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By S. H. Yi, J. R. Kim, Y. S. Lee

The viscosities of CaO-SiO2-Al2O3-MgO-FeO slags were measured under conditions ofCaO/SiO2=1.15–1.6, 10–13 percent Al2O3, 5–10 percent MgO and 5–20 percent FeO. Slag viscosity decreased with increasing FeO content at a fixed basicity (CaO/SiO2) of slag. Slag viscosity at low FeO (<7.5 percent FeO) exhibited a minimum value by increasing MgO content in slag. Viscosity decreased with increasing slag basicity up to 1.3 while it increased as slag basicity increased from 1.3 to 1.5. Thus, it was proposed that the driving force for the decreases of slag viscosity would be an increase in depolymerization of silicate network at C/S=1.3, while the viscous behaviour at C/S>1.3 would be increased with increasing the chemical potential of primary solid phase e.g. dicalcium silicate. A thermodynamic approach for the activity of primary solid phase in molten slags resulted in a reasonable relationship between viscosity and slag components. Therefore, it was confirmed that slag viscosity in basic slags system (C/S>1.3) could be determined by the chemical potential of dicalcium silicate. Keywords: viscosity, basicity, bosh slag, blast furnace, slag structure, FT-IR

Jan 1, 2004

By B. J. Buys

Rock bolt integrity is a critical issue for the mining industry because of its influence on the safety of mining operations. Guided ultrasonic wave testing of the defects associated with resin-anchored rock bolts was investigated. Axisymmetrical and three-dimensional finite element models were built, one of a partially encapsulated bolt and the other of a bolt with a simulated local corrosion crack. Experimental bolts were then installed in a testing block and typical responses were compared to finite element models of different defect scenarios. Encouraging results were obtained for the smaller axisymmetrical and three-dimensional finite element models, as well as during the experimental investigation. It is recommended that software with energy-absorbing elements should be utilized to consider higher frequencies and longer bolts. Once the integrity of models such as these has been established, the models could in principle be used to train neural networks for use in commercial equipment to determine the integrity of the installed bolt.

Jan 1, 2009

By C. Dixon

This paper is based on the assumption of some knowledge of the National Water Act. It will consider the question of how that Act fits in with: a) existing laws which overlap on the subject matter b) new laws either in draft or in the process of being compiled c) policies which will eventually find their provisions included in new legislation (e.g. minerals policy) d) international practices. The focus will be specifically on the interaction of legislation relating to water use and water pollution in the mining sector as well as the role of the Department of Water Affairs in mining matters. Hence the title of the presentation.

Jan 1, 1999

By R. Boom, K. C. Mills, S. Riaz

This paper details the recent trends in slag-related research from 1999 to 2003. The trends in thefollowing are outlined: • Annual publication rate • Geographical origin of the work • Nature of the research (e.g. thermodynamics, kinetics) • Nature of the slag studied. This study has revealed that slag research in the USA and Europe has decreased to about a half over the last 20 years and that there has been a significant decrease in Japanese research in this area in recent years. However, these decreases have been offset by significant increases in Chinese and Korean research activity. There has been a significant increase in the amount of work carried out on the recycling and environmental aspects of slags in recent years.

Jan 1, 2004

By R. J. Durrheim

The DEEPMINE Collaborative Research Programme was established to create the technological and human resources platform that would make it possible to mine gold safely and profitably at depths of 3 to 5 km. The DEEPMINE Programme has four goals: to acquire knowledge of and develop appropriate technology for new ultra-deep level mines, to stimulate education and training, to establish a culture of innovation, and to encourage rapid technology transfer and implementation. The research programme was launched in July1998 and will be completed in March 2002, with the final year focusing on the transfer of knowledge to the industrial partners. DEEPMINE represents a new model for conducting mining research: it is driven by industry needs; emphasizes collaboration between industrial partners, research organizations and tertiary education institutions; and has a novel joint-funding mechanism. DEEPMINE has employed a range of vehicles to transfer knowledge to its industrial partners. Novel aspects include: (a) electronic publication of Summary Reports and Guideline Handbooks that seek to consolidate the huge body of knowledge comprehensively and concisely, (b) a series of DEEPMINE Schools designed to enable industry practitioners to apply the knowledge to their current work situation, and (c) Consultancy Reviews, where DEEPMINE specialists seek to apply knowledge to specific real problems on mines.

