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Pond ditch extension. Specifically, there are two 90° bends in the reconfigured ditch, one <br />changing the direction of flow to the southeast at approximately Station 45+00 and the <br />other changing the direction of flow to the southwest at approximately Station 48+00. <br />These extreme angles are generally areas that can cause stability problems for ditches. <br />Please describe for the Division and include in the text for Exhibit 7, Item 140, how <br />Colowyo plans to address the possible stability problems at these two 90° bends in <br />the ditch extension. <br />Response: Colowyo plans to address the possible stability problems at the mentioned <br />90° bends in the ditch extension by taking extra care during construction to <br />ensure erosional stability in these areas. In addition to these precautionary <br />measures, Colowyo believes the final grade of the ditch will not exceed more <br />than 2% in any one area. The ditch is constructed on contour and must follow <br />the natural topography, much the same as the pre-existing perimeter ditch. <br />Bends of this nature are present on the pre-existing perimeter ditch at <br />approximately stations 37+00 and 10+00 and Colowyo believes no problems <br />have occurred in these areas leading Colowyo to believe even more that no <br />stability problems will occur in the extension of the perimeter ditch. <br />5. When Colowyo completes construction on the new Section 16 Pond extension ditch, <br />there will be a portion of the "old" Section 16 Pond (first) extension ditch that will <br />remain to the northwest of the new extension. The portion that will remain is from <br />approximately Station 45+00 to Station 55+00 on the currently approved Figures 1 and 2. <br />If the "old" portion of the Section 16 Pond ditch is not reclaimed it could cause major <br />maintenance problems with the remaining portion of the ditch north of Station 45+00. <br />The Division believes that this "old" portion of the ditch should be reclaimed concurrent <br />with the new ditch being constructed. Please provide the Division with details <br />regarding Colowyo's plans for the "old" portion of the Section 16 Pond ditch that <br />will not be needed after the construction of the second extension is complete. <br />Response: The "old" portion of the Section 16 Pond ditch extension was designed but <br />was not constructed. Therefore, no concurrent reclamation activities will be <br />needed around this portion of the ditch. Instead, the "new" Section 16 Pond <br />ditch extension is being constructed in accordance with Exh. 7-140-2. <br />This concludes Colowyo's first round of responses to the Division's preliminary adequacy review <br />for Colowyo Mine's Technical Revision 71.