GENERAL41292

• Permit No: C1994082
• IBM Index Class Name: General Documents
• Doc Date: 8/7/1996
• Doc Name: YOAST MINE C-94-082 POND 10 CONSTRUCTION
• From: DMG
• To: SENECA COAL CO
• Permit Index Doc Type: GENERAL CORRESPONDENCE
• Media Type: D
• Archive: No

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STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Depanment of Natural Resources
1313 Sherman St., Room 215
Denver, Colorado 80203
Phone: [phone]
FA%:[phone]
August 7, 1996
Charles B. McGltlloh
Seneca Coal Company
P.O. Drawer D
Hayden, Colorado 81639
RE: Yoast Mine (C-94-082)
Pond 10 Construction
Dear Mr. McGl311oh:
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DEPARTMENT OF
NATURAL
RESOURCES
Roy Romer
Governor
lames 5. Lochhead
E~eculive Director
Michael B. Long
Division Director
On August 5, 1996, Joe Dudash of the Division conducted an inspection of the construction
operations for Pond 10 at the Yoast Mine. Mr. Dudash informed me of his observations the
following day. Among those observations were:
- A keyway for the embankment was being constructed, and was roughly 3'a
complete.
- Approximate dimensions of the keyway were 10' wide, 2' deep.
- Ground conditions in the construction area were extremely wet, and crews were
pumping water from the excavation to facilitate construction.
- The material in which the keyway had been cut was a dark colored soil.
The reported conditions indicate there may be problems with the construction of Pond 10.
Division staff reviewed the design requirements and approved construction plan for Pond 10,
compared the requirements to the Division's observations, and identified the following concerns.
1. The approved permit application states that the pond embankment and keyway will be
constructed with material obtained from the facilities area of the mine. We are
concerned with this proposal for two reasons. First, the facilities area of the mine has
not yet been excavated, so the material is not currently available. Second, and more
important, it does not appear that Seneca Coal Company has performed tests on the
material to determine whether it has sufficient strength to achieve the required factor of
safety of 1.3 or greater (required by Ruie 4.05.6(I1)(k)).