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By C. Kirmanli

The purpose of this paper is to develop an expert system for hydraulic excavator and truck selection in surface mining. Hydraulic excavators and trucks are finding increasing applications in mining operations. Hydraulic excavators are extensively used especially when bringing electricity to rural areas is difficult and for small-scale mining. This paper describes an expert system, which selects the optimum hydraulic excavator truck configuration such that unit production cost is minimized and technical constraints such as geological, geotechnical and mining constraints are satisfied. The system has four modules: user interface, rules and an methods, databases and output module. The expert system in this study is developed within KappaPC shell. It supports object-orientated technology for the MS Windows environment. The software provides a very useful tool to practitioners, saving time and cost. Equipment selection is a recurring and expensive problem of mine planning and often involves interdisciplinary experts from different fields. It is very difficult and expensive to bring together all these experts. The capabilities of the expert system developed are illustrated in the paper. The software overcomes the difficulties of selecting the proper equipment for surface mining operations, which is very important, and results in substantial savings. Equipment databases for hydraulic excavators with 15-59 yd3 capacities and trucks with 35-360 tons are constructed and these databases are used to select the proper configuration. A case study is carried out for Soma Surface Coal mines in Turkey. Keywords: surface mining, expert systems, equipment selection, hydraulic excavators, diggability

Jan 1, 2009

In the previous chapters we did not concern ourselves with the fact that the geostatistical properties of the regionalized variable x (z) are affected by the size of the support w. Ideally, when analysing an ore body O, we would like to determine the properties of point values in O, i.e. the properties of a regionalized variable with an infinitely small support, say w°. In practice, point values are never known. To measure the value of x at a point z we must take a sample of size w centred at z. For example, if we are interested in the grade at point z, w will be the volume of the sample 'centred in z; if we are interested in the metal accumulation at point z, w will be the area of the cross-section of the sample centred in z. We say that the measured property is a regularized variable, and so the semivariogram (or covariogram) calculated from the values obtained is also regularized. In the majority of the mining problems which can be solved by geostatistical methods, we are interested in the properties of blocks of ore and of samples with a finite non-point support. It will be shown in the following chapters that these problems can be solved by calculating the average value of the point sernivariogram in volumes or areas of finite dimension, or between such volumes or areas. These calculations would be simple if we knew the point semivariogram. This means that the point semivariogram has to be estimated from the observed regularized semivariogram(s).

Jan 1, 1978

By H. F. Fuls

Skorpion Zinc, an integrated zinc mine and refinery located in the south of Namibia, has a production capacity of 150 000 t/a of special high grade (SHG) zinc. The Skorpion zinc oxide resource will be depleted by 2017. Extensive exploration drilling for additional zinc oxides was conducted without success. With the abundant availability of zinc sulphide concentrates regionally (Black Mountain and Gamsberg in the Northern Cape or Rosh Pinah Zinc and new deposits in the Rosh Pinah region) the life of the operation can be extended by processing of zinc sulphide concentrates. The leach kinetics of zinc sulphides is vastly slower than for oxides, preventing the processing of zinc sulphides in the existing process under current conditions, and Skorpion Zinc faces the challenge to identify a suitable zinc sulphide treatment process that can be integrated with the existing plant. Various zinc sulphide processing options were identified through an extensive literature search and non-viable options were eliminated. Mass and energy balances were established for potential options and an economic evaluation (including capital and operating cost estimation) was conducted to identify a suitable process. It is concluded that ferric leaching of sphalerite in a sulphate medium under atmospheric or pressure leach conditions are suitable processes for Skorpion Zinc. These processes present advantages over all other zinc processing options when elemental sulphur is preferred as the final deportment for sulphide sulphur. Both these processes can be integrated into the existing refinery and will be able to process concentrates with a wide composition range.

