Surface Effects and Cavity Resulting From the Detonation of a 16-Ton Charge Deep in Granite.
ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS
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This report describes the time history of the above-surface phenomena associated with the MINERAL LODE Event of the MINE SHAFT Series, 1969. The report also documents the subsurface cavity as inferred from postshot slant holes that had as an aiming point the original center of detonation. MINERAL LODE involved detonation of a 16-ton ammonium nitrate slurry at a depth of burial of 100 feet in granite at the MINE SHAFT test area near Cedar City, Utah. A summary of the MINERAL LODE results, particularly of the quantitative measurements obtained, is as follows 1Jointing patterns in the rock significantly affected the mound shape. The total volume of the mound was calculated to be 2700 or -50 cubic yards. 2The initial rise velocity of the ground surface immediately above the charge GZ was approximately 30 feet per second. After 250 milliseconds, the rise velocity was about 85 feet per second. 3Ejecta heights and ranges were probably less than 150 feet for both. Ejecta sampling showed that 75 percent of the visible surface lying fragments were smaller than 3.5 feet, 50 percent were smaller than 2 feet, and 25 percent were smaller than 1 foot. 4The mean radius of the below-surface explosion cavity was established as 20 to 25 feet.
- Ammunition and Explosives