Keywords: NTS - Big Hole Drilling 008.jpg en Nevada Test Site - Area 20 Big Hole Drilling <br/> An Emsco 1500 heavy duty drilling rig is drilling an 64-inch 3 850 foot emplacement hole for the Mandrel Jorum test which was detonated on September 16 1969 1141 Federal Government of the United States PD-USGov Drilling machines Mandrel Jorum Nevada Test Site Big Hole Drilling |