Jan 1, 2013

By A. Mainza

It is common practice in the mineral processing industry to use hydrocyclones for particle classification. However, classification in the UG2 platinum circuits using the hydrocyclone poses major challenges due to the differences in density between silica and chromite, the two major components of this ore. Silica,-the PGM carrying component, has an average density of 2.7 and the barren chromite component has an average density of 4.5. When conventional and flat bottom cyclone are used there is a misplacement of particles due to differences in density leading to inefficiencies in the classification by size. As a result of the density effect, coarse silica reports to the overflow, resulting in loss of recovery, and fine chromite reports to the underflow, resulting in loss of milling capacity and unnecessary production of fine chromite. A classifier based on a different concept was required in the classification of UG2platinum ore. The three-product cyclone, which is a hydrocyclone with two concentric vortex finders to produce three distinct products, has been tested in the UG2 ore application and indications are that misplacement of particles due to differences in the component densities can be minimized through the use of this unit. Industrial and pilot plant trials were conducted and indications are that the three-product cyclone can be installed to selectively produce a middlings stream that can be screened using Pansep screens to provide a screen oversize, which is predominantly coarse silica that can be preferentially reground to recover the PGM values contained in the coarse silica.

Jan 1, 2004

By M. Dobbins

Magnetic separation has long been used to upgrade and beneficiate a wide variety of industrial minerals. Advances in both wet and dry magnetic separators over the years has broadened their use, and questions are often raised about which separation technique or equipment type is most appropriate for a particular operation. This paper will provide a brief look at existing magnetic separation technologies, and discuss their potential advantages and disadvantages when applied to heavy mineral applications. Relevant case studies for the separation of ilmenite and chromite are then presented. The process development efforts undertaken for each case are described, and the rationale for selecting appropriate magnetic separation technology is explained. The nature of the material being treated must clearly be understood, knowledge and access to testing the best separation technologies is required, and careful process development and economic evaluations are a must. As is shown in the case study discussions, it is imperative that these principles drive the separation technology selection and placement, rather than looking at typical or existing similar flowsheets as rules. As examples, the ilmenite tailings case study presented in this paper shows how advances in technology have allowed for increased recovery of -45 µm ilmenite by utilizing a multi-stage SLon® wet magnetic separator circuit equating to an additional 30 000 tons of ilmenite produced per year. The virgin chromite case study presented shows that through careful testing and circuit design efforts using RED technology, a 20% increase in overall chromite recovery was achieved over previous demonstration work.

Jan 1, 2007

By J. Tikka, E. Bäcklund, N. -O. Lindfors

Tornados are the most violent weather events in the world, and we have all seen the forces and phenomena created by tornados in nature. Airgrinder AB has been working with a material treatment technology, which most easily could be described as an artificial tornado. The process consists principally of one air fan providing a high-velocity airstream that enters a mechanical cyclone. When the gas enters the cyclone, an outer vortex is created. This outer vortex rotates next to the cyclone wall, and at the bottom of the cyclone funnel the gas stream is turned and an inner vortex is created. The control of the air flow is tuned by a special device on top of the cyclone. The gas outlet is at the top of the cyclone and the material outlet at the bottom. The material is fed through a feeding device into the air stream channel prior to the inlet into the cyclone. The process is basically an improved grinding and dehydrating system, which is very efficient and environmentally friendly and can even be employed with very sticky materials. Also due to its rotating comminution, the material particles become rounded during grinding, hence more free flowing and easier to handle. MEFOS has already tested more than 30 different applications in the pilot equipment. The materials tested range from metallurgical slags containing 2?3% moisture to sludges with up to70% moisture. This technology has a potentially strong impact on mineral beneficiation, including the drying of sticky fine-grained materials, improved and selective gas scrubbing and the manufacture of free flowing powders.

Jan 1, 2007

By C. J. Liebenberg

This paper focuses on the application of ion exchange technology for the recovery of copper from a leach solution originating from a heap bioleach in which base metals are leached from a low-grade ore that bears platinum group metals. Screening tests indicated that Dow XUS43605 has high selectivity for copper over the other metals in the solution, namely nickel, iron, cobalt, zinc, manganese, and aluminium. Batch adsorption kinetic experiments showed that copper adsorption equilibrium is attained at a fast rate. The kinetics of adsorption increased as the temperature was increased from 25°C to 60°C due to the decrease in solution viscosity and the subsequent improved intra-particle mass diffusion. Single-component Langmuir and Freundlich isotherm models were fitted to the batch copper adsorption equilibrium data, and a maximum copper capacity of 26 g/l was observed for Dow XUS43605. The effects of flow rate, temperature, pH, and initial metal concentration on the dynamic recovery of copper were investigated in fixed-bed columns, and it was determined that temperature and flow rate had the most significant impacts on the loading of copper on the resin at copper breakthrough. A 36% increase in copper loading at breakthrough was observed when the temperature was increased from 25°C to 60°C. Finally, it was determined that a split elution is possible by using different concentrations of H2S04 to first elute co-loaded nickel from the resin, followed by the elution of copper.

