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Six ground water monitor wells were sampled by CEC on a quarterly basis in 1998. These wells are designated AMW-],AMW-2, DH-96, DH-122, FPW and SMW-2. Water quality analysis includes both the field and analytical laboratory testing of water samples collected from these wells. Field Measurement: Static water level is a tape measurement from the top of the well casing (a known ground elevation) to the current water level in the well preceding any sampling activity. Water sample temperatures are determined from a teinperahtre probe placed in the sample as soon as it is collected. Specific conductance is obtaured using are electrical conductivity meter. Each field water sample is tested for pH against a baseline pH neutral solution (7.0) after adjustment to the water temperahtre of the individual sample. All data collected during field testing is recorded in a field log book which is kept at the Keenesburg Mine office. A graphic display of this information (most recent five year period) can be found in the Section; "Analysis of Water Sampling Field Data". Laboratory analysis: • The wells are sampled in a sequence which follows the order of least to greatest level of salinity. At the end of 1998 this sequence was: (1) FPW, (2) AMW-1, (3) DH-96, (4) DH-122, (5) SMW-2. [Ash Monitor Well No. 2 (AMW-2) remained "dry" during 1998 as it has for previous years. The well is located near the northeast edge of A-Pit, in a lughly dishirbed reclaimed overburden area. The. well was redrilled in 1993, to specifications provided by the Colorado Division of Minerals and Geology (CDMG), and CEC must assume that ground water recharge of this area has yet to occur. It has also been noted in the records that numerous geologic faults were observed in the coal seam to the west of this well's location. There may then be an overall groundwater effect from the mining excavation activities on the groundwater recharge in this specific area.] Copies of the analytical laboratory test results are available in the pages following this text. Each ground water monitoring well was sampled in accordance with the "permit procedure". The "B" designation following the well identification indicates only that the laboratory sample was obtained after initial field sampling, well purging and a subsequent (second) field . sampling. The 1998 ground water monitoring test results appear to be consistent with results from previous water quality analyses. AHR-1998 -52- Stipulation #5