2015-01-27_REPORT - C1981025 - Laserfiche WebLink

Home Browse Search

MINREC, INC. AHR PAGE 4 Discharge Monitoring Reports (DMRs) DMRs are submitted quarterly to the Colorado Department of Public Health and Environment with copies to the Division of Reclamation Mining and Safety and are included herein by reference. ANTICIPATED IMPACT Discharge from outfall 001 may slightly impact the quality of water in North Thompson Creek. The mine water discharge has a low iron content and an acceptable pH, however its conductivity is moderately high. The following table presents the impact outfall 001 would have on the conductivity of North Thompson Creek at varying discharge rates. Anticipated Impact - North Thompson Creek NTC - 2012 Outfall 001 Flow gpm Conductivity Outfall 001 NTC Flow cfs Conductivity NTC Conductivity Combined % Increase (Decrease) 10 2202 5 494 502 1.5 15 2202 5 494 505 2.3 20 2202 5 494 509 3.1 25 2202 5 494 513 3.8 25 2202 5 494 513 3.8 30 2202 5 494 517 4.6 35 2202 5 494 520 5.3 40 2202 5 1 494 1 524 6.1 Conductivity Outfall 001 - umhos /cm - Calculated for 2011 An average flow of 25.0 gpm with a conductivity of 2202 discharging into a receiving stream with a 5 cfs flow and a conductivity of 494 (pre - permit mean) would increase the conductivity of the receiving stream to about 513 umhos /cm, an increase of about 3.8% which is considered insignificant. The Colorado Department of Public Health and Environment has regulations regarding saline discharges into the Colorado River. A discharge of less than one ton of salt per day is considered a no -salt discharge by the Department of Health. Please refer to Regulation 61 for a discussion of the one ton of salt per day issue. A flow rate of 100 gpm from with a TDS concentration of 1500 mg /I would yield a salt concentration of 0.9 tons per day, slightly below the one ton per day of salt discharge limitation. A flow rate of 25 gpm with a TDS of 1500 mg /I would introduce 0.23 tons of salt per day into North Thompson Creek.