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• The Eagle mines lie at the foot of the prominent Williams Fork Mountains in northwest Colorado. The elevation of the permit area ranges from 6,130 feet in the Big Bottom area, immediately below the confluence of the Williams Fork and Yampa Rivers, to 7,400 feet in the Williams Fork Mountains. Land uses in the permit area are cropland and rangeland/wildlife habitat, and most of the rangeland consists of riparian, pinyon-juniper woodland, or mountain shrub communities. Much of the area has been disturbed by previous surface and underground mining, which has been conducted in the area since the 1930's. The Bureau of Land Management (BLM) did not designate any Federal lands as unsuitable in their land use planning process. (See letter dated March 20, 1987.) However, BLM did identify certain areas to be protected for bald eagle concentration and roosting areas. These areas are protected under the Colorado permit, Stipulation No. 4. Amore thorough description of the affected environment within its resource setting is contained in Colorado MLRD's Decision and Findings of Compliance (pages 6 to 11). IMPACT ANALYSIS Impacts of Alternative 1, Approval with a Special Federal Condition The site-specific impacts of the mining and reclamation operations of the Eagle No. 5 mine and the majority of the impacts for the Eagle No. 6 mine, which lies directly below it, are described in the environmental documents referenced previously. The environmental resources that may be affected by • the Eagle No. 6 mine are surface and groundwater resources. The probable hydrologic consequences on surface and groundwater from the Eagle No. 5 and No. 6 mines are discussed in detail in Colorado MLRD's Decision and Findings of Compliance on pages 28 to 41. The cumulative hydrologic impacts of all existing and anticipated mining in the area are discussed in the Decision and Findings of Compliance on pages 42 to 48. Colorado MLRD notes that operations for the Eagle No. 6 mine are in the development stage, and no effects on alluvial valley floors are anticipated for the first five years. Some depletion of water from local bedrock aquifers is expected to result from the mining operations, but the depletion is considered minimal. The discharge of water from the mines will affect surface water quality, but not to the extent that use would be limited. Assuming that the portals are properly sealed when the mines are abandoned and allowed to flood, some effects on water quality in the Williams Fork alluvium is anticipated as a result of discharge of mine water through subcrops of the E and F seams. The magnitude of this impact is considered minimal. Impacts of the discharge of water from the flooded No. 5 and No. 6 mines on the quality of the Williams Fork River water itself would also depend on the volume of water discharge as well as the quality. Based on the volume estimated by the applicant for this future discharge, its impact on the quality of the Williams Fork River should be less than the impact of the present permitted mine water discharge. • -4