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By W. P. Erasmus

This paper will focus on the use of the ?wet-mix? steel fibre re-in forced shotcrete as a permanent lining in deep shafts, assessing gold bearing reef. It will cover all aspects relating to the choice of this material covering the geological conditions through to the final quality control. All procedures are in line with ISO 9001,as JCI projects who manage the project, are an approved company therof.

Jan 1, 2001

By N. L. Ayres

Tendon support systems have been successfully used to stabilize excavations. Tendon support systems are routinely designed using the axial load-bearing capacity of tendons, namely the tensile strength. To attain tensile strength the tendon must be loaded along its length, which often does not occur in practice. Tendons should optimally be installed at 90° to the surface of the excavation to achieve maximum penetration depth, yet this is often not physically or practically possible, and installations at angles less than 90° occur. Furthermore, the intersection of geological features within the rock mass frequently results in complex loading situations on tendons. The position and angle at which loading occurs results in different combinations of tensile and shear forces acting on the tendon, which can impact on the support performance of each unit and ultimately the whole system. All factors that influence the support system should be understood and taken into account to ensure a sound support design. Combination loading situations are further investigated and tested to obtain a better understanding of the mechanisms involved and the effects on tendon load-bearing capacity. Tendon support units were tested at different installation angles to establish the tendon performance, mechanical behaviour, and load capacity during these loading situations. The results and outcomes are aimed at providing rock engineers with additional data and improved understanding of how tendons could perform under certain conditions.

Jan 1, 2014

By F. Russo-Bello

TauTona Mine (the renamed Western Deep Levels East) is using a longwall mining method with stability pillars to extract the Carbon Leader Reef at a depth ranging from 2097 metres to 3456 metres below surface. Seismic activity and the complexity and hazards associated with negotiating geological features at great depth pose the most severe hazard to deep level gold mining in South Africa. It impacts negatively on safety and the profitability of the mining. The critical success factors in longwalling at depth are: ?Sound mining strategies and face shape control ?Ensuring follow behind development infrastructure is kept up to date ?Support system design as a strategy to effectively limit the serious effects of damaging seismicity. This paper describes the following: ?Implementation of the required mining strategies ?The evolution of a new stope support system and problems associated with its development and implementation. How this support system was adapted for the successful negotiation of major geological features with known seismic potential and problems encountered ?Current initiatives to optimize follow behind development infrastructure ?Current initiatives in designing a new gully support system and problems experienced with its development and implementation. Finally, this paper will deal with the way forward, briefly covering areas like the above-mentioned gully support system, the proposed phased introduction of technology, and the use of alternative mining layouts.

Jan 1, 2000

By J. H. Zietsman, S. Maharajh, J. Muller

In the chlorination process for TiO2 pigment production, blends of titania feedstocks such as ilmenite, synthetic rutile (SR), natural rutile, upgraded slag, and chloride-grade slag are reacted with coke and chlorine at a temperature of around 1000°C to form TiCl4 (the main product) and other waste metal chlorides. The TiCl4 is the main feed material for the TiO2 pigment-making process. Feeding different titania materials to the chlorinator affects the amount of coke and chlorine required for the process, the amount of waste generated, waste disposal costs, the amount of TiCl4 produced, and bed build-up rates. These factors influence the value of the feedstock. Generally, a higher TiO2 feedstock is more valued since less waste is generated and less reagents are consumed. To quantify the impact of different feedstocks on the chlorinator, a techno-economic model was developed to describe the chlorination process and estimate process variables at steady state. This paper describes the development of the model and studies in which the model has been used to quantify effects of using different feedstocks.

