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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 C. Tokoro, T. Kato

The objective of this study is to improve the shrinking core model for particles with a particle size distribution and clarify the activation mechanism of rare earth elements dissolution by mechanochemical activation. To achieve this objective, the method, called the doubly integrated micromodel, was applied for a shrinking core model in this study. This method consists of integrating the batch leaching rate of a single particle over the distribution of both feed particle size and reactor residence time to arrive at the fraction unleached. The usefulness of the shrinking core model improved by doubly integrated micromodel was confirmed by comparing it with a shrinking core model. To apply the shrinking core model improved by doubly integrated micromodel to rare earth elements dissolution from weathered residual rare earth ores by mechanochemical activation, leaching experiments were performed for grinding samples by planetary ball milling. The reaction equation of mechanochemical reaction by planetary ball milling for weathered residual rare earth ores was investigated by x-ray absorption fine structure analysis. As a result of a kinetics study, the rate-determining process of leaching changed from reaction to diffusion reaction control by planetary ball milling. Based on these results, it was revealed that the main mechanism of activated rare earth elements dissolution from weathered residual rare earth ores was a mechanochemical reaction by planetary ball milling. Keywords: Mechanochemical reaction, particle size distribution, shrinking core model

Jan 1, 2020

By M. R. MacIver, M. Pawlik, H. Alizadeh

Treatment of tailings is an integral component of mineral processing. Tailings with a high clay content are a challenge for the mineral processing industry; e.g. the clay slimes produced from production of phosphate in the mid-western United States and the fine tailings produced from oil sands production in western Canada. Dispersants are a commonly used process aid, but their impact on the structure and settling properties of high clay content tailings is not well understood. The paper describes the changes in composition and bitumen release that occur when mature fine tailings (MFT) are treated with a polymeric dispersant (lignosulfonate.) Synchrotron-source computed tomography (CT) was used to obtain high-resolution 3D images of samples prepared at varying dosages of dispersant. The CT method permits a powerful visualisation of the internal structure and composition of the samples. These insights will enhance our understanding of the structural characteristics of mineral tailings relevant to solid-liquid separation by flocculation and thickening. Keywords: Dewatering, dispersion, dispersants, chemical treatment, computed tomography

Jan 1, 2020

By R. Gurung, S. Asokan, Ch. V. G. K. Murty, R. Upadhyay

Tata Steel Limited which is Asia?s first and India?s largest integrated private sector steel company, as part of its vision to grow in related industries is also undertaking the Titania project. The project will involve mining, separation of ilmenite and other valuable minerals from the inland heavy mineral sands deposit in the Indian state of Tamil Nadu. The raw material will be beneficiated to synthetic rutile, titanium dioxide pigment and ultimately to titanium metal. The recently concluded feasibility study revealed that the deposit under consideration has 10.4%of total heavy mineral content and 15.2% slimes of the size below 63 µm, over an average sand thickness of 6.9 metres. The presence of about 15% slimes in ROM sand coupled with scarcity of water at the project site complicates the slimes handling/disposal system, requiring the development of an innovative, efficient and effective system for disposal of slimes. Mineral characteristics of slimes revealed the presence of kaolinite clay, which poses its own challenges in thickening/dewatering of slimes. This paper outlines the detailed studies conducted, including slime characterization, settling and thickening characteristics, and ge-technical studies to arrive at an efficient and effective slime handling/disposal system, with a view to plant saplings on the mined-out reclaimed land with species typically suitable to that environment.

Jan 1, 2007

By R. V. Ramani, R. Stefanko

"The favorable mining conditions in the United States of America that resulted in the development of the highly productive room and pillar systems are largely disappearing. Increasing mechanization, poorer natural conditions, and greater concern for health, safety and environment gave impetus to the enactment of the Federal Coal Mine Health and Safety Act of 1969. These regulations prescribe more stringent requirements in face ventilation and mine air distribution, necessitating significant changes in existing ventilation systems. Stringent mandatory standards were applied to respirable dust control for the first time, and simultaneous control of both gas and dust has affected the face as well as primary distribution, most notably on haulage entries.The size and complexity of the present-day mining operations, and the need to evaluate various system changes in a limited time, call for scientific methods in mine planning. In this paper, the authors trace the previous applications of computers to mine ventilation planning and discuss the results of their work in applying a ventilation simulator developed at Penn State. The paper includes an analysis of current trends and suggestions for future research and development."

