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Page 5 of 6 <br />fault zones, which may provide significant communication. Approved page 2.05 -142 <br />states that, fault zones penetrated to date have not yielded any significant long -term <br />inflows from the Trout Creek Sandstone or the Twentymile Sandstone and fault zones, <br />which have the potential to provide communication through the intervening marine shale <br />have not been identified within the proposed mining area. <br />With the PR -9 application, the proposed mining area is proposed to be modified. In <br />addition, the proposed extensions of panels 12LT, 13LT, 14LT and the addition of 11LT <br />will require mining through a major fault zones previously not mined through. Please <br />provide discussion identifying the fault zone proposed to be mined through and evidence <br />to ensure that the mining through the major fault zone will present similar effects to the <br />Trout Creek Sandstone and the Twentymile Sandstone. <br />TC Response: Pages 2.05 -135 through 137 provide a good discussion of groundwater <br />inflows to the Mine and the factors influencing the potential for groundwater movement <br />between the mine area and key units, including groundwater movement through fault <br />zones. The two faults which will intersect the WMD workings (refer to previous <br />response to Comment 6) have been characterized by recent seismic and drilling work, and <br />are not considered to be major faults (width and displacement) within the mining area, <br />based on the available information. Where these faults have been encountered during <br />panel development in the WMD, they have produced some water, but not in large <br />quantities, and similar to other fault crossings, inflow rates have declined fairly rapidly <br />after initial inflows. The discussion of PHC has been reviewed, and the specific <br />discussion addressing groundwater movement through the fault zones remains applicable <br />for the WMD panel extension given the nature of the faults in this area, and TC's <br />experience to date in crossing these faults. This response is adequate. <br />15. Division's Initial Comment. Approved pages 2.05- 181.10 and 2.05 -184.8 discuss <br />subsidence impacts to the Fish Creek Alluvial Valley Floor. Please revise the above <br />mentioned pages to include the proposed new panels and panel extensions. <br />TC Response: The discussion of mining impacts on the Fish Creek AVF has been <br />reviewed relative to consideration of the proposed changes in mining configuration. The <br />panel extensions will not result in any new or different subsidence impacts beyond those <br />discussed, so the associated discussion is not materially changes. Minor edits have, <br />however, been made for clarity and consistency. Copies of any revised pages accompany <br />these responses for replacement in the PAP. This response is adequate. <br />16. Division's Initial Comment: Based on the proposed mine plan submitted with PR -9, it <br />appears that well 006 -AY -1 may no longer be upstream from mining. Please provide <br />information on constructing a new Fish Creek Alluvial well to be monitored or the <br />justification that a new Fish Creek Alluvial well is not needed. <br />TC Response: The period of record for Well 006 -AY -1 is sufficient to reasonably <br />establish upstream flow and water quality conditions for Fish Creek. While the extension <br />