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Experimental investigation on the movement mechanism of top coal in steeply inclined ultra-thick coal seams

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Abstract

The pre-blasting zones have a significant influence on the coal broken and the recovery rate of the top coal caving mining. This paper explores the coal movement mechanism in the top coal with pre-blasting zones based on the geological parameters of Jiangcang No. 1 mine in the western of China. The steeply inclined ultra-thick coal seam was mined by using the sublevel top-coal caving mining method. The geo-image process system (GIPS) software was used to track the mark points on the coal and roof. The support was used to record the load on the top of the support during the caving mining process. The results show that the horizontal coal is moved to the shield window and the vertical coal is moved downward in the first level, while that in the second level shows consistency for the integrity of the coal. The vertical displacements of the corresponding points in the first level are lairger than that in the second level. However, the load on the top of the support in the first level is smaller than that in the second level. It indicated that the pre-blasting zones will give a more loosen top-coal and a small degree of difficulty in the top coal caving.

Graphical abstract

The steeply inclined ultra-thick coal seam was divided into three levels in horizontal direction (presenting 25 m in the real sublevel height of top coal) for each level. The technical tunnel was set at the bottom of the first level in the coal. Two rows pre-blasting zones were set with different dip angles and lengths from the technical tunnel to the coal with a proportional distance. The second level without pre-blasting zones was introduced to compare with the first level with pre-blasting zones during the caving process.

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Acknowledgements

This research was supported by the National Natural Science Foundation of China (Grants 51674264 and 51574244) and the National Key Research and Development Program of China (Grants 2017YFC0603002 and 2018YFC0604501).

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Authors and Affiliations

  1. School of Energy and Mining Engineering, China University of Mining & Technology, Beijing, 100083, China

    Jiachen Wang, Fei Liu & Zhaohui Wang

  2. Coal Industry Engineering Research Center of Top-Coal Caving Mining, Beijing, 100083, China

    Jiachen Wang, Fei Liu & Zhaohui Wang

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  1. Jiachen Wang
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  2. Fei Liu
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  3. Zhaohui Wang
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Correspondence to Fei Liu.

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Executive Editor: Xing-Long Gong

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Wang, J., Liu, F. & Wang, Z. Experimental investigation on the movement mechanism of top coal in steeply inclined ultra-thick coal seams. Acta Mech. Sin. 37, 631–648 (2021). https://doi.org/10.1007/s10409-020-01044-0

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  • DOI: https://doi.org/10.1007/s10409-020-01044-0

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