Jan 1, 2014

By More-O&apos, R. C. Ferrall, J. W. Wilson

SYNOPSIS The theory of elasticity has been shown to provide a means of determining the stresses and displacements induced by mining in deep level hard rock mines. This theory has been incorporated into an electrical resistance analogue on which the plane of a reef or ore-body can be modelled to enable the rapid determination of stresses and displacements at points in the plane of the reef. This electrical analogue has been used to determine energy release rates caused by scattered mining, which, to some extent, is a measure of the degree of hangingwall fracture. A correlation between predicted energy release rates and actual underground conditions in stopes in the O.F.S. goldfields has been encouraging enough to define parameters on which future stoping layouts can be based. The use of the elastic theory through the analogue has been extended to the assessment of the influence of stoping operations on off-reef excavations. Underground conditions at damaged and undamaged areas have been compared with predicted elastic stresses at the positions under review, resulting in the derivation of design parameters for use in siting off-reef excavations in the prevailing geological conditions in the O.F.S. and Klerksdorp goldfields. The analogue has also been used to assess the vulnerability of certain un mined dykes to bursting. Correlations between stresses induced on dykes by stoping and dyke behaviour underground has enabled critical stress levels to be determined for several persistent dykes occurring in the O.F.S. and Klerksdorp goldfields. A number of long and short term planning projects at mines operating in the Anglo American Corporation and General Mining and Finance Groups are described, where the data derived from the electrical resistance analogue is processed by computer programmes and assessed on the strength of the design factors derived from the correlation of field work and the elastic theory.

Jan 1, 1970

By V. E. Cogho

Optimum Coal Mine comprises numerous defunct, active, and future mining sections. The mine is primarily a large opencast coal mine; however, underground mining activities will be increasing steadily over the next five years. Opencast and underground mining activities have a significant impact on surface and groundwater resources. To ensure that the mine will be able to continue with its mining operations in the catchment, the extent of this impact requires that substantial intervention and mitigation measures need to be implemented to ensure the environmental integrity and economic use of the catchment's water resources. In developing a sustainable long-term mine water management strategy, numerous scenarios had to be analysed. The various scenarios are a combination of water and land management activities. The main components of the mine's integrated water management strategy include: ? Management of water recharge by continual and appropriate rehabilitation of disturbed land ? Beneficial re-use of impacted mine water for coal plant process water and mining operations ? Reclamation and desalination of remaining excess impacted mine water to potable standard. From the mine's long-term water balance, it is evident that the continued implementation of numerous water management actions is required to mitigate the water resources impact in a sustainable manner. In addition, the installation of a water reclamation plant at Optimum Coal Mine (15Ml/day) is a key step for the mine to achieve a zero impact target.

Jan 1, 2012

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 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 C. van Buuren, R. F. Sandenbergh, P. J. Pieterse

Gold extraction from double refractory ores using conventional cyanidation has proved challenging due to the presence of carbon within the ore. Carbon particles may adsorb leached gold resulting in gold losses to tailings, i.e. preg-robbing the gold. Some of the preg-robbed gold may be recovered by the application of the HiTeCC process on CIL tailings. The process developed by Metso Outotec involves caustic conditioning of the tailings followed by high temperature desorption and simultaneous adsorption onto virgin activated carbon of the aurodicyanide. The aim of this paper was to develop a model for the HiTeCC process which could be used to support design and optimisation of the process, based on the adsorption characteristics of the preg-robbing and activated carbons. It was found that accurate experimental isotherms can be used to predict the behaviour of preg-robbing adsorbents. Comparing the sorption isotherms for preg-robbing ores and activated carbon indicated similar dependencies on temperature and ionic composition. Applying boundary layer diffusion models coupled with experimentally determined isotherms for preg-robbing ore and activated carbon, the HiTeCC process was successfully simulated at experimental and plant scale. Gold recovery of the HiTeCC process is most sensitive to the temperature of desorption and gold loading of the activated carbon, with increased temperature improving recovery. The gold loading of the activated carbon in the process should always be maintained lower than that of the normalised pregrobbing carbon gold loading to ensure favourable conditions for adsorption onto the activated carbon. Caustic conditioning stabilises adsorption and is therefore not necessary during the desorption stages of the process, but potentially improves recovery during adsorption. Keywords: Preg-robbing, refractory gold ores, HiTeCC, aurodicyanide

Jan 1, 2020

By H. Karabulut, S. Gündüz, K. Karacif, M. A. Erden

The corrosion properties of iron-based composite materials containing graphite and silicon carbide (SiC) reinforcement were investigated. The effects of silicon carbide reinforcement were investigated by adding 0.5% graphite and 1%, 2%, and 4% SiC. A powder metallurgy method was used to produce the composite samples. Iron, graphite, and silicon carbide powders were blended for one hour with a threeaxis mixer and then unidirectionally pressed under a pressure of 750 MPa. After pressing, the composite materials were sintered at 1100°C for one hour. The corrosion properties and microstructure, density, and hardness properties of the composite materials that can affect the corrosion properties were also investigated. It was determined that the pore ratio and hardness of the composite material increased, and corrosion resistance decreased, with increasing silicon carbide content.

