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• 2.05.6 <br />As explained in Section 2.04-7, a clarification agent is added to the mine <br />water to assure compliance with discharge permit requirements. The <br />clarification agent is aluminum based, Aluminum Chloride Hydroxide 10 - <br />30% (w/w) and Calcium Chloride 5 -10% (w/w) for a maximum total chemical <br />load of 40% (w/w). The Colorado Department of Public Health and <br />Environment, Water Quality Control Commission, Regulation No. 35, <br />Classification and Numeric Standards for Gunnison and Lower Delores River <br />Basin, effective January 30, 1999 was reviewed to determine if there were <br />standards for the chemicals used in the clarification agent. The North Fork <br />of the Gunnison River does not have a numeric standard for Aluminum or <br />Calcium. These is a numeric standard for Chloride (CI) of 250 mg/I. <br />The clarification agent is added to the mine water at the rate of 100 parts per <br />million (mg/I). If the entire dosage was Chloride, the mine water would only <br />contain 40 mg/I liter of Chloride (40% X 100 mg/I dosage) which is well below <br />the numeric standard for Chloride. <br />• The clarified mine water is discharged from Pond C into the Deer Trail Ditch <br />and the Fire Mountain Canal. The dilution factor for the mine water flowing <br />into the Fire Mountain is approximately 400 to 1 (170 cfs Fire Mountain <br />Canal to 0.39 cfs mine discharge). Assuming all of the chemicals in the <br />clarification agent were present in the mine water at 40 mg/I as explained <br />above, the Fire Mountain Canal would see an increase of 0.1 mg/I of each <br />chemical considering the dilution factor. <br />The average Aluminum concentration in the lower Fire Mountain Canal is 1.1 <br />my/I with values ranging from 0.1 to 2.1 mg/I (2002 AHR). A 0.1 mg/I <br />increase in Aluminum is not considered significant. The average Calcium <br />concentration in the lower Fire Mountain Canal is 15.9 mg/I with values <br />ranging from 10.0 to 25.2 mg/I. A 0.1 mg/I increase in Calcium is not <br />considered significant. The average Chloride concentration in the lower Fire <br />Mountain Canal is 6.0 mg/I with values ranging from 2 to 26 mg/I. A 0.1 mg/I <br />increase in Chloride is not considered significant. <br />~J <br />PR-08 <br />2.05 - 73i - 07/03 <br />/j PPRoVE>7 <br />9/x5/03 <br />