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By E. Keskinkilic

Drying, calcination, prereduction, and smelting are the main steps in conventional crude ferronickel production. Industrially, these steps are conducted using the rotary kiln-electric arc furnace (RKEF) process. In this paper, calcination characteristics of Sivrihisar laterite ores from the Central Anatolia region are investigated. The extent of elimination of chemically bound water and other volatiles was studied by experiments conducted at various temperatures in the 250?800°C range. Phase changes were examined using X-ray diffractometry. For the particle size used in the study, 300°C was determined to be almost sufficient for complete transformation of goethite to haematite, and 700°C was required for effective elimination of all volatiles in the ore.

Jan 1, 2012

By B. Ndlovu

The world mineral industry has over the years experienced growth in the production of nickel (Ni) due to its use not only in the catalytic industry but mainly also to its demand in the stainless steel production industry. Hence there is a need to produce more pure and marketable grades of Ni through the use of efficient purification routes such as solvent extraction. The V10-LIX®84-IC system resulted in nickel (Ni) extraction isotherm shifting to lower pH levels. The pH window of opportunity for the extraction of Ni subsequently increased in solution containing magnesium (Mg) and calcium (Ca) even though the system also resulted in slight shifts to less positive pH values for Mg and Ca curves. Results showed a synergistic effect of LIX®84-IC when added to V10 for all elements, Ni, Mg and Ca. The pH50 values for elements Ni, Mg and Ca in the V10-LIX®84-IC system were 2.95, 8.10 and 7.70 respectively. Comparing results obtained when using V10 alone produced ?pH50 for Ni, Mg and Ca being 3.35, 0.15 and 0.70 respectively, which was a confirmation of the synergistic shifts for all the elements. The ?pH50 (Mg-Ni)value was 1.95 with no synergism and 5.15 with synergism and that for ?pH50 (Ca-Ni)was 2.10 with no synergism and 4.75 with synergism. This showed that the Ni-Mg separation factor was relatively larger than the Ni-Ca. Improved loading and stripping kinetics were also observed. Keywords: Nickel solvent extraction separation, magnesium, calcium, versatic 10 acid and LIX®84-IC.

Jan 1, 2008

By D. Limpitlaw, A. Alsum, D. Neale

"Ecological footprint analysis (EFA) was first described in 1996 as a measure of carrying capacity appropriated by human activities. EFA is a resource and emissions accounting tool designed to track the demand on the biosphere’s regenerative capacity. Ecological footprints are increasingly used as indicators of organizational and corporate environmental performance and product sustainability. There is a compelling argument to develop an EFA tool for mining companies.To determine the size of a mine’s ecological footprint, land requirements for all categories of consumption and waste discharge must be summed. This land is only made up of the ecologically productive land and water in various classes (cropland, pasture, forests etc.) required on an ongoing basis to provide all energy and material resources consumed and absorb wastes.A challenge in conducting an EFA for a mine is the shortage of accessible data. Undertaking an EFA for a corporation or individual site entails compiling consumption and emissions data (which can be used for other reporting applications). The footprint results themselves highlight the most critical aspects of an organization’s impact on the environment and provide a platform for focusing actions and for educating the workforce to improve their contribution to best-practice operations. This paper discusses the benefits and challenges of undertaking an EFA for a mining company, and provides examples of the various components of ecological footprints associated with mines, as well as showing how an EFA can be used to understand and communicate some of the impacts associated with mining activities.IntroductionFundamental biophysical and economic limits are now being experienced in many countries around the world. Herman Daly, a former World Bank economist, described this scenario as ‘uneconomic growth’, where the costs of growth exceed the benefits (Daly, 2005). This occurs when the economy’s expansion encroaches excessively on the surrounding ecosystem, sacrificing natural capital. Under such conditions the sacrificed natural capital is more valuable that the resulting economic growth. Consequently, the world faces largescale threats to sustainability and especially to the viability and continued existence of the ecosystems that support human settlements (El Zein et al., 2014). In recognition of this sustainability imperative, mining companies are increasingly concerned with their ecological footprint (EF)."

