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g. Why is the reclaimed Ditch 1's minimum elevation 100 feet <br />• lower than the mining Ditch 1? <br />Response: The minimum elevation of the reclaimed Ditch No. 1 is <br />the same as the minimum elevation of the Ditch No. 1 during mining. <br />h. Section 4.05.4 of the permit should be revised to detail the <br />Coal Gulch permanent diversion (Ditch 1). Rule 4.05.4 applies <br />to ephemeral streams drainage watersheds greater than one <br />square mile. <br />Response: Ditch No. 1 was constructed during previous mining <br />activity to pass flows from Coal Gulch around the area of <br />disturbance. Peerless has upgraded Ditch No. 1 to ensure adequate <br />flow capacity and minimize any impacts on the planned underground <br />mine, as well as minimize impacts to surface water flows in Coal <br />Gulch. As part of the Reclamation Plan, Peerless plans to leave <br />• Ditch No. 1 as a permanent structure. Therefore, Section 4.05.4 <br />Stream-Channel Diversions (Relocation of Streams) and <br />Stream-Channel Reconstruction of the Regulations of the Colorado <br />Mined Land Reclamation Board for Coal Mining have been addressed. <br />Peerless has designed the Ditch No. 1 channel, flood plain, and <br />longitudinal profile to provide sufficient capacity to pass the <br />peak flows from a 100 year, 24 hour precipitation event. Given the <br />slope of the channel, armoring has been designed for use in areas <br />where the channel bottom i s not i n bedrock. Armoring with 1 arge <br />riprap will minimize additional contribution of suspended solids. <br />This design essentially precludes any requirements for future <br />channel maintenance. Peerless will monitor the structure during <br />the active mining operation and evaluate the need for any <br />additional armoring or stabilization to ensure compliance with all <br />applicable regulations. <br /> <br />-7- <br />