From the organization and state of drilling and blasting operations largely depends the management of blasted rock mass reserves and the rhythmicity of open pit operations. As reported data show, the cost of rock preparation for excavation at open pits in the Arctic is 1.5 2 times higher than at open pits in the central regions of the country with similar mining conditions. Improvement of technology and organization of drilling and blasting operations at Arctic open pits has made it possible to significantly increase the supply of blasted rock mass to excavators.

The rhythmicity of work of open pits in the Arctic depends on numerous factors and, first of all, on severe climatic conditions, the influence of which leads to a decrease in the productivity of open pits and disruption of the rhythm of their work. To take into account the severity of the climate, correction coefficients are introduced to the production norms in different periods of the year. However, seasonal fluctuations have been insufficiently studied overall, although the patterns of seasonality are very important to take into account when planning and organizing production processes. On the other hand, at open pits in the Arctic it is very important to use favorable periods of the year for intensification of mining operations.

Mechanical drilling of boreholes in granite quarries of the Karelian Isthmus due to high strength and abrasiveness of rocks is an expensive and insufficiently productive method. To determine the possibility of application at granite quarries of fire drilling of boreholes by the department of open pit and drilling and blasting works of the Leningrad Mining Institute, the drillability of granites of several deposits of the Leningrad area (Rovnoe, Erkil, Vozrozhdeniya and Kamennogorsky) was investigated. The studies were carried out with the use of small-scale jet burners (RGR-2, RTB-V5, MIRGEM), operating on oxygen-kerosene and benzine-air mixtures. Their technical characteristics are as follows ...

At quarries in the Leningrad region, granite breaking is conducted, placing explosive charges in vertical wells with a diameter of 105 mm. Usually after explosions the floor of a bench turns out extremely uneven, protrusions (sills) sometimes reach one third of the height of the bench. Due to the uneven floor of the bench, the productivity of excavators EKG-4 does not exceed 250 thousand m³/year, i.e. about half as much as at leading mining enterprises