation and de-aggregation processes. Increase in solubility of fatty acid collectors was confirmed by low soluble (heteropolar) compounds. Oxyethylated esters of phosphoric acid are adsorbed on phosphorite by -O2PO2R2 and on other rock minerals by donation of OH bond. Same effect shows difference of adsorption of fatty iso alcohols on calcite and scheelite. The different forms of adsorption of ionic and nonionic compound on a sparingly-soluble mineral surface creates distinction of the flotation kinetics and technological balance of ore flotation. The results of the separation of flotation of scheelite from calcite depend on the order of pouring into pulp of fatty iso alcohols and oleate, and their ratio in the mixture. Increasing scheelite recovery into rougher scheelite concentrate by 3.6% for both the flotation and sludge classes was obtained. Calcite recovery varied slightly upwards or downwards by 0.8-2.4%. The use of the non-ionic surfactant phosphol in combination with a fatty acid soap allows for obtaining a phosphate concentrate with more than 28% P2O5 content and almost 80% recovery in flotation operation. It is not obtainable with other reagent regimes. Keywords: Flotation, calcium minerals, oleate, fatty isoalcols, neonol, oxyethylated esters, adsorption

Jan 1, 2020

By T. N. Matveev, V. V. Getman, A. Yu. Karkeshkina, L. B. Lantsova, N. K. Gromova

Sulfide-type tin deposits in Russia are characterised by the complex mineral composition of ores and dump products of their processing. Tin-sulfide ores contain industrial quantities of copper, lead, zinc, tungsten, silver, rare and trace elements (indium, scandium, etc.). In addition, the ores are characterised by uneven dissemination of sulfide minerals (chalcopyrite, galena, arsenopyrite, etc.) and tin minerals (cassiterite, stannine, etc.). X-ray phase and spectral analysis, scanning electronic microscopy (SEAM), laser SIM and AFM microscopy helped to identify the selective fixing of sodium dibutyl dithiocarbamate (DBDTC) on chalcopyrite and galena, as well as the tall oil fatty acids (TOFA) and IM-50 on cassiterite. For the first time, collectors and flocculants of slurry fractions of silver and tin, thermomorphic polymers TMPF were used to isolate more than 80% silver from the tin tailings of the Solnechny mine into a copper-silver rough concentrate. It has been established that preliminary ultrasonic treatment and desliming according to the 0.02 mm class removes up to 20% of sludge material, which impairs the process of gravity separation. The combined flotation-gravity scheme using new reagent compositions helped to obtain tin concentrate with a tin content of 5.42%, which meets the requirements for further metallurgical processing (at least 5%). This work was supported by the RSF according to the research project No. 17-17-01292. Keywords: Flotation, flotation reagents, tin-sulfide ores, casiterite, adsorption, flocculation

Jan 1, 2020

By J. J. Cilliers, I. K. Craig, J. D. le Roux, K. Hadler

An analysis of the state-observability characteristics of a dynamic tank-to-tank model of a flotation bank indicates that the concentrate-flow rate of each tank can be estimated from accurate measurements of the pulp height in each tank and the final tailings flow-rate exiting the final tank. Therefore, there is an opportunity to construct an observer (model-based soft-sensor) which can estimate the concentrate flow-rate of tanks in a flotation bank. The concentrate flow-rate, i.e. mass pull, is generally measured by means of froth image analysers on industrial plants. A model-based soft-sensor will not only provide a means to validate froth image analyser results, but could potentially substitute them as they are less expensive to implement and maintain. Keywords: Concentrate flow-rate, estimation, flotation, modelling, observability, soft-sensor

