2012-05-14_REVISION - C1980005

• Permit No: C1980005
• IBM Index Class Name: REVISION
• Doc Date: 5/14/2012
• Doc Name: Updates to the Vegetation Section
• From: Seneca Coal Company
• To: DRMS
• Type & Sequence: SL5
• Email Name: JDM
• Email Name: DIH
• Media Type: D
• Archive: No

Area
Allowable First Hit
Herbaceous Cover (x)
s
N
nmin
t
Phase II Bond Release Block
40.0
9.39
21
11
1.325
Mountain Brush RA
12. 8
5.1
15
29
1.345
Sagebrush RA
44.7
8.8
15
8
1.345
Area
Total First Hit Cover (x)
s
N
n
t
Phase II Bond Release Block
44.4
10.4
21
11
1.325
Mountain Brush RA
71.5
7.4
15
2
1.345
Sagebrush RA
71.1
7.8
15
3
1.345
Seneca II Mine
SL -5 Phase II Bond Release Request
June 2011
Table 2. Sample Adequacy Summary for Total First Hit Cover, Phase II Bond Release
Block and Reference Area (RA), Seneca II Mine.
Table 3. Sample Adequacy Summary for Allowable First Hit Herbaceous Cover, Phase II
Bond Release Block and Reference Area (RA), PCM.
' Mean for purposes of sample adequacy calculation; uppermost possible value of the mean,
15.1 taken forward for use in performance standard calculation; see text.
The lack of sample adequacy for the mountain brush reference area using allowable first hit
herbaceous cover necessitated an approach using an alternative approach as described below to
determine the allowable first hit herbaceous cover value for establishing the cover standard.
The historical cover success standard at the Seneca II Mine is an area- weighted average of first
hit herbaceous cover values determined from the mountain brush and sagebrush reference areas.
Further, the first hit cover is adjusted to allowable as discussed previously. In recent years
CDRMS has required sample adequacy using first hit herbaceous cover data. In the mountain
brush, achieving sample adequacy using first hit herbaceous cover data results in very high sample
numbers as a result of high variability. The mountain brush structure is dominated by a rather
dense woody canopy, but may also have some areas of relatively open canopy to the herbaceous
understory. These characteristics contribute to the highly variable first hit herbaceous cover data.
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