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Mr. Chris Rowe December 8, 2006 Page Three of Six approximately five to ten feet from the sand and gravel pit high-wall. Once the keyway is excavated around the perimeter of the pit floor, the process of backfilling begins using overburden that was stripped prior to mining. The backfill is placed in compacted one to two foot lifts around the perimeter of the pit from the floor to the top of the pit. This compacted overburden and shale core effectively seals the entire pit perimeter from the pit floor to the top of the pit high-wall. After the compacted core is in place, the remaining pit slope is backfilled and graded to a fmished 3:1 slope covered with topsoil and re- vegetated. After the pit has been sealed, it is monitored for a period of 90 days in order to demonstrate that the sealed pit meets the State Engineers performance standazd for lined sand and gravel pits. (See attached is a copy of the criteria for determining compliance with the SEO's guidelines for lining gravel pits). The Applicant does not anticipate any seepage from the clay liner nor from the floor of the excavation. However, in the unlikely event that there is groundwater seepage it is estimated that approximately 11-acre feet or 0.50 feet over the pit floor could seep into the pit without exceeding the SEO's criteria for compliance. It should be noted that above seepage does not take into account any evaporative loss, which the SEO calculates at 2.5 feet per surface acre of exposed water per yeaz. In the unlikely event that water does pond on the pit floor it will do so along the north and northwest side of the pit due to the direction of fall of the pit bedrock. In the event that groundwater seepage causes water to pond on the pit floor, the enclosed seed mix will be used in those azeas that are too wet to support the dry land seed mix. 2. There aze a number of DMG permitted sand and gravel pits between Boulder and Fort Collins that have been successfully sealed using the same compacted liner method as that proposed for the Camenish Borrow. Most recently, on June 22, 2005 the Division approved Amendment No. Am-1 for the Timnath Pit (Permit No. M-1975-042). The approved amendment changed the reclamation plan from an unlined pond to a clay lined sealed pit. With regazd to the Camenish 111 Special Operations Permit Application, the Division is not being asked to approve a reclamation technique that is any different from clay liner applications previously approved by the Division.