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Flooded mine workings could also impact the water quality in the area. <br />When the mines are sealed they will slowly fill with water. Although no data <br />for permeability or transmissivity of the saturated portions of the coal bearing <br />member of the Mesaverde Formation are available within the permit area, <br />the experience by others (Brooks, 1983) suggests the Mesaverde Formation <br />transmits little water. Therefore, the abandoned mine workings would not be <br />expected to transmit water to the surrounding strata. Based on the above <br />discussion, if the mine workings fill with water and discharge through the <br />portals, the impact on the North Fork of the Gunnison River would be less <br />than or equal to the mine water discharge analysis presented above. <br />The flooded mine workings could also affect the ground water quality and <br />quantity in the overlying Upper and Lower Perched Water Zones. However, <br />as stated above, the Mesaverde Formation transmits little water. Therefore, <br />the impact the flooded mine workings will have on the quantity and quality of <br />the surrounding strata should be minor. <br />The Rollins sandstone, as monitored in DH -34B, NM4X98 -29 and P- TC -03- <br />01(R) has pH in the range of 7.5 to 9.6, conductivity in the 1,200 to 7,900 <br />• umhos /cm range and total recoverable iron in the 0.2 to 62.0 mg /I range. <br />The Rollins sandstone is a confined aquifer under piezometric head. The <br />confining shale layers above the sandstone and piezometric head should <br />prevent any integration of water from either the D -Seam or B -Seam into the <br />Rollins sandstone. There are two drill holes (G -15) located near the mouth of <br />Dove Gulch and DH 98 -57 located in the central portion of the mine workings <br />that provide documentation of the hydraulic isolation of the Rollins sandstone <br />from the B -1 Seam, the lowest coal seam to be mined. In G -15 and DH 98- <br />57 there are 77.0 and 85.1 feet respectively of identified shale, sandstone <br />and coal between the B -1 Seam to near the top of the Rollins Sandstone. In <br />the western mine plan area, drill holeTC -03 -03 and CWI -DH -62 document <br />the isolation between the Rollins sandstone and the B -2 Seam, the lowest <br />coal seam to be mined. In TC -03 -03 there are 23 feet of mudstone, 28.3 of <br />sandy mudstone, 4.0 feet of sandstone and 19.2 feet of coal between the <br />Rollins sandstone and the B -2 Seam. In CWI -DH -62 there are 9 feet of <br />mudstone, 60 feet of sandy mudstone, 15.5 feet of sandstone and 20.5 feet <br />of coal between the Rollins sandstone and the B -1 Seam. Map 08 and 08a <br />provide section views that depict the hydraulic isolation of the Rollins <br />• <br />PR -12 2.05-115 11/10 <br />,q PPRov� <br />/ 1 / /6 /l o <br />