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STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Department of Natural Resources <br />1313 Sherman St., Room 215 <br />Denver, Colorado 80203 <br />Phone: (303) 866-3567 <br />FAX: (303) 832-8106 <br />INTERNAL MEMO <br />TO: Joe Dudash, Sandy Brown <br />FROM: Jim Burnell <br />SUBJ: Bowie TR-26 <br />Joe, <br />I reviewed Bowie TR-26 as per your request, concentrating on the hydrochemical effects <br />of discharging mine water treated with flocculant. <br />In summary, Bowie predicts that 30 gpm water will inflow the mine based on previous <br />experience. For conservatism, they calculate potential impact based on the discharge of <br />175 gpm -more than 5 times the volume of water anticipated. <br />The dilution factor of the discharge water plus flocculant, even at the conservative <br />estimate of 175 gpm, would not adversely impact the Fire Mountain Canal or the North <br />Fork. My calculations agree with those presented by Bowie. Further, the material - <br />NALCO 7880 - is rated "essentially non-toxic" as a biohazard. <br />Note that Bowie has committed in the permit that if the discharge proves to be <br />continuous, they will not discharge it into the Deer Trail Ditch (and thus the Fire <br />Mountain Canal) but rather will pipe it to D-Gulch and discharge it into the ephemeral <br />stream channel there. D-Gulch does not carry much water and has been dry in recent <br />years during sampling events. Under that scenario, the water reaching the North Fork <br />would be diluted to the point that it would provide no negative impact. The one possible <br />impact of running the discharge water through D-Gulch would be the contribution of total <br />dissolved solids and other constituents to the alluvial groundwater there. The analyses of <br />D-Gulch alluvial water, however, show that the quality is not as good as the discharge <br />water. For example, the measured TDS from D-Gulch groundwater is nearly double that <br />measured for the discharge water. <br />DIVISION OF <br />MINERALS <br />GEOLOGY <br />RECLAMATION <br />MINING•SAFETY <br />Bill Owens <br />Governor <br />10 June 2003 Greg E. Walther <br />Executive Director <br />Ronald W. Cattany <br />Division Director <br />For these reasons, it does not appear that discharging mine inflow water with flocculant <br />will create any negative impacts to either surface water or groundwater. <br />