REV02174

• Permit No: C1981028
• IBM Index Class Name: Revision
• Doc Name: MEMO KEENESBURG MINE C-81-028 MID TERM REVIEW
• From: DMG
• To: SHAWN SMITH
• Type & Sequence: MT2
• Media Type: D
• Archive: No

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999
STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Depanmenl of Natural Resources I~~~~
1313 Sherman SL, Room 215
Denver, Colorado 80203
Phone: [phone] ^
FAX. [phone]
DEk'ARTMENT OF
MEMO RESOURi CES
Roy Rnmer
TO: Shawn Smith cm-error
FROM: Tony Waldron4~ Aen sn~n ear
E vecw i.e Drtec W r
RE: Keenesburg Mine (C-81-028) , Mid-Term Review ^,i~h,eie ~°^ti
D misinn Dvec mi
Per your request I have reviewed the Keenesburg Mine Permit for
adequacy and compliance with respect to vegetation. In doing so I
reviewed the 1992 findings document and the permit application.
There do appear to be some inadequacies in the permit with respect
to revegetation sampling for bond release. These apply both to the
sampling methodology and the statistical demonstrations that will
be required for bond release.
The sampling methodology that the Keenesburg Mine intends to
use(per the permit application) is very subjective and in my
opinion prone to sampling error. The ability to duplicate results
with this method is also suspect. This method (if I understand it
correctly) calls for randomly placed plots which are further
subdivided into 1 foot square subplots. Cover will then be
ESTIMATED for each of these subplots. The narrative does not
explain if each large plot is to be considered a sampling point or
if each subplot is a sampling point. Furthermore, no discussion of
sample adequacy is provided and the statistical comparisons to be
made for successful establishment are not clearly defined.
I would propose that the mine utilize a more commonly used and
easily reproducible sampling method called the point intercept
method. This method utilizes a point frame with either an ocular
sighting device or a sharpened point for detecting vegetative
cover. The frame is placed at preset intervals along a transect of
set length and enough points (ie 100) are taken to provide one
sample. Then enough samples are taken to meet sample adequacy at
the 90$ confidence level. There are several advantages to this
method one of which is the more objective gathering of data and
diminished opportunities for personal bias. This method is also
easily reproducible and different individuals can collect data with
much less variability in the results.
The statistical demonstrations that are required for bond release
are also not clearly stated in the narrative. There are two
demonstrations that must be made for any type of bond release
involving successful establishment of vegetation to be approved.