REP14680

• Permit No: C1996083
• IBM Index Class Name: Report
• Doc Date: 7/13/1999
• Doc Name: BOWIE 2 MINE LAMBERT & ASSOCIATES ASSUMPTIONS FOLLOW-UP PN C-96-083
• From: DMG
• To: JOE DUDASH
• Permit Index Doc Type: STABILITY REPORT
• Media Type: D
• Archive: No

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STATE OF COLOIZP~llv
DIVISION OF MINERALS AND GEOLOGY
Depanmenl of Nnmral Resources
131 7 Sherman SL, Ruom ? 15
Denver, Colorado 8U7U3
Phone: [phone]
FA%: (}011 H}?8106
DATE: July 13, 1999
[Amends Memo of July 12, 1999)
TO: Joe Dudash
C'
FROM: Jim Pendleton ~,.-~
RE: Bowie No.-211'Iine - mbert & Associates Assumptions -Follow-up
ermit No: C-96-083)
DIVISION OF
MINERALS
GEOLOGY
0.ECLAM ATION
MINING•SAFETY
ern oven:
Governor
Creg E Wakhcr
Executive Direaur
Michael B. Lang
Drc~smn Dv¢aur
In response to your recent inquiry, I reexamined the Bowie No. 2 Gob Pile stability analysis
prepazed by Norm W. Johnston, P.E., of Lambert & Associates. As I understand your query, you
desire to know specifically whether Lambert & Associates' stability analysis demonstrates that
the refuse pile at Bowie No. 2 has a safety factor of 1.5 in it's present configuration.
On page four of the report, the third paragraph states;
"Our stability analysis is based on the assumptions of an intimate and competent contact
between the GOB fill material and the natural support material which include the organic
topsoil removed and the exposed surface of the natural foundation support soil materials
benched prior to placement of the GOB material."
This statement appears unambiguous, as faz as it goes. However, the report does not state
whether Lambert & Associates performed any examination or completed any inquiries which
determined whether the foundation had actually been benched prior to the placement of GOB
material.
The fourth paragraph on page four of the Lambert & Associates' report reads;
"The benching of the natural foundation support soil materials to expose competent
support material reduces the potential for developing a predetermined failure plane along
the GOB/natural material contact. We suggest that future plans include benching into the
natural material to receive the fill material prior to placing additional GOB material. The
benching should continue into competent foundation support material as the GOB
mate) ial is placed as the pile height is increased. The benching concept is shown on
Figure 7."