Ahmed Abul Fazal* and A.T.M. Shahidul Huqe Muzemder
Barapukuria Gondwana coal deposit is one of the largest coal basin situated in the Dinajpur and Saidpur with an area of 5.16 km2s in the north-eastern part of Bangladesh. Using a 3-D model it is possible to evaluate the distribution of sedimentary rocks, both through space and time. This study has aiming a better understanding of the Barapukuria coal basin through 3-D geological analysis and re-estimation of coal-reserve which has done by the means of continuous (top & base) surface modeling for the target coal seam. The continuous trends of coal seam is conceder for the volume calculation of coal seam which is not consider previously for volume calculation like of Barapukuria basin in Bangladesh. The coal deposit is bounded with a large normal fault to the east with an N-S striking axis structure of coal basin. The sub-crop of coal seam VI limits the deposit in the western part. The analysis shows seven correlated coal layer interbeded with shale. The upper seam sequences I, III, VI are in shallow depth, has less thickness and also discontinuous in nature. II, IV and VI are those only having noticeable continuity and the later one is an ultra-thick seam plan to mine out but not the other. The model did not plot coal sequence II as it rarely count in the boreholes though it has significant thickness at some location. The interbeded coal and shale layer is merging to related sandstone sequence instead of to coal seam VI as this may be misled the volume counted for seam VI. The calculated volume of coal for the seam VI is 273.33 Mt. The volume calculated only for coal seam VI as it occupies the 90% of the total reserve of coalfield and hold priority. As the seam VI only to mine out, the current analysis considers its reserve as total actual reserve. About 22.04 Mt of coal has been estimated as recoverable reserve, using multi-slice long wall mining of 9% recovery, within the structural limit of the basin.
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