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• implement the Conservation Measures that we believe are necessary to offset the likelihood of jeopardy. These Conservation Measures should be included as stipulations or conditions of the Office of Surface Mining permit. PROJECT DESCRIPTION Somerset Mining.Lompany proposes to mine the Sanborn East Tract adjacent to the already existing Sanborn Creek Mine. Sanborn East Tract is a 723.9 ha (1742 acre) area of which 28.3 ha (70 acres) are private land and 695.7 ha (1722 acres) are Federal land. The mine will be developed and mined using conventional room and pillar techniques. Annual production is projected to be 680,000 t (750,000 tons). No additional surface disturbance is planned for the addition of the Sanborn East Tract. The Somerset coal field lies on the southeast margin of the Piceance Basin and south of Grand Mesa. The Mesaverde Formation overlies the Mancos shale and contains two coal bearing formations. The Sanborn Creek and the Sanborn Creek East addition will extract coal from the B and C seams of the lower coal bearing member of the formation. It is expected that mining activities will result in an inflow of water to the mine. Water inflow may occur from the following sources: 1. Coal seams and sandstone and siltstone roof strata are likely to weep for short periods after mining and then eventually dry up. These areas are not regional aquifers. • 2. Mining activity will occur in close proximity to abandoned and possibly flooded mine workings. A 30.5 m (100 foot) buffer will be maintained to protect the new operation from possible inundation. 3. Inflow may occur from ephemeral and intermittent streams that are undermined. These flows will likely occur only following storm events and are not interconnected with ground water. 4. Both B and C seams are below the North Fork of the Gunnison River. Groundwater is expected to flow downdip from the river through the coal and overburden into the mine workings. These flows are expected to be minor due to the low permeability of the coal and overburden. The Sanborn Creek Mine workings will not extend under the alluvium of the North Fork, another possible source of inflow to the mine workings. The permit application uses two methods for calculating the amount of water that could flow into the mine workings. One calculation, based on the possible inflows to each of the potential water bearing zones around the coal seams, yielded a total inflow of 432 gpm for both seams. The other method calculated the inflow based on projections from mine inflow in other mines in the area with similar conditions to the Sanborn Creek Mine. This method yielded an inflow of 407 gpm. for the purposes of projecting inflows, the operator is using 425 gpm as the maximum inflow rate. • The mining operation has been designed to prevent material damage to the hydrologic balance outside the permit area.