2008-10-10_REVISION - C1981008

• Permit No: C1981008
• IBM Index Class Name: REVISION
• Doc Date: 10/10/2008
• Doc Name: Adequacy Review
• From: Joe Dudash
• To: Marcia Talvitie
• Type & Sequence: SL11
• Email Name: JJD
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF RECLAMATION, MINING AND SAFETY
Department of Natural Resources
1313 Sherman St., Room 215
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
DATE: October 10, 2008
TO: Marcia Talvitie
COLORADO
D IV IS I ON OF
RECLAMATION
MINING
SAFETY
Bill Ritter, Jr.
Governor
Harris D. Sherman
Executive Director
FROM: Joe Dudash ?? Ronald W. Cattany
Division Director
Natu I Resource Trustee
RE: New Horizon me, Permit Number C-1981-008, Western Fuels Colorado
SL-11, Partial Phase 1 and 2 Bond Release, Soil Loss Comparison Adequacy
Review
As you had requested, I have reviewed the soil loss comparison submitted by Western Fuels
Colorado for the Partial Phase 1 and 2 Bond Release (SL-11) at the New Horizon 2 Mine. My
review has shown that the Division can accept the soil loss comparison methodology and
conclusions as submitted.
The Division's guideline document for bond releases, as well as the Rules and the Act, require
that, for a phase 2 bond release, no suspended solids in excess of pre-mining levels for the same
area or in excess of suspended solids levels found on adjacent undisturbed areas can be generated
from the reclaimed area. Western Fuels Colorado used the revised universal soil loss equation
(RUSLE) to demonstrate compliance with this requirement. No sediment ponds are proposed to
be reclaimed in SL-11.
The reclaimed land proposed for phase 2 bond release consists of approximately 60 acres of
dryland pasture and approximately 240 acres of irrigated pasture. Vegetation cover data from the
1987 baseline vegetation studies, found in Section 2.04. 10 of Volume 2 of the permit application,
were used in the RUSLE pre-mining sediment loss demonstration while the vegetation cover
data gathered in the 2007 vegetation sampling study submitted in SL-11 were used in the
RUSLE postmining sediment loss demonstration.
Western Fuels Colorado used conservative and well documented values for the parameters they
used in RUSLE. The general conclusion drawn from the soil loss comparison is that sediment
loss from the reclaimed area is less than that from the same area before mining. The calculated
annual sediment loss from the pre-mining dryland pasture land is 0.817 tons per acre while that
from the postmining dryland pasture land is 0.472 tons per acre. The calculated annual sediment
loss from the irrigated pasture land is 0.217 tons per acre in the pre-mining condition while that
of the postmining condition is 0.194 tons per acre.
cc: Sandy Brown
c:/word/newhorizon/sl l l memo 1
Office of Office of
Mined Land Reclamation Denver • Grand Junction • Durango Active and Inactive Mines