2015-02-26_REPORT - C1981028

• Permit No: C1981028
• IBM Index Class Name: Report
• Doc Date: 2/26/2015
• Doc Name: Annual Hydrology and Reclamation Report
• From: Coors Energy Company
• To: DRMS
• Annual Report Year: 2014
• Permit Index Doc Type: Hydrology Report
• Email Name: TNL
• Email Name: DIH
• Media Type: D
• Archive: No

Keenesburg Mine 2014 Vegetation Monitoring Report
6 DISCUSSION
6.1 Vegetation Cover
Based on the results of the quantitative sampling, Reclamation Area 30 met the total cover
vegetation success standard by exceeding 90% of the total vegetation cover calculated standard
value (Table 7). Reclamation Area 31 had total vegetation cover greater than the standard, but
when cheatgrass was removed from the cover total it no longer met the standard.
Table 7: Vegetation Cover Success Standard Comparison
Vegetation Cover
Reclamation
Area 30
Reclamation
Area 31
Mean
46.8
37.2
Mean (minus noxious)
33.8
20.2
St Dev
10.6
7.6
N
10
10
Nmin
19
27
Standard
34.7
90% of Standard
31.3
Standard Passed? I
Yes I
Yes
Both Reclamation Areas exhibited increased cover from 2012 which was the last year when
vegetation cover data was collected. This is likely due to the above average precipitation in the
year preceding sampling (September 2013 — July 2014). However, this increased cover resulted
from increases in introduced species, because native species absolute cover actually declined
(Figure 4). Cheatgrass increased from 2.8% cover in 2012 to 13% in 2014 in Area 30, and a
similar trend was observed in Area 31 (5.8% to 8.2 %). Introduced annual forb populations of
prickly lettuce (Lactuca seriola), kochia ( Kochia scoparia), and Russian thistle (Salsola tragus) also
exploded from 0% to 12.2% in Area 30 and from 0.2% to 3% in Area 31. A pre- emergent
herbicide was applied prior to the 2012 growing season which was credited with the decrease in
cheatgrass and other annual weeds in 2012. Given the 2014 data it may be advised to complete
another application in these areas.
Vegetation data have been collected in Reclamation Area 30 since 2009, which allows for some
evaluation of trends. In 2009, the area was dominated by cool season perennial grass species
which comprised over 72% of the relative cover while warm season species comprised only
4.6% (Table 8). However, over the past six years this composition has reversed. Cool season
grass species have steadily declined to only I% relative cover in 2014 and warm season grasses
have steadily increased, peaking at over 63% relative cover in 2012. Warm season grasses
decreased slightly from 2012 to 2014 (by 3.4 percentage points of absolute cover), but the
relative cover decrease was drastic due to the increase in cheatgrass cover.
Habitat Management, Inc. 13 September 2014