2015-08-14_REVISION - C1982056 - Laserfiche WebLink

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7b) Division's response: L Revised page 2.06-25.7 references two reports in Exhibit 7e-2 and 7e-4. The Division believes TC meant to reference Exhibit 4e-2 and 4e-4. Please revise this page accordingly. ii. Revised page 2.06-25.8 indicates that TC conducted a vegetation study on the Fish Creek AVF; this study is located in Exhibit 7J-1 of the permit. This page indicates that productivity between the AVF bottomlands and uplands are not significantly different. However, upon review of Exhibit 7J-1, the data indicates the production from the valley floor is about twice that of the upland area. Given this, the statement made on Page 2.06-25.8 does not appear to be correct. Please revise this page and evaluate if the conclusion drawn is still accurate. The State of Colorado owns a significant amount of land in the area to be subsided. Please provide documentation that the reduction in pastureland/grazing land as a result of subsidence induced flooding will not significantly interrupt, discontinue or preclude agricultural activities on State land. iv. Revised Page 2.06-25.9 indicates that there are areas where sub -irrigation occurs within the AVF. Map 5 of Exhibit 4e depicts areas where sub -irrigation occurs along Fish Creek. Please evaluate the impact mining in the WCR will have on these areas that are sub -irrigated and to what degree mining may interrupt, discontinue or preclude agricultural activities on these areas. V. Revised Page 2.06-25.9 indicates that water quality is monitored at Station 900 on Foidel Creek downstream of previous mining in the Eastern Mining District and the proposed mining in the WCR. This station appears to be upstream of the proposed mining in the WCR. Please revise this page accordingly. Response: The exhibit references on page 2.06-25.7 have been corrected. Exhibit 7J-1 was reviewed, and the relevant statements on page 2.06-25.8 were revised for accuracy and consistency. The potential effects of both sub -irrigation and flooding were reviewed, and the discussions on page 2.06- 25.9 revised and expanded to clarify and address the anticipated impacts. It should be noted that subsidence has the very real potential to enhance vegetation conditions and productivity by lowering the ground surface relative to the local stream gradient and water table, resulting in conversion of limited areas of upland vegetation to more productive lowland vegetation, and increasing sub -irrigation. Rather than being deleterious to vegetation and agricultural activities, these changes would potentially be beneficial. Given that Station 900 now falls within the eastern limits of the planned WCR mining area, TC will utilize existing Site 29, downstream on Middle Creek (as shown on Map WC23) as the downgradient surface water monitoring point. Copies of the relevant revised map and text accompany these responses for replacement in the PAP. 8h) Division's Response: Alluvial Well AVF15 is located above the 9 Right Long Wall Panel and is within the affected area associated with mining in the WCR. Given this, it would be appropriate to install a new downstream monitoring well outside of the affected area to evaluate impacts to the Fish Creek Alluvium.