REP41933

• Permit No: C1981041
• IBM Index Class Name: Report
• Doc Date: 10/21/1997
• Doc Name: FAX COVER
• From: DMG
• To: OSM
• Permit Index Doc Type: Waste Pile/Fill Report
• Media Type: D
• Archive: No

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STATE OF t
COLORADO
DIVISION OF MINERALS AND GEOLOGY
Depanmenl of Natural Resources ~ ~-
1313 Sherman St., Room 215 rd

Denver, Colorado 80203 I
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II
Phone: [phone]
FAX: [phone]
DEPAIZTMEM' OF
NATURAL
RESOURCES
DATE: September 12, 1997 Roy Romer
Governor

TO: Dan Mathews

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_
lames S. Lxhhead
Executive Duetlor
Michael B. Long
FROM• Jim Pendleton Division Director
RE: Roaaside ne - Re a Disposal Pile - Piezometet• #307
(Permit No: C-81-041)
I have reviewed the information which you sent via facsimile to my attention. I understand your
concern regards the status of piezometer #307, installed on the second bench of the refuse
disposal pile at the Roadside mine. It is my understanding Larry Reschke informed you, during
your recent inspection of the pile, that this piezometer has been unusable (incapable of entry with
the m-scope water table depth probe) for the majority of its life. You have requested my opinion
whether this piezometer needs to be replaced by the operator.
In 1994, a series of thirty piezometers were required [o be installed within the refuse pile after
seeps had developed above the second facial bench. The Division wanted the operator to
determine whether this seep was [he expression of a perched seep along the surface of the-bench,
or rather an indication that the entire pile was saturated to that elevation. The assemblage of
piezometers have satisfactorily demonstrated to the Division that the seep was an expression of
a perched water bearing lens within the pile, probably resulting from.the_high compaction of a
surface exposed [o truck tire traffic for an extended period of time. Further, as the pile's
thickness increased and [he upslope diversion of surface drainage was improved, the flow from
these seeps diminished. Finally, there has beer. no evidence of renewed instability of [he refitse
saturated by the seepage.
No other of the thirty piezometers has indicated any potential problematic ground water
elevations. Nor has the refuse pile demonstrated any slope stability problems. I do not believe
it would be warranted at [his time to require the operator to replace piezometer #307. I
recommend that we require the operator to continue to attempt to monitor piezometer #307. A
changed condition in [he future might warrant a more in depth reconsideration of the situation.
cc: Larry Routten
doc: M:\COALVAP\piez307.wp5
JP/jP