"A rock testing program is defined and carried out to determine the mechanical constants of an underground coal gasification chamber overburden. It encompasses tensile tests and uniaxial/ triaxial compressive tests. It allows the determination of the overburden tensile strength and compressive strengths for different confining pressures as well as the calculation of average values for Poisson's Ratio and Young's Modulus of Elasticity. Results are reported in tabular and graphical forms. Assuming a linear elastic behavior of the rock and a failure process governed by the Mohr's Criterion, empirical, analytical, and numerical techniques are implemented to assess roof stability and surface subsidence. Among these methods are the classical roof beam calculations, various pressure-arch theories, the bulking factor theory, the U.K. National Coal Board prediction curves, two different elastic models developed by Berry and Sales, and a finite element simulation. The quantitative results yielded by the above procedures are complemented by qualitative considerations. Conclusions are drawn and recommendations are expressed."