Jan 1, 2015

The University of New South Wales (UNSW Australia) has been a world leader in the development of innovative virtual reality technologies over the last 15 years. AVIE (Advanced Visualisation and Interactive Environment) was developed by iCinema as a collaborative venture between UNSW?s Faculties of Engineering and the College of Fine Arts. This is the world?s first 360°-surround, virtual reality (VR) stereo projection theatre system. The School of Mining Engineering at UNSW Australia has developed 18 different virtual reality modules aimed at mine safety training and mining engineering education. These modules are being regularly used in both the mining industry and the university. The School of Mining Engineering is continuously involved in the development of different modules. Research is also currently being conducted on the implementation of other technologies into this environment. Artificial intelligence (AI) and fuzzy logic are tools that the authors would like to consider implementing in future module development. This paper will review current research in both these areas and consider options for applying these technologies.

Jan 1, 2014

By A. A. Debrah

Artisanal and small-scale mining (ASM) plays a fundamental role in the national and local economies of resource-rich countries in Africa. As such, more effort must be geared towards fostering this type of economic activity to sustain livelihoods in rural communities. Across Africa, efforts to operationalize ASM based on a sustainable development framework have been quite tedious and often ineffective. This is because most of these frameworks lacked context and an understanding of the continuum from the artisanal through small-scale and up to the junior miner, grouped under the general term ?ASM?. Driven by the need to contextualize some of the definitional issues in this niche sector, and gain a clearer understanding of their peculiar challenges, this paper aims to contribute to the debate on ASM by considering two of Africa?s resource-rich countries ? Ghana and South Africa. Since South Africa has made greater inroads in protecting the interests of small-scale miners, we thus draw comparisons from both countries? approach to ASM, outline the lessons learnt, and provide recommendations regarding the ways forward.

Jan 1, 2014

By G. I. McPhail

The authors have conducted several investigations into the prediction of the beach profile of high-density tailings and have found that there are a number of important considerations that need to be taken into account over and above the reliability of the beach profile prediction methodology. These considerations relate to the chemistry of the slurry and specifically the influence of pH and flocculation, both of which have a significant influence on the rheology of the slurry at the discharge point. A number of examples are discussed and a potential testing protocol that will assist in assessing the influence of chemistry ahead of the beach profile predictions is presented. A methodology for assimilating the results of the testing into the likely field situation is discussed, and suggestions are made on application of the results in beach profile prediction. The suspected influence of residual flocculation on the stratification

Jan 1, 2012

The Mineral Sector Development Project, sponsored by the World Bank, has been set up to revise the legal, regulatory and fiscal framework for the minerals industry in Tanzania, with a view to attracting mining companies and investors to the country and facilitating future minerals development. One component of this project, the Environmental Management Framework for the Mineral Sector, was awarded to Wardell Armstrong of the UK and ENV Consult of Tanzania. In developing a new framework of environmental regulations, emphasis was placed on developing realistic standards which reflect local conditions and prevailing values. The main corner-stones of this approach are; effective environmental impact assessment procedures; establishment of environmental management procedures; and monitoring and auditing of companies? performance. The favoured approach involves a three-tier framework, as follows: ?Framework environmental provisions within the new Mining Act; ?Regulations covering more detailed environmental requirements ?Guidelines and/or Codes of Practice, which may in future become regulations in their own right. Careful consideration has been given, in developing the framework, to the limited resources likely to be available for implementation to the Ministry of Energy and Minerals and this has influenced the approach that has been adopted. This paper outlines the main components of the environmental management framework and discusses some of the important issues raised by these proposals.

