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RED CANYON MINE - 2 - September 3, 1985 To obtain an accurate representation of the aquifer at each sample site, depth to water should first be measured at each site. The well (piezometer) should be evacuated at least once, and allowed to recover to near its original level. A water sample should then be taken from the hole. Field parameters will include specific conductivity, pH and temperature. The full suite ground water analyses will be for those parameters previously approved for Grand Mesa Coal. II. REASONING We have a fairly complete monitoring record from all the holes near Grand Mesa coal for the past four (4) years. Since the mine is in temporary cessation, no disturbance to the prevailing hydrologic regime is anticipated. Quarterly water levels at the refuse pile piezometers will still give an accurate representation of the water table. A full suite analyses of a sample taken in June should provide a 'worst case' water quality picture. This is because the unconfined aquifer should be passing its spring runoff water at this time. Monthly water levels at the pond piezometers will indicate if leakage is occurring. If, due to increasing water levels or increases in conductivity, water leakage through the impoundment is suspected, increased monitoring may be required. Again, we have sufficient baseline data at this time to justify a reduction in monitoring. Coal and alluvial aquifers have in the past shown normal seasonal variation in quality and water surface elevation. Quarterly water levels will reveal any major changes in aquifer characteristics. Semi-annual field parameter sampling (June and October) will provide 'high water' and base flow measurements. Due to the abundance of baseline alluvial data collected in the past, four piezometers may be dropped from the program at this time. Due to the intermittent pumping of water from the mine, measurements may be made approximately once a month. Finally, Spring No. 2 is a series of seeps in a draw which is diluted by irrigation return flow. The monitoring of this spring, due to local conditions, provides no useful information and, therefore, may be discontinued. The Division should reserve the right to require re-implementation of the discontinued monitoring if conditions change, as shown by current monitoring, or when the mine starts operating again.