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By N. B. Strydom, P. L. Jooste, H. F. Kotze, W. H. Van Der Walt

Note: A revised method of heat acclimatization by N. B. STRYDOM, W. H. VAN DER WALT, P. L. JOOSTE, and H. F. KOTZE INTRODUCTION Climatic-room acclimatization was introduced in the gold-mining industry in 1965 and was rapidly adopted by all mines because it reduced the number of days required for heat acclimatization from 12 to 8. The method has been adequately described in previous papers1, 2 but, briefly, requires four hours of heat exposure per day while the work rate is progessively increased from 35 W on Day 1 to 70 W on Days 7 and 8. Several attempts to shorten

Jan 6, 1976

By R. C. J. Goode, W. S. Rapson, W. R. Lawrie, L. W. P. Van Der Bosch

W. R. Lawrie (Member): As all the Institute members present are aware, the Ninth Commonwealth Mining and Metallurgical Congress was held in Great Britain from 3rd to 24th May, 1969. The Congress opened in London and the first week was devoted to technical sessions. Several receptions and other forms of entertainment were held in the evenings. The Congress was attended by some 1 200 delegates, many of whom were accompanied by their wives. As can be imagined a large organisation was needed to cater for all the whims of these delegates, to arrange accommodation and to provide transport for the technical trips, for the receptions and for the sight-seeing tours. Papers presented at the technical sessions proved of great interest. It was stimulating to hear of the developments taking place in the various branches of mining and metallurgy. The discussions which developed between men from so many different countries were thought provoking, led to new friendships and most of us made valuable contacts for the future. There were 141 papers presented in the one week. They were given in four separate halls with two, three and sometimes four papers coming up for discussion in each of the three sessions per day in each hall. Among the more interesting subjects were those concerning off-shore drilling and the facilities for production of petroleum and natural gas. Beach mining at Consolidated Diamond Mines drew a large audience. Automation, mechanization and other technical developments were well described and we were brought up to date with modern techniques of mineral prospecting. There was general discussion on the future of the mineral industries together with comments on the consumption and price trends of these metals and minerals. The future of uranium, of vital interest to us in South Africa, came in for much debate. During the first week, besides attending the technical sessions and seeing some of the sights of London, we were royally entertained. There was a banquet, attended by some I 400 people, where we were welcomed by Princess Alexandra, a reception by H.M. Government in the Banqueting House, and we were entertained at the House of Lords on a terrace overlooking the bustling and rather muddy river Thames. Then there was the visit to the Glyndebourne Opera. It is only in London that at 3 o'clock of an afternoon, nearly 1 000 people all togged up in dress suits and long dresses and carrying packets of sandwiches for supper could arrive at a station to catch a train, and not even cause a stir of interest or a raised eyebrow! This is the way we travelled 60 miles to the opera from London. Surely there can be no more picturesque or romantic a setting for an opera than this large 400-year old red brick manor house nestling in the green valleys of the unspoilt Sussex countryside. It was a glorious evening and though we returned somewhat late and tired, not one of us would have missed this experience. After the first week in London there was a choice of tours of one week to London and the Home Counties, Cornwall, a Geological tour to Scotland, South Wales, and North England. These were followed by further one week tours to Yorkshire and Lancashire, Scotland, West Country and Midlands, a Geological tour of Wales, and a Mining and Geological tour to Jurassic Iron Mines. We then returned to London for the final session and closing banquet. Post-congress tours were arranged to Europe and to Ireland. It was a wonderful Congress, a great experience, we made many friends and may there be many more congresses! . L. W. P. van den Bosch (Member): Much has already been said in appreciation of the excellent organisation and arrangements made for the delegates who attended this Congress. This report is confined to a brief discussion of the personal impressions gained from the papers presented and the technical visits attended. The papers covered a wide variety of subjects ranging from highly theoretical observations to practical descriptions of operations. There were three main themes, VIZ: 1. The attention given to research and its forceful application to practical operation. 2. A steady development in mechanization and automation leading to savings in manpower. 3. Improvization, modernization and adaptation of exisitng facilities. Thoughts on these themes can best be illustrated by comments on some of the industries visited. COAL The National Coal Board (N.C.B.) has been most progressive and all of us have heard of the Bevercotes Colliery with its completely automatic mining and coal handling equipment. This was not, unfortunately, on show but there is no doubt that this is one of the greatest advances in coal mining leading towards continuous production. Coal in Britain is fighting for its life against oil, North Sea gas, imported gases and nuclear power. Output is dropping, the less efficient collieries are closing down and efficiencies are steadily rising as the following tabulation indicates: In 1931: 1 million men produced 300 million tons of coal In 1947: 0.7 million men produced 230 million tons of coal In 1968: 0.4 million men produced 160 million tons of coal