Jan 1, 2013

By Luis Rudolphy, Pekka Tähkiö

"Flotation plant design, construction and start-up can be challenging tasks, because multiple factors and disciplines have to be combined in an efficient manner, in order to execute a project that meets the technical, financial and timeframe expectations. Key considerations that need to be addressed when designing a flotation plant are process requirements, equipment integrability, automation, and up- and downstream processes/designs. Furthermore, several other lifecycle factors need to be considered, such as servicing and maintainability, operational costs, future expansions and decommissioning, among others. To address these challenges, Outotec has developed a new approach to designing flotation plants that targets eliminating most of the inherent risks that can be found in these types of projects. The new Outotec® plant is a fully modular approach in which the above-mentioned challenges have been taken into consideration in the design phase. As a result, the cPlant concept can give several benefits for new and experienced companies involved in the minerals processing business, such as lower risk investments, fast and cost-efficient flotation plant delivery, faster ramp-up period, easy plant expansions, fully automated processes and operation and maintenance ease. As well, dismantling and transportation of the cPlant to a new location is easy and fast, hence the new cPlant concept makes possible to exploit small, short-lifespan ore deposits and also retreat old tailings ponds that might contain valuable minerals and where the ore quantities are limited. Furthermore, cPlant is easily implemented for brownfields and temporary expansions during bigger expansions."

Jan 1, 2015

By D. Sager

Middleburg Ferrochrome (MFC), a company in Samancor Chrome, commissioned a new ferrochrome smelter in March 2009. This is a 60 MW DC-arc furnace with a DC power supply for the smelting of Transvaal chromite ore fines. With the benefit of 12 years' experience with this technology while operating a 44 MW DC-arc furnace, MFC mitigated all known challenges and considered up-scaling risk in the new plant, which had a rapid ramp-up to full power in 02 of 2009. Good operating practices, as made possible by robust equipment selection, including a thyristor rectifier set of proven technology, and operation with optimal slag chemistry, leads to a safe and effective plant operation. With the optimized furnace design and a correctly sized power conditioning system, using only standard (static) harmonic filters and a correctly sized smoothing reactor, the arc furnace is not a 'dirty load' for the utility, staying well within IEC limits for power quality. A patented arc compensation system is installed and allows for full arc position control (to compensate for magnetic field induced arc deflection) so that a symmetrical crucible is maintained, significantly benefiting refractory life. The principal benefits gained from the MFC process is the fact that ore fines are processed, without metallurgical coke, and higher chrome recoveries are achieved compared to other smelting technologies when using a DC open arc for smelting. Keywords Samancor Chrome, Middelburg Ferrochrome, ABB, smelting, DC arc furnace, arc compensation, power factor correction, anode, harmonics, thyristor, reactor, maintenance, refractory, ores, reductants.

Jan 1, 2010

By D. Van Dyk

Horizontal rotating mills are being used all over the world in different mineral and power generation industries. David Brown South Africa, with over 140 years of experience in gear manufacture and design, has been supplying these industries with innovative designs at exceptional quality. The gearing systems associated with these industries are challenged daily with operating conditions that are not always fully understood. Failures are therefore experienced, over time in the industry, which cannot always be fully explained. David Brown South Africa has developed a gear monitoring system, the Intelligent Gearing System, in association with Transmission Dynamics (UK), in order to monitor and analyse these operating conditions in real time. The system has been designed on the principles of Six Sigma, incorporating Design for Six Sigma. The purpose with this system design is to monitor the operating conditions on the pinion, record the information and analyse the data in relation to the rate of fatigue damage to the girth gear and pinion. This is done in real time and unattended. The output from the Intelligent Gearing System can be fed back into the operating system of the mill user, in order to display an alarm for operating conditions exceeding the design criteria as well as information on the rate of fatigue damage due to these operating conditions. When the mill operating and the effect on the fatigue life of the mill gearing components, conditions are better understood, mill users can forecast critical spare holding levels with an increased accuracy. The Intelligent Gearing System also allows early actions to remove reasons for system overloads.

