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1 <br />:. <br />• <br />• Backfilling of the lower one third of the cut slope on the east <br />edge of the lower terrace. <br />• Removal of facilities including culverts C4 and C7; <br />• The construction of a drainage channel to divert runoff azound <br />the #1 Portal; and <br />• Removal of all groundwater monitoring wells. <br />III. FINDINGS AND OBSERVATIONS <br />Topsoil had been redistributed on the terrace benches. The lower terrace <br />outslope showed signs of geotechnical instability in that a slump, about 20 feet <br />wide was present and evidently resulted from surface runoff from the terrace <br />bench. This will need to be repaired and possibly a rock drain placed on the <br />outslope to prevent future slumping. NCIG should submit a technical revision <br />which addresses plans for stabilizing and handling runoff over the face of the <br />outslope. The permit indicates, in an engineer's analysis found in Exhibit <br />4.7-5, that water draining over the outslope may affect the stability of the <br />outslope. The technical revision should also address the culvert (C3) at the <br />base of the slump which should also be removed. Although the permit does <br />not specifically address culvert C3, the Division sees no justification for <br />leaving the culvert in place. <br />The portal areas have been backfilled and graded. The Portal #1 area (west) <br />does not exhibit signs of geotechnical instability. The Portal #2 area (east) <br />exhibits some slumping over the portal itself. The slump was up to one foot <br />at the west end of the portal, and there was a separation of several inches <br />between the portal and the fill at the slumped area. The slump must be <br />repaired prior to the approval of the Phase I bond release application. Prior <br />to repairing the slump, the square edge of the portal should be broken off to <br />minimi~r the potential for future slumping down the face of the portal. The <br />portal area is not covered with the required minimum of 16 inches of topsoil. <br />According to the operator, some waste rock was placed inside the portals. <br />That rock which was not placed inside the portals was piled at the foot of the <br />terrace outslopes. The reclamation plan, as shown on Plates 4-1 and 4-2, calls <br />for placing the rock at the foot of the cut slope on the east end of the terrace. <br />However, the text of the reclamation plan does not make this clear. The <br />Division recommends that NCIG submit a technical revision to clarify, in the <br />text, that the waste rock is to be placed at the toe of the cut slope and buried. <br />2 <br />