Jan 1, 2002

The slags produced by the Imperial Smelting Process (ISP) are based on the system ZnO-?FeO?-Al2O3-CaO-SiO2. The slag chemistry is important to the process since it determines the fluxing practice and the operating temperature of the furnace required to produce fluid slag. The paper presents the results of the first systematic experimental investigation of these ZnO-containing slags in equilibrium with metallic iron, and provides information on the primary phase fields and liquidus temperatures in these slags over the range of compositions used in ISP practice. A feature of the slags is the presence of alumina, which has a major influence instabilizing the spinel phase. This information presented in the form of pseudo-ternary sections ZnO-?FeO?-(Al2O3+CaO+SiO2) enabling the data to be readily used by plant engineers. Keywords: liquidus temperature, ISP, EPMA, ZnO-?FeO?-Al2O3-CaO-SiO2, phase equilibria.

Jan 1, 2004

By F. T. Cawood

The new South African Mineral Policy has major implications on the way mineral rent will be collected and shared between the stakeholders in future. Although the policy does not supply details on how this will be done, drastic departures from practices under the previous dispensation require a new approach. For example, there introduction of the ?right to mine? principle implies that the repealed lease consideration concept will be expanded to all minerals. The new policy also makes provision for predetermined standard terms and conditions for all prospecting and mining permissions. It also states that, regardless of whether the mineral rights are state or privately-owned, all prospecting fees and mineral royalties will be determined by state officials after consultation with the registered holder of the mineral rights. This paper proposes a standard mineral royalty formula that complies with the principles mentioned in the White Paper and has been shown to be internationally competitive.

Jan 1, 2001

By C. J. Cutler

Metallurgical accounting for toll treatment smelters pose a number of challenges. Multiple feed stockpiles have to be accounted for as part of the monthly recovery estimation. Moreover, multiple metallurgical intermediates make up part of the in-process inventory, which also influence the monthly recovery calculation. Errors propagate from the measurements of volumes, assays, moisture fractions and bulk densities in the various material types through multiple steps up to the point where the final recovery is calculated. These errors contribute non-linearly to the variance in the final recovery estimate. This paper develops the mathematical formulation for variance propagation in toll smelting operations, including the effect of in-process inventory, assuming measurement biases have been eliminated beforehand. Operational data from a Southern African copper smelter is used for a case study. The method of propagation of variance showed that uncertainties in stockpile assays were the main contributors to variance in the recovery estimate. Variance in the volume and bulk density uncertainties contributed a secondary, yet significant, proportion to the overall recovery variance. It was determined, for the given case study, that the recovery variance depended on the calculation method used and that variance propagation via the two-product formula was smaller than recovery variances calculated via the standard recovery formula. However, the probability that the two product formula will give inaccurate (versus imprecise) results is significantly more due to the practical difficulty of equiprobable sampling of tailings streams from smelter plants (which includes materials such as slags and flue dust). Recommendations are made on how to achieve a reduction in overall uncertainty for toll treatment smelters. Keywords: metallurgical accounting, copper smelters, pyrometallurgy, variance propagation, errors, precision, sampling

Jan 1, 2006

By A. Burger Pintér

To be meaningful the sharing of ideas about the National Environmental Management Act (NEMA) and social issues within the context of Mining and Metallurgy (M&M) requires an honest scrutiny of the M&M/social environment relationship, both past and present. It is not a secret that this relationship has been and is fraught with difficulties. Thus from all perspectives (M&M, society and environmental and social consultants) such a dissection, that highlights the realities, both good and bad, is uncomfortable. For this section of the colloquium to have any value, the honest but difficult approach needs to be taken.

