2015-06-30_REVISION - C1981035

• Permit No: C1981035
• IBM Index Class Name: Revision
• Doc Date: 6/30/2015
• Doc Name: Adequacy Review #2 Response
• From: GCC Energy
• To: DRMS
• Type & Sequence: TR20
• Media Type: D
• Archive: No

King Coal Mine (C-1981-035) TR -20 Adequacy Review 2 Response
Section 2.05.3, page 3 now directs the reader to Section 6.5.1 of the Trautner
report for inspection frequency and elements.
e) Appendix C of Trautner was prepared by a sub -contractor, CDS Laboratories. Their results indicate that
subsurface water was found only in TB -1, not in TB -6 as Trautner states. Please address this apparent
contradiction on the location of water found in the Test Borings.
This question does not appear to have been addressed in GCC's 06 -Oct -2014 response.
This question has been addressed on page 8 of the Trautner report.
g) In 6.5, Trautner recommends the CMW be placed with a moisture content within 3% of optimum and
compacted to a minimum of 90% MDD (standard Proctor). An initial lift thickness of 12" is recommended,
possibly adjusted to 24" as field monitoring and testing is done. These recommendations are acceptable; Rule
4.10.4(3)(a) requires that CMW be spread in layers no more than 24" in thickness, and (b) requires compaction
of 90% MDD to prevent spontaneous combustion and provide the strength required for stability of the waste
bank.
6.5.1 says that Trautner should be contacted to observe the materials exposed, to identify any potential
sources of moisture that would require the installation of a subdrainage system. Has Trautner evaluated the
foundation since the CMW Backfill was removed? (Yes - the Division was present at a site meeting with GCC
and Trautner on 11 -Sep -2014.) The second paragraph of this subsection addresses Trautner's monitoring of
CMW placement, once construction of the waste bank has commenced. The approach described is generally
acceptable. Rules 4.09.1(11) and 4.10.2 address the inspection requirements for spoil and CMW. Please note
that 4.09.1(11)(4) requires that an engineer (or representative) be on -hand during placement and compaction
of fill materials. On this point (frequency of testing), the current permit is inadequate. Please update the
permit to address the frequency of compaction testing that will be conducted for both the West Waste Bank
and the Refuse Pile.
This item (frequency of compaction testing) does not appear to have been addressed in GCC's 06 -Oct -2014
response, but can be incorporated into GCC's response to paragraph c), above. (Generally, compaction tests
are conducted at least quarterly, if any material is placed in a given quarter, and the results are included
with the quarterly report required by 4.10.2.).
Section 2.05.3, page 3 now directs the reader to Section 6.5.1 of the Trautner
report for inspection frequency and elements.
7.0 Slope Stability Analysis
c) (New) GCC's 06 -Oct -2014 submittal included a Revised study by Trautner, dated 30 -Sep -2014. The Slope
Stability Analysis fails to incorporate the configuration evaluated by Trautner in Feb -2013, i.e. the pile height
of 30 feet, with a 2.5:1 face. Now that the Trautner study has been updated, it does not make sense to omit
the proposed design from the Stability Analysis. Please update the Revised study to include the proposed
design configuration of the West Waste Bank.
The Revised study by Trautner, dated June 29, 2015 now includes the current
proposed pile height and slope.
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