2020-07-09_REVISION - C1981028 ‎(12)‎

• Permit No: C1981028
• IBM Index Class Name: Revision
• Doc Date: 7/9/2020
• Type & Sequence: TR47
• Media Type: D
• Archive: No

Coors Energy Company: Keenesburg Mine
Technical Revision 47
Modification of Reclamation Success Standards
1 INTRODUCTION
Technical Revision 47 (TR47) changes the reclamation success standard for species composition
at the Keenesburg Mine. Current plant species composition success criteria require that there be
at least four perennial species each meeting minimum and maximum relative cover percentages,
of which three are warm season grasses and one is a cool season grass. This revision removes the
cool season grass composition requirement and now requires that at least four perennial non-
noxious grass species be present that meet the minimum/maximum relative cover percentages for
final vegetation bond release.
The following sections provide explanation and supporting references to show that the current
standard is:
1. Inappropriate for the location;
2. Improbable given the current seed mixture; and
3. Unnecessary to provide the diversity and high-quality forage needed to support the post-
mining land use.
2 RECLAMATION SUCCESS STANDARDS
Final revegetation success will continue to be evaluated using the methods currently contained in
the permit. Vegetative cover and herbaceous production will be evaluated using the approved
sampling and analytical methods.
Plant species composition will be evaluated using the approved evaluation method with new
composition criteria. The current species composition standard requires that there be at least four
perennial species, of which three are warm season grasses and one is a cool season grass. None
of the four species may contribute greater than 40%nor less than 3% of the relative cover. The
species composition standard is modified to remove the seasonal requirement and simply require
that there be at least four perennial, non-noxious grass species none of which may contribute
greater than 40% nor less than 3% of the relative cover.
3 APPROPRIATENESS FOR THE LOCATION
The current reclamation standards are based on data collected on the Osgood Sand Reference
Area(OSRA)between 1994 and 2004 and presented in TR37 (Savage and Savage 2002 and
2005). TR37 explained that it is inappropriate to use the OSRA for a straight comparison to the
reclaimed communities because the revegetated community is developing in a significantly
altered physical environment, and revegetation success comparisons should not be made between
a mature community and an early seral community. Instead, TR37 suggested the use of
predictive equations for the vegetative cover and production standards and the use of a technical
standard for diversity. However, these standards were still based on the reference area
vegetation.
As stated in TR37, the OSRA was representative of the pre-disturbance community at the
Keenesburg Mine which was dominated by sand sage (Artemisia fillifolia). The long-term data
from the OSRA show a rangeland community dominated by sand sage with contributions from
green needlegrass (Nassella viridula), blue grama(Bouteloua gracilis), cheatgrass (Bromus
tectorum),prairie sandreed(Calamovilfa longifolia), and sand bluestem (Andropogon hallii).
1 July 2020