In the course of experimental drilling, critical values of the axial load were established at which the mechanical penetration rate reaches its maximum values. The obtained axial load values were taken as rational. As a result of the research carried out, a formula suitable for calculating the rational axial load on a cutter bit has been found analytically and verified experimentally.

Exploration of the Tyrnyauz deposit, carried out on the flanks mainly by means of mining and drilling operations, is complicated not only by specific features of the highlands, but mainly by thick (from 50 to 180 m) deluvial-moraine deposits. These sediments are represented by unconsolidated fragments of altered rocks of different hardness and abrasiveness: mudstones, siltstones, tuff-sandstones, granite-gneisses and hornfels of various compositions. In addition, on the northern slopes of the ridge there are widespread areas of permafrost, which makes the specifics of drilling operations close to the conditions of the Far North.