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RN07 <br />Page 21 <br />5/30/18 <br /> <br />user on Trout Creek with an alluvial well, which is not currently in use. Review of the PHC indicates that the <br />current discussion identifies and describes the potential for elevated values of these constituents adequately, so no <br />modifications are necessary or appropriate at this time. It is also appropriate to note that TC has maintained full <br />compliance with applicable effluent limitations under all relevant CDPS permits. <br /> <br />Resolved <br /> <br />2.05.6(6) Subsidence Survey, Subsidence Monitoring, and Subsidence Control <br /> <br />55. Please depict and label the powerlines that exist within the Permit Area on Map 23b. <br /> <br />Response: - Map 23b has been reviewed and updated to show the location of all powerlines within and crossing <br />the Permit Area. Copies of the revised map accompany these responses for replacement in the PAP. <br /> <br />Resolved <br /> <br />56. Section 2.05.6(6)(c) of the Permit discusses the subsidence monitoring program for the Foidel Creek Mine. <br />Since the last Permit Renewal (RN-06), it appears mining and subsequent subsidence has occurred in the <br />Western Mining District. Pages 2.05-191.6 to 191.8 discuss the monitoring requirements that pertain to the <br />areas mined/subsided since the approval of RN-06. Page 2.05-191.8 indicates that subsidence reports will be <br />submitted to CDRMS semi-annually, 60 days after the end of the period. The format of the report is included <br />in Exhibit 34. The last subsidence monitoring report submitted to the Division was received on July 18, 2007. <br />Based on the review of the subsidence monitoring program and approved mining sequence, it appears <br />subsidence monitoring should have been conducted and semi-annual reports submitted since the approval of <br />the RN-06 application. Was monitoring conducted for the structures and renewable resources lands in <br />accordance with the plan discussed on in Section 2.05.6(6)(c) of the permit? If so, please submit a report in <br />accordance with the format approved in Exhibit 34 with the results of the monitoring. <br /> <br />Response: - For the Northern Mining District, Western Mining District, and Wolf Creek Reserve, the introductory <br />portion of the subsidence monitoring discussions (pages 2.05-191.5 and 2.05-191.8) notes that TC is not planning <br />on establishing further subsidence monuments, or conducting further monitoring, other than as specifically <br />described. The rationale, as accepted and approved by the CDRMS in the related revisions, is that extensive prior <br />monitoring has demonstrated that the subsidence projections are conservative and effectively provide a reasonable <br />and accurate basis for projecting anticipated subsidence and related subsidence effects. Given these considerations, <br />the limited monitoring that occurred/will occur focuses on specific structures owned by outside parties (Routt <br />County, powerline owners, UP Railroad), for which coordination occurs directly with those parties. The referenced <br />reporting commitment previously existed for the Southwest and Eastern Mining Districts, and was apparently not <br />deleted when the text for the Northern and Western Mining Districts was added. For these reasons, inclusion of the <br />referenced reporting commitment for the Northern and Western Mining Districts was not appropriate, and has been <br />deleted (note that there is no similar commitment for the Wolf Creek Reserve area). Copies of the revised text are <br />included with these responses for replacement in the PAP. <br /> <br />Resolved <br /> <br />57. Page 2.05-191.7 indicates hydrologic monitoring of surface and alluvial wells sites will be conducted along <br />Fish Creek to assess the subsidence impacts resulting from mining in the WMD. This page indicates that results <br />of relevant ongoing hydrologic monitoring will be incorporated into the semi-annual subsidence reports.