Based on the results of statistical analysis of a large amount of measured data in mining engineering

the statistical model of rock mass displacement is established by using the statistical theory. The theoretical formulas are developed and applied to the prediction of the rock mass displacements and deformations due to underground mining by pillar-and-room method in mountain areas. The agreement of the theoretical results with the field measurements shows that the model is satisfactory and the formulae obtained are valid and thus that can be effectively used for predicting the movements and the natural slope failure due to underground mining by pillar-and-room method in mountain areas.