This report describes a system designed to return coal mine waste to the operating underground mine generating it. This system, which was installed and tested at a site operated by the Millers Cove Energy Company, Inc. in Lee County, Virginia, limits the size of the surface facilities and incorporates state-of-the-art hydraulic transport and backfilling technology and equipment to systematically backfill areas in the active mine. The cost of returning coal waste underground at the Millers Cove site was estimated at $0.67 Per ton of marketable coal (1982 dollars), which is slightly higher than the surface disposal cost of $0.61 Per ton of marketable coal (1982 dollars). The underground disposal costs do not include cost savings that could be realized in the preparation plant and treatment facilities at the surface. Preliminary tests of the system were conducted at the surface because funding restrictions prevented an in-mine trial.