2010-04-20_REVISION - M1977300 ‎(8)‎

• Permit No: M1977300
• IBM Index Class Name: REVISION
• Doc Date: 4/20/2010
• Doc Name: 11
• From: Whetstone
• To: DRMS
• Type & Sequence: TR11
• Media Type: D
• Archive: No

Environmental Protection Plan, Schwartzwalder Mine 11-1
• 11. SURFACE WATER QUALITY DATA
Surface water quality in Ralston Creek has been monitored by Cotter Corporation since the water treatment
plant began discharging in 1983. Water quality in Ralston Creek is affected by natural runoff and
groundwater inflow, upgradient abandoned mines, and by fill material in the valley at the Schwartzwalder
mine. Prior to 2002, water quality in Ralston Creek was also influenced by discharge from the
Schwartzwalder water treatment plant.
This section of the EPP summarizes the water quality standards for Ralston Creek, the locations of
historical monitoring stations, the available surface water quality data, and trends in uranium concentrations
in the creek.
(a) Surface Water Quality Standards
•
(i) Discharge Permit Limits
The discharge permit (#CO-0001-244) issued by the State of Colorado listed effluent limits for water
discharged from the water treatment plant operated at the site. Those limits included specific metals,
uranium (0.776 mg/L) and radium 226/228 (3 pCi/L), as shown in the following table.
Table 11-1. Discharge Permit Effluent Limitations

Effluent Parameter Effluent Limitations
Maximum Concentrations
30-Da Average Daily Maximum
Flow, MGD 0.288 Report
COD, mg/1 100 200
Total Suspended Solids TSS , mg/1 20 30
Potentially Dissolved Uranium, ug/1 776 1243
Radium 226 +228 (total), Ci/l 3 10
H, sm. minimum-maximum NA 6.5-9 d/
Oil and Grease, mg/1 NA 10 d/
Total Recoverable Antimony, u 1 6 Report
Boron, m l 0.75 Report
Total Recoverable Chromium, u 1 11 16
Potentially Dissolved Copper, u l 5.4 7.7
Potentially Dissolved Silver, u 1 0.027 0.73
Potentially Dissolved Zinc, u 1 71 71
Weak Acid Dissociable Cyanide, ug/1 NA 5
Fluoride, mg/1 NA 2
Totak Recoverable Thallium, u 1 0.5 NA
Whole Effluent Toxicity, Chronic Lethality
Cerioda hnia species NA IWC = 100%
Fathead Minnow (Pimephales promelas) NA I'WC = 100%
The permit limits listed above are Water Quality Based Effluent Limits (VVQBELs) which are calculated
based on EPA effluent limits for mine drainage. The following table lists the EPA effluent limitations for
mine drainage from open-pit and underground uranium mines as listed in 40 CFR 440.32 and used
in the calculation of the WQBELs shown in Table 11-1.
4109C.100419 Whetstone Associates