By J. Saunders, N. Pretorius, G. Krafft, T. P. Katakwa

Imagine being able to see all the future planned mining activities in real time. This is exactly what SIMS (Short Interval Management System) will enable you to do. SIMS is a real time short interval control system that continuously measures and sets optimised plans for mining production processes. The system utilises algorithm-based software that takes resources (people, equipment, tasks, and workplaces) and gives you the best achievable plan. The algorithm was developed using methods found in the field of metaheuristics. A metaheuristic is a strategy to designed to efficiently search for optimal or near optimal solutions to problems that are very complex computationally. (Glover, 1986) There are several algorithms that have been developed to solve optimisation problems which are difficult to solve using traditional techniques. This has given rise to a field called evolutionary computing. (Simon, 2013) Examples of these techniques are genetic algorithms, particle swarm optimisation, and ant colony optimisation. These methods are used to solve problems in a variety of fields. As an example, Kok and Lane (2012) used particle swarm optimisation for equipment allocation in a mechanised underground mining environment. The first SIMS deployment took place in a platinum underground tabular mechanised mine near Burgersfort (province?) from 2017-2019. This included the development from a paper-based system to a fully operational online system. SIMS then moved to a second site and is currently being tested in a second platinum underground tabular mechanised mine in South Africa. Full deployment of the system is currently being phased in. SIMS was built in response to issues that have been plaguing the mining industry for years. These issues are all aligned into one major problem statement: how can we optimise mining production processes without compromising safety? This product was developed by combining years of mining experience with software development. SIMS is based on a four-pillar concept. Safety, productivity, accountability, and business improvement. SIMS uses a set of pre-configured mining and production rules, and with the resources that are available, to determine valid short term production plans. A background algorithm then determines the optimum plan to be executed. The system continuously produces a set of job cards that are pushed to respective operators on their allocated tablets. The management portal component allows you to view and manage all current and planned work on any connected device available. This allows real time visibility of completed, current, and planned work to operators, service departments and management, i.e., seeing into the future.

Sep 1, 2021

By K. Dewar

The catalytic converter industry is composed largely of global multinational manufacturers who supply to vehicle manufacturers (original equipment manufacturers ? OEMs) from facilities strategically located internationally, including plants in South Africa. The South African catalytic converter production facilities were established at the request of the OEMs and commenced manufacture in the early 1990s. This near 100 per cent export focused industry exists in South Africa because of the incentives offered by the Motor Industry Development Programme (MIDP), which ultimately provide the OEM with import duty rebates. The South African catalytic converter industry is a complex vertically-integrated supply chain with a local content in excess of 85 per cent, substantially more than any other exported automotive component. The industry remains one of the very few downstream manufacturing industries where South Africa has a significant global footprint. This is even more important when it is considered that this industry is the key end-user for two of South Africa?s most important mineral resources, namely platinum group metals (PGMs) and chromium, and is in an industry which will see massive global growth as the developing nations of the BRICs grow their auto industries. In over 15 years of existence in South Africa, the catalytic converter industry has achieved remarkable growth, averaging compound growth in the region of 14 per cent per annum. The industry is the highest contributor to automotive component export revenue. South Africa holds >8 per cent% of global PGM reserves. During 2011, South Africa supplied 59 per cent, 29 per cent, and 72 per cent of the global demand for platinum, palladium, and rhodium respectively, as well as over 50 per cent of the global chromium demand. Global autocatalyst production remains the largest consumer of PGMs, and South Africa alone beneficiated 15 per cent of locally mined PGMs in the production of catalytic converters ? all is converted from PGM sponge (powdered metal) into PGM solutions for coating onto catalysts. Beneficiation of PGMs also takes place via the production of jewellery and electronic goods; but compared to catalytic converters, this volume is negligible. The industry is also the largest consumer of locally produced stainless steel (>50 000 t/a), exceeding 38 per cent of local consumption. The industry is a substantial generator of highly skilled employment, with over 5 000 direct jobs (excluding OEMs and stainless steel manufacture) and an estimated more than 30 000 indirect jobs resulting from upstream and side-stream suppliers. The industry places a high focus on skills transfer and development, with all companies providing high-tech training and education both locally and overseas. The industry has invested in excess of R5 billion in plant, equipment, people development, and process development over the last 15 years to support transfer of production and new technologies to South Africa. This has resulted in significant skills development in the support industries as well as within the catalytic converter industry. The current projections for local PGM beneficiation via catalytic converters reflect a downward trend as a result of production being moved to other global locations due to uncertainty around changes to government incentive programmes. The industry is currently capacitated to support 23.7 million units per annum. During 2011 it utilized about 70 per cent of this capacity, but forecast projections suggest that this will be at 46 per cent of this level by 2016. At full capacity the industry would represent 19 per cent of global autocatalyst production compared with the current 13 per cent in 2011. The industry believes that there is potential to make South Africa the preferred location for catalytic converters worldwide, given suitable support from the mines and Government.

