1986-03-03_REPORT - C1981013 (4)

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Wells PAW-1 and PAW-2 were established to monitor the existing refuse pile at the New Elk Mine. Table 3 presents the range and mean for field parameters collected over the 1985 water year. The main difference was an increase in conductivity from a mean of 336 at PAW-1 to 723 at PAW-2. Water in both wells is a calcium-bicarbonate type (Figure 8) with total ions measured at 5.21 and 11.47 me/1 at stations PAW-1 and PAW-2, respectively. Metals analyzed for PAW-1 were near or below detection limits while manganese was elevated at station PAW-2. During March and April of 1985, 500 feet of the Middle Fork of the Purgatoire River was diverted to the north to create additional room for the coal stockpile at the New Elk Preparation Plant. As the diversion was cut through an existing refuse disposal area, two alluvial wells have been established to monitor water elevation and chemical parameters as outlined in Stipulation No. 8 of Technical Revision No. 1 to the New Elk Permit. Monitoring began in april of 1985 with the data presented in Tables 203 and 204 of Appendix 1 for stations PAW-3 and PAW-4, respectively. The wells were cased with 18 inch galvanized CMP and completed in the cobble and gravel fill of the channel. Total depth of PAW-3 is approximately 20 feet from the top of the casing with the water elevation at 17 feet below the top of the casing. Total depth of PAW-4 is approximately 15 feet from the top of the casing with water elevation at 12 feet below the top of the casing. Static water level in both wells corresponds closely with static water level in the Purgatoire River. Water quality monitoring shows water in these wells to be a calcium- bicarbonate type water (Figure 8) and disturbed (refuse disposal) conditions as monitored at PAW-1 and PAW-2 (Table 3). Wells PAW-5 and PAW-6 were established to monitor the Golden Eagle Mine. Analyses of all water chemistry parameters at PAW-5 were similar to those of PAW-1 indicating negligable effects of the New Elk Mine on the Purgatoire alluvium. Table 3 presents the range and mean for field parameters measured. Again, the major difference was observed in conductivity from a mean of 455 to 755 umhos at stations PAW-5 and PAW-6, respectively. Total ions measured also increased from 9.05 me/1 at PAW-5 to 16.61 me/1 at PAW-6. Figure 8 shows that the water in PAW-5 is a calcium-bicarbonate type while that of PAW-6 is more a sodium-bicarbonate type. Metal concentrations in both wells were near or below detection limits. Changes in water chemistry may be attributed to the Golden Eagle Mine Discharge and refuse disposal in Ciruela Canyon. -22-