Laserfiche WebLink
Twentymile Coal, LLC. <br />Page 4 <br />September 4, 2015 <br />The following discusses TC's response to the Division's second adequacy letter datedMay S, 2015. <br />7. According to Exhibit 7K and the revised permit text, flooding/ponding resulting from subsidence <br />will increase Foidel Creeks surface area by 5 acres and Fish Creek surface area a maximum of 70 <br />acres under high water conditions. Please update section 2.06.8(5) of the permit to include a <br />narrative that addresses all of the applicable items required by Rule 2.06.8(5) associated with <br />mining of the WCR under the Fish Creek and Foidel Creek Alluvial Valley Floor. <br />a. TC's response: Section 2.06.8 of the currently approved PAP has been reviewed and <br />revised to address the proposed mining activities under PR10 and their relationship and <br />effect on any overlying AVF areas. <br />b. Division's response: <br />v. Revised Page 2.06-205.9 indicates that water quality is monitored at Station 900 <br />on Foidel Creek downstream of previous mining in the Eastern Mining District <br />and the proposed mining in the WCR. This station appears to be upstream of the <br />proposed mining in the WCR. Please revise this page accordingly. <br />1. TC's Response: Given that Station 900 now falls within the eastern <br />limits of the planned WCR mining area, TC will utilize existing Site 29 <br />downstream of Middle Creek (as shown on Map WC23) as the down - <br />gradient surface monitoring site. <br />2. Division's Response: Site 29 is past the confluence of Middle Creek <br />and Foidel Creek. Given this, it would be difficult to assess the impacts <br />mining in the WCR will have on Foidel Creek since Site 29 measures <br />flow received from both Foidel and Middle Creek. The Division <br />believes a new surface water monitoring site should be established along <br />Foidel Creek upstream of the confluence of Middle Creek. Please revise <br />this page accordingly and update Exhibit 4E-11 and Exhibit 14 as <br />necessary to add this additional monitoring point. <br />8. Please submit an environmental monitoring program that includes hydrologic monitoring, <br />vegetation monitoring and subsidence monitoring similar to the one submitted as Exhibit 4e-7 <br />(Fish Creek AVF Monitoring Program) for mining in the NMD. This plan should be designed <br />based on mining of the Wolf Creek Reserve and the projected impacts on the AVFs of Foidel and <br />Fish Creek. <br />a. TC's response: Please recognize that extensive resource and impact monitoring and <br />analyses were completed to validate the initial mining activities and related subsidence <br />effects for the Fish Creek AVF. The results of these extensive monitoring and related <br />analysis efforts confirmed that the projected surface subsidence and related subsidence <br />effects on surface and ground water hydrology and vegetation communities were <br />consistent with actual measured subsidence and subsidence effects. All subsequent <br />mining, subsidence evaluations, monitoring requirements, and impact analyses tiered off <br />and were built on this foundation of confirmed mining and impact results. Given these <br />considerations, very limited monitoring is considered necessary for the mining activities <br />