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COLORADO <br />Division of Reclamation, <br />Mining and Safety <br />Department of Natural Resources <br />1313 Sherman Street, Room 215 <br />Denver, CO 80203 <br />April 14, 2016 <br />To: Brock Bowles <br />From: Jason Musick <br />RE: New Horizon Mine, C-1981-008 <br />TR -70, Adequacy Review Response Memo <br />Per your request, I reviewed the proposed new sediment pond (Pond 016) and the proposed new <br />postmining drainage which includes the Tailwater and the channel below the tailwater ditch designs <br />associated with the above referenced revision and provided my comments in a memo dated February 26, <br />2016. The review included the proposed designs to determine if the if the demonstrations meet the <br />design criteria for Rules 4.05.3 and 4.05.6. <br />Based on the Division's initial review of the existing Pond(s) 009, 012, 013, 015, and new Pond 016 <br />designs, the ponds are designed and constructed to meet the revised postmining drainage requirements <br />for the newly modeled and proposed postmining topography delineated watersheds. <br />The Division had the following preliminary adequacy comments: <br />Approved Attachment 2.05.3(3)-1 provides collection/diversion ditch and culvert design <br />parameters for the New Horizon Mine. Based on a review by the Division, a revised Attachment <br />2.05.3(3)-1 was not included which would contain the addition of the proposed collection ditch <br />below the Tailwater ditch. In addition, there is no discussion of the existing Tailwater Ditch in <br />Attachment 2.05.3(3)-1. Please revise Attachment 2.05.3(3)-1 to include all proposed ditches <br />and culverts throughout the mine site or provide revised text to discuss the omission of the <br />designs in Attachment 2.05.3(3)-1 and inclusion in another portion of the PAP. <br />Tri-State March 21, 2016 Response: Attachment 2.05.3(3)-1 has been revised to no longer <br />include designs for ditches C10 and D1W. Due to the changes being proposed to the post -mining <br />topography within the drainage areas of these ditches, they are no longer required. <br />Division Response: This item has been adequately addressed. <br />Approved Map 2.05.3(3)-1 delineates Ditches C-10 draining a basin of 5.2 acres to Pond 013 and <br />D1W draining a basin of 25.1 acres to what appears to be Pond 015. Both C-10 and D1W are not <br />identified on the proposed revised Map 2.05.3(3)-1 submitted with the TR -70 application. Based <br />QF cQ�Q <br />1313 Sherman Street, Room 215, Denver, CO 80203 P 303.866.3567 F 303.832.8106 http://mining.state.co.us <br />John W. Hickenlooper, Governor I Mike King, Executive Director I Virginia Brannon, Director * * 1g76 <br />