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Yampa River Big Bottom Alluvial Valley Floor The approximate boundary of the Big Bottom AVF is shown on Map 25 of the permit application, Hay fields and pasture land are located in the Big Bottom (AYF) area and are flood irrigated. The Big Bottom AVF will not be affected during this permit term by the Eagle No. 5 or 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 7ongwall methods 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 this reason, the permit approval is for the 5 year mine plan only of the Eagle No. 5 and 6 Mines. 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 CMLRD 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 5 year permit term. The No. 9 Mine is presently flooding and the operator is in the process of reclaiming the portal area. 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 2.06.6(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 will 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 sepporting flood irrigation. Crop production may be augmented by subirrigation,,however, subirrigation is considered to be minor. The Round Bottom alluvial valley floor primarily supports flood irrigated hay fields and pasturelands. The Eagle No. 9 Mine workings are not in close proximity to nor.• do they impact areas tributary to the Round Bottom AVF. Therefore, no impacts to the essential hydrologic functions of the Round Bottom alluvial valley floor occurred. The Eagle No, 5 Mine does not extend under the Round Bottom alluvial valley floor. The 2 West workings of this mine did however, undermine approximately 90 acres containing surface and ground waters tributary to the Round Bottom alluvial valley floor. The 2 West workings -18-