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2.05.6 <br />• <br />L~ <br />PR-10 <br />~`~Rov~ <br />I//zy~o $ <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 nearthe 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. <br />Map 08 provides a section view of the hydraulic isolation of the Rollins <br />Sandstone. The perched water below the D-Seam and above the B-Seam is <br />or was monitored by drill holes D-58a and DH-67-D-Blw. The quality of water <br />in this perched water being zone, as reported in the 2007 AHR show pH in <br />the range of 7.8 to 11.6, conductivity ranges from 485 to 5030 umhos/cm <br />and total recoverable iron ranges from 0.03 to 31.4 mg/I. Based on the <br />quality of the mine water discussed above, mine water seepage into the <br />perched water below the D-Seam and above the B-Seam would improve the <br />water quality in the perched water bearing zones. <br />The perched water above the D-Seam is or was monitored by drill holes D- <br />58, 66 and DH-67-D-Abv. The quality of water in this perched water being <br />zone, as reported in the 2007 AHR show pH in the range of 6.9 to 13.5, <br />conductivity ranges from 652 to 5500 umhos/cm and total recoverable iron <br />ranges from 0.08 to 17.7 mg/I. Based on the quality of the mine water <br />discussed above, mine water seepage into the perched water above the D- <br />Seam would improve the water quality in the upper perched water bearing <br />zone. <br />2.05 - 75ii o9/os <br />