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A New Blastability Index for Hard Roof Management in Blasting Gallery Method

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Abstract

The presence of hard and massive sandstone above the coal seam in underground coal mines often leads to delay in caving of overlying rock beds thereby causing excessive load on supports and posing danger to underground workings. The problem is more prominent in blasting gallery (BG) as well as longwall mining methods in Indian coal mines. Induced caving by blasting is a promising means for hard roof management in underground coal mines. Based on extensive studies and data collected from different mines in India, a Blastability Index (BI) has been developed which can be used for the classification of roof according to the degree of ease in caving by induced blasting. Different charge factors have also been suggested based on the Blastability Index. Due to wide change in the method of extractions, ‘Cavability Index’ for longwall panel was found ineffective in case of BG method of working as well as bord and pillar working. For this reason, this proposed Blastability Index would be of immense help for caving of hard roof by induced blasting.

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Acknowledgments

The present paper is a thoroughly modified version of the paper presented in the National Seminar on “Meeting Rock Mechanics Challenges of Deep Underground Mining”, April 22-24, 2010 held at CIMFR, Dhanbad. The permission given by the Editorial Board of the Seminar for its reproduction is deeply acknowledged. The authors are grateful to the Director, CIMFR for giving permission to publish this paper. Thanks are also due to Sri K. L. Bandopadhyay, Ex-scientist of CIMFR for editorial help. Opinions made herein are of the authors and not of CIMFR.

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Authors and Affiliations

  1. Blasting Department, Central Institute of Mining and Fuel Research, Dhanbad, 826 015, Jharkhand, India

    Chhangte Sawmliana & Pijush Pal Roy

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  1. Chhangte Sawmliana
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  2. Pijush Pal Roy
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Correspondence to Pijush Pal Roy.

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Sawmliana, C., Pal Roy, P. A New Blastability Index for Hard Roof Management in Blasting Gallery Method. Geotech Geol Eng 30, 1357–1367 (2012). https://doi.org/10.1007/s10706-012-9550-1

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