2010-09-03_ENFORCEMENT - C1981019 ‎(5)‎

• Permit No: C1981019
• IBM Index Class Name: ENFORCEMENT
• Doc Date: 9/3/2010
• Doc Name: Request to Vacate Package
• From: Colowyo Coal Company
• To: DRMS
• Violation No.: CV2010004
• Email Name: JRS
• Email Name: SB1
• Media Type: D
• Archive: No

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sheet flow from the topsoil surface. Due to the specific equipment used for the Sagebrush
Steppe areas, topsoil will be left in a more smooth condition to ensure proper seeding depth
as described in the text. Any topsoil put into final position with a dozer will by practice be in
a state of rough condition. Previous roughening efforts at Colowyo have been extreme,
leading to difficulties in placing seed at biologically viable depths. The addition of more
contour furrows will reduce sheet flow and moderating the roughness will allow a greater
percentage of seed to germinate and provide ground cover that will also alleviate rilling and
sediment control issues. As Coloywo transitions into areas of steeper slopes, density of cross
ripping will be tightened to increase surface roughness and more contour furrows will be
used to break up the slopes and minimize sheet flow conditions and reduce any concentration
of flow from rain /snowmelt events. Seedbed preparation, other surface manipulation
and seeding will be completed primarily during the fall months. Contour furrows,
practices
approximately 4 -6 inches deep at the deepest point and 20 -25 inches wide, which have been
used on slope areas very successfully during the past several years, will be used to reduce
erosion potential, conserve moisture, and maintain site stability until vegetation is sufficiently
established. The size of the furrows may be increased if necessary to control erosion, and the
distance between the furrows will vary, but will be approximately 10 to 75 feet along the
slope. Small rock check dams may also be used where appropriate to aid in control of
erosion both prior to seeding and if necessary, after an area has been seeded. In East Pit
reclamation areas, Colowyo specifically commits to the use of contour furrows and topsoil
surface roughening techniques to minimize the potential of sheet flow in this area. Structure
function of these activities will be similar to those utilized in 2009. Frequency, size and
and
specific location of contour furrows will depend primarily on the slope and size of the area
being reclaimed in any given year.
in the
Given recent changes to Federal legislation (30 C.F.R. §816.22(d)(1)(i)) as published
Federal Register (August 30, 2006, - pages 51683 - 51706), mine operators are now allowed to
use "non- uniform redistribution of topsoil in their reclamation plan to encourage plant
Division of Wildlife has requested Colowyo replace
diversity...." Furthermore, the Colorado
topsoil in a non - uniform manner as indicated by their statement: (see complete CDOW letter in
Section 4.15.8)
"DWM Wangnild discussed the possibility of changing reclamation efforts in the new [South Taylor] permit
Specific changes would ideally be focused on dramatically varying topsoil depths in an effort to mimic
area.
natural depths and thus provide more suitable environments for woody species establishment. One example of
this would be to create some sites with extremely shallow topsoil designed at reducing grass stand establishment
and their resulting competition with shrubs for water and soil nutrients. Another example would be to create
other sites with extremely deep topsoil depths. These sites would ideally benefit woody species like aspen and
chokecherry"
In this regard, and depending on site - specific opportunities, Colowyo will utilize the planned
post -mine topography (PMT) to help identify candidate (and prime candidate) areas for targeting
Sagebrush Steppe post- mining communities. Key to this analysis will be considerations for the
risk of erosion and for long -term stability. One such "threshold" value to be used for this analysis
will be a slope break at 10% gradient. Slopes greater than 10% will be considered too risky to
make attempts at targeting shrub communities, largely due to snowpack runoff scenarios that can
often lead to serious erosion and stability failures. For example, snowmelt runoff in the early
1980s caused widespread and severe down- cutting of the natural drainages to the immediate west
of Colowyo. Unless proven otherwise by hydraulic and /or erosion modeling, slopes less than
10% will be identified as candidate locations for shrub community establishment. Another
"threshold" value to be used in the PMT analysis is the size of units that may exhibit slopes 10%
or flatter. Areas small in aerial extent (e.g., less than about 5 acres) will not be identified to
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receive shrub - conducive metrics. Only those areas that are larger will be identified. The exact
2.05 -30 Revision Date: 8/10/10
Revision No.: TR -87