2008-11-24_PERMIT FILE - C1996083 ‎(12)‎

• Permit No: C1996083
• IBM Index Class Name: Permit File
• Doc Date: 11/24/2008
• Doc Name: Geotechnical Data Report Bruce Park Dam, GEI Consultants, April 2001
• Section_Exhibit Name: Volume X Bruce Park Dam Geotechnical Studies
• Media Type: D
• Archive: No

Geotechnical Data Report Bruce Park Dam
Bowie Resources, Limited
April 2001
0;
vertical joints. The jointing is generally tight to slightly open, slightly rough andiron
stained in places. The silty sandstone was encountered to the total depth explored of
63.5 feet. The silty sandstone is described as moderately hard, moderately to well
cemented, light brown to tan with some lighter colored calcareous zones, slightly to
moderately weathered, fine to medium grained with predominantly quartzose and
some feldspathic and mafic mineral grains and with occasional claystone clasts up to
2 inches in size. The sandstone structure includes thick to massive, nearly horizontal
bedding with some cross bedding and widely to moderately spaced jointing that
parallels bedding. The measured in-place dry density of the silty sandstone is 123 pcf
at a natural moisture content of 8.4 percent. The laboratory testing results also
indicate the sandstone has an unconfined compressive strength of 1,750 pounds per
square inch.
The bedrock encountered in Borings BD-103 and BD-105, below the maximum
section of the Main Dam, consists of silty sandstone to the total depths explored of 53
feet and 113.5 feet, respectively. The silty sandstone is described as light brown, fine
to medium grained sandstone, similar to the sandstone described in Boring BD-102.
40) 7.1.5 Groundwater
Groundwater was encountered below the main embankment in Boring BD-103 at a
depth of 32 feet, Elevation 8098, and in BD-105 at a depth of 88 feet, Elevation 8099.
The groundwater depths were measured in open standpipe piezometers on December
12, 2000, 15 toll days after drilling. Groundwater was not encountered in Borings
BD-101, left abutment, and BD-102, right abutment, to the total depths explored of
20 feet and 63.5 feet, respectively. The reservoir was empty at the time the
piezometers were installed and measured.
7.2 Saddle Dam
Generalized subsurface conditions identified in the two borings drilled in the Saddle Dam
embankment are discussed in the following paragraphs and also presented graphically on the
centerline profile and cross section shown in Figure 5. In general, the Saddle Dam
embankment consists of new embankment similar to that found in the main dam. The
foundation consists of bedrock.
7.2.1 New Embankment Materials
New embankment materials were encountered in Boring BS-102, drilled near the
maximum section of the embankment. These materials are generally low to high
plasticity clays with varying amounts of sand. They are visually classified as CL and
CH materials according to the Unified Soil Classification System (USCS). These
GEI Consultants, Inc. 18 99292 0+-04-16 Geotechnical Data Report