Peculiarities and Efficiency of Support and Protection of Mine Excavations in Potassium Salt Rock Masses at Great Depths
M. A. Zhuravkov1, M. A. Nikolaichik1, S. N. Lopatin1, V. A. Misnikov2, N. M. Klimkovich1
1Belarusian State University, Minsk, Belarus
2Belgorchemprom LLC, Minsk, Belarus
Keywords: Mine excavation, great depths, geomechanical condition, mechanical-mathematical and numerical modeling, expansion gaps, rock bolting, relaxation excavations
Abstract
The article analyzes efficiency of safety and support of underground excavations at great depths in potassium salt rock masses as a case-study of the Starobin and Petrikov deposits. Various protection technologies are discussed. It is found that owing to formation of block structures and cohesion loss zones nearby the perimeter of mine excavations, the expansion gaps can have both beneficial and adverse influence on excavation stability. The relaxation excavation technology allows a great reduction in the dimensions of limiting state zones in rock mass surrounding mine openings. The model of block movement is proposed, and it is shown that mutual displacements of blocks by more than 1-2 mm in the vicinity of an excavation perimeter can be a cause of the dynamic failure of blocks into mined-out areas. It is recommended to install rock bolting as soon as cohesion loss is detected on sliding surfaces.
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