Tests of Rock Cores, Castle Study Area, California.
Abstract:
Laboratory tests were conducted on rock core samples received from seven core holes in the Castle area of Mariposa and Madera Counties, California. The results were used to determine the quality and uniformity of the rock to depths of 200 feet below ground surface. Specific gravity, Schmidt hardness, wave velocity, and compressive strength tests indicated the rock to be highly variable in physical properties. The core was identified as predominantly soda tonalite. Approximately one-third of the rock tested was sufficiently weathered and fractured to be classed as incompetent material. An assessment of the area on a hole-to-hole basis indicates that the area in the vicinity of only two of the seven holes appears to offer possibilities as a uniform, competent hard rock medium. Author