Jan 1, 2012

"Chairman: Professor B. W. MacKenzieRapporteur: Professor D. A. PretoriusPapers:Optimum spacing for soil sample traverses by W. A. HodgsonEvaluation of geochemical data by C. J. LenzResearch in oil exploration decision-making by J. W. Harbaugh and A. Prelat A drill hole data bank by M. R. AndertonOre reserve estimation and depletion planning for a beach diamond deposit by M. M. OosterveldIn opening the session, the Chairman indicated that the papers and discussions would revolve about quantitative methods of analysis and optimization of various aspects of exploration planning. The five papers would cover a wide range of topics within a general theme of exploration analysis, and it would be appropriate, therefore, to present the. papers as representing a sequential information-gathering process, namely, (i)geochemical and geophysical types of surveying for the location and identification of anomalous zones, (ii) tren¬ching and drilling of the anomalous zones found, and (iii) further refinement of the data for ore reserve calculations and production planning.The first paper, which was presented by Dr W. A. Hodgson, dealt with the optimum spacing between soil sample traverses conducted during geochemical prospecting. The theme of the paper was that the critical sampling interval should be based on the concept of element continuity, and that this interval could be determined by means of a correlogram. Ensuing discussion concerned the probability of the method, designed for areas where dispersion was high, working in localities where dispersion was either low or virtually non-existent. In the latter eases, specific orientation surveys for varying topographic, climatic and geological conditions would possibly be more useful than the preparation of correlograms. A further suggestion was made that cost versus risk should be taken into consideration when deciding upon the spacing between traverses. A balance could be struck by mathematical optimization. If the exploration budget was fixed, then the variance of risk could be minimized.The second paper was a short contribution by Mr C. J. Lenz. Computer-based plotting and evaluation of geochemical prospecting results were carried out because the low cost of analysis in Rhodesia permitted very large volumes of data to be accumulated in mass-coverage operations. Anomalous areas were demarcated within different environments by selecting probability or population boundary values from frequency distributions. In the short discussion which took place it was debated whether the method should be used only in the early high-risk stages of geochemical exploration and whether the introduction of geological bias could influence the actual results of an exploration program."

Jan 1, 2014

By P. Ramphisa

In South Africa reprocessing used oil into industrial fuel is commercially attractive. The reprocessed product is sold as a substitute for heavy fuel oil that is derived from crude oil (Rose Foundation, 2008). The objective of this investigation is to evaluate the use of petroleum products such as oil, petrol and diesel in Driefontein Gold Mine. The recovery of oil through recycling has costs implications to the mine while the release of petroleum hydrocarbons due to the poor management of the use of petroleum products has potential to cause pollution and negatively affect soil and water. Environmental legislation such as the Minerals and Petroleum Resources Development Act (Act 28, 2002) requires that such negative impacts to the environment be rehabilitated. The rehabilitation cost of pollution caused by petroleum products to the environment increases operational costs in business. Field assessment is conducted to identify the main sources of petroleum product contamination such as leaks in piping, overfills and petroleum spills. The areas that require mitigation would be mapped in the study. Recommendations for mitigation measures will focus on using the best practicable environmental option (BPEO) as well as the best available technology not exceeding excessive cost (BATNEEC). The recovery of oil from the mining industry is generally low and very poor. In this study, the effect of proper management of petroleum products to the mine?s operational costs is investigated and compared to there mediation costs of the impacts caused due to poor management of these products. The study investigates the financial benefit that could be obtained from proper environmental practices and efficient usage of petroleum products in the mining.

