From the organization and state of drilling and blasting works largely depends on the management of stocks of blasted rock mass and rhythmicity of work of quarries. As reported data show, the cost of preparation of rocks for excavation at the quarries of the Polar region is 1.5-2 times higher than at the quarries of the central regions of the country with similar mining conditions. Improvement of technology and organization of drilling and blasting operations at the quarries of the Polar region allowed to significantly increase the provision of excavators with blasted rock mass.

The rhythmicity of work of quarries in the Polar region depends on numerous factors and, first of all, on severe climatic conditions, the influence of which leads to a decrease in the productivity of quarries and violation of the rhythm of their work. To take into account the severity of the climate, correction factors are introduced to the production rates in different periods of the year. However, seasonal fluctuations in general are insufficiently studied, although the laws of seasonality are very important to take into account when planning and organizing production processes. On the other hand, at the quarries of the Polar region 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