Jun 2, 2022

By M. Mathey

The application of the Monte Carlo technique to production planning and everyday economic decisionmaking in mine production management is demonstrated. The logic is detailed using an example of underground production with continuous miners (CMs) and truck haulage. It is argued that availability of equipment and personnel are the predominant variables influencing mine output and productivity and that those availabilities may be well represented by binomial probability distributions. The probabilistic model is implemented in a standard Excel® spreadsheet with Palisade’s @Risk add-on to facilitate simulations. Starting from model calibration against data obtained from a mine’s annual reports, some general interdependencies of availability, utilization, productivity, and costs of production processes are outlined. Finally, several possible options and their consequences as regards production improvements are explored.

Dec 13, 2022

By N. Hanief

This research involves the investigation of phase transformations in the platinum-chromium coated system. Single-layer 0.1 µm platinum coatings were deposited via electron beam deposition on 99.98 percent pure chromium substrates. Specimens were subjected to systematic heat treatment in a vacuum furnace at 900°C for up to 20 hours. Phase formation and the changes in surface morphology were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM).Both CrPt and Cr3Pt phases are formed during heat treatment for different times at 900°C. Significant changes in the morphology of this coated system were detected after heat treatment at 900°C for 20 hours.

Jan 1, 2012

By J. Zwartendyk, A. Azis

"Every nation must decide how it should exploit its mineral resources so as to contribute most to its national objectives. It is argued that the present value of the future corporate income tax flow derived from mineral exploitation may serve as a useful indicator in moving toward a taxation policy that would contribute optimally toward the greatest public benefit.The future stream of corporate income taxes depends largely on the mineral endowment, consisting of deposits now being mined, known unmined deposits, and unknown deposits.Unknown deposits may be estimated by geological inference. Both known and unknown deposits can be categorized according to grade and size, and divided into economic and uneconomic deposits on the basis of certain prices, costs, rate of return and taxation levels.Computer simulations can be run of discounted cash flow models at various taxation levels to show the impact of taxation changes on future tax revenues."

Jan 1, 2014

By B. Jack, A. Vervoort

During pillar extraction, sidewall fracturing and spalling at some collieries constitute a severe stratacontrol problem. In order to obtain a better understanding of this phenomenon, a survey of pillar corner conditions before and during pillar extraction was conducted at one particular site. For the various successive mining steps, the vertical stresses on the pillar corners were calculated by use of a three-dimensional boundary element program. A significant correlation was found between the calculated vertical stress prior to the extraction of the panel and the sidewall conditions. During the extraction of the panel, a significant deterioration of the sidewall conditions at a pillar occurred only when the adjacent pillar was mined, causing an increase in vertical stress on the remaining pillar.

Jan 1, 1992

By M. A. Ford

This paper reviews the history, sources, mineralogy, extraction metallurgy, conversion, and enrichment of uranium in South Africa. Over the past 40 years extraction plants were built at 27 sites, an9.over 140 kt of uranium have been produced. Older plants have had to adapt to changing market conditions, no single technology has had the opportunity to become entrenched, and costs have been reduced to a third of those of the original flowsheet. The research efforts aimed at developing the country s nuclear raw materials have been particularly rewarding, as they have enabled South Africa to become a world leader in the extraction of uranium from low-grade ores and to develop methods for uranium enrichment and the production of nuclear fuels.

Jan 1, 1993

By J. Ning, T. Bu, J-Q. Jiang, L. Jiang

"In coal mining in China, the cutting height of the shearer in longwall faces is increasing. Owing to the increase of extraction height, the caved roof strata area is enlarged, and new issues are being encountered, such as determination of a suitable working resistance for the shield and control of the roof. Through field observation and theoretical analysis of the first longwall face with a height of 6.0 m in the Bayangaole mine, a three-stage structural model was developed. Stage I is defined as the period in which the lower immediate roof (LIR) caves into the goaf and is broken into irregular shapes of various sizes. Stage II is defined as the period in which the upper immediate roof (UIR) breaks and impacts the LIR. In stage III, the main roof breaks into blocks and then impacts the UIR. With respect to these three stages, a suitable method was identified for calculating the working resistance of the shield support for a super-great mining height longwall face (SGMHLW). Introduction and backgroundThe coal seams in the Shendong coalfield, located in the northwest of China, are characterized by low dips and large thicknesses and are thus suited for full thickness extraction. Since the mid-1990s, the Shendong coalfield has been developed into one of the largest in the world (Ning, Liu, and Tan. 2014; Ning et al., 2017). Recent developments in mining equipment have made it possible extract entire seams up to 5.0 m thick in a single cut. This method, termed the ‘super-great mining height longwall face’ (SGMHLW) method, has been widely adopted in the Shendong coalfield (Table I) (Ju and Xu, 2013; Peng, Li, and Zhou 2015; Zhang, Fan, and Ma 2011). According to some studies, sudden support-closure incidents often occur when using the SGMHLW method. The key to solving this engineering issue is to have a clear understanding of the structural characteristics and movement laws of the overlying strata. For instance, the load on the supports is related to the movement of the roof stratum as a response to the mining activities."

