Results and interpretation of preliminary aquifer tests in boreholes UE-25c {number_sign}1, UE-25c {number_sign}2, and UE-25c {number_sign}3, Yucca Mountain, Nye County, Nevada

Pumping and injection tests conducted in 1983 and 1984 in boreholes UE-25c {number_sign}1, UE-25c {number_sign}2, and UE-25c {number_sign}3 (the c-holes) at Yucca Mountain, Nevada, were analyzed with respect to information obtained from lithologic and borehole geophysical logs, core permeameter tests, and borehole flow surveys. The three closely spaced c-holes, each of which is about 3,000 feet deep, are completed mainly in nonwelded to densely welded, ash-flow tuff of the tuffs and lavas of Calico Hills and the Crater Flat Tuff of Miocene age. Below the water table, tectonic and cooling fractures pervade the tuffaceous rocks but are distributed mainly in 11 transmissive intervals, many of which also have matrix permeability. Information contained in this report is presented as part of ongoing investigations by the US Geological Survey (USGS) regarding the hydrologic and geologic suitability of Yucca Mountain, Nevada, as a potential site for the storage of high-level nuclear waste in an underground mined geologic repository. This investigation was conducted in cooperation with the US Department of Energy under Interagency Agreement DE-AI08-78ET44802, as part of the Yucca Mountain Site Characterization Project