Jan 1, 2000

By M. Vandewalle

What separates the support of mining openings from the support of similar civil engineering structures is the fact that mine openings have to survive large deformations as a result of changing stress conditions induced by progressive mining. Steel fibres impart to concrete and shotcrete a high degree of ductility which not only allows the shotcrete and concrete linings to absorb important rock movements but also to increase its bearing capacity by a redistribution of the loads. A range of applications will be discussed technically and economically.

Jan 1, 1998

By S. Sarac

Solving ventilation networks of natural splitting is a basic problem in mine ventilation. Several mathematical techniques are used to solve this problem. This paper proposes a new method which combines the advantages of both classical Hardy Cross method and unconstrained optimization techniques. The trials carried out on model networks have shown that the method offers some facilities in the analysis of mine ventilation networks. Keywords: Ventilation network analysis, Hardy Cross method, Steepest Descent method.

Jan 1, 2000

By A. W. Bester

Paper written on project work carried out in partial fulfilment of B. Eng. (Mining Eng.) Cullinan Diamond Mine currently handles 3.2 million tons of run of ore per annum. This is done by means of an underground train system, which is located at 763 metre level. Four trains, one in each quarter of the pipe, collect ore from passes and transport it to centrally located tips in the north and south of the pipe. The ore is then split into coarse and fine fractions. The coarse fraction proceeds to the primary crushers in the north and south. Historically, mining has been performed in such a manner that an equal amount of ore has reported to each quarter of the pipe. However, the tonnage profile of the mine will change such that the ore will no longer be split equally. For approximately five years the majority of ore will report to the east and thereafter most of the ore will report to the western portion of the mine. This will continue for the remainder of the current infrastructure level?s operational life. Coupled with this is the fact that the mine is aiming to increase its annual production to 3.8 million tons. The result is that the current ground handling system cannot accommodate the additional tons and therefore alternative ground handling options have been investigated. The continued existence of Cullinan Diamond Mine relies on finding a system that can economically handle the additional tonnage. Three options were investigated. Firstly, a train option, which would be an upgrade of the current system, was investigated. Two truck options were also investigated, the first of which was a conventional truck option. The second truck option was more interesting and involved an unfamiliar Combi truck system. The truck options were investigated primarily due to the fact that the block height of the BA West (a new production block) can be increased by 15 meters if a truck option is decided upon. This would create a significant increase in revenue for the BA West project. Each of the options was assessed in terms of its physical and financial feasibility. In terms of the physical constraints, it was found that all three systems could work. Detailed financial analysis indicated that either of the two truck options would be a suitable solution. However, due to the limited information regarding the Combi truck option, it should be further investigated. This applies particularly to the actual running and maintenance costs for the equipment.

Jan 1, 2005

Council for 1999/2000 President M.H. Rogers President Elect Dr L.A. Cramer Vice Presidents Senior A.A.B. Douglas Junior S.J. Ramokgopa Immediate Past President J.R. Dixon Honorary Treasurer J.A. Cruise [ ] Annual report In accordance with the current management policy, this report on the activities of the Institute is presented under eight main headings: 1. Interests of Individual Members 2. Technical Meetings 3. Publications 4. Regional Development 5. Engineering Science and Technology in South Africa 6. International Liaison 7. State Liaison 8. Management and Administration.

Jan 1, 2001

By P. J. van der Walt

Some 30 years ago exposure to dense-medium separation in South Africa, culminated in the adaptation of the process for the treatment of -0.5 mm fines. The first commercial plant at Greenside Colliery apparently operated for some 18 years. Three further plants followed, including one treating tin ore. It is gratifying to learn, therefore, that there is renewed interest. The objective of making the process easier to operate (?more practical??) is commendable but the cumbersome technical approach could be counter productive. Perhaps a brief outline of the original thinking might be helpful when analysing the problem.

