It was established the increase of movement angles with mining depth and the mechanism of forming the stable natural arching in underground mining of ore deposits. The conditions and parameters of forming the stable natural arching were determined, under which the zone of dangerous deformations localizes inside the ore mass and does not manifest itself on the earth surface. The nomogram for analytical determination of the rock movement angles was developed, and the table was drawn up of the natural arching conditions with due account of main mining-and-geological factors of ore deposit occurrence and its mining.
