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Mountain Coal Company 1997 Annual Hydrology Report Wes/ 61k Aline <br />Both SOM-45-H-1 and SOM-45-H-2 were reinstated into the monitoring program in 1996. The <br />• 1997 observed water level measurements for both wells fall within the baseline range of reported <br />data (i.e., 1480 to 1987) and were consistent with WY96 observations. Multiple laboratory and <br />field water quality values were obtained for SOM-45-H-2 as part of the baseline re- <br />establishment. All WY97 values were within the historically observed range. As previously <br />stated, monitoring well SOM-45-H-1 was monitored per the regular monitoring program in WY97, <br />so only one full-suite analysis was obtained. This well will be monitored again for baseline <br />conditions in WY98 as mining will not impact this well for more than a year. <br />F-Seam Wells <br />There are currently three monitoring wells that are completed in the F-Seam coal. These include: <br />SOM-C-76, SOM-2-H and SOM-16-H. <br />Monitoring well SOM-C-76 (a.k.a. C-76) was reinstated as an F-Seam monitoring well in WY96 <br />and continued in WY97. Water level data obtained during WY97 were all within 0.5 feet of <br />each other and approximately 1.5 feet above the average water level elevation established <br />between 1980 and mid-1987 when monitoring ceased. Insufficient information is presently <br />available to suggest why this small water level increase occurred, especially given its location <br />within the Dry Fork of Minnesota Creek, upgradient of all mining activities. Water quality <br />results obtained from WY97 were within the range of baseline data previously collected. <br />Well SOM-2-H (a.k.a. SOM-2) continued to demonstrate a decline in water level which began in <br />• mid-1994, roughly coincident with the advent of longwall mining operations. A decreasing rate <br />of decline (initially evident in WY96) continued in WY97. Water quality results obtained from <br />WY97 were within the range of data previously obtained for baseline purposes. <br />The WY97 data for SOM-16-H (a.k.a. SOM-16) appeaz to follow the same general downward <br />trend which began in 1982, lessening in ] 987. While this decline of the water level <br />(approximately 15 feet) is much smaller than that observed for SOM-2-H (approximately 90 <br />feet) during the same period, there may be some dewatering of the F-Seam occurring in an up- <br />dip direction as a result of the B-Seam longwall mining to the north of these wells. However, the <br />observed water level in well SOM-C-76 (an upgradient F-Seam well) has increased since last <br />measured in 1987 which includes the period in which longwall mining began. Therefore, the <br />explanation for the declining or increasing water levels is not clear. Water quality results <br />obtained from WY97 were within the range of data previously obtained for baseline purposes. <br />E-Seam Wells <br />There are currently three monitoring wells that are completed in the E-Seam coal. These <br />include: 96-2-2, 96-27-1 and SOM-23-H-2. <br />Monitoring wells 96-2-2 and 96-27-1 were completed both in and above the E-Seam, <br />respectively, during the 1996 exploration project. Baseline water level and water quality data <br />collection began in the fall of 1996 and continued through WY97. These wells will be <br />incorporated into the regular monitoring program in WY98 as there are sufficient baseline data. <br />• <br />831-0 1.4 age Wrig 1 afer ngineers <br />