2000-02-10_GENERAL DOCUMENTS - C1981041

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monitoring parameters and frequencies for mine dewatering sites are listed in Table 18-1. Whole effluent toxicity testing will be conducted quarterly at these sites, in addition to the testing applicable to sediment pond discharges. Flow volume will be monitored at flume installations on Rapid Creek and Cottonwood Creek at the following locations; SWGS-02-- located on Cottonwood Creek in the NE 1/4 SE 1/4 Section 12, immediately upstream of No. 3 South Mains, SWGS-03--located on Rapid Creek upstream of current mining activity, and SWGS-01-- positioned on Rapid Creek downstream of the confluence with Cottonwood Creek. Flow at SWGS-02 and SWGS-03 will be recorded bimonthly during low flow(June through November). Flow measurements on SWGS-01 will be collected with continuous flow recorder when the creek is not frozen. Monitoring or Coal Creek and Jerry Creek was initiated in 1995. In 1999, monitoring requirements were reduced to downstream stations SWGS-06 on Coal Creek and SWGS-08,on Jerry Creek. The ephemeral flow in Coal Canyon will be monitored at the"dip section"culverts located between CRDA-1 and CRDA-2. The intermittent flow of Jerry Creek will be measured at a culvert near the Highline Canal, a short distance upstream from the creek's confluence with the Colorado River. Instantaneous flow and peak flow will be measured quarterly at the culverts, for which flow ratings have been provided. Peak flow will be estimated from high water marks on the culverts. G. Transfer of Wells 1. Information on the final disposition of monitoring wells and other pertinent data is found in the permit application beginning on page 14-29. All mine openings and wells will be permanently closed using concrete seals. The operator projects no discharge from the Roadside North Mine following permanent sealing. At the Roadside South Mine, water will be allowed to fill abandoned areas to the elevation of the sealed Northwest intake portal. A drain has been installed in the portal seal at this location to allow discharge through Outfall 002 of the CDPS permit (p. 17-6), and this discharge would continue following final reclamation of the mines (see further discussion in Section B.IV., "Sealing of Drilled Holes and Underground Openings"). Wells in contact with aquifers will be filled with concrete or other suitable sealant and plugged with a concrete seal. The permittee is not proposing to transfer any well. H. Stream Buffer Zones The overland conveyor system and a portion of the disturbed area at the loadout facility are within 100 feet of the Colorado River. A portion of the overland conveyor crosses the Colorado River. That portion of the overland conveyor is completely enclosed. This conveyor is an existing structure; therefore,the Division authorized those activities associated with the overland conveyor and disturbed area near the loadout facility within 100 feet of the Colorado River. No further disturbances within 100 feet of the river are proposed. The following finding is required in order to allow Powderhom Coal Company to conduct surface coal mining operations within 100 feet of the Colorado River: 30