Scielo RSS <![CDATA[Journal of the Southern African Institute of Mining and Metallurgy]]> http://www.scielo.org.za/rss.php?pid=0038-223X20080010&lang=en vol. 108 num. 11 lang. en <![CDATA[SciELO Logo]]> http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za <![CDATA[<b>Rock mass characterization: A comparison of the MRMR and IRMR classification systems</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2008001000001&lng=en&nrm=iso&tlng=en The MRMR classification system was developed specifically for mining applications, namely caving operations, and is one of three rock mass classification systems used in the South African mining industry today. Increased usage of the MRMR classification system has raised concerns that it does not adequately address the role played by discontinuities, veins and cemented joints in a jointed rock mass. To address these concerns, Laubscher and Jakubec introduced the In-Situ Rock Mass Classification System (IRMR) in the year 2000. Although the IRMR system is more applicable to a jointed rock mass than the MRMR system, a quantitative comparison of the MRMR and IRMR classification systems indicates that there is not a significant difference between the resultant rock mass rating values derived from the two classification systems. <![CDATA[<b>Importance of pore pressure monitoring in high walls</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2008001000002&lng=en&nrm=iso&tlng=en Groundwater and associated pore pressure represent elements that can have a negative impact on surface mining and slope stability. Groundwater flow and deformation within a slope influence each other. An increase in pore pressure will result in a decrease of effective stress; and conversely, if the pore pressure decreases, the effective stress increases. Slope analysis and slope design calculations require good information on pore pressure distribution around an open pit excavation. Until recently very little pore pressure data were available and assumptions had to be used. Location and design of measuring points depend on geological and structural setting, geotechnical domains and practicality. Good planning and the use of sensitive point piezometers to measure in situ pore pressures means that real-time data can be collected and used for the construction of flow nets, the determination of pore pressure distribution around an open pit mine, the validation of the dewatering/depressurization requirements, the calculation of the efficiency of the dewatering system and finally the use of pore pressure data in slope stability analysis. The recommended layout for a monitoring system, types and design of piezometers, data collection and use of the pore pressure data are presented <![CDATA[<b>Improving the safety performance of the UK quarrying industry through a behavioural based safety intervention</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2008001000003&lng=en&nrm=iso&tlng=en This paper summarizes a behavioural safety project undertaken in seven quarries in the UK in order to investigate its applicability as a means of raising the standards of health and safety in the UK quarrying industry. A behavioural safety methodology was developed and trialed at two quarry sites in the UK. During the study the number of unsafe acts and minor accidents had decreased and at one of the quarries there was a 95% reduction in the number of working days lost. It was then introduced at a further five sites of varying sizes and within this focused specifically on lone workers as well as behaviours that affected quality and environmental issues. Positive improvements were noted in most of these operations. The project also looked at the effectiveness of health and safety performance indicators. Here, the common lead and trailing indicators for both safety and health that are commonly used by industry were identified. In consultation with the UK quarrying industry these were then used to identify specific performance measurement criteria that can be used by the quarrying sector to measure performance. Following on from this, a quarry specific health and safety management system specification was developed for large and small quarries <![CDATA[<b>Effect of using plastic spacers on toxic fume generation by permitted explosives</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2008001000004&lng=en&nrm=iso&tlng=en Toxic gases, mostly carbon monoxide (CO) and nitrous oxides (NOx), are invariably generated by commercial explosives under practical conditions of usage because of oxygen unbalance and nonideal chemical reaction. Permitted explosives are statutorily required to meet the criteria stipulated by regulatory authority for their toxic fume quality for their safe use in underground coal mines. Solid blasting using P5 explosives contribute around 60% production from Indian underground coal mines. Low pull and yield per blast in solid blasting has been identified as a reason for low production and productivity of Indian underground coal mines. In an effort to improve performance of solid blasting, it was envisaged to apply air decking between suitable P5 explosives using high density polyethylene (HDPE) spacers under a Ministry of Coal, Government of India funded project. A non-deflagrating slurry explosive composition having high air gap sensitivity was specially developed for this purpose, so that air decked cartridges get detonated sympathetically