Jan 1, 2009

By D. T. Jordan, L. C. Coetzee, G. Kalenga, T. Mahlangu, W. J. Shipman

Although online free cyanide analysers are widely available and used in gold leaching operations worldwide, reliable automated free cyanide concentration control is not consistently achieved in many of these operations. Effective cyanide concentration control is complex owing to amongst others, the long residence times and ore feed variations. Model Predictive Control (MPC) has been proven to provide superior cyanide concentration control over traditional proportional-integral-derivative (PID) control, leading to savings in operational costs and reduced leachable gold losses. In the first example reported in this paper, MPC has improved control of the free cyanide concentration by keeping it within the required range 73% of the time during testing, compared to the previous PID controller that only achieved this target 30% of the time. This represents a 143% improvement. Another example demonstrates a 22% reduction in cyanide usage as a result of using MPC. MPC functionality is rarely available on the programmable logic controllers (PLCs) and control systems installed at gold plants, hence it is implemented on a personal computer (PC) networked to the cyanide analyser and plant infrastructure. Mintek has developed an embedded MPC that installs into the Mintek Cynoprobe analyser, adding MPC functionality without the need for additional PC and network infrastructure, reducing installation costs. This allows plants to minimise their expenditure on additional infrastructure while gaining the benefits of superior MPC technology for multiple cyanide dosage points. This paper will present results showing that the embedded MPC performs as well as Mintek’s existing PC-based StarCS MPC controller, making it a viable alternative for infrastructure-constrained gold plants. Keywords: Model predictive control, gold cyanidation

Jan 1, 2020

By S. J. Webber

This paper reports on the use of the MINSIM-D stress-analysis program for the modeling of two large seismic events that occurred on the same fault eleven years apart. It was found that the first event (magnitude 5,2) could not be ascribed to purely mining-induced stresses, indicating that the largest seismic events probably result from the interaction of mining-induced stresses with large scale tectonic stresses. However, the stress changes induced during eleven years of mining were found to be capable of generating sufficient excess shear stress (ESS) to be responsible for the second event (magnitude 4,3), The upper limit for the magnitude of purely mining-induced events was found to be approximately 4,3.

Jan 1, 1990

By L. Ozdemir, B. Asbury, T. G. Rozgonyi

A new type of bit, that has been developed and is being evaluated, shows great potential in expanding the range of rock strength that can be cut by continuous miners and roadheaders. This new style of bit is called the frustum. The tools tested in this program were developed, manufactured and patented by Briese Industrial Technologies, Inc. The frustum derives its name from the unique geometric shape of the cutter, or cutting insert. The frustum shape cutting tool has previously been proven as an effective cutting tool for machining metals, metal matrix composites and polymers. The frustum rock bit has a very dense carbide frustum shape tip mounted on the end of a steel body similar to the conical bits typically used on continuous miners and roadheaders. In between the carbide frustum cutting tip and the steel body there can be a bearing that allows the frustum to rotate around the bit axis. When the bit is forced into the rock at a skewed angle, the frustum tip rotates as it travels. This rotation greatly reduces the cutting forces acting on the bit when compared to the current state of the art conical drag bits. This cutting force reduction, derived from the frustum’s cutting action, allows for much harder and more abrasive rock to be cut without quickly wearing out the bit. Full scale laboratory cutting tests have been performed with the frustum bit in direct comparison to the current state of the art conical bits. Field trials of the frustum bit are currently being planned. Test procedures, results and findings are presented.

Sep 1, 2001

By P. J. D. Lloyd

The Federation of Societies of Professional Engineers (FSPE) recently conducted a survey of professional engineering manpower in South Africa. This article presents the data relevant to mining and metallurgical engineering. FSPE in their survey attempted to determine the supply of engineers in South Africa both from local universities and by immigration. The immigrants gave some problems in that it is difficult to know whether a man who claims to be professionally qualified really is. However, it was estimated that the ratio of immigrants who claimed to be qualified to those who really are the equivalent of our local graduates was between 1,0 and 1,9 for mining engineers, and between 2,0 and 4,1 for metallurgical engineers.

