PERMFILE139426

• Permit No: C1980006A
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: PART 816 Part 2
• Media Type: D
• Archive: Yes

As backfilled disturbance areas reach the design postaiein9 grade,
they are rough graded to the final configuration and ripped tf
necessary Lo alleviate compaction. Replaceeent of topsoil on the
rough graded surface and chisel plowing result in a good bond between
soil and spoil eaterials, a roughened soil surface which is resistant
to rind and water erosion and promotes aalsture infiltntion, and
conditions which proaote good root penetration.
Contour furrows rill be established on all reclaimed areas to licit
overland flow and promote moisture infiltration. All contour furrows
will have approximately the same configuration, as illustrated by
figure 19, Typical Oesign -Contour Furrow, horever spacing will be
dependent upon slope conditions. Vertical spacing is determined by
the equation;
YI xS+y
Mhere: YI is vertical interval in feet
x is an independent variable
(0.8 for northern Colorado)
S is land slope in feet/100 feet
y is an independent variable
(1.0 for erosive soil rith limited
protection-worst case)
Using this equation, appropriate vertical spacing for contour furrows
was determined to be: slopes 3H:1V or steeper - 30 feet; slopes
3H:lY to 1H:IY - 25 feet; slopes 4H:1V or less 20 feet. For all
slopes horizontal spacing is approximately uniform at 85 feet. -_
For any slopes of 4H:lY or greater, the contour furrows rill be
established at gradients ranging between 0.1 and 0.5 percent and rill
route minor surface flows to designed permanent drainagerays. For
slopes of less than 4H:lY,,contour furrows rill be closed features
established at flat or minimal gradients.
61ven the nearly constant exposure of the Kerr mine area to strong
prevailing rinds, Kerr is proposing establishment of strip plantings
of tall grass to serve as natural rindbraaks. These windbreaks, or
816-151Ra Revised - August, 1990