1988-04-11_PERMIT FILE - C1981008A ‎(20)‎

• Permit No: C1981008A
• IBM Index Class Name: PERMIT FILE
• Doc Date: 4/11/1988
• Doc Name: Facilities
• Section_Exhibit Name: Tab 13
• Media Type: D
• Archive: Yes

Peabody typically constructs ditches on the inside of roadway cuts and safety berms for
drainage. A typical V-ditch section would be a minimum of two feet deep with side slopes
1.5:1 or flatter. As most road cuts are into resistant bedrock-type material, ditches
normally do not require lining. Culverts will be designed and installed to minimize the
runoff volume conveyed in each ditch. Culverts and ditches will typically be designed
using SEDIMOT II to predict the peak runoff and Manning's equation to determine the peak
velocity and flow depth (see Attachments I and J).
If the ditch is not stable, then Peabody will use a larger ditch section and/or adequately
line the ditch in order to comply with applicable regulations.
Drainage from haul roads within the areas disturbed by mining and reclamation activities
(see Exhibits 12-2 and 12-3) will be constructed to meet the requirements of 4.05.2 and
such haul roads will at a minimum be constructed and maintained to minimize erosion of the
disturbed area. Erosion control measures to be used singly or in combination include but
are not limited to:
a. Stabilizing all exposed surface areas to promote a reduction in the rate and
volume of runoff;
b. Using straw dikes, riprap, check dams, berms, geotextile materials, mulches,
vegetation sediment filters, contour furrows or other measures that reduce
overland flow velocity, reduce runoff volume, or trap sediment; or
C. Such other measures to minimize erosion resultant siltation and disturbance to
the prevailing hydrological balance.
Surfacing. See Exhibit 13-20 for typical detail .
Culverts. Each haul road will be designed, constructed, and maintained to have adequate
drainage using ditches and culverts to safely convey the peak runoff from a 10-year,
24-hour precipitation event to sediment ponds before being released from the permitted
area (see Exhibits 13-4 and 13-5 for general locations and Exhibit 13-20 for typical
details of drainage structures).
Culverts will be installed to avoid plugging or collapse and to avoid erosion at the
inlets and outlets. Riprap will be installed as necessary to reduce the exit velocity.
The minimum width will be the width of the natural downstream channel . The riprap will be
sized in the field by Peabody's project engineer based on the "as-built" slope of the
13-17 Revised 04/11/88