2024-05-14_REVISION - C1981028

• Permit No: C1981028
• IBM Index Class Name: Revision
• Doc Date: 5/14/2024
• Doc Name: Application
• From: Habitat Management
• To: DRMS
• Type & Sequence: SL12
• Email Name: RDZ
• Email Name: AME
• Media Type: D
• Archive: No

Coors Energy Company Keenesburg Mine—Phase II/III Bond Release Application
Sedimentology Demonstration
1 Introduction
This sedimentology evaluation supports and is part of an application for Phase IUIII bond release
for Reclamation Areas 23, 29, 30, and 31 at the Keenesburg Mine. Reclamation Areas 23, 29,
and 31 have previously received Phase II bond release in 2010 (SL-05) and 2019 (SL-10),
respectively. However, Reclamation Area 30 has only received Phase I bond release in 2014
(SL-07). Thus,the current bond release application includes both Phase II and Phase III bond
release requests for this area. This sedimentology demonstration is only for Area 30.
Reclamation Area 30 has been backfilled, graded, topsoiled, and revegetated. Site specific data,
regional information relative to the erosion and sedimentation condition of these reclaimed areas,
and data pertaining to the native sand-sage vegetation community adjacent to the mine are used
in this evaluation. Quantitative sampling of vegetation with these reclaimed units was performed
in August 2021 and August 2022 in compliance with Colorado Mined Land Reclamation Board
Surface Coal Mining Rules and Guidelines and is appended to the bond release application. This
sedimentation and erosion analysis has been performed by Habitat Management, Inc.
2 Methods
To achieve Phase II bond release,reclaimed areas must be shown to contribute equal or less
sediment to receiving waters than similar adjacent lands undisturbed by mining and reclamation.
In a previous Keenesburg Mine Phase II application(SL-10), the DRMS approved the use of the
Revised Universal Soil Loss Equation(RUSLE) v1.06c MN(mining version, 02/20/2004)to
demonstrate sediment yield rates between undisturbed and mined/reclaimed land(Agricultural
Research Service 2004). This evaluation uses similar methods and values to the previous
application.
The RUSLE uses site specific information for rainfall,topography, soil particle size
characteristics, vegetation, and cultivation practices to generate the amount of soil yield in
tons/acre/year.
The RUSLE equation takes the form:
A=R*K*LS*C*P
where:
A= soil loss in tons/acre/year
R=rainfall factor accounting for the interrelationship between the erosive force
of rainfall and runoff
K= soil erodibility factor addressing a given soil's susceptibility to erosion
LS =length slope factor providing the ratio of soil loss at any length and slope to
a standard slope and length
C = cover factor accounting for plant and litter cover on the ground surface
P = control practice factor addressing the erosion reduction effectiveness of soil
conservation practices
Value determinations for the RUSLE factors are discussed below for conditions at the
Keenesburg Mine site and adjacent area. The locations of transects used in RUSLE
calculations are shown on Figure 1.
SL-12 1 May 2024