PERMFILE118832

• Permit No: C1981039
• IBM Index Class Name: Permit File
• Doc Name: Rockcastle 5/21/92
• Section_Exhibit Name: Reclamation Project Binder
• Media Type: D
• Archive: No

May 1992 Rockcast/e Coal Company • Grassy Creek Mine ~ 3
• Response: The referenced design documentation was apparently inadvertently omitted
from the previous response package. Copies of the Pit 5, 25-year, 24hour SEDCAD runs
accompany these responses for Division review and reference.
8J The slides numbered 1, 3 and 4 do not seem properly located on the slide map contained in
the report titled "Response to Stipulation No. 12 ". Please correct this discrepancy.
Response: Map 1, Grassy Gap Mine -Unstable Slope Segments, included as part of the
10/23/85 response to Stipulation No. 2, showed the approximate locations of those areas
identified by field inspection as representing potential mining related stability concerns.
While these areas were not surveyed, the mapped locations are believed to reasonably
represent the areas of concern. All field inspections and design discussions of potential
slide areas completed subsequent to the 1985 report reflett the original numeric slide
designations. In order to insure that the remediation measures proposed to provide for
the long-term stability of specific slide areas are applied to the appropriate areas and will
adequately address Division concerns, Rockcastle proposes a joint field review with
Division Staff prior to initiation of field attivities.
9) What type of filter blanket is to be used under the road crossings?
Response: Rockcastle has committed to removal of culverts and establishment of
riprapped drainage crossings on all roads providing access to individual pit areas. In order
to minimize under-cutting and erosion of riprapped crossings, Rockcastle will place a 2-3
• inch layer of minus 3 inch pit-run rock as a gravel filter prior to riprap placement.
10) The ponmining sediment yield values for Pit 2 and Pit 3 are well in excess of the pre-mining
values, although the volume of sediment is relatively small. Based on Section II/ 2.a of the
June 26, 1990 Settlement Agreement, those sediment ponds and the associated sediment
control can only be removed after compliance with Rule 4.05.2 has been demonstrated Rule
4.05.2 requires ponds to remain until the disturbed area ceases to contribute additional
suspended solids above natural conditions and the quality of untreated drainage meets the
State and Federal water quality standards for receiving streams. We therefore cannot approve
pond removal at this time.
Pond removal is still considered to be a task which should occur. Several options maybe used
First, Rockcastle may want to allow further vegetation establishment, then attempt a revised
sediment yield demonstration at some time in the future. Second, if Rockcastle does not want
to commit to any work beyond 1992, then we will need to retain some additional amount
of bond money to allow the Division to complete the job. Finally, we believe that Pan IV.3.a
of the Settlement Agreement may provide some flexibility in designing appropriate alternative
sediment control systems at Pits 2 and 3. Such an alternative plan must comply with Rule
4.05.5, and it will be necessary to show that the alternative rystem would provide treatment
of disturbed area flow suffuient to ensure compliance with the existing effluent limitations.
Please provide your plan to address this issue.
Response: Sedimentology calculations for Ponds 2 and 3 for existing reclaimed
conditions have been revised to reflex the slope distance between contour furrows of
• approximately 50 feet. This adjustment reduces the calculated annual sediment loss
approximately 55-60 percent. This reduction results in a difference in calculated annual
sediment loss between the pre-mining and postmining (current reclaimed) condition of
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