Jan 1, 2017

By J. -Y. Jia, G. -B. Qiu, C. -G. Bai, D. -F. Chen

Due to the great importance of the smelting process, it is essential to establish a calculation model on the viscosity of the slag system containing titania. In this paper, the calculation models of mass action concentrations and viscosity for the CaO-SiO2-TiO2slag system have been established according to the coexistence theory of the slag structure, as well as the referenced viscosities ofCaO-SiO2-TiO2at different temperatures and TiO2compositions. With the two models, corresponding calculated programs are made by means of programming language Matlab5.3, and the curves of viscosity of the TiO2concentration (?TiO2/%) at 1400°C, (R=0.9~1.0) are plotted. The results show that mass action concentrations of TiO2increases with increasing percentage ofTiO2, while the viscosity of CaO-SiO2-TiO2system is decreased. The results show that the models are in good agreement with the experimental and referenced data. They also shows that the models are reasonable for the CaO-SiO2-TiO2slag system. Keywords: coexistence theory; CaO-SiO2-TiO2slag system; viscosity ; calculation models.

Jan 1, 2004

[The following notations will be used: O an ore body. W a sample of size w located in O; the size of this sample. W a block or a sample, of size W, located in O; the size of this block or sample. z' a point in W. W' a block or a sample, of size W' greater than or equal to W, located in O; the size of this block or sample. z" a point in W'. y (h) point semivariogram in O. s (h) point covariogram in O. In the previous chapter, we saw that the point semivariogram y (h) usually cannot be estimated directly from the data available. Rather, the values of samples of size w are available in O, and from these a regularized semivariogram y w (h) can be estimated. The following relationship has been proved (5.8): Y w(h) = Y (w;w+h) - Y (w;w). y (w;w+h) is the average value of y (z' z") when z' takes all possible positions in a sample w and z" all possible positions in a sample w+h of the same size, h being the distance between w and w+h. y (w;w) is the value of y (w;w+h) for h = 0, i.e. the average value of y (z' z") when z' and z" take all possible positions in w. We also saw that the regularized covariogram aw(h) is related to the point covariogram a (h) as follows (5.9): w(h) Gr In the following chapters, it will be shown that calculation of the average value y of y, or -a of a, in the general case relating to samples or blocks W and W' which need not be of the same size, plays a very important part in all the practical applications of geostatistical theory. The purpose of this chapter is to introduce various methods of calculating y and a-. Furthermore, mathematical equations and graphs are provided which can be used when the point semivariogram can be represented by one of the more common equations, and when the blocks W and W' are of simple shape. By definition (Fig. 6.1): [ ] Y (W;W) = WW f dz' f y (z' z") dz" (6.1) in W z" in W']

Jan 1, 1978

By D. J. Fourie

During the production of pure TiO2for the pigment industry, ilmenite, containing 35?60% TiO2, is reduced to high titania slag, containing 70?95% ?TiO2? and pig iron. The high titania slag produced, consists mainly of titanium in different oxidation states and FeO in equilibrium with liquid iron. To predict the phase and chemical reaction equilibria in a furnace, a suitable solution model is required with accurately determined binary interaction parameters, as slag melts tend to behave very non-ideally. This paper investigates two popular slag models, namely, modified quasi-Chemical (MQC) model and the cell model and provides the binary interaction parameters based on recently published data of the ternary system and critically assessed published unary and binary data. Very few modelling results have been published on the ternary Ti-Fe-O system pertaining to high titanium slags. The solution models, with their regressed interaction parameters, can subsequently be implemented in commercial software of the slag-metal phase equilibria to predict how much and which type of solids will precipitate for a given bulk slag chemistry and operating temperature or, alternatively, above which temperature should a furnace be operated to avoid excessive solids precipitation.

Jan 1, 2005

By E. J. Magri

Consideration is given to the problem of the estimation, from limited data, of the likely grade and tonnage for a new mining property that is to be exploited by the selective mining of two metals that have substantial contributions to make to the total revenue. In particular, the case of a new gold and uranium mine in South Africa is analysed as follows. (I) The applicability of the underlying lognormal bivariate model for different support (i.e. ore unit) sizes is examined. (2) The necessary parameters for the bivariate lognormal models for different block sizes are estimated from abundant chipsampling data from a section of the Hartebeestfontein Gold Mine using alternative approaches, and the results are compared. (3) A method is given for obtaining the necessary parameters for a tonnage-grade relationship relative to a joint pay limit from the very limited information likely to be available at the end of the exploration stage of a gold mine, and the results are compared with those obtained from the large volume of data available from a minedout area.

