Geological Survey investigations in the U12b.03 and U12b.04 tunnels, Nevada Test Site

Abstract

The papers comprising the various parts of this report contain preliminary results of the U. S. Geological Survey investigations in the Ul2b.03 and Ul2b.04 tunnels at the Nevada Test Site, Nye County, Nevada (fig. 1). The geologic studies were undertaken to define the structural, chemical, mineralogic, and some of the physical properties of the tuffaceous rocks that enclose the explosion chambers at the end of each tunnel. The U12b.03 and .04 tunnels are part of the Ul2b (Rainier) tunnel complex that was driven northwestward from the steep east slope of Rainier Mesa (a prominent topographic feature in the northwest part of the Test Site (fig. 2)).The U12b.03 tunnel trends north from a point about 980 feet from the portal of the Ul2b tunnel (fig. 3).The Ul2b.03 tunnel consists of 620 feet of tunnel, two alcoves, and a shot chamber. The tunnel is irregular, ranging from 6 to 10 feet in width, and 6 to 9 feet in height.The shot chamber at the north end of the tunnel is 22 feet on each side. The vertical and minimum cover over the shot chamber are 610 and 510 feet, respectively.

Simple estimation of fastest preferential contaminant travel times in the unsaturated zone: application to Rainier Mesa and Shoshone Mountain, Nevada

“…Differences in the ages of water in the matrix and fractures of the zeolitic tuff elucidate the degree of hydrologic connection between the saturated matrix of the zeolitic tuff and the fractures. Water age estimates at Rainier Mesa in the fractures and matrix of the zeolitic tuff, where the majority of nuclear tests were conducted, exist from a variety of age-estimation techniques, including bacterial ecology (Amy et al, 1992;Haldeman and Amy, 1993), stable isotopes (Russell et al, 2001), isotopes from atmospheric nuclear testing (Clebsch and Barker, 1960;Norris, 1989), water chemistry (Jacobson et al, 1986), and temporal patterns in fracture discharge (Diment et al, 1959;Jacobson et al, 1986). These age observations suggest that the residence time of water in the zeolitic tuff matrix is on millennial timescales and the fracture water has a much smaller residence time and appears to be recharged by modern waters.…”

“…Full 2). Information from (Diment et al, 1959;Dickey et al, 1962;Thordarson, 1965;Fernandez and Freshley, 1984;Russell et al, 2001;Russell et al, 2003;National Nuclear Security Administration, 2004;National Security Technologies, LLC, 2007). Full 3.…”

Interim geological investigations in the U12e.07 tunnel, Nevada Test Site, Nye County, Nevada

“…The laboratory procedures used to determine porosity, bulk density, and grain density have been described by Diment and others (1959, p. 51-53).…”