Rock permeability in displacement zones at coal deposits: A case study of underworked inundated mines

Abstract

Rock displacement in some sites of coal mines is accompanied by changes in the permeability and fil� tering structure of the host rock massif. Transforma� tion of a massif resulting from the appearance of such hydrogeological channels significantly affects the con� ditions and environmental impact of mining; such a channel provides water flow through it and is called a “zone of water conducting displacement cracks” (ZWCDC). The maximal changes take place at the sites of a collapsed mine roof. The operational practice has revealed the ability to keep the minimal increment in through permeability of a dividing rock mass within the ZWCDC and to pre� serve the zones of minimal permeability values within the massif. These conclusions, supplemented with the studies of cracked structures based on equivalent material models, were also reported in [1] and became standard for Russian norms regarding the determination of coal extraction conditions near water objects.