2007-01-11_PERMIT FILE - C1982057

• Permit No: C1982057
• IBM Index Class Name: Permit File
• Doc Date: 1/11/2007
• Doc Name: As-Built Report Sedimentation Structure Pond 016A
• Section_Exhibit Name: Tab 13 Attachment 13-5F Appendix 2 Part 2
• Media Type: D
• Archive: No

March 2004 Seneca Coal Company *Seneca H W Mine Sedimentation Pond 016A As -built Stability Analysis ♦ 2
•
2.0 RESULTS
Using the described inputs, the stability analysis indicates a static FOS of 1.7 for a downstream slope,
which meets the required FOS under applicable provisions of Rules 4.05.9 (6) and 4.05.9 (8) (b). The
SLOPE /W computer printouts, located in Appendix B, document all inputs and stability analysis
results. This stability analysis result is based on the assumption that construction practice employed
for this embankment resulted in embankment material compaction of at least 95% Standard Proctor.
3.0 REFERENCES
• Northwest Colorado Consultants (July, 1994). "Geotechnical Investigation, Haulroads Y -A & Y -B and
Sedimentation Pond 010, Seneca 11 W Mine Area, Routt County, Colorado'. Prepared for Seneca
Coal Company.
Northwest Colorado Consultants (August, 1996). "Geotechnical Investigation/Summary Report Pond 01.0
Embankment — Permit C -94 -082 Seneca 11 W Mine, Roun County, Colorado'. Prepared for Seneca
Coal Company.
ICJ
MWH, 1801 California .Street, Suite 2900 * Denver, Colorado 80202 * (303) 291 -2222
J. \2470108 Seneca Coal\PondsAsblt \Word\ POND 16A ASbuiltSTABILI7Y.doc
03102104 djm
INDEX AND oSTRENGTH. PROPERTIES OF SOILS .FOR ;PONDS,
SAMPLE
ATTERBERG
PARTICLE SIZE
EFFECTIVE
EFFECTIVE
LIMITS
DATA
FRICTION ANGLE,
COHESION,
(LL — PI)
(% passing No.
0
c' (psf)
200 )
Pond 016 Foundation
49-20
96
29.9
0
Pond 16A
37 — 19
86
-
-
Embankment Fill
38— 22
86
27.5
338
Pond 010 Embankment
Fill
2.0 RESULTS
Using the described inputs, the stability analysis indicates a static FOS of 1.7 for a downstream slope,
which meets the required FOS under applicable provisions of Rules 4.05.9 (6) and 4.05.9 (8) (b). The
SLOPE /W computer printouts, located in Appendix B, document all inputs and stability analysis
results. This stability analysis result is based on the assumption that construction practice employed
for this embankment resulted in embankment material compaction of at least 95% Standard Proctor.
3.0 REFERENCES
• Northwest Colorado Consultants (July, 1994). "Geotechnical Investigation, Haulroads Y -A & Y -B and
Sedimentation Pond 010, Seneca 11 W Mine Area, Routt County, Colorado'. Prepared for Seneca
Coal Company.
Northwest Colorado Consultants (August, 1996). "Geotechnical Investigation/Summary Report Pond 01.0
Embankment — Permit C -94 -082 Seneca 11 W Mine, Roun County, Colorado'. Prepared for Seneca
Coal Company.
ICJ
MWH, 1801 California .Street, Suite 2900 * Denver, Colorado 80202 * (303) 291 -2222
J. \2470108 Seneca Coal\PondsAsblt \Word\ POND 16A ASbuiltSTABILI7Y.doc
03102104 djm