APPCOR11463 - Laserfiche WebLink

Home Browse Search

• Division of Wildlife Issues and Responses for June 5, 1997 Letter (continued) Water quality issues A number of issues were raised by the DOW regarding overall water quality and impacts to the surface water system and resident aquatic life. Flathead chub The DOW has expressed concerns that mining activity could impact the flathead chub population identified in portions of Lorencito Canyon and the Purgatoire River. The applicant responded that the control and treatment of discharges form the mining azea, water quality monitoring and NPDES discharge monitoring (including Whole Effluent Toxicity testing) should be adequate to protect resident chub populations. Discussions with the DOW indicate that they believe actual, periodic population sampling is necessary to determine the on-going status of chub populations. The DOW has verbally committed to discuss this issue and respond with a recommendation toward the end of June. This issue remains inadequate at this time. • Response It is believed that surveys to monitor the chub may result in mortalities [hat would impact populations within Lorencito Creek and the Purgatoire River. Therefore, surveys for this species are not proposed at this time. It is LCC contention that all known populations of the chub within Lorencito Creek occur well upstream of any proposed mining disturbances, and would not be impacted by mining. Also, water quality monitoring and NPDES discharge monitoring should be sufficient to protect any populations occurring in the lower reaches of Lorencito Creek. Dilution of any mine discharge within the Purgatoire River would be sufficient to protect populations within the river. LCC would grant the DOW access to the mine property should they want to investigate the chub population. Brown Trout The DOW has concerns based on past experience that iron concentrations of 2.4 mg/1 indicate other metals (specifically cadmium, copper, and zinc) are present at toxic levels to aquatic life. While no specifics were provided, the Division assumes that acid conditions likely prevail under this scenario, causing the metals problem. The applicant has presented baseline data indicating the concentrations of cadmium, copper, and zinc. The Water Quality Control Commission determines effluent limitations as part of the Colorado Discharge Permit System, based on steam classification and standards. • Furthermore, the Division's experience indicates iron and manganese concentrations are relatively high in coal basins, while pH levels are neutral to alkaline and other metal concentrations are below the detection limit. Not withstanding, the Division believes that 5