Hydraulic resistance to movement of a drill suspended by a cable in a bore-hole in travels

Equations are given for calculation of the hydraulic resistance force to movement of a drill suspended by cable and the speed of its movement as a function of the dimension and mass of the drill and properties of the hole liquid. The most significant factor influencing the hydraulic resistance during drill movement in the hole is the radial clearance between the drill and bore-hole walls. The methods of experimental study of the drill movement on the laboratory stand are described. The results of the theoretical calculations and measurements of the speed of the drill movement obtained during drilling on Vavilov glacier (Severnaya Zemlya archipelago) are compared : the discrepancy does not exceed 10%.