Matching Pairs Drilling RigOnline version Parts of drilling rig by Tatiana Yaikina 1 mud pit 2 derrick 3 kelly 4 draw works 5 rotary drive 6 travelling block 7 crown block Steel tank used as a mud collector. A machine used to impart rotational power to the drill string. A steel frame on beams at the top of the derrick. A hoisting mechanism which raises or lowers the drill pipe and drill bit. A large structure standing on four legs and reaching the crown block. A steel frame with wheels which moves up or down in the derrick A steel pipe, located at the top of drill string.