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Tom Bird, GCC Energy, LLC <br />C- 1981 -035 / TR -20 / AR #2 <br />14- Nov -2014 <br />Page 3 of 7 <br />Appendix 10(4) — Revised Geotechnical Engineering Recommendations (Trautner Geotech, LLC) <br />3.0 Field Study <br />a) In subsection 3.2 Site Description and Geomorphology, the report says, "the proposed <br />abatement / reconstruction of the deposits will not affect the surface drainage system that <br />was previously constructed." Trautner considered the current system of collection drains <br />and ditches, but it is not clear that the proposed configuration of the West Waste Bank has <br />considered the final reclamation of the site, wherein the stream channel will be <br />reestablished from south to north. Please address the relation of the proposed West Waste <br />Bank to the post- mining topography and surface drainage for the King I site. (This issue <br />would be appropriate to address in the permit, not necessarily in the Trautner Report.) <br />The Division was unable to find any updated text that addresses this comment, but a <br />revised Map King 1 -011 (Final Contour) was submitted with GCC's 06- Oct -2014 response. <br />This item is resolved. <br />6.0 Reconstruction of Bench and Highwall Mine Waste Bank <br />In general, the outline proposed for construction of the West Waste Bank is in conformance with <br />the Rules and permit. We do, however, have a few comments on this section: <br />a) In 6.2, Trautner recommended that they should be present during the earthmoving phase to <br />evaluate the uniformity and general consistency of the material as it is moved. Was a <br />representative of Trautner present during any part of the earthmoving process? <br />This question does not appear to have been addressed in the 06- Oct -2014 response. Please <br />expand the Mine Waste Rock Disposal narrative in Section 2.05.3 of the permit to describe <br />actions taken by GCC as they relate to the Trautner study (the placement and ultimate <br />removal of the coal mine waste against the portal highwall, any participation by Trautner, <br />etc.). <br />b) In 6.3, Trautner recommends compacting the material to 95% of the maximum dry density <br />(standard Proctor). This exceeds the minimum of 90% required by Rule 4.10.4(3)(b), and <br />contradicts the 90% requirement provided in subsection 6.5. Please be aware that if a <br />commitment to 95% is made in the permit, then that will be the standard GCC will be <br />required to meet. <br />The Division notes that this comment refers to preparation of the subgrade rather than to <br />placement of coal mine waste. <br />c) Subsection 6.4 addresses the subsurface drainage system proposed for the West Waste <br />Bank. Trautner evaluated the permeability of the CMW to determine how much water was <br />likely to percolate into and through the waste bank. Rules 4.09.1(13) and 4.10.3(1) are <br />pertinent to this waste bank project. Subdrains should need to be constructed only to <br />intercept water from springs or seeps and prevent it from saturating the pile. Please note <br />that in 4.10.3(1)(c), the subdrainage system is to be covered to protect against entrance of <br />surface water or leachate. Typically this is accomplished by placing an impermeable <br />membrane on top of the subdrainage installation. <br />