Jan 1, 1982

By C. Banff, E. C. F. Hamman, J. Venter

Open pit slope stability analyses for large scale instabilities are often carried out using limit equilibrium, finite element or finite difference computer programs. All of these require empirical estimates of rock mass shear strength when calibrated values are not available, which is a common occurrence. A common method of estimating rock mass shear strength is the Hoek-Brown failure criterion, which often over- or underestimates rock mass shear strength when used in limit equilibrium or elastic linearly plastic slope stability analyses, resulting in published alternative estimates for the coefficients of the Hoek-Brown failure criterion. This paper investigates the differences between limit equilibrium and elastic linearly plastic slope stability analysis based on the Hoek-Brown failure criterion. The investigation consisted of a comparison of 3840 RS2 finite element analysis models completed with strain softening, and 216 Slide2 limit equilibrium models. The models were used to evaluate a methodology to determine equivalent limit equilibrium and elastic linearly plastic shear strength parameters that provide the same stable slope angles and instability back break distances as the more representative strain softening stress analysis methods. This paper presents the methodology and compiles the results into design charts and equations for equivalent limit equilibrium Mohr-Coulomb shear strength parameters, that simplify calibration against actual case studies. The results compare well with older empirical shear strength estimates, however, a detailed calibration of the results against case studies will need to be carried out. The analysis also did not consider pore pressure effects; this is left for future publication.

Sep 1, 2025

By D. F. Malan, R. P. Els

The limit equilibrium model, used in displacement discontinuity codes, is a popular method to simulate pillar failure. This paper investigates the use of physical modelling to calibrate this model. For the experiments, an artificial pillar material was prepared and cubes were poured using the standard 100 mm × 100 mm civil engineering concrete moulds. The friction angle between the cubes and the platens of the testing machine was varied by using soap and sandpaper. Different modes of failure were observed depending on the friction angle. Of interest is that significant loadshedding was recorded for some specimens which visually remained mostly intact. This highlights the difficulty of classifying pillars as failed or intact in underground stopes where spalling is observed. The laboratory models enabled a more precise calibration of the limit equilibrium model compared to previous attempts. Guidelines to assist with calibration of the model are given in the paper. The limit equilibrium model appears to be a useful approximation of the pillar failure as it could simulate the stress-strain behaviour of the laboratory models.

May 3, 2023

By D. Zhou, T. Hamano, Tsukihashi. F., W. -G. Seo

The thermodynamic properties for the CaO-CaF2and CaO-BaO systems were calculated by molecular dynamics (MD) simulation using Born-Mayer-Huggins type pair potential. The parameters of interatomic potential were obtained by fitting the thermodynamics properties of CaO, CaF2and BaO with the experimental data. The phase diagrams for the CaO-CaF2 and CaO-BaO systems were calculated by the thermodynamic properties obtained by MD simulation. The eutectic composition and temperature of the CaO-CaF2system calculated by MD simulation were about 28 mole per cent CaO and 1575K, respectively. The calculated eutectic point agrees very well with experimental data, which are about 22 mole per cent CaO and 1633K, respectively. Keywords: molecular dynamics simulation, thermodynamics, phase diagram, calcium oxide, calcium fluoride, barium oxide.

Jan 1, 2004

By P. R. Mothemela

The objective of the investigation is to optimize the truck and shovel operations for pre-stripping at New Vaal Colliery by introducing campaign mining. The aim of campaign mining is to improve the efficiency of the loading, hauling, dumping, and maintenance operations which are critical to the success of truck and shovel operations. The current loading (single-sided loading method), hauling, and dumping operations at New Vaal Colliery were found to be inefficient. Time studies were used as a major indicator to highlight the inefficiency of the truck and shovel operations, and it is recommended that an improved loading configuration, hauling, and dumping operations be implemented by using campaign mining. It is also recommended that a service truck be used to maintain the pre-stripping fleet in order to reduce travelling times to the main workshop. As expected, the improved operating conditions will lead to an increase in pre-stripping production.

Jan 1, 2013

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 R. C. D. Phillis

The management of critical resource inventories is an important productivity lever and a significant risk factor?risk in the sense that poor resource availability lends itself to disempowerment of workers, unsafe work practices, wasted spending (high unit costs),and poor quality of work (including mining waste/rework). Most underground platinum mines experience lost blasts that directly lead to reduced productivity. In most surveyed shafts, 30% of lost blasts can be attributed to shortages of critical material and/or equipment. The problem is prevalent despite the existence of conventional transitory surface and underground stores. This paper discusses the introduction of buffer stores as a complementary materials storage system in order to improve health and safety in mines as well as reduce lost blasts. Both quantitative and qualitative results have shown that buffer stores result in dramatic improvements in productivity and are readily acceptable by stakeholders. Keywords Buffer stores, lost blast.

