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<br />The amount of depletion of flow in the Purgatoire River alluvial aquifer <br />has been estimated to be 5 gpm for the New Elk Mine, and 2.3 gpm for the <br />Golden Eagle Mine. The combined predicted depletion of the <br />stream/alluvial system is 7.3 gpm (0.016 cfs) which amounts to <br />approximately 0.1~ of the Q7-10 low flow in the Purgatoire River <br />(10.9 cfs ). <br />This minor loss in stream flow would be offset during mining by the <br />discharge of mine waters from the underground workings. The most a rrent <br />average discharge is 85 gpm from the New Elk Mine, and 184 gpm from the <br />Golden Eagle Mine. Full development at the currently inactive New Elk <br />Mine, however, could increase mine discharge to 180 gpm; fu]1 development <br />at Golden Eagle could result in a discharge approaching 500 gpm. <br />Only the Golden Eagle Mine, as a result of encountering an artesian water <br />flow in company with a fracture zone in the Second Right entries, has the <br />apparent potential to impact bedrock aquifers below the mining level. <br />F]ows of water from this source initial]y approached 500 gpm and <br />currently are under 200 gpm. Depression of the potentiometric surface in <br />the underlying aquifer as a result of this continuing flow is no doubt <br />occurring. The Trinidad Sandstone would appear to be the likeliest <br />source of this water. It is a regional aquifer with potential recharge <br />areas at and above the water level maintained by the fracture zone in the <br />mine. Because the Trinidad aquifer lies some 900 feet below the level of <br />the lowest coal worked in the New Elk/Golden Eagle Mines, no wells in the <br />area are producing water from this sandstone. As a result, continued <br />production of water from the fracture zone does not reduce use made of <br />this aquifer. Water flowing from the fracture zone into the mine is <br />discharged as mine water to the Purgatoire River at Golden Eagle. <br />During operations, water quality in the stream/alluvial aquifer system <br />would be affected by the discharge of water from the underground workings <br />and by seepage from existing and proposed coal refuse piles. At the <br />New Elk Mine site, existing and proposed coal refuse piles and maximum <br />mine water discharge add approximately 180 mg/1 to the total dissolved <br />solids concentration during Q7-10 low flow conditions in the Middle Fork <br />of the Purgatoire. This would add approximately 32 mg/1 during the low <br />f]ow in the vicinity of the Golden Eagle Mine due to dilution by the <br />North Fork. Maximam anticipated mine water discharge at the Golden Eagle <br />Mine would add another 58 mg/1 to low flow total dissolved solids <br />concentrations in the Purgatoire. The cumulative effect of the mine <br />discharges and the New Elk refuse pile is to increase the total dissolved <br />solids concentrations by 90 mg/1 in the Purgatoire River at Golden Eagle <br />under low flow conditions. Added to baseline concentrations of <br />approximately 200 mg/1, this increase would not limit the use of water <br />for either flood irrigation, livestock watering, domestic or municipal <br />purposes downstream. <br />-24- <br />