Jan 1, 2020

1. Book review . Australasian coal mining practice, edited by C.H. Martin. Reviewer: R.B. MacGilIivray This book is an extremely comprehensive coverage of coal-mining practice in Australasia, the countries covered being Australia, New Zealand,and Papua New Guinea. 2. From The Institute of Metals The folowing are available from The Institute of Metals, 1 Carlton House Terace, London SWl Y 5DB. Physical and elastic characterisation, edited by M. McLean. 1989. 228 pp. £25.00. High nitrogen steels, edited by J. Foct and A. Hendry. 1989. 461 pp. £49.50. Proceedings of the First International Calcium Treatment Symposium. 1988. 116 pp. £15. New cored-wire injection techniques, particularly as Design for recyc/ability, by Michael E. Henstock. 1988. 150 pp. £15. Solidification processing. 1988. 549 pp. £45. Marine engineering with copper-nickel. 1988. 103 pp. £18. Characterisation of High Temperature Materials. 3. New journal FMJ International Publications Lid have announced a new quarterly publication, Aluminium Today. 4. Other new publications Algorithms in real algebraic geometry, edited by Denis S. Arnon and Bruno Buchberger. London, Academic Press, 1988. 274 pp. £15.95. Proceedings, Foundry and Heat Treatment 88. R150 per set of 5 volumes, or R40 per volume.

Jan 1, 1989

Notices COMPETITION FOR STUDENT MEMBERS OF THE SOUTH AFRICAN INSTITUTE OF MINING AND METALLURGY Each year the Institute offers a prize (or prizes should the entries warrant it) of up to RlOO for the best paper or dissertation on a topic appropriate to the interests of the Institute. The competition is open to all Student Members of the Institute. APPLICATION AND PRACTICAL OPERATION OF HYDROCYCLONES Dr H. F. Trawinski of Amberger Kaolinwerke, Hirschau, West Germany, gave a very interesting lecture on this subject to an audience of over one hundred, composed largely of members of the Institute, on 15th August, 1973, at the University of the Witwatersrand. ROTARY INTERNATIONAL Applications are invited before 15th March, 1974, for the following awards of The Rotary Foundation: Post-graduate Fellowships Under-graduate Scholarships Awards for Technical Training Awards for Teachers of the Handicapped. NIM REPORTS Report No. 1509 The instrumentation developed for electrochemical studies of the le(Whing of uranium dioxide. Report No. 1550 A fundamental study of the dissolution in (Wid solutions of uranium minerals from South African ores. Report No. 1552 The preparation and analysis of minerals for use as reference material.Progress report No. 2. Report No. 1556 The spectral analysis of solutions.2. The analysis of leach liquors, concentrates, slags, and residues. Report No. 1559 A cost assessment of the production of elemental sulphur by chlorination roasting. Report No. 1562 Application of a flotation model to an industrial plant

Jan 11, 1973

By Ronald J. Roman

All mining and milling complexes can, within limits, operate at a variety of production rates. Factors of economic importance that are affected by production rates are costs per unit production, recovery and product grade. Once the relationship between the production rate and cost is established, dynamic programming techniques can be used to define the optimum production schedule (that is, the production schedule that maximizes the present worth of the operation) for the life of the deposit. In general, assuming that the capacity and efficiency of the physical plant remain unchanged throughout the life of the deposit, the optimum production rate is not constant for the life of the deposit, but declines gradually as the deposit is being exhausted.

Jan 1, 2014

By Y. Jiao, V. S. Thompson, D. W. Reed, Y. Fujita, J. E. Aston

Rare earth elements (REE) are vital components in modern electronics and green technology products. Supply is tight and global demand is expected to increase, leading to high risk for the economic and national security of countries largely dependent upon foreign supplies. Recycling of REE from consumer and industrial waste materials is a possible way to help meet demand. We have shown previously that biohydrometallurgy can play an economically and environmentally sustainable role in REE recycling, particularly if agriculture or food wastes are used to produce organic acid bioleaching agents. A challenge for organic acid-based bioleaching is the incomplete conversion of the carbon substrate to an optimal organic acid biolixiviant with high REE extraction capability from a variety of REE-containing feedstocks (e.g., mining wastes, magnets from end of life products, spent batteries, etc.). To help meet this challenge a metabolic model was developed for Gluconobacter oxydans to identify options for improving sugar conversion to organic acids. Model predictions were consistent with laboratory data for the microbial consumption of glucose and production of gluconic acid, and suggested that providing growth conditions with relatively high C:N molar ratios could result in lower pH biolixiviant production and thus improve bioleaching. Keywords: Gluconobacter oxydans, bioleaching, metabolic modelling, rare earth elements summaries 2019: U.S. Geological Survey, 200 p., https://doi.org/10.3133/70202434.

Jan 1, 2020