Weighs sand, clay, and other dry materials on scale and dumps materials into hopper of mixing machine. Turns water valve and opens hopper gate to admit specified quantity of water and dry mix into mixing chamber of machine. Tests mud sample for viscosity, using viscometer.
Starts pumps that force mud to drilling wells.
Lubricates, adjusts, and repairs machinery, using handtools and grease gun. Replaces defective parts of mud pumps and hoisting equipment, using handtools and following repair orders.