Research into Impact of Leaving Waste Rocks in the Mined-Out Space on the Geomechanical State of the Rock Mass Surrounding the Longwall Face

Adam Smoliński (), Dmyto Malashkevych, Mykhailo Petlovanyi, Kanay Rysbekov, Vasyl Lozynskyi () and Kateryna Sai
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Adam Smoliński: Central Mining Institute, Plac Gwarków 1, 40-166 Katowice, Poland
Dmyto Malashkevych: Department of Mining Engineering and Education, Dnipro University of Technology, 49005 Dnipro, Ukraine
Mykhailo Petlovanyi: Department of Mining Engineering and Education, Dnipro University of Technology, 49005 Dnipro, Ukraine
Kanay Rysbekov: Mining and Metallurgical Institute Named after O.A. Baikonurov, Satbayev University, Almaty 50013, Kazakhstan
Vasyl Lozynskyi: Department of Mining Engineering and Education, Dnipro University of Technology, 49005 Dnipro, Ukraine
Kateryna Sai: Department of Mining Engineering and Education, Dnipro University of Technology, 49005 Dnipro, Ukraine

Energies, 2022, vol. 15, issue 24, 1-16

Abstract: Backfilling technology is not always used by mining enterprises, which is conditioned by technological and economic factors, such as the need for high mining rates and costs for the technological processes of transporting backfill materials from the daylight surface to the mined-out space. This concerns the underground mining of hard coal, which is a strategic energy resource, in the mines of Ukraine. This paper aims to study the effect of leaving the waste bottom rocks in the mined-out space of the longwall face without their drawing to the earth’s surface on the geomechanical state of the rocks surrounding the longwall face. The geomechanical assessment of the stress state of the rock mass surrounding the longwall face, when leaving the waste rocks from the seam bottom rocks in the mined-out space, is performed by the finite element method using the Ansys software package. A geomechanical model has been developed and substantiated, which adequately reflects the mining-geological conditions for seam mining within the extraction site, the actual structure and properties of the coal-bearing rock stratum, the parameters of the longwall face and the modified powered support for the processes of leaving the rocks in the mined-out space. The values and patterns have been determined of the decrease in the stress intensity concentrations in the coal-bearing roof mass in the frontal bearing pressure zone and destressing zone with an increase in the ratio of the rock pack thickness to the extracting seam thickness. The relative indicators of the load on the powered support section and the lowering of its roof have been determined by the ratio of the thickness of the rock pack formed in the mined-out space to the extracting seam thickness. The proposed mining method is of significant commercial and research interest for owners of coal mines developing thin coal seams because environmental costs for placing waste on the surface are reduced, and the energy potential of coal is increased due to the separation of waste rocks from coal in underground conditions. The need for a cycle of beneficiation of mined mass is eliminated and the geomechanical conditions of coal mining processes are improved.

Keywords: coal seam; longwall face; selective mining; undercut rocks; rock pack; stress concentration; support loading (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2022
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (5)

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