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West Elk Mine <br />• The primary reason for selecting seasonal sampling is that, in the case of groundwater <br />monitoring, these aze the only periods of significant changes in groundwater levels. The <br />groundwater baseline data cleaziy indicate that there is no reason to attempt to sample these <br />locations during winter. The adverse conditions encountered in the remote azeas of the West Elk <br />Mine lease azea severely hamper sampling procedures and influence the collection of meaningful <br />data. As a result, by restricting sampling to the periods of flow and insuring sample integrity, <br />Mountain Coal Company will be able to provide meaningful data to the Division while reducing <br />the costs associated with collecting unnecessary data or data that is not meaningful. <br />B-Seam and Rollins Sandstone Hydrology Monitoring <br />Baseline hydrology monitoring has taken place on the West Elk mine block since about 1978. <br />Baseline data has been collected for the entire Mesa Verde Formation including the Upper and <br />Lower Coal members which contain the minable F, E, and B coal seams. A description of the <br />hydrology and baseline data is contained Section 2.04. Additional baseline data aze contained in the <br />Quarterly Hydrology Monitoring Reports (1978 to present) and the Annual Hydrology Reports <br />(1982 to present). <br />Monitoring of SOM 23-H-1 was discontinued. It appeazs that the PVC casing in the well was <br />fractured or split by a neazby landslide. It also appeazs that better quality, alluvial water is seeping <br />into the casing diluting the B-Seam water and changing the well head. Therefore, drill hole SOM- <br />23-H-1 was deleted from the monitoring program. Historical data from this well obtained in 1977, <br />should accurately represent the conditions existing in the B-Seam. <br />Water in drill hole SOM C-72-H exhibited high pH which may be due to contamination from grout. <br />Mountain Coal Company flushed the well with water and jetted the well dry utilizing drilling <br />equipment. Hydrologic consultants, as well as Mountain Coal Company geologists, feel that the <br />high pH, if grout related, may be remedied in this manner. This well was eliminated from the <br />monitoring program in 1999, as the bottom of the well was mined through with the B-Seam. <br />Monitoring well SOM 127-H is located on the West Elk Mine site and was completed in the fall of <br />1988 to monitor the B-Seam. This well was sealed in June, 1993, because methane liberated from <br />the well had caused a safety concern in the maintenance shop constructed over the well. SOM 129- <br />th was drilled neazby to replace SOM 127-H in the monitoring program. <br />Monitoring well JMB-12 was completed in the B-Seam (see Exhibit 12) during the Jumbo <br />Mountain exploration project in the summer of 1993. Baseline data monitoring was begun in early <br />fall of the same year and continued until one yeaz of data was obtained. JMB-12 was then <br />incorporated into the regular monitoring program. This well was removed from the monitoring <br />program in 1999, as the well was mined through with the B-seam. <br />Well So.W-1 was completed into the B-seam in 1994. Baseline data were collected on the well and <br />the well was then incorporated into the regulaz monitoring program. <br />Well So.W-3 was also completed in 1994, but was completed in the Rollins Sandstone. Due to a <br />problematic completion (i.e., an unusual blockage), the well never provided any data, and was <br />2.05-76 Revised Dec. 1997 MR208; Revised Jan. 1999 TR88; Rev. Apri11006 PRI G <br />