Excavations near the rig into which drilling mud is circulated. Mud pumps withdraw the mud from one end of a pit as the circulated mud, bearing rock chips from the borehole, flows in at the other end. As the mud moves to the suction line, the cuttings drop out leaving the mud "clean" and ready for another trip to the bottom of the borehole. See Reserve Pit.a reservoir or tank, usually made of steel plates, through which the drilling mud is cycled to allow sand and fine sediments to settle out. Additives are mixed with mud in the pit, and the fluid is temporarily stored there before being pumped back into the well. Mud pits are also called shaker pits, settling pits, and suction pits, depending on their main purpose.
