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classification of potentially usable quality is selected for these two specified areas in this review. The TDS level criteria of potentially usable quality is 10,000 mg/1 for both of these specified azeas. Post mining spoil water was expected to have average TDS values of 3,000 mg/1 (PAP page 2.5-96). However, discharges from sedimentation ponds fed by spoil springs have TDS values in the 4,OOOs, and at times approach 5,000 mg/I. Water from the spoil aquifer would be expected to have TDS levels that correspond to the spoil springs. Values of TDS in monitoring well WR-1, a spoil sampling point, have ranged as high as 4570 mg/1 to date. [This prediction is called to the attention of the operator in an adequacy letter.] As indicated above, spoil spring discharges appear to have an impact on specified Trout Creek alluvium with TDS values in the 4,OOOs. All these values are less than 10,000 mg/1. Thus the Edna mine is in compliance with potentially usable quality criteria with regazd to Trout Creek alluvial and spoil aquifer specified areas. There is a known domestic use of the Trout Creek Sandstone within a zone of potential impact, and this aquifer could possibly serve as a ground water supply for the postmining rangeland use. However, the potential impact from mining activities to the Trout Creek Sandstone is limited. The shale bedrock in the low-wall of the mine pit may be a permeability barrier to subsurface discharge of leachate. The Trout Creek is a few hundred of feet deeper than the mined coal sequence, and most likely is not in hydraulic communication with the bottom of the pits due to relatively impervious intervening layers. In addition, leachate has lower head than adjacent bedrock in most place, and there is minimal opportunity for leachate to infiltrate these bedrock units. Regional hydrology indicates ambient head in any permeable bedrock unit can be expected to be several tens of feet above the elevation of the unit; the head exerted by spoil leachate ranges between only 25 ft. and 50 ft. In addition, there has been no change in the range, and no indication of rising values in, the monitored well TCS-1. The TDS threshold for this classification is also 10,000 mg/1. The maximum TDS value in TCS-I was 860 (except for a likely error) during the monitoring period 7/1995 through 10/2003. There was no sample taken during 2004.monitoring. Thus the mining activity is considered to be in compliance with this rule for this specified area. Colorado Discharge Permit System Dischazges at the Edna mine aze regulated by the Colorado Dischazge Permit System permit number CO-0032638. The AHR does not include information on applicable monitoring. The operator is asked to include the information by reference (Discharge Monitoring Reports are provided to the Division under separate cover). No dischagges exceeded permit criteria during water year 2004 with the exception of a WET test in the first quarter of 2004. Page 7