Project PRE-Schooner II. Postshot Geologic and Engineering Properties Investigations
ARMY ENGINEER NUCLEAR CRATERING GROUP LIVERMORE CA
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The Pre-Schooner II Event was a chemical explosive single-charge cratering experiment in hard, dry rock. The detonation was centered 71 feet below the ground surface and consisted of approximately 85.5 tons of nitromethane. The explosion produced a crater with an apparent radius of 95.2 feet and an apparent crater depth of 60.7 feet. Postshot explorations of the crater consisted of excavating three radial trenches through the lip material and then extending two of the trenches into the fallback within the crater. Both bulk densities and block-size distribution of the ejecta and fallback were obtained. Bulk densities averaged 103.8 pcf except for an anomalous value of 93.1 pcf in one trench. Block sizes varied from fines of clay size to blocks greater than 6 feet in diameter. The true crater radius and the lip upthrust were measured at the three trenches and averaged 100 feet and 11 feet, respectively. The crater slope angles measured before, during, and after completion of the fallback excavation averaged 37, 42, and 38 degrees, respectively.
- Mining Engineering