"United States Atomic Energy Commission Dr. Glenn I. Seaborg Chairman Project Faultless January 19, 1968 A nuclear detonation was conducted below this spot at a depth of 3,200 feet. The device, with a yield of less than one megaton, was detonated to determine the environmental and structural effects that might be expected should subsequently higher yield underground test be conducted in the vicinity.
No excavation, drilling and/or removal of material is permitted without U.S. Government approval within a horizontal distance of 3,300 feet from the surface ground zero location (Nevada State Coordinates N1,414,340 and E629,000 Nye County, Nevada.) Any reentry into U.S. Government drill holes within this horizontal restricted area is prohibited."
Plaque on pipe.
The ground was level with the top of the pipe before the blast.