2012-09-05_PERMIT FILE - C1982057A ‎(2)‎

• Permit No: C1982057A
• IBM Index Class Name: Permit File
• Doc Date: 9/5/2012
• Doc Name: Pond 016 Area Slide Remediation Plan
• Section_Exhibit Name: Tab 20 Attachment 20-D
• Media Type: D
• Archive: Yes

Postmine Drainage Channel PM -2 (relocation)
The existing PM -2 postmine channel will be relocated through the shrub plot slump area
and the Pond 016A area and discharge to the existing channel that empties into Pond 016.
The original approved PM -2 design is found in Appendix 20 -1, Post Mine Drainage
Channel Design, Channel PM -2 design.
The new design specifies a ten (10) foot bottom width with nine (9) inch riprap or
vegetated TRM and a minimum depth of 1.5 feet. The relocated portion will pass
through the shrub plot slump area, through the slump area on the southwest edge of Pond
016A and continue through the original embankment at Pond 016A and into Pond 016.
The new location of PM -2 will allow the subsurface and surface waters causing the
instabilities to be captured and the flow directed away from the areas susceptible to
saturation and movement. See Exhibit 20 -D.2, Pond 016 Area Remediation Plan and
Post Mine Cross Sections, for conceptual locations and design details of the overall plan.
It should be noted that the final channel locations will be determined in the field as
conditions dictate.
Previously Abandoned Wells
Grading and seeding will have to be conducted in the vicinity of the abandoned wells;
however, extreme care will be taken not to cause any disturbance to the wells or drain.
DISTURBED AREA EXPANSION
9 Buffer Area and Equipment Access — 4.9 acres
POND 016 AREA STABILIZATION PLAN SUMMARY
® Slide Scarp Cut Slope
- Slope — 0.5H:1 V or shallower (final configuration will be in competent material)
(See Typical Cross - Section for probable configurations Exhibit 20 -D.2)
- Height — variable
Slide Trenches
East/West Trench
- 10 foot trench bottom width
- Trench will be excavated to below source of water
- 6" perforated PVC placed along bottom of trench
- 4" minus gravel at minimum 1 foot depth
Down Drain
- 5 foot trench bottom width
- 6" perforated PVC placed along bottom of trench
- 4" minus gravel at minimum 1 foot depth
TR -73 3 6111