Jan 1, 2006

This paper examines manning best practice in the Australian mining industry, comparing the mining of gold with mining of other commodities. In particular, the paper considers a range of mining operations and their manning levels as measured by operational benchmarking. The benchmarking results presented cover 7 open pit and 14 underground studies of gold mines in Australia from a database of over 50 studies. The data were collected as part of AMC?s benchmarking and operational improvement studies conducted between 1999 and 2009. The results examine overall manning levels in mining, processing and administration functions. Manning levels for a range of mining methods, including open pit and underground methods, are segmented. Productivity measures such as ore tonnes per man day and metres developed per man day are presented and where direct relationships can be established, the relationships are described. The proportion of supervisory to operations personnel and labour costs as a percentage of total operating costs is highlighted. Minimum manning requirements for the range of mining methods are indicated, irrespective of the size of the operation. The benchmarking results provide guidance by indicating a range of manning numbers and trends which are likely to be appropriate for the scale and type for a range of mining operations. When combined with benchmarked productivity and cost data, manning results help identify potential areas for business improvement, driving gains in the efficiency of labour. Finally, the paper considers perspectives on best practice for manning and the limitations in application of this type of analysis in a global context.

Jan 1, 2009

By G. J. de Korte

South Africa is reliant on coal for the generation of almost all the electricity used in the country, and several large industrial concerns such as Sasol are also coal based. Research relating to the mining, beneficiation and utilization of coal is important in order to ensure the optimal exploitation and use of coal within the country. The Fuel Research Institute (FRI) of South Africa was established in 1930 to investigate all aspects of coal beneficiation and utilization in South Africa. The FRI went on to conduct world-class research and in 1957 a pilot coal preparation plant was constructed in Pretoria to enable large-scale practical experimentation. The pilot plant played a pivotal role in the establishment of South Africa?s low ash coal export project. Political and economic factors contributed to the eventual closure of the FRI and South Africa experienced a period of about 10 years between 1990 and 1999 during which very little public coal preparation research was done. This changed for the better towards the end of 1999 when Coaltech 2020, a collaborative research program was established. Participants included the CSIR, universities, the government and the major coal producers. Coal preparation research conducted under Coaltech thus far include dewatering and drying of fine coal, size classification of ultra-fine coal and dense-medium fine coal beneficiation. Currently, the Coaltech focus is on the beneficiation of low-grade coal reserves and is investigating existing as well as new techniques that can be utilized to provide cost-effective beneficiation of low-grade raw coals and reject coals.