Jan 1, 2003

By J. Bongardt

Ecologically acceptable techniques are described for the handling of waste materials from the fabrication industry. New production methods and the recycling of sludges from grinding and other waste materials are suggested.

Jan 1, 1997

By R. M. Kear

Strategic and tactical planning are both required in the mining industry but have completely different objectives and require different environments. If these are not fully understood, then the best value for a mining operation may not be realized. This paper examines the differences in these approaches and how they interface in the mining environment. The objectives, content, skills required and the implied management issues for these two components are examined with the hope that this will assist management and the planning teams in defining their respective roles and expectations. The opinions are those of the author based on his experience on several mining operations and projects.

Jan 1, 2006

By S. J. Ramokgopa

The development of the modern State and the growth of capitalism involves a complex process of interaction between cross-cutting structural dimension: first between politics and economics and, second, between market and hierarchy. Central to such developments are political economies of scale. Mineral specialization in the Third World developed within the framework of an international extension on oligopolistic structure of the advanced capitalist economies of Western Europe and North America. Up to the late 1960s, the world mineral and metallurgical industry was closely controlled by a handful of Western mining and industrial groups. To the extent that, foreign control of the mining sector was seen in the Third World producing countries both as the essence of foreign domination and as its major symbol. In some newly industrializing countries, the State took a more direct role in tying the economy and society together. Central to this process was the growth of large-scale finance capital. From early 1959to the mid-1970s, metal consumption in industrial countries expanded well beyond their domestic mineral endowments. And a free access to Third World minerals was a major element of the economic dynamism of these countries throughout that period. With the change in the characteristics of international investment, Africa has become less important as an outlet for capital exports of European countries. Actually, the African continent now receives only a very minor share of direct foreign investments of Western enterprises. International political economy is concerned first of all with the relationship between the economic and political domains across territorial boundaries. Second, attention should be drawn to the role of the State as the focus of decision-making in a system of competitive States, that is in turn, interdependent with a trans-national market economy in which mining and metallurgy are essential activities that affect the politics of the State, and how this in turn, rebounds on the politics of the international system. Understanding the role of the State must go beyond the glib pronouncements on the ?national interest?. How, and whose interest, the ?national interest? is determined, is precisely the problem. This implies a third theoretical problem that must be addressed: the linkage between the domestic and international domains (or levels of analysis), given that political-economic processes clearly cut across the lines of political decision-making constituted by the institutional structures of the State. Situating the State and economic interests within this vast ?state-society? complex that we call the global order will be a crucial problem for any theoretical approach that involves mining and metallurgy.

Jan 1, 2002

By Stafford McKnight, Larissa Koroznikova, Steve Hall, Cameron Klutke

This paper outlines a simple methodology for mineral characterisation, developed as part of the Australian Mineral Industry Research Association (AMIRA) managed research project P777 ?The Development of Heavy Suspension Techniques for High Density Separations (Replacement of Clerici?s Solution)?. The project was sponsored by De Beers, Rio Tinto and Iluka Resources. Heavy mineral characterisation of samples arising from exploration, mining or metallurgical processes is frequently conducted using laboratory heavy liquid analysis. Unfortunately, there are only a limited number of high density (?heavy?) liquids and these tend to be more toxic as their density increases. Low-toxicity inorganic solutions, based on tungsten compounds, have been developed that can be utilised at relative densities (RD) up to 3.0. Beyond this value organic liquids can be used, however this presents significant health and safety hazards. Diiodomethane (methylene iodide) having a relative density of 3.31 is commonly used. Mixtures of thallium formate and thallium malonate were found in the early 1900?s by Clerici to provide liquids having specific gravities between 4.0 and 5.0. For the characterisation of the heavy components of mineral sand deposits (e.g. anatase RD 3.9, rutile RD 4.2, ilmenite RD 4.4 ? 4.7 and zircon RD 4.6 ? 4.8) there is currently no heavy liquid alternative to Clerici?s solution. Clerici?s solution is highly toxic and testing is now conducted by few laboratories worldwide with costs reflecting the chemical costs, infrastructure costs and health and safety regimes (e.g. blood testing of exposed staff). A simple laboratory technique of density fractionation has been developed, employing suspensions of fine tungsten carbide particles in lithium heteropolytungstates solutions, that can replace Clerici?s solution in the evaluation of fine mineral sands samples (e.g. -250 +150 microns). The developing methodology that can achieve low-cost, low toxic separations at relative densities above 4.0 is outlined and the comparison of results with Clerici?s solution presented. In addition, preliminary work on density fractionation of zircon samples is presented. Zircon fractionation relates to their inclusion, radionuclide content and metamictization.

