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• Groundwater discharges from the western backfill area have not reached steady-state levels. This is primarily due to the fact that the large strip of open pit exists in the middle of this area which would tend to intercept flows from the updip portion of the backfill. Once this area is fully reclaimed, a ground- water flow system similar to that existing in the eastern backfill area would be expected to develop. Projections of the potential discharge area may be based on this assumption. The area of recharge for the western backfill is approximately 8.5 x 10'ft~ With similar recharge rates that appear to be prevalent in the eastern backfill, the western area would be expected to eventually yield a total annual recharge volume ,of about 2.1 x 10' ft3(Appendix II,D). If this area also has the characteristic of approaching a closed system, then a large proportion of this volume would be expected to be discharged. This volume is projected to be equivalent to an annual average discharge rate of 300gpm based on comparison with the eastern backfill area. A similar fluctuation in discharge rate seen at the eastern area is likely to be seen in the western area. Peak discharge rates will tend to eventually reach approximately 2500gpm. The average discharge during this high flow period is projected to be about 1300gpm. Discharges during the majority of the year are project- ed to be about 100gpm. Total backfill discharges form the entire Eckman Park operation are thus projected to vary between 180 and • 4500gpm through the year with an average rate of about SOOgpm. Water quality of the western backfill discharges similar to that seen at the Pond F Spring. projected discharge from the backfill areas average dissolved solids concentration of about loading to Foidel Creek of approximately 3700 projected to result from backfill discharge at operation. Salt Load Analysis will probably be Using the total and assuming an 4000mg/1., a salt tons per year is the Eckman Park Records of flow in Foidel Creek, upstream from the major mine related discharges, are available from the USGS gaging station 09243800. Prior to 1980, flow was usually only measurable for about four months of the year, following the spring snowmelt period. After 1980, discharges from CYCC's Eckman Park mine at Pond A resulted in an extended period of flow at the USGS site. Downstream from the site, contributions to Foidel Creek occur at the discharge points of several sediment ponds associated with the CYCC Eckman Park and Mine No. 1 operations and the Twentymile Coal Company (TCC) Foidel Creek Mine. The major discharges occur from sediment Ponds D and F. Discharge of groundwater inflow to the adjacent Foidel Creek underground mine occurs via Pond D. Overflow of the flooded Area 2 Pit also contributes to Foidel • Creek via sediment Pond D. The major source of inflow to the Area 2 Pit is discharge from updip backfilled areas. Discharge 14