APPCOR10792

• Permit No: C1981026
• IBM Index Class Name: Application Correspondence
• Doc Date: 7/31/1980
• Doc Name: OSM COAL PRODUCTION & RECLAMATION FEE REPORT
• Media Type: D
• Archive: No

i ~ .~ ~ ., i
4.15.7(3)(b • n July 17, 1981, Dave St• of Wyoming Fuel Company
and Mike Savage of the CMLR staff discussed
sample adequacy of plant communities and reference
areas. From this discussion Wyoming Fuel Company
understood that more calculations were necessary
to determine the need for additional sampling during
1982. Mr. Savage needed "t" values calculated for
the vegetative communities in question. Once these
values are provided to Mr. Savage and he has had a
chance to review the data, Dave Stout and Mr. Savage
will meet to determine whether additional vegetative
data needs to be acquired.
Following are responses to Mr. Savage's specific
comments and the information requested during the
meeting of July 17, 1981.
1. The t-test formula utilized in the statistical
analysis:
t = X - X
m r
Sp2 nm+ nr
n n
m r
where Sp2 = ~+ ~
n + n -2
m n
m = mine area
r = reference area
1. No comment is necessary.
2. Wyoming Fuel Company understands the Division
policy of 10% accuracy. However, at the time
this vegetation study was undertaken,' discussions
with the CMLR staff (Carol Pahlke) did not sugges
that accuracy levels of 20% would be unacceptable
In fact, after the 1979 data was reviewed by the
CMLR staff there was no question as to the accura
levels used by the consulting firm contracted by
Wyoming Fuel Company. Therefore, in planning
for 1980 vegetative studies, Wyoming Fuel Compan}~
assumed a 20% accuracy level with,80% confidence
would be adequate for production and 'woody plant
density data.
3. The discrepancies between Tables 8F and 1F result
in rounding errors. The data in Table 8F are the
actual means for vegetative cover.
4. The discrepancies noted between Tables 9F, 1F any
2F result from rounding, significant '.figures.
The data in 9F is accurate for mean comparisons.
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