... cone drill bit ,3 cone bits,rotary bit, TCI tricone bit,PDC drill bit ,diamond core bit,bicenter bit,single ... mining and tectonic industries ,oil field, construction, geothermal, directional boring, and underground foundation work all over the world. 2> ... call) .Recommended drilling parameters of tri-cone rock bits Rock formationBit typeBit sizeDrilling weightRotary speedmminchkN/mmr/minVery softSoft ...