Jan 1, 1980

National Coal Board. Gate belt conveyors. London, H.M.S.O. (Price 95p.) Although the preface of this handy little book states that it has been written for the guidance of miningoperation trainees, it will prove valuable to the practising engineer as well. NIM reports Report no. 1733 A mineralogical investigation of weathered carbonatite from Salpeterkop. (14th Apr., 1975; re-issued 28th Feb., 1978). Report no. 1823 The recovery of gold and pyrite from a residue dump at Crown Mines. (10th Jul., 1976; re-issued 28th Feb., 1976). Report no. 1829 An investigation of weathered carbonatite from Salpeterkop. (20th Jul., 1976; reissued 28th Feb., 1978). Report no. 1932 A BASIC computer programme for the evaluation of intensity data from the Telsec Lab-X-250 Analyser. (12th Jan., 1978). Report no. 1940 The extraction of the noble metals with n-octylaniline,and its application to the analysis of platinum-bearing materials. (30th Jan., 1978). Report no. 1945 Analyses of the NIMROC reference samples for minor and trace elements. (28th Feb., 1978). International futures conference A conference entitled 'The Road Ahead' is being organized by the 1820 Settlers National Monument Foundation to be held in Grahamstown from 3rd to 7th July, 1978. Conference of metallurgists The technical programme has been established for the 17th Annual Conference of Metallurgists sponsored by the Metallurgical Society of the Canadian Institute of Mining and Metallurgy. This year the Conference will be held in Montreal, Quebec, on 27th to 31st August, 1978, together with the 8th Hydrometallurgy Meeting.

Jan 1, 1978

The general standard of engineering in South Africa will, it is believed, reach new heights after the establishment of the S.A. Council for Professional Engineers (SACPE) in February, 1969. The Council is being created to establish standards for professional engineers in this country and ensure that the quality of engineering is maintained at a high level. In terms of the Act of Parliament under which the new Council will operate, all consulting engineers will have to be registered if they wish to remain in private practice. While engineers who are not in private practice cannot be compelled to register, it will be in their interests to do so, according to a statement issued by Mr M. R. Gericke, chairman of a Shadow Council which is at present preparing for registration and drafting the requirements for registration. Registration is seen as an important move towards maintaining the quality of engineering in South Africa. Engineers will be encouraged to strive for professional status by gaining the necessary qualifications and the varied range of experience required by the Council before registration. All work done by registered professional engineers will have to conform to certain minimum standards. A spokesman for the Council has urged all engineers to ensure that they apply for registration when the Act comes into force in February. The Council is also anxious to gain the co-operation of employers in ensuring that the holders of professional engineering posts will be registered. Full information regarding registration will be sent to engineers throughout South Africa early this year, and announcements will appear in the press.

By I. E. Teymenson, N Fedunets

Mining-metallurgical complex is the base of any economics and influences directly on practically all branches of world economics. Therefore the task of estimation and selection of investment decisions in mining industry adequate to modern market conditions and the task of decreasing multidimensional alternatives selection uncertainty are very actual. An uncertainty of investment alternatives is explained by a number of reasons, main of which are a presence of several investors types, an unstable situation on the market and an absence of evident relations between appraisal criteria used. Maximum increasing of formalization and objectivity of information technologies applied for an estimation permits to reduce the uncertainty of investment variants estimation. A number of principled innovations, allowing to solve the task of decreasing of multidimensional alternatives selection uncertainty, are introduced into the information technology of estimating and selecting investment decisions in mining-metallurgical branch, developed by us. In the article the necessity of including a cognitive model into developed selection mechanism, which allows to take into consideration inter-influences of used critera, has been grounded. Besides, the forecasting model considering interconnected time rows has been applied for increasing the world conjuncture forecast quality. Further in the article main metrics types have been characterized and application of weighted Chebyshev’s metrics as the most compromised from all studied metrics for variants selecting has been proved, and also the developed procedure of directional search of effective compromise decisions has been described. Brief characteristic of designed instrumental means of multi-criteria variants estimation and selection finalizes the article. In conclusion expedience and efficiency of using the developed information technology for reduction of multidimensional alternatives selection uncertainty have been grounded.

