2010-12-17_REVISION - C1981019 ‎(153)‎

• Permit No: C1981019
• IBM Index Class Name: REVISION
• Doc Date: 12/17/2010
• Doc Name: Exhibit 7 Item 21 Collom Project Pre-Feasibility Hdyrology Report
• Type & Sequence: PR3
• Email Name: JRS
• Media Type: D
• Archive: No

Groundwater 61
Table 5.7 Summary of measured hydraulic conductivities
Unit
Maximum
Minimum
Geometric
# of
# of
(ft/day)
(ft/day)
mean
datapoints
wells
(ft/day)
Valley fill
1.96E +02
1.44E -03
3.26E +01
16
9
F sandstone
5.24E -02
7.87E -03
1.76E -02
6
6
F/G sequence
1.98E -01
4.28E -04
3.88E -02
18
18
Fab seam
7.70E -01
6.66E -03
1.84E -01
9
6
G seams
5.72E -01
9.69E -02
1.97E -01
4
4
H sandstone
7.9E -03
1.67E -04
1.44E -03
4
4
1 sandstone
3.20E -02
9.03E -04
8.06E -03
3
3
J seam
4.28E -04
1
1
Trout Creek Sandstone
8.90E -02
5.80E -03
2.06E -02
6
3
5.2.9 KM sample permeability
Samples of the KM marker bed were collected from two locations and submitted for
laboratory permeability testing. The KM marker bed, which is composed principally of
smectite clay, was sampled in exploratory borings C -04 -26 and C- 04 -39. The samples
were submitted to Advanced Terra Testing, of Lakewood, Colorado for measurement of
their vertical hydraulic conductivity using ASTM Method D 5084. The tests were run
from November 11, 2004 to January 6, 2005. The calculated permeabilities of the
samples are less than 1 x 10 -10 cm /sec (2.8 x 10 -7 ft/day). This indicates that material in
the KM layer is effectively impermeable. A detailed description of the testing method
and results are presented in Appendix 5.1.
5.2.10 Water level measurements
Water level measurements were collected and analyzed to evaluate the piezometric
surfaces of the different units, their gradient, and the direction of groundwater flow.
Piezometric data were also used to evaluate the vertical gradients between units as well
as the interactions between bedrock units, valley fill, and streams.
Bedrock water levels
Site -wide, water levels in wells and piezometers were monitored monthly by WMC and
KEC from August 2004 through May 2005. Collection of water level data by KEC is
ongoing. Water levels were collected using transducers, vibrating wire piezometers, and
an electric well sounder. Water level data are provided in both tabular and graphical
form (hydrographs) in Appendix 5.J. Hydrographs are provided by location (e.g.,
MWC -03 -29 FS, FG, and H). This provides information on variations in head as a
function of depth at a given location as well as temporal and spatial variations within a
given unit. Table 5.J.1 lists all water levels collected from both the alluvial and bedrock
wells. Water level measurements that are clearly anomalous are highlighted in the
comments column and were not included in the hydrographs or groundwater maps.
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