with single priming. However, statutory authority in India apprehended that the use of oxygen negative HDPE spacers can influence the generation of toxic gases. The effect of using HDPE spacers on the generation of toxic gases was studied under simulated laboratory conditions with newly developed as well as with three commercial P5 explosives. The results of studies presented in this paper revealed that the level of carbon monoxide increases linearly and there is no significant effect on the level of oxides of nitrogen due to the use of HDPE spacers with selected explosives. Studies also revealed that this newly developed slurry explosive can be used for air decking up to 15 cm using HDPE spacers of weight not more than 21 g without exceeding the permissible limits for toxic gases <![CDATA[<b>Reflections on the quality of mining EIA reports in South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2008001000005&lng=en&nrm=iso&tlng=en Environmental impact assessment (EIA) in South Africa is administered by the Department of Minerals and Energy (DME) for the mining industry, and the Department of Environmental Affairs and Tourism (DEAT) for all other sectors. Thus far, EIA research has focused on the process under the auspices of DEAT but none has focused on the EIA process that has been mandatory in the South African mining industry since 2004. Using the Lee and Colley (Lee et al.13) review package as a basis, a review model specifically tailored to the needs of the mining industry was applied to review the quality of a sample of 20 environmental impact reports (EIRs) approved by the DME. Results reveal that 85% of the EIRs are of a satisfactory quality. Presentational and descriptive components generally achieved higher quality grades than the analytical components such as impact magnitude and alternatives. The results show that in spite of some areas of weakness, and in spite of being conducted in terms of different legislation, EIR quality in the mining sectors appears to conform to the overall standard of quality of EIRs in other sectors in South Africa, and is also on a par with quality abroad. Hence, despite the criticism that DME is usurping the role of DEAT, it is concluded that EIRs of comparable standard are being produced, and that the quality of EIRs in the mining sector do not provide supporting evidence for this criticism. However, EIR quality is only a single aspect of EIA effectiveness, others including action and implementation of EIA proposals and mitigation measures <![CDATA[<b>The design of a suspended concrete transport pipeline system</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2008001000006&lng=en&nrm=iso&tlng=en Environmental impact assessment (EIA) in South Africa is administered by the Department of Minerals and Energy (DME) for the mining industry, and the Department of Environmental Affairs and Tourism (DEAT) for all other sectors. Thus far, EIA research has focused on the process under the auspices of DEAT but none has focused on the EIA process that has been mandatory in the South African mining industry since 2004. Using the Lee and Colley (Lee et al.13) review package as a basis, a review model specifically tailored to the needs of the mining industry was applied to review the quality of a sample of 20 environmental impact reports (EIRs) approved by the DME. Results reveal that 85% of the EIRs are of a satisfactory quality. Presentational and descriptive components generally achieved higher quality grades than the analytical components such as impact magnitude and alternatives. The results show that in spite of some areas of weakness, and in spite of being conducted in terms of different legislation, EIR quality in the mining sectors appears to conform to the overall standard of quality of EIRs in other sectors in South Africa, and is also on a par with quality abroad. Hence, despite the criticism that DME is usurping the role of DEAT, it is concluded that EIRs of comparable standard are being produced, and that the quality of EIRs in the mining sector do not provide supporting evidence for this criticism. However, EIR quality is only a single aspect of EIA effectiveness, others including action and implementation of EIA proposals and mitigation measures <![CDATA[<b>Germanium recovery by co-precipitation of germanium and iron in conventional zinc metallurgy</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2008001000007&lng=en&nrm=iso&tlng=en A modified germanium recovery process in conventional zinc metallurgy, based on the understanding that ferric hydroxide has strong ability to coprecipitate germanium element, was presented. The relaxed lab-scale experiments were conducted to evaluate its technological feasibility. The experimental results obtained show the new process has great competitive advantage over the conventional one <![CDATA[<b>Blast fragmentation optimization at Tarkwa Gold Mine using 6 Sigma methodologies</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2008001000008&lng=en&nrm=iso&tlng=en A modified germanium recovery process in conventional zinc metallurgy, based on the understanding that ferric hydroxide has strong ability to coprecipitate germanium element, was presented. The relaxed lab-scale experiments were conducted to evaluate its technological feasibility. The experimental results obtained show the new process has great competitive advantage over the conventional one