Author 1:
Name & Surname: Skryabin R. M.
Company: Ammosov North-East Federal University (Yakutsk, Russia)
Work Position: Head of department, Professor
Scientific Degree: Candidate of Engineering Sciences
Contacts: yakutsk_09@mail.ru

Author 2:
Name & Surname: Timofeev N. G.
Company: Ammosov North-East Federal University (Yakutsk, Russia)
Work Position: Senior Lecturer

The paper presents designs and recommendations on improvement of technology and equipment of exploration shaft drilling in prospecting of placers on the north–east of Russia, in permafrost zone. The authors state the low productivity, high labor content and extra cost of the currently employed technology and equipment in exploration shaft drilling, and point at the insufficient research effort and recommendations aimed at reengineering of exploration shaft drilling-assisted geological survey of placers in permafrost zone. Based on the analysis of literature, practice of exploration shaft drilling and personal research, the authors offer the method of rotation drilling of exploration shafts with broken frozen rock removal at intervals (auger–coring tool with a diameter of 750 mm) as the most efficient and promising method of prospecting placers in permafrost zone. For the purpose of representativity, completeness and quality of sampling, the authors recommend to use kelly bars, to arrange the worm in the core barrel, to take samples at intervals and to equip the drill rig with a rotating platform. A detail discussion covers recommendations on selecting rock cutting tool and its optimized operation at exploration shaft bottom in permafrost formations. It is recommended to arrange cutters at varied height to make stepshaped (uneven) shaft bottom. Areas of further research toward improvement and reengineering of auger–coring drilling of geological exploration shafts under conditions of permafrost are identified.

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