Results of rock property measurements made on core samples from Yucca Mountain boreholes, Nevada Test Site, Nevada; Part 1, Boreholes UE25A-4, -5, -6, and -7; Part 2, Borehole UE25PNo.1

Laboratory measurements of resistivity, bulk and grain density, porosity, compressional sonic velocity, water permeability, magnetic susceptibility, and remanent magnetization were made on core samples from Yucca Mountain boreholes located in Drill Hole Wash at the Nevada Test Site. The samples are representative of lithologic variations to be found in the Tiva Canyon, Yucca Mountain, Pah Canyon, and the upper Topopah Spring Members of the Paintbrush Tuff. Boreholes penetrated to a depth of approximately 152 meters (500 ft.). The Paintbrush Tuff consists primarily of nonwelded to densely welded rhyolitic ash-flow tuff with relatively thin beds of ash-fall tuff typically separating each Member. Resistivity and bulk density measurements were made on samples containing natural pore waters and repeated following resaturation with local tap water. Density comparisons indicate the samples to be undersaturated in their natural environment as expected in that the boreholes did not intersect the water table