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 13 kilometres (8 mi) SE of the town of Grand Valley, Colorado (now named Parachute, 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 feet 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 ...