This paper continues an experimental investigation of stress relaxation in rocks under various types of stressed states at different deformation phases, including the transcriptional region. The tests were done in the conditions of uniaxial compression, compression under hydrostatic pressures varying up to values at which the rock strength characteristics attained a plateau, and a for bending. All testes with stress relaxation were done in the laboratory on rock samples. The procedures are described. When characterized by the drop of stresses close to the ultimate strengths during the time equal to the first 3 minutes of relaxation, the rocks in tests with uniaxial compression formed the following series according to decreasing relaxation activity: bauxite 57%, brown coal 50%, potassium and rock salt 35%, schist 15% marble 13%, burst-safe sandstone 5%, and apatite 4%. The test data on stress relaxation in rocks make it possible in any mining situation to evaluate the reduction of the released elastic energy due to stress relaxation and, on this basis, determine the potential efficiency of controlling the bed destruction pattern.