The methodology of calculating the normative strength of backfill in the system of mining with sub-stage ore stripping in diamond-shaped chambers is considered. It is proposed to take as normative the largest design value of strength determined from the conditions of stability of the diamond-shaped chamber vault and stability of the complex in shape and structure inter-chamber pillar formed between the chambers.

The methodology of calculation of reinforced concrete slabs constructed at the bottom of the pit to isolate the underground mine during the transition to underground mining operations is described. The conclusion is made about the inadmissibility of a simplified approach to the definition of such slabs, which does not take into account the technology of development of underground reserves.

Mining of ore deposits in conditions of increased mining pressure is often associated with dangerous stress concentrations that can cause harmful consequences for production: deformation of workings and separate sections of the ore body, crushing of pillars, self-collapse of ore and other phenomena that increase the danger of work, losses of minerals, labor and cost.