Jan 1, 2003

By C. M. Rule

High pressure grinding rolls (HPGR) technology has come a long way in its application for comminution duty in hard rock mineral processing in the last three years. Several major projects in copper, nickel, gold, molybdenum, platinum, and iron ore have opted for this technology. Advances in wear abatement technology have established the HPGR as a reliable machine with the required high utilization and availability. The HPGR captures the imagination as the next step change improvement in ore processing, based on the following benefits: ?Energy efficiency (potentially 10?30% more efficient)?very topical in an increasingly ?green? society, and in times of rapidly increasing energy costs and availability concerns. 2008 has shown this to be especially important in Southern Africa ?High (and stable) throughput with a relatively small footprint ?Lower operation cost ?Liberation benefits ?Creative ?mine-to-metal? system improvements made possible by HPGR. The platinum industry, renowned for its historically conservative approach, has not been left behind with two significant new HPGR installations, one in Platreef application and one in UG2 application, commissioned in 2008. While the decision for the Platreef application was driven primarily by comminution circuit capacity and design imperatives, the UG2 application seeks to develop a flowsheet that will have a significant recovery benefit in addition to capacity increase and reduced operating cost. The Platreef application of HPGR also provides the opportunity to introduce a novel comminution flowsheet and to demonstrate exceptionally low wear rates treating very hard, abrasive and variable ore types. The HPGR lends itself for inclusion in existing SABC circuits to increase the capacity of the plant and mills. With current PGM prices many operations are attracted to the HPGR technology benefits. The HPGR clearly has the potential to transform entrenched opinion and provide decision makers with significant alternative comminution options. This paper aims to provide an overview of the current applications and to speculate on the transforming stimulus that the HPGR exerts on industry.

Jan 1, 2009

By G. M. Evans, S. Mitra, G. J. Jameson, M. M. Hoque, E. Doroodchi, R. Moreno-Atanasio

In this study, the detachment behaviour of 314 μm diameter silica particles from a single 3 mm diameter bubble rotating in a confined cavity connected to a cross-flowing water channel was investigated. The liquid cross-flow generated a rotating flow inside the confined cavity, which was quantified using 2D particle image velocimetry (PIV) measurements. The fluctuating (x-y) velocity components inside the cavity for each cross-flow velocity, U, were then used to estimate the corresponding time/volume average turbulence intensity values, Ti. Turbulence intensity ranged from 9.3-16.2%. In the absence of a bubble, the rotating vortex within the cavity created a pressure field which decreased towards the centre of the vortex; wherein the lowest pressure zone was located at the centre of the cavity. The vorticity into the cavity was found to increase with increasing the turbulence intensity. A bubble, both without and with particles attached, was introduced into the cavity under different flow conditions and its motion was tracked using the shadowgraphy technique. Experimentally, it was found that the bubble-particle aggregate was trapped at the centre of the cavity (low-pressure region) following a spiral trajectory. An interface resolved 3D computational fluid dynamics (CFD) model was developed to predict the particle detachment conditions within the confined cavity. CFDpredicted vorticity in the absence of a bubble agreed well with experimental observation. The CFD analysis indicated that the vorticity inside the cavity was not significantly changed when a single bubble was introduced. On this basis, the computed vorticity was utilised in describing the force balance applied to the attached particle. Computationally, it was found that the critical turbulence intensity, beyond which the particle was detached from the bubble, was 14%. This value was consistent with the experimental observation of detachment at Ti at 15.7%, and above, but not at lower values. Keywords: Bubble, particle, turbulence intensity, vorticity, particle detachment, CFD, PIV

