[Music] the main purpose of the drill rods is to transfer torque rotation speed and lifting or feed force down to the drill bit and the core barrel in wire line drilling since the inner tube assembly is sent through the drill rods the inside of these rods must be produced with a high quality therefore each wire line core barrel dimension requires the same drill rod dimension in deep hole drilling the weight of the drill string increases the requirements on the drill rig torque and lifting force to maximize the depth capacity of the core drilling machine special
drill rods are designed with a thinner body to decrease the weight of the drill string wire line drill rods are made out of a seamless blank of high quality steel either the blank is heat treated before turning the threads or the blank is threaded first and then the threads are heat treated conventional drill rods are made out of steel or aluminum the steel drill rods are equipped with steel couplings which are threaded and heat treated or friction welded to the steel body and then heat treated since no inner tube needs to pass through the drill
string one dimension of conventional steel drill rods can be used for two or three core barrel dimensions the aluminum drill rods are also equipped with steel couplings but these are threaded and glued to the aluminum body with only half the weight this gives the aluminum drill rod almost the same properties as the steel rods but with higher wear the dimension of the aluminum drill rods must be adapted to the dimension of the core barrels before reaching the rock mass and extracting a core sample the driller needs to go through the overburden with a casing shoe
that drills the hole and casing tubes that prevent non-consolidated formations from caving in this phase requires casing shoes with diamonds or tungsten carbide and in some cases telescopically adapted casing tubes in order to be able to drill as deep as necessary the dcdma standard casing tubes have thicker walls than the cms standard casing tubes and are therefore more suitable for heavy and demanding casing tube drilling the water swivel connects the rotating drill string to the water hose from the flush pump there are two types of water swivels one is used on underground core drilling machines
with synchronized make and break systems and the other is used on surface core drilling machines using main hoist
