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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/3527

Title: Evolving an efficient method for mining nondredgeable areas at Dunkwa Goldfields Limited
Authors: Asiedu-Asante, Stephen Kwadwo
Issue Date: 12-Sep-1993
Series/Report no.: 2020;
Abstract: The placer gold deposit of Dunkwa Goldfields Limited (DGL) covers the flood plains and the bed of the Off in River and is mined by the use of bucket ladder dredges. In the course of dredging, some mineralized areas are encountered which cannot be dredged with the available dredges on the mine due to one or more of the following factors: 1. Low water level above bedrock especially during the dry seasons. 2. High banks. 3. Deep gravel depth. The occurrence of any of these conditions prevents the dredging of potentially rich portions of the deposit. So far, the mine has not been able to employ any other method to exploit these areas. It is evident that the mining of these areas will increase revenue to the mine. The objective of this thesis is to develop a computational methodology for the delineation of the non-dredgeable areas at DGL and to work out an efficient method to mine these areas. A portion of Lower Off in part of the deposit where enough sampling data are available is used for this study. Since grade, flotation, bank height and gravel depth are regionalized variables geostatistical estimation method is used. Ordinary kriging is used to estimate flotation, bank height and gravel depth within the area under study and based on the results, contour maps are generated to depict the possible non-dredgeable areas. Indicator Kriging (IK) which mitigates the effects of outliers and unequal support is used to delineate mineralized zones and to estimate grades. The result of the 1K estimates is compared to that obtained by the weighted average method of local grade estimation used at DGL. By intersecting the possible non-dredgeable areas with the mineralized zones, in line with set theory, mineralized non-dredgeable areas of mining interest are delineated. It is observed that significant percentage of the mineralized zones in the area under study is non-dredgeable, implying loss of revenue if left unmined. Applicable mining methods for exploiting the mineralized non-dredgeable areas are reviewed and based on economic analysis of suitable mining methods, the most appropriate method is selected to exploit the mineralized non-dredgeable areas.
Description: A thesis presented to the University of Science and Technology in fulfilment of the requirements for the Award of the Degree of Doctor of Philosophy (Mining Engineering),1993.
URI: http://hdl.handle.net/123456789/3527
Appears in Collections:College of Engineering

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