Journal of Mining The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Rock Load Estimation in Development Galleries and Junctions for Underground Coal Mines: A CMRI-ISM Rock Mass Rating Approach Sun, 09 Mar 2014 14:19:43 +0000 Rock mass rating (RMR) plays important role in design and selection of support system (Ghosh, 2000). For stability assessment of rock mass it is very important to know the amount of rock load mobilized around the development gallery which is estimated using RMR (Singh et al., 2003, Barton et al., 1974, Bieniawski, 1984, and Ghosh et al., 1992). In Indian coal mines, Central Mining Research Institute-Indian School of Mines rock mass rating (herein after referred to as CMRI-ISM RMR) is mostly used for formulating design guidelines for supports. In this paper an attempt has been made to correlate CMRI-ISM RMR values and rock load of galleries and junctions for different gallery widths, ranging from 3.6 m to 4.8 m, at different densities of roof rocks. The proposed empirical expression can help in quick design of support system for underground coal mines working in the same regime. Avinash Paul, V. M. S. R. Murthy, and Ajoy Kumar Singh Copyright © 2014 Avinash Paul et al. All rights reserved. Maintainability Analysis of Underground Mining Equipment Using Genetic Algorithms: Case Studies with an LHD Vehicle Wed, 19 Feb 2014 12:52:57 +0000 While increased mine mechanization and automation make considerable contributions to mine productivity, unexpected equipment failures and planned or routine maintenance prohibit the maximum possible utilization of sophisticated mining equipment and require a significant amount of extra capital investment. This paper deals with aspects of maintainability prediction for mining machinery. A PC software called GenRel was developed for this purpose. In GenRel, it is assumed that failures of mining equipment caused by an array of factors follow the biological evolution theory. GenRel then simulates the failure occurrences during a time period of interest using genetic algorithms (GAs) coupled with a number of statistical techniques. A group of case studies focuses on maintainability analysis of a Load Haul Dump (LHD) vehicle with two different time intervals, three months and six months. The data was collected from an underground mine in the Sudbury area in Ontario, Canada. In each prediction case study, a statistical test is carried out to examine the similarity between the predicted data set with the real-life data set in the same time period. The objectives of case studies include an assessment of the applicability of GenRel using real-life data and an investigation of the impacts of data size and chronological sequence on prediction results. Sihong Peng and Nick Vayenas Copyright © 2014 Sihong Peng and Nick Vayenas. All rights reserved. Exploitation of Bacterial Activities in Mineral Industry and Environmental Preservation: An Overview Sun, 29 Dec 2013 10:38:19 +0000 Since the identification and characterization of iron and sulfur oxidizing bacteria in the 1940s, a rapid progress is being made in minerals engineering based on biological activities. Microorganisms can play a beneficial role in all facets of minerals processing, from mining to waste disposal and management. Some of the applications, such as biologically assisted leaching of copper sulfide ores, uranium ores, and biooxidation of refractory sulfide gold ores, are now established on the scale of commercial processes. A variety of other bioleaching opportunities exist for nickel, cobalt, cadmium, and zinc sulfide leaching. Recently, other uses of microorganisms are potentially possible. These include the bioleaching of nonsulfide ores, bioflotation, and bioflocculation of minerals, and bioremediation of toxic chemicals discharged from mineral engineering operations. These activities acquire considerable opportunities for further research and development in these areas. This paper is an attempt to provide a critical summary on the most important efforts in the area of bacterial activities in the mineral and mining industry. Ahmed A. S. Seifelnassr and Abdel-Zaher M. Abouzeid Copyright © 2013 Ahmed A. S. Seifelnassr and Abdel-Zaher M. Abouzeid. All rights reserved. Nickel and Zinc Removal from Acid Mine Drainage: Roles of Sludge Surface Area and Neutralising Agents Thu, 21 Nov 2013 10:30:44 +0000 During acid mine drainage (AMD) treatment by alkaline reagent neutralisation, Ni and Zn are partially removed via sorption to Fe and Al hydroxide precipitates. This research evaluated the effect of surface area of precipitates, formed by neutralisation of AMD using three alkalinity reagents (NaOH, Ca(OH)2, and CaCO3), on the sorption of Ni and Zn. The BET surface area of the precipitates formed by neutralisation of AMD with NaOH (173.7 m2 g−1) and Ca(OH)2 (168.2 m2 g−1) was an order of magnitude greater than that produced by CaCO3 neutralisation (16.7 m2 g−1). At pH 6.5, the residual Ni concentration was 0.32 and 0.41 mg L−1 for NaOH and Ca(OH)2 neutralised AMD, respectively, resulting in up to 60% lower Ni concentrations than achieved by CaCO3 neutralisation which had no effect on Ni removal. The residual Zn concentration was even more dependent on precipitate surface area for NaOH and Ca(OH)2 neutralised AMD (0.33 and 1.02 mg L−1), which was up to 85% lower than the CaCO3 neutralised AMD (2.20 mg L−1). These results suggest that the surface area of precipitated flocs and the selection of neutralising reagent critically affect the sorption of Ni and Zn during AMD neutralisation. William E. Olds, Daniel C. W. Tsang, Paul A. Weber, and Chris G. Weisener Copyright © 2013 William E. Olds et al. All rights reserved. Magnetic Behavior of Natural Fe2O3 from Lhoong Iron Ore Mining Area, Aceh Province, Indonesia Sat, 24 Aug 2013 09:00:34 +0000 The mineral composition and magnetic behavior of nano-Fe2O3 of iron ore from Lhoong mining area, Aceh province, were studied. The iron ore was prepared by mechanical milling method. The mineral and chemical compositions of samples were investigated by XRD and XRF analysis tests. The XRF test showed that the Lhoong iron ore contains Fe2O3 (93.88%) in association with other isomorphous impurities, such as SiO2, MnO, and Al2O3, in varying proportions. Compared to XRD results, it was consistent with XRF; the phase compositions of iron ore were mainly hematite (Fe2O3). The XRD revealed that hematite was the major mineral component in the Lhoong iron ores. SEM observation showed fine crystalline structure of Lhoong iron ore after the milling process. The main mineral morphology was microcrystalline in agglomerate forms. The magnetic properties of the samples after milling showed the increasing in the remanent (Br) and coercivity (Hc). This increasing can be explained that nano-Fe2O3 phase after milling for 20 hours plays an important role in the magnetic behavior of Lhoong iron ore. It is understood that the longer milling time is sufficient to complete the transformation of hematite (Fe2O3) to magnetite (Fe3O4). Adi Rahwanto, Mustanir Yahya, and Zulkarnain Jalil Copyright © 2013 Adi Rahwanto et al. All rights reserved.