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Section 16 Taylor Ditch (Version 2) may not be necessary. Please review the drainage <br />control plans for the South Taylor Pit, including the East Taylor Fill area, to determine <br />whether the Section 16 Taylor Ditch (Version 2) is necessary. Based on the conclusions <br />of this review, please revise Map 12, Map 33A, Map 41 and Map 41A as necessary. <br />Response: All of the referenced Maps have been carefully reviewed and updated. The <br />consolidation of the various maps will hopefully eliminate the discrepancies with <br />certain ditches. <br />d. With the proposed change to the post-mining topography, Colowyo is proposing to <br />dramatically alter the final cut of the Section 16 Pit. In the approved post-mining <br />topography Colowyo has a permanent ditch, the East Taylor Ditch, running down the <br />middle of the final cut of the Section 16 Pit, which ultimately reports to the East Taylor <br />Pond. In the proposed post-mining topography Colowyo has eliminated this ditch and has <br />returned the final cut of the Section 16 Pit to more of a peak/ridge, like it was prior to <br />mining. While the Division generally likes this approach, there are several issues that <br />need to be addressed. First, based on the proposed post-mining topography, Colowyo <br />will be eliminating a large portion of the East Taylor Ditch. The final cut of the Section 16 <br />Pit will be filled to approximately station 95+00 of the East Taylor Ditch. This will <br />eliminate the entire upper portion of the East Taylor Ditch (form approximately station <br />95+00 to approximately station 150+00). Colowyo still shows this ditch in its entirety on <br />Map 12, Map 33A and Map 41. Second, with the complete filling of the final cut of the <br />Section 16 Pit proposed in Technical Revision 81, Colowyo has not addressed how the <br />runoff from this area will be handled. The elimination of the upper 5,500 feet of the East <br />Taylor Ditch leaves a large area of reclamation that will have no hydrologic control. This <br />could lead to massive sheet flow and erosion. Third, it appears as though the size of the <br />East Taylor Watershed will be decreased in the Section 16 Pit area and the size of the <br />Streeter Watershed, the Section 16 watershed and possibly the Prospect watershed will <br />be increased. <br />i. Please change the design of the East Taylor Ditch to reflect the proposed <br />changes to the post-mining topography. Please change the design on Map 33A and <br />please provide new SEDCAD modeling for the redesigned ditch. Please include the <br />new location of the East Taylor Ditch on Maps 12, 41 and 41A. <br />Response: This item has been addressed in the enclosed submittal. The East Taylor Ditch is <br />now consistently shown on all maps. The East Taylor Ditch has been substantially <br />shortened due to PMT changes (from about 15,000 feet to about 8,200 feet). <br />The design for the ditch is presented in Volume 2C, Exh. 14L <br />ii. Please review the proposed changes to the area of the final cut of the Section <br />16 Pit and determine how Colowyo will control the runoff from this area. Please <br />include ditch locations and SEDCAD modeling for these ditches as necessary. <br />Response: The final cut of the Section 16 Pit will be filled in by the new Postmining topography. <br />With the new PMT there is no longer a valley running through the center of Section <br />16. This new PMT will divert water to the revised Taylor Trib. Drainage, revised East <br />Taylor Drainage and to the Streeter Gulch Drainage. See Maps 41 and 41A for ditch <br />locations.