Crown BHA 102 - T 51.VRS MX 20.00

New, not used, drill bit, pin, d.102 mm, thread T51, with a flat face, retrac, 15 spherical pins, peripheral 9x12 mm, frontal 6x12 mm, the angle of inclination of the peripheral pins 35 degrees, 3 washing holes d.11 mm. Length 167 mm, weight 5,5 kg.
Confirmed durability in drilling conditions of rocks represented by siltstones with interlayers of sericite-quartz shales, multidirectionally medium-cracked, tectonically disturbed, medium-thinly dissected, with rare quartz veins, dip to the north at a 75-80° angle, medium stability, strength coefficient according to the scale of Prof. Protodiakonov, fcr = fcr = fcr, fcr = fcr, fcr = fcr. Protodyakonov, fkr = 7-8, category of rocks on drillability with a coefficient on the scale of Prof. Protodyakonov f=13, continuous polymetallic ore, massive texture, fine-medium-grained structure, in some places oxidised, fracturing increased in the form of formation, fkr = 12-16, medium stability, category of rocks on drillability with a coefficient on the scale of Prof. Protodyakonov.