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Oxbow Mining, LLC- Terbnica! Reoirion TR43 I] Wert Caal Refure FadGty TecbnkoJAdegnary Comment/Rerponrer September S, 2003 Page 4 In the unlikely event that discharge were to occur, the existing railroad drainage ditch and adjacent track would be protected from erosive flows by the designed grouted riprap splash apron (refer to the MWH design repon in Exhibit 2.05-E4). Any discharge flows would be carried through the existing railroad ditch to the nearest railroad culvert. If the culvert did not have adequate capacity to pass the flows, any excess flows would continue down the raikoad ditch to the next raikoad culvert. 13) On page 2.04-103, the lart sentence reguirrs support. Bared on dinwssionr, Oxbow personnel feel that the existing database rovers the area proposed far disturbance. Thu it not dearly desiribed in this session. Please elabora/e on the existing data and its coverage of the proposed disturbance, explaining in detail the contention that the requirements for baseline data are satisfted Response: As described in the baseline vegetation survey report (Western Resource Development Corporation, 1982), "A plant ecologist conducted a reconnaissance of the entire project site and selected mapping units based on vegetation structure and species dominance. The vegetation boundaries were delineated upon a USGS base map at a scale of 1":500' and verified through field excursions." The limits of the baseline vegetation survey and vegetation unit boundaries aze showri on the Regional Vegetation Map, Map 2.04M8, and include the II West Coal Refuse Facility project azea. Based on the Regional Vegetation Map, the project azea is dominated by the Juniper Woodland vegetation type, but also includes areas of the Mountain Shrubland vegetation type. Both of these vegetation types were.quandtatively sampled in close proximity to the project area, as shown on the Regional Vegetation Map. The field work conducted for the proposed II West Coal Refuse Facility did not identify any vegetation communities in the project area beyond those previously identified and mapped. A previous vegetative baseline reconnaissance conducted for the existing West Valley Coal Refuse Facility (Hayes Environmental Services, Inc., 1996), included in Exhibit 2.04-E6, indicates similar. considerations (i.e.: limited disturbance azea, previous vegetation mapping, nearby quantitative sampling, and no additional vegetation communities). As documented by a letter from Mr. Tony Waldron of the CDMG (included in Exhibit 2.04-EG), it was determined that additional baseline vegetative sampling would not be necessary, given these considerations. In order to address potential riparian and "Waters of the U.S." issues, OMLLC contracted with Cedaz Creek Associates.to conduct a wetlands and "Waters of the U.S:' survey of the II Wes[ Coal Refuse Facility project area. The results of this survey, included in the TR-43 submittal package (Exhibit 2.04-E4), provide supplemental information on vegetation species within the project azea, which is consistent with mapping of the azea as Juniper Woodland. Survey results also indicate the absence of a discernable riparian community and that affected areas would probably not qualify as "Waters of the U.S.". Considerations relative to a negative determination for "Waters of the U.S." include the lack of a deEned streambed or channel, the absence of any wetlands, and the lack of a connection with other "Waters of the U.S.". The text on page 2.04-103 has been revised to reference relevant information in Exhibits 2.04E4 and 2.04-E6 and to clarify that no riparian or wetland vegetation was identified in the project area. Copies of the revised text accompany these responses for replacement in the Mining and Reclamation Plan document.