Sengupta, S. and Mandal, S.K. and Chakraborty, S.K. and Haque, N. and Dutta, A.K. (1981) Some observations on the depositional characteristics of coals, as reflected by their quality, occurring in the Churi and Ray blocks of north Karanpura coalfield. Journal of Mines, Metals & Fuels, 29 (1&2). pp. 21-25. ISSN 0022-2755

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North Karanura coalfield is the westernmost amongst the Damodar Valley coalfield. In this coalfield, the Barakar and the Karharbari formations are coal-bearing. The present investigation was carried out on the coals of the Karharbai measure. The Karharbai formation was found to be prospective only in the south-central part of the coalfield, though it occurs in the eastern and north-central parts also. During 1975-76 detailed drilling was undertaken by CMPDI in Churi and Ray blocks lying side by side in the south-central part of NKCF, and subsequently processing and analytical study of the coal cores were taken up by CSL, Ranchi. During the investigation of the coal cores and the evaluation of the analytical data of these two blocks, certain sedimentological features were observed which have been incorporated here. In the present area of investigation, comprising Churi and Ray blocks, only the coal seams of the Karharbari formation have been encountered, which consist of two coal seams, viz., the Lower Bachra seam and the Upper Bachra seam. It has been observed that in the east-central part of the area, there is a small zone trending almost NNE-SSW, where (1) the ex-band ash content of the coal of the Lower Bachra seam shows highest figures, indicating possibly accumulation of more mineral matter during deposition; (2) the Lower Bachra seam contains highest in-band ash percentage, which is probably due to the concentration of dirt materials in that region than in the rest of the area; (3) the Lower Bachra seam shows maximum splits in that tract, which also goes to show in crease in dirt materials in that zone; (4) practically, similar phenomenon has been observed in the case of Upper bachra seam also; and (5) the low ash bottommost band-free section of the Lower Bachra seam is not properly developed in htat particular zone. This incongruity during the deposition of the coal seams is possibly due to sedimentary channeling [3]. In addition to the above, attention has also been drawn to the selective mining of the low ash band-free bottom-most section of the Lower Bachra seam which has been delineated and found to be about 1.2 to 3.8 m in thickness and the ash percentage of coals normally ranges between 8.2 and 12.2. Even as low as 6.6 per cent ash has been recorded, which is rather rare for the Gondwana coals in India.

Item Type: Article
Subjects: Coal Preparation
Depositing User: Dr. Satyendra Kumar Singh
Date Deposited: 13 May 2012 05:39
Last Modified: 13 May 2012 05:39

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