... ,dia of drill head is increased, 2,the derrick,self-traction device are advanced 3,auxiliary transmission gear box GENERALIn order to ... head is increased, and we add a derrick, a self-traction device, as well as a auxiliary transmission gear box.The drilling ... rope dia. (mm)15.5Drum capacity (four layer, m)52Retraction device stroke (m)400Power (by clients request)Diesel engine2135type.30kW,1500r ...