Jan 1, 2010

By von Wielligh. L., D. G. Hattingh, M. N. James, W. Thomas

"SynopsisThe process of joining materials by friction is based on generating the heat necessary to create a solid-state mechanical bond between two faying surfaces to be joined. In simple terms, the components to be joined are subjected to frictional heating between rubbing surfaces, causing an increase in interface temperature and leading to localized softening of interface material, creating what is described as a ’third body’ plasticized layer. This plasticized zone reduces the energy input rate from frictional heating and hence prevents macroscopic melting. The plasticized layer can no longer transmit sufficient stress as it effectively behaves as a lubricant (Boldyrev and Voinov, 1980; Godet, 1984; Singer, 1998; Suery, Blandin, and Dendievel, 1994). The potential for this solid-state frictional joining process to create high-performance joints between, for example, dissimilar materials with limited detrimental metallurgical impact, and reduced defect population and residual stress level, has had a very significant impact on fabrication and repair in industrial sectors such as transport. This paper presents a brief overview of the advances made within the family of friction processing technologies that could potentially be exploited in the nuclear industry as alternative joining and repair techniques to fusion welding.Modern friction processing technologies can be placed into two main categories: those that make use of a consumable tool to achieve the intended repair or joint (friction stud and friction hydro-pillar processing) and those making use of a non-consumable tool (friction stir welding). The most mature friction joining technology is friction rotary welding, where a joint is formed between original parent materials only. A new addition in this category is linear friction welding, which opens the potential for joining complex near-net-shape geometries by friction heating. The continuous innovation in friction processing over the last 25 years has led to the development of a number of unique processes and applications, highlighting the adaptability of friction processes for specialized applications for high-value engineering components.IntroductionAssessing the potential for using alternative joining and repair techniques for specific applications in a given industrial sector is informed by an appreciation of the current size and potential growth in that sector. Power generation by nuclear fission has been out of favour over the past few years, due to several high-profile nuclear incidents, e.g. the Fukushima Daiichi nuclear disaster, as well as concerns over disposal of nuclear waste and spent fuel rods. However, due to rapid increases in the demand for electricity, coupled with many fossil-fuel fired plants reaching end-of-life, there is renewed interest in installing additional nuclear capacity."

Jan 1, 2015

By N. V. Moraka

In dealing with transformational aspects, the South African Constitution aspires for a balance between attempts to broadly represent the country’s demographics in the way in which organizations are structured and the need to maintain the necessary skills to ensure continual retention of skills for optimum and efficient organizational performance. Through the Mining Charter, government aimed to redress gender and racial imbalances in the mining industry as part of transforming the demographic representation of mining companies to include black people, women, and people living with disabilities in all job levels up to top management. While the Constitution calls for an appropriate balance between demographic representation and competency, this aspiration for mining poses challenges for companies due to the proficient and competent skills needed in this industry. To this end, the South African mining industry has been subjected to substantial criticism from government regarding the slow progress of transformation. The mining industry justifies its slow pace of transformation by pointing at inconsistent, varying legislation and definitions governing transformation, limited skills available from historically disadvantaged groups, and cautioning not to compromise the sustainability of mining companies by marginalizing white males and white youth with the objective of addressing racial imbalances. This lack of understanding between industry and the government has led to considerable confusion regarding the accountability of stakeholders in transforming the industry. This article presents the perspectives of ten mining executives on transformation in the South African mining industry. The theoretical description of transformation, as well as other mining stakeholders’ interpretations of transformation. is presented. Qualitative data from interviews with mining executives demonstrates their understanding of transformation through rich descriptions, interpretations, and implications in their contexts. The findings demonstrate that transformation in the mining industry is not simply about race and gender, but about cultural change, a change in mind-sets, embracing diversity, equalizing rights and opportunities, and attaining social justice. Moreover, transformation is clearly a gradual process. The article concludes with a recommendation for the definition of transformation to be corroborated with the views of mining executives and that of the Constitution of South Africa. This will create an overarching, simplified definition of transformation that can be accepted and interpreted by all stakeholders.

Jan 1, 2016

By M. Ataei, F. Sereshki, R. N. Masir

Given the inherent risks and disruptions in underground coal mining operations, strengthening the resilience of critical infrastructure has become a vital priority. This paper aims to evaluate the resilience of the underground coal mining environment using historical data and expert judgment. The study serves as a framework for optimising the utilisation of critical infrastructure to minimise operational disturbances. To achieve this, a practical methodology has been developed, incorporating nearly two and a half years of collected operational data, a hierarchical structure, and a systematic approach. Furthermore, a case study is conducted to demonstrate the real-world applicability of the proposed method. Finally, the resilience index isintroduced as a straightforward summation of ranked impact factors, providing a clear metric for resilience assessment.

