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-37- The two operations are expected to cumulatively effect the flow in the Purgatoire River stream/alluvial aquifer system. The Allen Mine is located on the Middle Fork of the Purgatoire River. This fork joins the North Fork of the Purgatoire to form the Purgatoire River. The Maxwell Mine is located adjacent to the Purgatoire River immediately downstream from the Allen Mine. Both operations have undermined and will further undermine the stream/alluvial aquifer systems. The amount of depletion of flow in the Purgatoire River alluvial aquifer has been estimated to be 5 gpm for the A7]en Mine, and 2.3 gpm for the Maxwell Mine. The combined predicted depletion of the stream/alluvial system is 7.3 gpm {0.016 cfs) which amounts to approximately _ 0.3% of the low flow in the Purgatoire River (5 cfs). This minor loss in stream flow would be offset during mining by the discharge of mine waters from the underground workings. The current average discharge is 123 gpm from the Allen Mine, and 30 gpm from the Maxwell Mine. Each mine is predicted to discharge 180 gpm at full development for a total discharge of 360 gpm (.8 cfs). During operations, water quality in the stream/alluvial aquifer system would be affected by the discharge of water from the underground workings and by seepage from existing and proposed coal refuse piles. At the Allen Mine site, existing and proposed coal refuse piles and mine water discharge add approximately 48 mg/1 to the total dissolved solids concentration during low flow conditions in the Middle Fork of the Purgatoire. This would add approximately 29 mg/1 during the law flow in the vicinity of the Maxwell Mine due to dilution by the North Fork. Mine water discharge at the Maxwell Mine would add another 47 mg/1 to low flow total dissolved solids concentrations in the Purgatoire. The cumulative effect of the mine discharges and the Allen refuse pile is to increase the total dissolved solids concentrations by 76 mg/1 in the Purgatoire River at Maxwell under low flow conditions. Added to baseline concentrations of 300 mg/1 or less this increase would not limit the use of water for either flood irrigation, livestock watering, domestic or municipal uses downstream. The Ciruela Canyon refuse pile at the Maxwell Mine will increase the total dissolved solids concentration. The effects of this refuse pile cannot be assessed at this time without additional information. Following mining, mine water would no longer be discharged to the river. Only seepage from the coal refuse piles would continue to effect water quality in the stream-alluvial aquifer system. Continued seepage from the Allen waste piles would add approximately 16 mg/1 to total dissolved solids concentrations in the Purgatoire River under low flow conditions. This increase would not be expected to limit water use. Since the applicant's baseline data is deficient in estimating recharge, water movement, discharge of ground water and the presence or absence of alluvial aquifers in the tributary drainages in the two mines' permit and adjacent areas, it is not possible to determine fully what the cumulative hydrologic impact would be upon surface and alluvial ground water resources in the general area. Assessments cannot be made about the cumulative hydrologic impacts to the springs, seeps and stream/alluvial water in the tributaries to the Purgatoire River at this time.