Jan 1, 1998

By J. J. Stacey

Large mining companies generally follow the distributed ownership corporate model, with a board of directors responsible for decisions that affect both shareholder value and stakeholders of the company. The board is simultaneously responsible for setting the culture and values of the corporation, which drive performance and priorities. Companies listed on the Johannesburg Securities Exchange (JSE) commit to sustainable development in various ways, either by virtue of implementing the King Code of Governance 2009 (King III) and/or through their own public reporting on social and environmental matters. Many mining companies make public statements regarding their support for environmental stewardship, ethical behaviour, and fair treatment of communities. It is a local, regional, and indeed, global phenomenon that companies fail to deliver on these statements. Research was carried out through the Institute of Directors of Southern Africa in 2007, and followed up in 2012, regarding directors? understanding of sustainable development issues, the relative priorities, what is needed for ?radical change? to effect sustainable development, and what enables or constrains the latter. Pertinent findings of both surveys are presented in this paper, and it is suggested that ?on-the-ground? performance may be indicative of the nature of leadership and decisions in the topmost ranks of the company. The results indicated that environmental concerns fall consistently below social issues. Financial capital ranked most important, and while environmental issues are recognized as being of strategic concern for the long-term, they ranked as being the lowest importance of all ?Five Capitals? (Financial, Manufactured, Social, Human, and Natural). Social capital ranked second lowest, with black economic empowerment being the only high-priority social issue. There is also evidence that certain companies within the mining sector fail to recognize their absolute dependence on natural resources. Much is made in academic and popular literature of the need for a new type of leadership for the radical shift to sustainable development: at company level this implies therefore a new type of director. The research found that only 14 per cent of directors felt that board decisions are consistent with their personal values; while intentions are strong to behave ethically and serve sustainable development, actions to give effect to these intentions lag significantly. Respondents indicated that the top impediments to courageous leadership for sustainable development related to personal issues of maintaining the image of being a director, fear of appearing weak, fear of being a lone voice, and bowing to board-colleague peer pressure.

Jan 1, 2014

By P. F. Ledwaba

South Africa?s Northern Cape Province houses a variety of gemstone minerals. Diamonds remain the primary gemstone in the province, but there are also tiger?s eye, sugilite, rose quartz, jasper, amethyst, amazonite, tourmaline, and topaz deposits. This paper gives an overview of the tiger?s eye (TE) mining sector in the Northern Cape, with the objective of assessing the potential of TE to contribute to job creation and poverty alleviation in the province. Mining of TE started in 1803, but gained momentum during the 1960s. Mining is conducted on a small-scale basis, and in most cases without any legal framework. The majority of the residents are not benefiting from TE. It has been reported that an estimated R700 000 to R800 000 worth of TE is leaving the country every week through illegal trading. The potential for TE mining to contribute to socioeconomic development is hindered by illegal operations, lack of technical skills and knowledge, exploitation by dealers, lack of market information, community rivalries, and absence of value addition. A multi-stakeholder approach is needed to formalize the sector and reap the benefits. Mintek is spearheading a TE project in the Prieska area of the Northern Cape, which aims to establish a gemmological centre where TE can be beneficiated into saleable and high-value products..

Jan 1, 2014

An efficient and portable mathematical model has been developed for simulating heat transfer in six-in-line slag-resistance-heating electric furnaces for smelting sulphide ores to produce base metals and platinum group metals. This model is a steady-state one relating furnace conditions and performances to various control and input parameters. Some transient effects occurring in electric furnaces are neglected for computation efficiency. This article describes the model development and modelling results. The present model is capable of predicting: (i) temperatures at various locations in a six-in-line furnace, such as slag bath, matte bath, solid charge, freeboard space, freeze lining, cooling water, and air gaps between solid material components, etc. (ii) freeze lining thickness, (iii)smelting rate, and (iv) heat loss rate, etc. A typical feature of the model is that it is easily portable to different application platforms and sufficiently efficient with execution times less than a few seconds. Therefore, it is possible to apply the model for online prediction and control of heat transfer and freeze lining thickness in industrial electric furnaces.

Jan 1, 2011

By M. Kawakami, K. Suzuki, T. Takenaka, S. Yokoyama

Molten NaNO3-NaNO2-KNO3mixture is used as a heat transfer medium at high temperature. One of the most important properties of this mixture is the heat capacity. In the present work, the enthalpy change with temperature was measured by the drop calorimetric method to evaluate the heat capacity. The results are summarized as follows: The enthalpy of the mixture increased linearly with the temperature. From the slope of the line, the heat capacity was evaluated. The heat capacity of pure NaNO3, NaNO2and KNO3was 0.129,0.110 and 0.142 kJ/mol/K, respectively. These values are in fairly good agreement with the published data. In the binary and ternary systems, the molar additivity of heat capacity, which is well known as Neumann-Kopp’s law, was obtained. The heat capacity of HTS1and HTS2, which are well known ternary mixtures of practical use, were in the range of published data.

