Mathematical modeling of bituminous coal seams burning contemporaneously with the formation of a variegated beds body

Abstract

Partial burning of three bituminous coal seams in the Upper Silesian Coal Basin (USCB) of the Czech Republic was modeled by the numerical solution of the nonlinear initial-boundary value problem for a heat equation. It was assumed that a variegated beds body (VBB) formed around burned out coal seams. In addition, laboratory results for thermal alteration and oxidation of rocks were considered in addition to thermally altered coal from the vicinity of the variegated beds body. Models of two variegated beds profiles with three coal seams were derived with FEMLAB using the finite elements method for the discretization in space along with the method of lines. Maximum temperatures within burned out coal seams ranged from about 350 to 800 °C inside the variegated beds body, whereas outside the body they were below 350 °C. It took about 2000 years for all coal seams to burn out. The calculated results show very good geologic credibility of the derived model.