Nov 1, 2018

By P. L. Crouse

"SynopsisFluorine – in the form of hydrofluoric acid, anhydrous hydrogen fluoride, elemental gaseous fluorine, fluoropolymers, volatile inorganic fluorides, and more – has played, and still plays, a major role in the nuclear industry. In order to enrich uranium, the metal has to be in the gaseous state. While more exotic methods are known, the standard and most cost-competitive way of achieving this is by means of uranium hexafluoride (UF6). This compound sublimates at low temperatures, and the vapour is enriched using centrifugal processes. The industrial preparation of uranium hexafluoride requires both elemental fluorine gas and anhydrous hydrogen fluoride (HF). HF is prepared by the reaction of sulphuric acid with fluorspar (CaF2). Fluorine gas in turn is prepared by the electrolysis of HF. Yellowcake is first converted to uranium tetrafluoride (UF4), using HF, after which the compound is treated with fluorine to yield UF6. After enrichment, the UF6 is reduced to UO2 for use in fuel elements in pellet form.South Africa has the largest reserves of fluorspar internationally, and is the third largest producer after Mexico and China. Fluorine technology has many associated difficulties, because of the reactivity of fluorine and the toxicity of HF. The main barriers to entry into the fluorochemical industry are thus the abilities to produce both HF and F2. Both these substances are produced locally, at the industrial scale, at Pelchem SOC Ltd. Should South Africa contemplate developing its own nuclear fuel cycle as part of the awaited new-build nuclear project, it will be imperative to leverage the existing skills with respect to fluorine technology, resident at both Pelchem and Necsa, for this purpose. This paper summarizes the fluorochemical skills developed locally over the past several decades, and suggests strategies for maintaining the technology base and developing it for the next generation of scientists and engineers.IntroductionFluorine chemistry has always had a very close relationship with the nuclear industry. Although the first mention of fluorspar was recorded in the sixteenth century, and the fundamentals had been well-developed by the Second World War, it was only during the Manhattan Project (Banks et al., 1994), when almost unlimited funds were made available for the large-scale industrialization of fluorine and related compounds, that the technology took off. Expertise in both the chemistry and the engineering aspects of fluorine is essential for the design and running of several of the unit processes in the nuclear fuel cycle."

Jan 1, 2015

The 114th Annual General Meeting of The Southern African Institute of Mining and Metallurgy was held at The Country Club, Johannesburg, Napier Road, Auckland Park on Thursday, 11 August 2011. Welcome The President extended a special welcome to the guests and representatives of our sister institutes and other associations, and also to recipients of awards, senior members of industry, Honorary Life Fellows, past-presidents, our members and other guests, among them the following: F. Cawood, President, Institute of Mine Surveyors of South Africa C. Roode, President, Mine Metallurgical Managers&apos; Association of South Africa M. Cresswell, Chairman, South African Coal Processing Society A. Hay, Immediate Past President, South African Institute of Electrical Engineers L. Gardner, President, South African National Institute of Rock Engineers J. Krynauw, President, The Geological Society of South Africa (GSSA)

Jan 1, 2011

The 90th Annual General Meeting of The South African Institute of Mining and Metallurgy was held at Kelvin House, Johannesburg, on 19th August, 1987. Dr H. Wagner (President) was in the Chair and declared the meeting open at 16h00. Obituaries The President read out the names of the departed Members as follows: N.M. Airey, F.J. Kisbey-Green, Dr R.A. Pelletier, C.B. Anderson, A.R. Cator, J. van Heerden, P.J. Burman, C.C. Crosson, M. Livingstone¬Blevins, S.T. Firman, V.E. Kisbey-Green, and A.L. Corna. All stood and observed a moment of silence as a mark of respect. Minutes The minutes of the 89th Meeting of the SAIMM, which was held on 20th of August, 1986, were confirmed.

Jan 1, 1987