The most important task of exploration core drilling is to ensure high recovery and quality of core – the source material for geological and engineering geological sampling. Analysis of production data of a number of organizations engaged in drilling in permafrost rocks shows that when drilling with flushing, the core recovery is 60 70% for bedrock with moisture content of 2 5% and 20 30% in rocks with moisture content of 15% and more. In production conditions, very often in order to increase core recovery, one switches to “dry” drilling. However, the core quality deteriorates sharply. Partial or complete thawing of the core occurs, with violation of its structural characteristics.

Currently, hard rocks account for about 25-30% of the total volume of exploration core drilling. Drilling is carried out by shot drilling. By the end of the seven-year plan (1959-1965) about 50% of shot drilling will be replaced by fine-diamond drilling. Thus, the improvement of shot drilling technology still plays a major role in accelerating the exploration of mineral deposits. One of the ways to improve the technology of shot drilling is flushing the bottom hole with compressed air instead of flushing with water. Air, as a flushing agent, is not able to keep the walls of the well from collapse, but this is not required in shot drilling in strong rocks, as a rule. Compressed air successfully fulfills the other requirements to the flushing agent.