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• 2.05.6 <br />As explained in Section 2.04-7, a clarification agent and flocculent are added <br />to the mine water to assure compliance with discharge permit requirements. <br />Metering pumps are utilized to ensure proper dosage, 100 ppm and 2 ppm <br />for the clarification agent and flocculent respectively. The clarification agent <br />is aluminum based, Aluminum Chloride Hydroxide 10 - 30% (w/w) and <br />Calcium Chloride 5 - 10% (w/w) for a maximum total chemical load of 40% <br />(w/w). The Colorado Department of Public Health and Environment, Water <br />Quality Control Commission, Regulation No. 35, Classification and Numeric <br />Standards for Gunnison and Lower Delores River Basin, effective January <br />30, 1999 was reviewed to determine if there were standards for the <br />chemicals used in the clarification agent. The North Fork of the Gunnison <br />River does not have a numeric standard for Aluminum or Calcium. These is <br />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 />When the flocculent is properly applied into a water stream containing solids, <br />most of the product will be attached to the solids. Therefore, flocculent use <br />should not adversely affect surface or ground water. <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 />mg/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 />TR-026 2.05 - 731 - 08/03 <br />9~PRo vep <br />`T ~i q ~0 3 <br />