2017-05-12_PERMIT FILE - C2010089A ‎(10)‎

• Permit No: C2010089A
• IBM Index Class Name: Permit File
• Doc Date: 5/12/2017
• Doc Name: Pond NHN-002 As-Built
• Section_Exhibit Name: Appendix 2.05.3‎(4)‎-10
• Media Type: D
• Archive: Yes

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CONSULTING GEOTECHNICAL ENGINEERS AND MATERIAL TESTING
Western Fuels Association, Inc.
12050 North Pecos Street, Suite 100
Westminster, Colorado 80234
Attention: Mr. Dave Anderson, PLS
Subject: NHN Pond 002
Summary Discussion of the
Compaction Test Results
Slope Stability Analysis
Mr. Anderson,
15 June 2015
2 September 2015
PN: M15018MT
M15018MTr
This letter submits summary of the tests we performed at the subject site and of the calculated
theoretical slope stability analyses are also included.
Our on site testing services for the project were provided on an on-call as -needed basis, 20, 21,
and 22 January 2015. The test results were presented tabulated and submitted with our 10 June
2015 report. Our test methods were in accordance with ASTM Test Method, D2922 and D3017,
for Nuclear Moisture Content and Dry Density and accepted material testing practices in the area.
The field density tests results indicate that all of the test results indicated 90% or greater relative
compaction based on ASTM Test Method D1557.
Our stability analyses of the embankment soil material was based on the Bishops Method of
Slices. This method is based on the assumption that the slope soil mass will fail in a rotation
mode on a circular are plane. In this method of analysis the mass of soil is divided into vertical
slices. The forces acting on each slice are evaluated from the equilibrium of the slices; that is,
the forces that tend to drive the slice downhill and the forces that tend to resist the movement of
the slice. The equilibrium of the entire mass is determined by summing the driving and summing
the resisting forces acting on all slices and comparing these forces.
Our slope stability analysis was performed using "XSTABL" software by Interactive Software
Designs Inc. Our slope stability analysis considered the existing cross section consisting of a 10
foot high 3:1 (horizontal to vertical) slope inclination, with a total of about 225 separate possible
failure surface iterations for each condition to help identify the potential theoretical slope stabil-
ity. Our presentation is based only on the calculated critical circle which presented the lowest
factor of safety against failure. Our presentation does not include the results of all of the itera-
tions which resulted in a theoretical factor of safety greater than the lowest factor of safety and
P.O.Box 3986
Grand Junction, Co. 81502
[phone]
P.O.Box 45
Montrose, Co. 81402
[phone]
Appendix 2.05.3(4)-10 Page 2 September 2015 (TR -10)