Dec 15, 2025

By S. Mohanta, B. C. Melkap

"SynopsisDry beneficiation of coal by air dense medium fluidized bed is an emerging trend. It is widely believed that the particle size of the medium has a significant effect on the separation efficiency. This investigation demonstrates that medium particle size has a major effect on separation efficiency. Experimental results show that different size fractions of the same feed respond differently to the same size fraction of medium solids. Furthermore, a particular size fraction of feed coal responds differently with different size fractions of medium solids. The Ep values and overall metallurgical performance parameters, obtained from experimental results, clearly indicate the superior performance of an air dense medium fluidized bed separator when using –150+106 µm magnetite powder as the fluidizing medium. These observations reinforce the importance of sizing the medium particle size for the air dense medium fluidized bed.IntroductionIn an air dense medium fluidized bed (ADMFB), a fluidizing bed of a particular density is created by suspending solid particles in an upward air flow. A feed containing coal particles of different densities is introduced into this fluidizing bed. The particles with relative density less than the bed density float on the top of the bed, while particles denser than the bed density sink through it. Since there is a general correlation between ash content and density of coal particles, it is possible to remove ash-forming impurities from a raw coal to the required level by regulating the density of the fluidizing bed. Recently, the ADMFB process has received significant attention world-wide for its specific advantages of low operating cost and less restrictive for small capacities (Luo and Chen, 2001; Houwelingen and de Jong, 2004; Dwari and Hanumantha Rao, 2007; Sahu et al., 2009; Mohanta et al., 2012). This process is not recognized as a well-established industrial practice because of the availability of efficient wet processing technology. However, with the revival of interest in dry beneficiation of coal in general, and ADMFB in particular, there is a concerted effort to improve the efficiency of the ADMFB process, and successive improvements have made the process a competitive and viable option for beneficiating coal."

Jan 1, 2015

By J. L. Havenga, L. J. van der Walt, J. T. Nel

"SynopsisThe development of plasma technology at Necsa started in the early 1980s, when the applicability of high-temperature plasmas in the nuclear fuel cycle was investigated. Since 1995, this plasma expertise has expanded to other industrial applications, for example mineral beneficiation, nanotechnology, fluorocarbon production and waste treatment, all of which are also of relevance to the nuclear industry.Necsa has demonstrated the manufacture of plasma-dissociated zircon, zirconium metal powder, carbon nanotubes, silicon carbide (SiC), zirconium carbide (ZrC) and boron carbide (B4C) at the laboratory and pilot plant scale. These materials are commonly used in the nuclear industry. Zirconium alloys are used as fuel cladding material for nuclear fuel assemblies.Necsa manufactured the monomer tetrafluoroethylene (TFE), using 150 and 450 kW DC plasma systems, from which the polymer polytetrafluoroethylene (PTFE) was synthesized for use in filters and as seals in nuclear plants. With the nuclear renaissance at hand, it was demonstrated that plasma technology can be used to produce hydrofluoric acid (HF), which is used in the manufacture of fluorine gas (F2) for the production of uranium hexafluoride (UF6) directly from the mineral calcium fluoride (CaF2) without the use of sulphuric acid as in the conventional process. The recovery of valuable uranium from nuclear waste such as filters, oils, and solids with plasma processes will also be discussed. The destruction of low-level nuclear waste by a plasma gasification system can reduce the volume of this waste by several orders in magnitude, resulting in huge savings in the storage costs. Another product of plasma technology is the encapsulation process for nuclear waste and the production of vitrified product, which could be used as filler material for medium-level nuclear waste.IntroductionDuring the 1980s, a plasma research and development programme was launched at the erstwhile Uranium Enrichment Corporation of South Africa (UCOR) at Valindaba outside Pretoria. The main purpose of this programme was to develop alternative and more economical processes for the processing and manufacturing of uranium compounds used in the nuclear fuel cycle. The conversion of UO2 (as received from uranium mines) to UF6, which is needed for enrichment, conventionally involves several laborious, expensive, chemical processing steps. Plasma processes can eliminate several of the intermediate steps. Enriched UF6 is converted to UO2, which is pressed into pellets that are used in nuclear power plants. Plasma technology could also be used in a modified and optimized conversion process."

