Mathematical modeling of tight roof periodical falling

The paper proposes a method to determine of a coal seam roof
falling step basing upon the analysis of stress and strain state of the rock
mass area with mine workings formed as a result of coal preparatory and
extraction operations. A boundary element method has been applied to
define stress and strain state (SSS). Fissuring of enclosing rocks was
modeled by means of transversal-isotropic medium. Dependence of
destructed rocks zone height within the roof of a seam being mined upon
the weakening of the rock mass due to its fissuring and mine working
geometry has been determined. Effect of fissility on the periodical roof
falling step has been studied. Changes in support loads in the process of
stope advance have been determined. A scheme of partial backfilling of the
worked out area has been proposed to maintain the support in its working
order.