Geomechanical processes at closed mines in Donbass coalfield and their potential effects at surface

Abstract

One of the principal technical problems that arises in the Donbass coalfield, Ukraine, during the closure of mines that are no longer viable is the activation of geomechanical processes and their effect at the surface. The main precondition for the initiation of such processes is the presence of voids and foliations underground. It is not possible to predict when the closure of these voids will occur, but the results are repeated slumping of the rock mass, ultimately affecting the surface. The consequences can be surface collapse or deformation. Collapse cones appear above the collars of vertical shafts, shallow workings, fissures and gaps in thick, solid seams. Additional movement and deformation are possible above stopes when the rock mass has been been made wet by flooding of the mine and also when zones of concentrated deformation become active. The knowledge that can be derived from experience so far and from the monitoring of closed mine sites needs to be collected and applied. The monitoring scheme in the Stakhanov District of the Donbass is reviewed along with the first observations of surface deformation above closed mines - where anomalous movement was already observed when the mines were operational.