Project Rulison, named after the rural community of Rulison, Colorado, was an underground 40-kiloton nuclear test project in the United States on September 10, 1969, about 8 miles (13 km) SE of the town of Grand Valley, Colorado in Garfield County. The location of "Surface Ground Zero" is 39°24′19.0″N 107°56′54.7″W. The depth of the test cavity was approximately 8,400 ft (2,600 m) below the ground surface. It was part of the Operation Mandrel weapons test series under the name Mandrel Rulison, as well as the Operation Plowshare project which explored peaceful engineering uses of nuclear explosions. The peaceful aim of Project Rulison was to determine if natural gas could be easily liberated from underground regions. This site remains under active monitoring by the U.S. Department of Energy Office of Legacy Management.