Jan 1, 2020

By A. Fouchee, N. Naudé, K. Schommarz

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

Jan 1, 2016

By K. Forsberg, Ş. Kaya, C. Dittrich, M. Svärd, E. M. Peters

Scandium can be recovered from waste streams of other metallurgical processes such as red mud from the Bayer process and titanium dioxide acid waste. This is accomplished by an integrated process comprising leaching using acidic media, solvent extraction using organic solvents and stripping of Sc from the organic phase using NH4F solutions. The precipitation of scandium as (NH4)3ScF6 from NH4F strip liquors has been demonstrated at lab-scale with recoveries and purities greater than 98% and 98.3%, respectively. It is desired to assess the possibility of recovering the solvents for re-use in the process to improve its economy and environmental friendliness. Investigations have been conducted to recover alcohol by simple distillation from strip liquor-alcohol mixtures containing about 50 v/v% alcohol. The mixtures were obtained after anti-solvent precipitation of (NH4)3ScF6 using an alcohol to strip liquor volumetric ratio of 1:1. The starting strip liquor contained about 2000 mg/L scandium in 3 mol/L NH4F solution. In the recovery of methanol, the first distillate product collected had a purity of about 87 v/v% and this decreased slightly with time over two hours. The methanol distillate collected in the first 30 minutes with a purity of ca. 85 v/v% was re-used in anti-solvent crystallisation of (NH4)3ScF6 from the initial strip liquor, and the scandium recovery attained was about 98.6 w/w%, almost similar to that of 99.2 w/w% obtained using 100 v/v% methanol. For ethanol recovery, the first distillate product collected was approx. 84 v/v% pure and the distillate collected in the first 30 minutes with a purity of about 75 v/v% achieved a scandium recovery of about 97.2 w/w% in comparison to 98.5 w/w% obtained using 100 v/v% ethanol during anti-solvent crystallisation. Keywords: Alcohol recovery, methanol, ethanol, anti-solvent crystallisation, (NH4)3ScF6

Jan 1, 2020

By M. R. Khalesi, S. Arfania

"Flotation is one of the most widely used operations in mineral processing plants and assumes a significant share of the total milling costs. The purpose of this paper is to introduce a new set of capital and operating cost models for major flotation machines based on the application of single (SRA) and multiple regression analysis (MRA). Thirty-seven major flotation machines were analysed for this purpose. Depending on the machinery type, different technical variables such as diameter, required air flow rate, required floor space, cell volume, required air pressure, and power were considered as predictor variables, individually (in SRA) or simultaneously (in MRA). Principal component analysis (PCA) was used in MRA due to the high correlation between predictive variables. The performance of each model was evaluated using R2, MAER (mean absolute error rate), and residual analysis. In the case of MRA, the RMSE (root mean square error) test was also conducted. Maximum obtained MAER of 13.5% and minimum R2 of 0.86 indicated that these models could be applied as credible tools in estimation of capital and operating costs of flotation machines for design and feasibility studies.IntroductionMineral processing is a vital part of mining projects and mainly involves comminution, sizing, concentration, extractive metallurgical processes, and dewatering. Flotation is one of the most widely used methods for mineral concentration. Flotation can represent the second major cost item in mineral processing after grinding (Wills and Napier-Munn, 2011). Accordingly, it is a main concern of mining project managers to select and optimize flotation circuits in order to decrease costs and increase productivity. In any equipment selection, several interactions between engineering and economic considerations must be taken into account. Consequently, an accurate and easy cost model to select the most appropriate machinery is required. Moreover, cost models could be used in flow sheet simulations applied in design and optimization. Models of unit operations built into the simulators could be improved by linking the equipment cost models (Khalesi et al., 2015)."

Jan 1, 2017

By I. Zh. Bunin, M. V. Ryazantseva, V. A. Chanturiya

The paper proposes a new method for selective calciferous separation. The effect was achieved through the application of the combination of high-power electromagnetic pulses (HPEMP) and a specific reagent regime of the flotation. The combined application of HPEMP with the special reagent regime allowed for the improvement of the scheelite floatability: the recovery of CaWO4 rises from 41.2 % (untreated sample) to 58.5 (sample treated at 103 pulses). In contrast, the floatability of calcite decreases significantly: the recovery of calcite drops from 74.7% (untreated sample) to 41.1 % (sample treated at 103 pulses). The conditions were found for the selective separation of the minerals with very close flotation properties. Keywords: Calcite, scheelite, flotation, high-power electromagnetic pulses, DRIFT, XPS

Jan 1, 2020

By M. A. Roberts

Oebswana's Jwaneng Mine (south-central Botswana) is the richest diamond mine? in the world and has been contributing substantial revenue to Botswana since the mine started operating in 1982. The resource consists of 3 separate volcanic pipes/vents namely North, South and Centre pipes (2 additional small kimberlite bodies have also been intersected within the mining pit) which erupted through Transvaal strata and the overlying Karoo sediments -245 million years ago. Although earlier drilling and geophysical surveys suggest that the 3 pipes extend to depths greater than 1 km below the surface, the resource is only at an indicated level of confidence to a depth of 400m, and mining activities will start exploiting the inferred resource material below 400m in 2014.

Jan 1, 2010