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sandstone aquifers is fairly constant over the whole period of measurement. The tables include either all data collected through 1984 plus an additional sample collected in March 1985. Also, carbonate data is included when it is greater than zero (this applies for all the water quality data). COAL .Flows Plots of the measured discharges are presented on Figure 15 and figure 16. ' The flaws from the No. 5 and No. 9 Mines are measured at the discharge end of their respective settling ponds. The flow from the No. 5 Mine is also measured by a totalizing flow meters on the discharge ends of the mine dewatering pumps. The flow meter readings were used to prepare the N o. 5 Mine discharge figure while the pond discharge numbers for both mines are reported with the NPDES data as required by the NPDES permit. The measured discharge form the No. 9 Mine reflects the intermittent pum ping of the mine, and during the spring minor snow melt influx. None of the flow rates significantly exceeded the predicted values of 200 to 33G gpm ' for the No. 9 Mine and 760 to 890 for the No. 5 Mine. The 1984 ave discharge from the No. 5 Mine was 737 gpm and'the average discharge rage from the No. 9 Mine was 156 gpm. During the period from August 20, 19Eµ to September 27, 1984, there was no discharge from the No. 5 Mine because its ' new underground sump was fi 11 i na and the new mine dewatering system was being tested and installed. ' Water Quality Summaries of the water quality data for the two mine discharges are ' presented on Table 13 to Table 16. The mine discharges are NPDES discharge points. The data indicates that the water quality of the discharges has been generally constant through time. The only parameter which seems to be varying is zinc. The zinc values appear to exceed standards occasionally. This may be a natural phenomenon because samples from most of the aquifers and surface water sampling points also occasionally exceed the standards. The NPDES effluent limitation for zinc ' has been changed and if the new standard were in effect for the entire year, the standard would not have been exceeded. The NPDES limitation for pH was exceeded infrequently at the No. 9 Mine discharge. The prob~em was ' remedied by upgrading the C02 treatment system. All noncomplying discharges were reported to the appropriate agencies. ' ALLUVIUM Sediments in two stream valleys are monitored: the Williams Fork River Alluvium (3 wells) near the confluence v:ith the Yampa River and the Yampa River Alluvium (5 wells) in the Big Bottom area. - 3-