Jan 1, 2007

By H. Thomas, I. N. M. Nday

"*Paper written on project work carried out in partial fulfilment of BSc.Eng (Mining Engineering) degreeThe optimization of the cycle time to increase productivity at Ruashi Mining was an on-site project investigation conducted from December 2017 to January 2018. The main objective of the investigation was to determine the actual cycle time components. These comprise the queuing time, loading time, hauling time, and dumping time of ADTs (articulated dump trucks). Data was also collected on two hydraulic shovels to identify where these could be optimized. The actual cycle time obtained was compared to the theoretical cycle time to ascertain the constraints, which affect productivity. By applying Systems Thinking to the cycle time, man-made constraints of the actual cycle time were identified and recommendations to mitigate them suggested to optimize the cycle time. However, rainfall is a natural constraint that adversely affects the actual cycle time, and which cannot be mitigated.In addition, both the theoretical and actual cycle time were analysed, as well as the theoretical and actual productivity for the year 2017. Based on the findings, conclusions and recommendations were made to optimize the cycle time. IntroductionThe aim of the project was to increase Ruashi Mining’s productivity by 39%, from about 7.537 Mt of broken material mined to 12..367 Mt targeted in 2017.BackgroundRuashi Mining is a copper (main commodity), cobalt (by-product), and acid producer located in the Democratic Republic of Congo (DRC), 10 km from the city of Lubumbashi. Figure 1 shows the location of the Ruashi Mining open pit.Ruashi Mining started production in 1911 and in 2005 the mine was registered as a DRC company owned by Metorex Group Limited. In November 2013, the Chinese company Jinchua Group International Resources Co. Ltd. bought a majority stake in the business. Ruashi Mining currently produces 38 000 t of copper and 4400 t of cobalt per annum. The company has contracted NB Mining (a contract mining company) to transport its ore. To optimize the productivity of the mine, considering ore flow delivery at Ruashi Mining, the cycle time is the indicator used in this project. The cycle time components were recorded on site using a stopwatch."

Jul 1, 2019

By H. Simonsen

Risk assessment consists of a search for the answers to: ?What can happen? ?How likely it is that it can happen? ?What are the consequences if it does happen? Perhaps the most important aim of risk analysis is to predict the likelihood that a planned profit will be achieved over a given period of time. A typical risk model employed for this purpose includes a stochastic connection between the dependent variable of an expression that describes a process and independent variables represented as random quantities. The output will be a probabilistic distribution. The uncertainties in a planned mining operation include: ?Commodity market characteristics, particularly price ?Ore reserves and mineralogical composition ?Mining method ?Process performance ?Capital and operating costs ?Schedule duration ?Economic environment effects. The processes employed in the probabilistic estimation of a project?s outcome include both Monte Carlo simulations and simulations where variable correlation is considered important. The risk model, once developed and tested, provides a framework for a rational approach to risk analysis and the testing of alternatives.

Jan 1, 1999