Jan 1, 2011

By M J. Daniel

The diamond industry is no newcomer to High Pressure Grinding Rolls (HPGR) as it has used the technology for more than 20 years, predominantly in secondary crushing and recrushing roles. In fact it could be argued that the diamond industry has led the way for the wider minerals industry to consider its application. In existing conventional secondary cone crushing applications, large valuable diamonds are" won" through meticulously managing the recovery process within defined particle size ranges. Conventional crushers operate with relatively large closed side settings, but have the potential to damage diamonds by making direct contact with the sides of the crusher. Cone crushers also result in steep product size distributions that run a high risk of losing many of the smaller, unliberated but more abundant diamonds from the rock. This current comminution paradigm of particle size reduction management results in recrushing processing applications or plants where HPGRs are often used.

Jan 1, 2010

By A. Chuma, K. J. Nyembwe, H. Simonsen, J. H. Potgieter

Different concentration techniques were evaluated for preconcentration of a mineral ore at a coarser size to avoid energy and resource wastage. Specifically, the aim was to reduce milling costs and energy required in the beneficiation of tin. In this study, cassiterite (0.17% Sn) was the mineral of interest in a pegmatite ore body associated with quartz (SiO₂ > 60%) and alumina (Al₂O3 > 20%). Three concentration techniques, namely dense media, shaking table, and flotation, coupled with characterization analysis, were used to assess the concentration response. The results confirmed that particle size and mineral liberation impact the separation process. High recovery and grade were obtained with gravity concentration methods (dense media and shaking table) for coarser (+300 to +212 μm) and intermediate (+150 to +53 μm) particle sizes. Lower recovery and grade were identified for much finer sizes (−53 to −38 μm). Flotation produced a high-grade product at a relatively low recovery and appeared to be only applicable to finer grains. Separation efficiency based on Schulz’s equation measured a segregation performance of 74.8% for dense medium separation and 60.7% for the shaking table for the coarse and intermediate particle sizes. Flotation only achieved a separation of 30%–40%. The results suggest that use of dense media separation as a rough preconcentration method prior to further grinding, and the utilization of a more advanced concentration technique for mineral recovery and upgrade, constitute a successful approach to improve process economics.

Apr 14, 2024

By PC Pistorius, DR Groot

The South African base metals industry has been one mainly focused on the production of metals or metal compounds from primary ores. This is true for metals such as titanium, vanadium, chrome, manganese, cobalt, nickel, copper, zinc and aluminium. The steel making industry has traditionally used a substantial portion of scrap steel, and could thus be considered to be somewhat of an exception. Secondary sources have played much less of a role, possibly due to at least some of the following factors. Scrap material is often of unknown composition, and thus it requires additional chemical analysis, and possibly special treatment. Tonnages are relatively small, and the incorporation of secondary materials is possibly seen to carry undue risk and inadequate benefit. South African consumers are still not very conservation and recycling conscious, which limits the amount of scrap made available. This attitude might also be expected to influence decision makers in these industries. Finally, pressure from environmentally motivated activists locally has not been unduly large. This landscape has been changing, and is continuing to do so. Various municipal authorities such as those of Pretoria, Johannesburg and Cape Town are reporting increasingly limited landspace for waste (Bondolfi, 2007). There are increasing concerns regarding the leaching of hazardous metals such as chromium, mercury and cadmium from landfill waste, especially electronic and electric wastes ? the so-called eWastes. In more developed countries such as the United States of America and Western Europe the problem of eWaste has grown to the extent where legislation has been enacted, such as the Waste Electrical and Electronic Equipment (WEEE) legislation of the EU (European Union Directive 2002/96/EC). The 19th and 20th centuries have seen major technological advances. Relevant to this paper is the availability of centrally generated electrical power, telecommunication, entertainment through recorded and transmitted music and images, the growth and pervasive influence of electronics, and the handling of digital data by computers and microprocessors. These developments have placed ever increasing demands on resources for the manufacture of electrical and electronic equipment, as well as on the generation of electrical power. Most of the resources required are non-renewable: copper, steel, aluminium and other metals, various thermoplastic polymers such as PVC (polyvinyl chloride), polyethylene and ABS ( acrylonitrile-butadiene-styrene), thermosetting polymers such as epoxies, elastomers such as butyl rubber, glasses and ceramics, and composites such as fibre reinforced plastic (fibreglass). The conservation of non-renewable resources inevitably includes recycling. To a certain extent, recycling of materials locally is well established. Thus glass, paper, used oil, car batteries, ferrous scrap such as beverage cans and non-ferrous scrap such as

