2008-10-22_REPORT - C1981008 (3)

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• Narrative and Discussion • PERMIT AND SAMPLE INFORMATION NPDES permit #: Type of sample: Date and time of sample: Date and time of test start: Dilution water: Receiving temperature: • TEST ORGANISMS CO-0000213 Effluent Grab 10/06/08 11:30 10/07/08 11:45 Reconstituted Laboratory Water 2.6°C Pimephales promelas Age: 10 days old • PROCEDURE Acute, 96-hour bioassays as outlined in the most recent protocols specified by the Water Quality Control Division of the Colorado Department of Health (1998). • DISCUSSION According to the Western Fuels New Horizon Mine discharge permit (CO-0000213), an acute WET test is failed whenever the LC50, which represents an estimate of the effluent concentration which is lethal to 50% of the test organisms in the time period prescribed by the test, is found to be less than or equal to 100% effluent. To determine if the facility complies with the "Automatic Compliance Schedule" of the acute WET portion of the Colorado State Permit System Authorization to Discharge, SGS North America Inc. conducted an accelerated one species acute bioassay on the Western Fuels New Horizon Mine, outfall 011 discharge. The test organism utilized was Pimephales promelas. The results for the second sample of the accelerated testing schedule indicate this effluent sample was not acutely toxic to P. promelas survival. • DATE OF REPORT October 13, 2008 Report p red by: Stepha ' Green Hawki s f? fgA C j O??I C.t?1?4 0 Vo Supervise Bio ssa aboratory Date H