Jan 1, 2004

By N. M. Skarbøvig

Safety nets have been used selectively in several South African mines over the years. Recently, however, an increased emphasis on mine safety has seen a resurgence of their utilization underground. This renewed interest has, however, also raised questions about the design and performance of these nets and their practical applications underground; these are the subjects of this paper. Generally, mine safety nets are used to protect personnel from falling rock in temporarily supported development ends, tunnels, ASGs and stopes. These diverse applications each require specific net designs, resulting in a wide product range. As a rule, however, mine safety nets need to carry specified static or dynamic loads with the least possible deformation. Because of the application-specific characteristics of mine safety nets, there is no South African national standard for them. Consequently, neither the SABS, nor the CSIR, performs standard tests on these components. In 2007, therefore, SIMRAC made available their Savuka facility for the testing of mine safety nets; the Savuka drop test became the accepted industry test standard for mine safety nets. From late 2007 to mid 2009, Norsenet, in collaboration with SRK Consulting, the designated operators of the site, conducted approximately 200 tests, which formed the core of Norsenet's database of safety net performance under various loading conditions. The test specimens comprised a wide range of net materials and config¬urations; the materials included: high density polyethylene, polypropylene, polyester, nylon, as well as a blend of polyester and polypropylene used primarily for reinforcement ropes. Net configurations encompassed the following parameters: net type, i.e., knotted nets or sewn nets; net strand type, i.e., braids, twines, or webbing; strand size; mesh size; mesh orientation, i.e., parallel or oblique to the net edge; net edge reinforcement, i.e., knotted, tied, with or without reinforcement ropes; internal reinforcement ropes, i.e., diagonal ropes and/or orthogonal ropes; as well as net attachment options, including loops and chainlinks. From the number of variables listed above, and the limited number of tests available, it can be appreciated that the findings of the test series required careful scrutiny. Nevertheless, principal performance factors clearly emerged: besides the obvious net mesh variables, such as net strand material, strand diameter and mesh size, it was the configuration of the reinforcement ropes and their attachment to the net panel which had the strongest influence on net performance. All the structural elements of a safety net need to work together to transfer the imposed load from the net panel, through the reinforcement ropes, to the net attachment points. In this load transference chain, the weakest link limits the strength of the structure. From this development work, Norsenet has gained valuable expertise to custom-design and manufacture nets to clients' specifications. The examples presented in the paper will also show the experience acquired in the installation of nets underground. Future work will include the establishment of a state-of-the-art net testing facility at Norsenet's factory in Vredenburg.. Keywords Mine safety net, safety net, protective device, mine safety, safety net design, safety net performance, safety net applications.

Jan 1, 2011

It is estimated that the tailings dam of the Mouteh Gold Mine, in Iran, contains more than 770 kg of gold. Microscopic analysis reveals that sulphide minerals and active carbon are the main sources of the gold in the tailings residue. Flotation and cyanidation tests on the samples of tailings were conducted. Flotation concentrates, containing around 87.79% of the gold, which were associated with sulphide minerals, were recovered. By regrinding, roasting, and cyanidation of the flotation concentrate, the gold dissolution recovery was in the range of 87.8 to 98.4%. The carbon-in-column method was used to recover 98% of the gold from the solution. Keywords: gold ore, pyrite, flotation, roasting, cyanidation

Jan 1, 2009

By J. Kraemer, A. Preusse

In the federal state of North Rhine Westphalia (Germany) small and medium sized companies are beginning to extract the related gas via old shafts or boreholes and to use it as a source for the production of electricity and heat. More than 100 applications for the separate mining right on mine gas had already been filed by beginning of 2002, since mine gas is treated as a mineral resource under the Federal Mining Law. Meanwhile more than 40 mine gas concessions have been granted and first projects are being developed with encouraging results so far. To enhance the applied techniques and their efficiency Aachen University has formed a research team in this discipline. Scope and goals of this research activities are being presented in this paper. Keywords: extraction mine gas, Renewable Energy Act, Ruhr District.