Jan 1, 2007

By Valérie Léveillé

As new legislation drives to lower SO2 emissions from metallurgical plants, plant managers face the challenge of keeping their costs under control. The Cansolv® SO2 Scrubbing System has been broadly adopted in the non-ferrous industry as a cost effective solution for smelter operators to meet the new SO2 emissions targets. The Cansolv® SO2 Scrubbing System is an amine-based regenerable process that selectively absorbs SO2 from a variety of gases, including dilute smelter gases, such as furnace and converter gases. The system produces a pure, water-saturated SO2 byproduct stream, which can then be directed to the front end of a sulfuric acid plant for conversion to sulfuric acid. When deployed in a smelter complex, the Cansolv® SO2 Scrubbing System may also be used to process acid plant tail gas, allowing single absorption sulfuric acid plants to achieve emissions an order of magnitude lower than that of a double absorption acid plant with a lower capital investment. Depending on inlet gas temperature SO2 emissions in the treated gas can be controlled to as low as 55 mg/Nm3. This paper will describe some of the applications where customers have or are planning to use the Cansolv® SO2 Scrubbing System and what as well as which features and cost advantages for the treatment of smelter gases were key to the technology choice.

Jan 1, 2009

By V. Léveillé

As new legislation drives metallurgical plants to lower SO2 emissions, plant managers face the challenge of keeping their costs under control. The Cansolv® SO2 Scrubbing System has been broadly adopted in the non-ferrous industry as a cost-effective solution for smelter operators to meet the new SO2 emissions targets. The Cansolv® SO2 Scrubbing System is an a mine-based regenerable process that selectively absorbs SO2 from a variety of gases, including dilute smelter gases, such as furnace and converter gases. The system produces a pure, water-saturated SO2 by-product stream, which can then be directed to the front end of a sulphuric acid plant for conversion to sulphuric acid. When deployed in a smelter complex, the Cansolv® SO2 Scrubbing System may also be used to process acid plant tail gas, allowing single absorption sulphuric acid plants to achieve emissions an order of magnitude lower than that of a double absorption acid plant with a lower capital investment. Depending on inlet gas temperature, SO2 emissions in the treated gas can be controlled to as low as 55mg/Nm3. This paper will describe some of the applications where customers have or are planning to use the Cansolv® SO2 Scrubbing System, as well as which features and cost advantages for the treatment of smelter gases were important in the technology choice.

Jan 1, 2009

By A. J. S. Benade, A. J. A. Heyns, N. B. Strydom

The maximum oxygen intakes of samples of about 30 Bantu, weighing less than 50 kg from different tribal groups (Zulu, Xhosa, Sotho and Shangaan) were measured on a treadmill. The mean maximum oxygen intake of the 164 men was 2,12 litresjmin and only 18 men (11 per cent of the sample) had maximum oxygen intakes of 2,5 litres/min or above (the minimum requirement for such tasks as shovelling rocks and tramming it). The samples of the different tribes differ in age, but when the age effect is taken into account then there were no significant differences between tribes in maximum oxygen intakes. An incidental finding was that both age and body weight correlated significantly with the maximum oxygen intakes of these underweight subjects. Not one of the subjects who weighed less than 45 kg or who was older than 40 years had maximum oxygen intakes high enough to permit their being able to do strenuous work underground. It is clear therefore that Bantu who weigh less than 45 kg or are older than 40 years should not be employed on such strenuous tasks as shovelling rock and tramming it.

By A. G. R. Coreejes, G. Ferreira

The paper sets out briefly the methods used for the planning and control of the construction work at Grootegeluk Coal Mine near EIIisras, Transvaal. It includes a discussion of the programming, the updating of programmes, and the progress reporting.

Jan 1, 1982