The flushing or slicing of coal or other material broken down by water jets along the floor and into flumes. Coal will flow back toward the flume if sufficient water is available and the gradient is not less than 6 degrees to 7 degrees in favor of the flow. Flexible low-pressure hoses (150 to 200 psi or 1.0 to 1.4 MPa) are sometimes used to assist in the flushing operations.