Jan 1, 2003

By P. J. Hancox

Heavy mineral deposits have been known from Liberia since the1950s from both river and beach placers. The heavy mineral content of beach sands ranges between 28?62% and the suite includes ilmenite, rutile, zircon and magnetite. These occur together with kyanite, sillimanite, staurolite and garnet. The average ilmenite content is 82% with minor zircon (11%), rutile (6%) and monazite (1%). The ilmenite is, however, of poor quality with haematite intergrowths and a titanium content ranging from10?42.4% (average ±25% TiO2). The amounts of rutile and zircon, while of suitable quality, have also previously been deemed too low for economic exploitation.

Jan 1, 2000

By Q. C. Reynolds

Keywords: Pyrometallurgy, plant, photography, GIS, satellite images, Google Earth Google Earth is a piece of software able to display an interactive three-dimensional map of the world, combining aerial and satellite photography with maps, terrain, and user-generated geographical information systems (GIS). Many structural features of the planet, both natural and man-made, are of great interest to the mining and metallurgy field, and in this paper a study is made of the current state of the art of data accessible by Google Earth.

Jan 1, 2006

By G. Lyman

The cross-belt sampler is a device that is very widely used even though it has not been ratified by the Standards associations. This paper is concerned with the bias testing of two cross-belt sampler designs against stopped belt samples and a cross-stream cutter at the belt end. The bias analysis is carried out using size distribution as the analyte and conventional t-testing and the Hotelling T squared test, which are compared for their effectiveness. The paper considers the issue of detectable bias and the statistical planning of bias tests.

Jan 1, 2010

Although not fully accepted in South Africa, the Theory of Sampling originally proposed by Pierre Gy is fast becoming the cornerstone of sampling practice throughout the world. The growing acceptance of Gy?s Theory of Sampling in South Africa can be attributed to a number of factors, chief amongst them being the development of a tradable mineral asset market, the promulgation of the Mineral and Petroleum Resources Development Act (MPRDA), the growing number of commercial and academic courses that are offered on sampling, and the regulation of the industry through internationally acceptable guidelines and rules for reporting and trading in mineral assets. The size of the South African minerals industry and the dependence of our economy on mineral production have also meant that correct sampling is of key importance to mineral trade. ISO standards have been the principal guides for producers of mineral bulk commodities who produce to customers? specifications, whereas Gy?s insights have been most readily accepted by precious and base metals producers whose product is sold into metal markets. Understanding of small-scale variability is essential in the precious and base-metal industries, but detailed studies of the effects of heterogeneity have not been as productive in the bulk commodities. Sampling practices at different stages of mineral development from exploration, face sampling and grade control, ore processing and handling, metallurgical sub-sampling, point of sale sampling, and sampling in the laboratory are considered in the gold, platinum, ferrous metal, and coal industries. A summary of the impact of poor sampling in these industries is presented. Generally it appears that poor sampling practice is most likely to erode mineral asset value at the early stages of mineral development. The benefits of good sampling are considered, especially with regard to the financial implications of bias and error on large and consistent consignments of bulk commodities. Keywords theory of sampling, sampling errors, ISO standards.

Jan 1, 2014

By G. J. de Korte

South Africa’s best-quality coal, located in the central Highveld basin, is becoming depleted and alternative sources of coal, such as the Waterberg coalfield, will have to be developed to supply the country with coal in the future. The quality of the coal being mined in the central basin is gradually becoming poorer. This necessitates that more of the coal be processed to improve the quality to meet customer requirements. The challenge to the coal processing industry is to process low-yielding coals to produce goodquality products and at the same time ensure that coal mining remains economically viable. This requires that more cost-effective coal processing technologies be investigated and implemented.

Jan 1, 2015