2009-05-22_GENERAL DOCUMENTS - C1981044

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Round Bottom alluvial valley floors. Each of these alluvial valley floors are discussed separately, along with the potential impacts of mining. Yampa River Big Bottom Alluvial Valley Floor The approximate boundary of the Big Bottom AVF is shown on Map 25 of the permit application. Hayfields and pastureland are located in the Big Bottom (AVF) area and are flood irrigated. The Big Bottom AVF will not be undermined during this permit term by the Eagle No. 5 or No. 6 Mine. Portions of the Big Bottom AVF were previously undermined by the Eagle No. 5 Mine. Monitoring has shown no impacts to the alluvial valley floor due to previous undermining by the No. 5 Mine. The life-of-mine projection shows undermining by longwall methods of a small portion of the Big Bottom by both the No. 5 and No. 6 Mines. The application contains no information on possible impacts to the Big Bottom AVF or on mining methods to be utilized to mitigate such impacts for future extraction under the Big Bottom AVF. For this reason, the permit approval is for the five-year mine plan only of the Eagle No. 5 and 6 Mines. The Eagle Mine Complex operation ceased coal extraction in December 1995 and entered into temporary cessation. No additional underground development or coal extraction has occurred since that time. The now abandoned Eagle No. 9 Mine has development entries under the Big Bottom AVF; however, full extraction mining was not conducted. An AVF exemption for this past mining was requested and approved by the Division and OSM. A copy of the AVF exemption request is presented in Exhibit 4, and the extent of the No. 9 Mine workings is shown on the mine plan map, Map 23. No mining is approved for the No. 9 Mine during this five-year permit term. The No. 9 Mine is presently flooding and the operator is utilizing the portal area for a coal processing waste pile. Subsidence monitoring conducted by the operator has shown no effects to the Big Bottom AVF due to past development mining. The essential hydrologic functions of this AVF have not been affected. Surface coal mining operations conducted within the geographic extent of the area eligible for the exemption are not required to comply with the requirements of Rule 2.06.8(5)(a)(i) and (ii). Operations eligible for the exemption, however, are required to restore the essential hydrologic functions of the affected alluvial valley floors by implementing the approved reclamation plan. The Division finds that upon completion of the reclamation plan, the essential hydrologic function of both the Yampa and William Fork alluvial valley floors should be restored. Yampa River Round Bottom Alluvial Valley Floor The approximate extent of the Yampa River alluvium of the Round Bottom area is shown on Map 25 of the permit application. The essential hydrologic function of the Round Bottom alluvial valley floor is its capacity for supporting flood irrigation. Crop production may be augmented by subirrigation; however, subirrigation is considered to Eagle Mine Complex 38 Permit Renewal 05 C-1981-044 May 22, 2009