Geology of the U12n. 10 UG-1 horizontal drill hole, Rainier Mesa, area 12, Nevada Test Site, Nevada
The U12n.10 UG-1 horizontal exploratory hole was collared at Nevada State coordinates N. 895,008.84, E. 633,702.99 at an altitude of 1,850.8 m (6,072.26 ft). This location is 136.9 m (CS 4 + 49 ft) into the face of the U12n.10 bypass drift. The boring was drilled along a bearing of N. 73/sup 0/54'11''W. to a total depth of 427.2 m (1,401.5 ft). The drill hole starts in tunnel-bed subunit 4F; passes down the stratigraphic section through subunits 4E, 4CD, 4AB, 3D, 3BC; penetrates the northwest limb of a northeast-trending syncline; and terminates in subunit 3A, all of Tertiary age. A fault observed in the core at 376.4 m (1,235 ft) has been correlated with a lineation mapped on the surface of Rainier Mesa. The distance between the end of the boring and the underlying pre-Tertiary surface is about 88.4 m (290 ft). A fault cuts the pre-Tertiary surface and is down-thrown 30-61 m (100-200 ft) to the east. The trace of this fault would project vertically to 466.3 m (1,530 ft) in the drill hole; however, no evidence of this fault is seen in the boring, and, therefore, it is assumed to be pre-Tertiary in age. No serious construction or support problems are anticipated for any drift mined along the drill-hole alinement. The rock is generally competent and there are no zones of extensive argillization.
- Research Organization:
- Geological Survey, Denver, Colo. (USA)
- OSTI ID:
- 7326246
- Report Number(s):
- USGS-474-218
- Country of Publication:
- United States
- Language:
- English
Similar Records
Geology of the U12n.07 UG-3 drill hole, area 12, Nevada Test Site
Geology of the Rainier Mesa-Aqueduct Mesa Tunnel Areas-- U12n Tunnel