PERMFILE43341

• Permit No: C1981039
• IBM Index Class Name: Permit File
• Doc Name: MRLD 4/24/91
• Section_Exhibit Name: Reclamation Project Binder
• Media Type: D
• Archive: No

Mr: Brent Anderson - 2 - April 24, 1991

Rule 3,03 and 34-33-125 both indicate that the applicant must include
"a description of the results achieved .. ". It is the Division's
opinion and policy that topographic mapping and cross-sections are the
appropriate descriptions for backfilling and grading results, There is
no substitute for the mapping. Therefore, we reiterate our request that
topographic mapping and cross-sections or AOC slope analysis be provided
for Pits 5 and 6.
Rock castle has amended the map to include permit and disturbance
boundaries, title block, and professional certification. As an aside, it
is apparent that the topography depicted in Pits 5 and 6 on the map
Reclaimed Topo~raQhy 1990 is not reclaimed topography. Therefore, the
cer i~ica~ion is ~n error.
The Division does not agree that theoretical drainage modeling is
incompatible with site specific remediation measures. Prudent, site
specific hydraulic designs require the use of careful topographic
mapping. It is also not apparent that the designs found in Attachment 2
are the worst case.
T, The Pit 5 prainage Remediation Plan calls for the mixing of undisturbed
and reclaimed area drainage. This is acceptable if the drainage
structures are sized to handle the runoff from these areas. Please
• ensure that your mapping includes the entire drainage above Pit 5 and
documents the entire extent of the disturbed area (pit and stockpile
areas). In addition, re-evaluate the acreages noted on-F'igure 1 of
Attachment 2, Acreages shown for the Pit 5 ditches are vastly
underestimated.
2. The Division is unable to accept the general concept behind the Pit 5
Drainage Remediation Plan until we have a certified post-mining
topography map. The Division is very concerned about the steep slopes
along the north perimeter ditch and west of the access road and on the
west edge of the disturbed area. It is the Division's preference that
Rockcastle armor drainageways through the steep slopes on the north and
south central portions of the pit perimeter.
3. Provide calculations to document that the reconstructed natural
drainageway (No. 1) can handle the 100-year 24-hour event. ~
4, Commit to removal of the diversion ditch on the northeast end of Pit 5
and provide quantitative documentation tied to a 10-year 24-hour event
that the surrounding area qualifies as a small area exemption per
IV(4)(a) and Rule 4.05.2(3).
5, All permanent drainageways at the site must be designed and constructed
to handle the 100-year 24-hour event, per Rule 4.05.4(2)(1), Revise the
ditch, riprap and culvert calculations to reflect this sizing.
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