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Sustainable Management of Mine Induced Water
Published in Sheila Devasahayam, Kim Dowling, Manoj K. Mahapatra, Sustainability in the Mineral and Energy Sectors, 2016
Muhammad Muhitur Rahman, Dharmappa Hagare, Muttucumaru Sivakumar, Raghu N. Singh
Steps involved in the processing of coal are different from extracting metals from ores. This is because the mineralogy (structural and physical characteristics) of metallic deposits is generally more complex than coal deposits. Compared to coal deposits, metallic deposits produce more than one commodity. Coals and metals also differ in the process of geological formation. While coal deposits always occur in stratigraphic layers (or beds), metallic deposits can occur in such layers but also in strips and in stockworks (in geology, a stockwork is a complex system of structurally controlled or randomly oriented veins). Due to this reason, in an aboveground metal mine, most of the mined material is waste, and only a small portion of the collected material is economically viable. According to McLemore (2008), a profitable lead or zinc mine may result in 90% or more of the total rock mined being placed in waste storage facilities; for copper mines, the wastage is 95% and for gold mines, almost 99% is waste material. On the other hand, coal produces much less waste rock from underground as well as open pit mines. The diversity and amounts of recovered minerals and chemical reagents involved in extracting metals are far greater than those used in coal extraction. Therefore, the potential for impacting the environment by the diverse range of chemicals used in metal extraction is higher in metals processing than in coal. Steps involved in coal as well as metal processing are shown in Figures 15.4 and 15.5, respectively. As shown in Figure 15.4, coal processing typically requires crushing, grinding and sizing followed by physical separation of pyrite and shale by gravity or flotation. Impurities such as rocks, soil, iron compounds and carbonates are usually removed by utilising their differences in specific gravity through the process of sedimentation. In the washing process, approximately 20%–30% by weight of the coal is lost and rejected. Coals are unwashed when supplied for the cement and power generation industry, and washed for the supply to steel works and export market. The washing process may be carried out at the colliery and at the steel works site.
Gravity and magnetic data processing further constrained inversion for 3D modelling and tonnage calculation
Published in Applied Earth Science, 2020
Saâd Soulaimani, Saïd Chakiri, Ahmed Manar, Ayoub Soulaimani, Abdelhalim Miftah, Mustapha Boujamaoui
As far as mining is concerned, the Hercynian basement of the Marrakech region hosts a large number of sulphide massifs. They are found as stratabound polymetallic mineralised bodies and often associated with volcanic rocks which crop up as submarine effusions of rhyolite and rhyodacite. These are volcano-clastic type mineralisations presenting a relatively distal character regarding the emplacement of the contemporaneous volcanic expressions (Bernard et al. 1988). Such mineralisations are often associated with underlying stockworks zones. Their mineralogical and chemical characteristics indicate a strongly reducing environment leading to the paragenesis formation of syngenetic pyrrhotite of highly dominant primary origin of Variscan age. In the Guemassa-Jebilets metallogenic province, pyrrhotite ore deposits outcrop as limonitic products forming gossans. They are roughly organised along sub-meridian lineaments (Jaffal et al. 2010; Admou et al. 2018). They are formed of mineral occurrences or ore bodies within the Visean volcano-clastic deposit of Sarhlef (Bernard et al. 1988). Felenc et al. (1986) proposed a genetic model in which such massive sulphide deposits are supposed to be emplaced during an extensional phase, during which sandy clay deposits infill in a sedimentary basin (Felenc et al. 1986). The development of this basin is favoured by the action of normal faults leading to horst and graben structures. Such an extensional regime, dated to ca. 330.5 Ma (U-Pb on zircons) by Essaifi et al. (2003), is followed by important magmatic activity characterised mainly by a bimodal plutonism emplacement. This led to high thermal perturbations generating a hydrothermalism which could appear as convection cells affecting magmatic bodies as well as their host rocks (Essaifi and Hibti 2008). However, the proximity of sulphide ore enriched in base metals and the acid plutonism (depleted in base metals) may indicate that this kind of plutonism is the main source zone for this hydrothermal system (Essaifi and Hibti 2008). The sulphide ore deposits of the Visean metallogenic province of Guemassa-Jebilets (Figure 1) may have been emplaced in an epicontinental rift environment of the external zone of the Hercynian chain (Lescuyer et al. 1997).