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The effect of blasting on the rockmass for designing the most effective preconditioning blasts in deep-level gold mines

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dc.contributor.advisor Kabongo KK en
dc.contributor.advisor Ozbay MU en
dc.contributor.author Toper AZ en
dc.date.accessioned 2016-09-22T11:14:13Z
dc.date.available 2016-09-22T11:14:13Z
dc.date.created 1994 en
dc.date.submitted 2003 en
dc.identifier.uri http://hdl.handle.net/20.500.11892/106387
dc.description.abstract According to the accident database compiled by CSIR Division of Mining Technology (Miningtek), a significant percentage of fatalities have resulted from faceburst incidents throughout the South African gold mining industry. In order to address this problem, an extensive research programme has been undertaken.<br><br> Two different preconditioning techniques have been developed; namely, face- perpendicular preconditioning and face-parallel preconditioning. Both have prevented face bursting in the areas to which they have been applied, even though several large seismic events have occurred close to the faces in some areas. In addition, minimal overall damage was observed in the preconditioned panels following these events, compared to similarly exposed unpreconditioned panels. Preconditioning has also provided some protection from distant events to the face area, through the capacity of the preconditioned ground to absorb energy.<br><br> Although the main purpose of preconditioning was to prevent facebursts, an improvement in hangingwall stability and a significant increase in the face advance rate, consistent with improved fragmentation, have been noted in preconditioned areas. During preconditioning, the average face advance rate increased significantly compared with unpreconditioned periods. Owing to this increase in face advance rate, the mining cost per area mined decreased in preconditioned panels. The effect of preconditioning on improving the drilling rate of production holes was also significant. The preconditioning experiments also indicated that it was possible to implement this method in a deep-level longwall mining environment without significant disruption to the mining cycle. Guidelines for both preconditioning techniques have been compiled.<br><br> In order to determine the optimum blast parameters for achieving the most effective preconditioning, an extensive optimisation study was carried out for the face-perpendicular preconditioning technique. While optimum values for parameters such as hole length, diameter and spacing were determined, it was ultimately concluded that the differences in results obtained by varying the preconditioning parameters were less significant than the clear positive differences observed when comparing preconditioned areas with non- preconditioned areas.<br><br> In order to assure successful implementation of the techniques in the mining environment, a structured implementation procedure has been developed from experience gained at research sites. This procedure consists of education and training of all levels of the production personnel as well as the personnel of the training and safety departments of the mine. en
dc.language English en
dc.title The effect of blasting on the rockmass for designing the most effective preconditioning blasts in deep-level gold mines en
dc.type Doctoral degree en
dc.description.degree PhD (Min Eng) en

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