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Mounlain Cool Compnrry 1997 Annual Hydrology Report Wesr E!k ~l4ine previously reported, but of insufficient quantity to obtain full water quality analysis samples, • WWE believes that the observed fluctuations suggest that there is a minor amount of groundwater in these wells during runoff periods. The WY97 data for GP-3 and GP-4 show a continuation of these historic observations. The WY97 data for GP-5 are more than 8 feet higher than the historic range dating back to 1985 and approximately 3 feet higher than WY96 even though the well again is reported as being dry. While this observed departure from historic data is pooling, the historic and continued observation that there is insufficient water to sample is consistent with the past record for the three Lower Refuse Pile wells. Barren Member Wells There are currently twelve monitoring wells that aze completed in the Barren Member of the Mesa Verde Formation. These include: B-32, SOM-13, SOM-38-H-1, SOM-45-H-1, SOM-45- H-2, SOM-80, SW-l, SW-2, SW-3, SW-4, SW-5 and SW-6. The Barren Member averages 1,000 feet in thickness and is located immediately above the F-Seam coal (i.e., approximately 400 feet above the B-Seam coal). There were no significant changes in water levels observed in the Barren Member wells during WY97 with the exception of well SOM-38-H-1, as discussed below. Shallow wells (depths less than 70 feet) include SW-1 through SW-6 and B-32. Each of these wells have historically shown some indication of a connection with surface waters (i.e., seasonal fluctuations), with high levels coinciding with the spring run-off. The remaining Barren Member monitoring wells (i.e., SOM- 13, SOM-38-H-1, SOM-45-H-1, SOM-45-H-2 and SOM-80) have depths greater than 140 feet and show little if any seasonal fluctuations. Water levels in wells B-32, SOM-13, SOM-80 and SW-1 through SW-6 during WY97 were consistent with previous observations. In the case of wells B-32, SW-1, SW-2 and SW-4 through S W-6, the water levels were at or near the bottom of the wells as indicated by "damp" or "dry" notations in the field records. In the water that was available, field parameters of pH, temperature and conductivity were generally consistent throughout the water year. A gradual increase in the reported bottom elevation of well S W-2 suggests that formational material may be entering the well. This may also be the explanation for the 0.75 foot elevation increase in the total depth of wells SW-4 and SW-5 as compazed to those first observed in the spring of 1995. Regardless of the explanation for this discrepancy, there is generally insufficient water in the SW series of wells with the exception of well SW-3. Monitoring well SW-3 continues to show seasonal fluctuations with high water levels generally occurring with spring runoff in June. Nevertheless, the higher water levels are usually insufficient to obtain water quality samples. Mining impacts to water levels at well SOM-38-H-1 were previously recorded after F-seam room-and-pillar retreat mining and B-seam longwall mining. The well recovered both times. Measurements taken in WY96 showed a declining water level that continued in WY97. However, no mining was occurring near this well during this period. Starting in the fall of 1996, water quality samples have not been obtained from this well because water levels have fallen below a pinched portion of the casing, preventing access with even a small sampling bailer. • 3!- .450 age Wrig r arer ngineers