Jan 1, 2015

By W. Mackenzie

The development of a resource project inevitably requires the investigation of a vast range of issues across most engineering disciplines - mining, metallurgical, chemical, civil, electrical, mechanical and environmental - as well as the geosciences. It is also a characteristic feature of the resource industry that no two orebodies - and hence no two development projects - are the same. So these technical issues have to be addressed to a greater or lesser extent in evaluating any resource project's development potential. Not surprisingly then, technical issues tend to predominate when assessing the development potential of a project in the process typically referred to as `doing a feasibility study'. But the principal purpose of a `feasibility study' is to determine whether a development opportunity makes good business sense, not just whether it is technically possible. Resolution of technical issues is often seen as the primary focus of a feasibility study, whereas in reality, these technical issues are the basis upon which an asset delivery and business plan is built. This is not to say that technical issues are unimportant - they are a prerequisite to the demonstration of a project's viability. The feasibility study process must therefore demonstrate that not only have the technical issues been satisfactorily addressed, but also that the broader commercial, economic and social issues have been considered in the development of a comprehensive business plan, which includes an assessment of the risk-reward profile of the proposed development. This paper will present a framework for the conduct of `feasibility studies' and provide guidance to minimum standards and best practice.

Jan 1, 2007

By C. R. Royal, B. E. Friedland

Energy & Densification Systems (EDS) has developed patented new technology crushing/milling equipment. The EDS Multishaft Mill is a compact vertical mill – utilising high-speed impacts to break down particles with large reduction ratios, low energy consumption and improved liberation. The milling action combines several processes to provide a multitude of output products to satisfy various specifications. Comminution often accounts for more than 60% of the total power consumption on a mine. Two of the key problems to be solved in comminution is to bring down the specific energy required to reduce particle sizes; and to improve liberation or improve the efficiency of the beneficiation and recovery of the required elements. The EDS Mill has shown extensive improvements in both these areas with energy efficiencies up to 75% better than conventional milling equipment and improving liberation beyond the standard beneficiation processes. Conventional comminution equipment requires massive, heavy parts to be moved or rotated, consuming a lot of energy in doing so and not inputting that energy into the breakage of particles. In the EDS Mill, ramping up the relatively small shafts to speed is all that is required. Once at speed, the momentum, together with the minimal amount of constant drive required, means that the energy can be transmitted directly and efficiently into breaking down the particles. The high-speed impacts allow for a shattering effect of the particles and this quickly generates a high ratio of fines. Furthermore, the single impact force breaks particles in a very different manner to conventional compressive force breakage. With compressive force breakage, the particle breaks from point to point. With high-speed impact force breakage, the force tends to migrate through the weakest areas of the particle, which tend to be the mineral boundaries. This, therefore, means that when the particles break, the various minerals are exposed and hence liberated. Keywords: Comminution, high-speed impact, liberation, energy efficiency, novel comminution

Jan 1, 2020

By E. Govender-Opitz, L. Lelia

The South African mining industry plays a significant role in the economy of the country. Nonetheless, the negative impacts on the environment continue to prevail. In regions where mining exists in proximity to communities, mining activities have led to the disruption of modality. Rural communities are mostly affected as they depend on land use for agriculture to sustain their livelihoods. The conversion of land for mining activities often leaves the communities vulnerable when mines close because of the limited life span of mines. An ongoing discourse focuses on how the mining industry can contribute to sustainable development of the communities in which they operate. Post-mining transformation offers an approach for the mining companies to contribute to sustainable livelihoods post-mine closure by strengthening rural-urban linkages, which ensures inclusive development of both rural and urban areas. The paper employs a case study approach to Richards Bay Minerals and the adjacent rural communities of Sokhulu and Mbonambi. It sets out to understand the post-mining transformation employed by RBM and explore the rural-urban linkages that manifest as a result. Findings show that sand dune rehabilitation employed by RBM is successful in restoring soil fertility and establishing the natural ecosystem. The casuarina planted to rehabilitate the dunes is used to spur an alternative charcoal industry post-closure. The main rural-urban linkages that manifest are flows of people due to job opportunities and flows of goods from the sale of charcoal produced. However, there is a lack of communication and lack of authority to ensure responsible management of the casuarina plantation and equitable sharing of benefits. The paper recommends that other post-mining transformation strategies such as eco-tourism should be explored and that the government, at both national and local level, the community and the mine should be involved to ensure overall success and sustainability of the strategy. Keywords Post-mining transformation, rural-urban linkages, alternative land use

Jan 1, 2020