2007-11-07_HYDROLOGY - M1977300

• Permit No: M1977300
• IBM Index Class Name: HYDROLOGY
• Doc Date: 11/7/2007
• Doc Name: Hydrologic evaluation of mine closure & reclamation
• From: Whetstone Associates
• To: Cotter Corpoartion
• Media Type: D
• Archive: No

Schwartzwalder Mine -Hydrologic Evaluation of Mine Closure and Reclamation 52
6.5 Ralston Creek Water Quality
Water quality in Ralston Creek is affected by runoff from the drainage basin, groundwater inflow,
upgradient abandoned mines, fill material in the valley at the Schwartzwalder Mine site, and, prior to June
2002, discharge from the mine's water treatment plant. The backgroundwater quality and the magnitude of
these loading sources was evaluated during the 1998-1999 baseline hydrology study, in previous studies,
and more recently with the latest water quality sampling results for the creek.
Water in Ralston Creek upstream of the Schwartzwalder Mine is acalcium-bicarbonate type water, with
low levels of TDS (averaging 140 mg/L). Most metals are below detection at upstream monitoring stations
SW-UP, SW-UC, SW-AWD, and SW-A001 (Table 24). Uranium at upstream stations SW-AWD and SW-
A001 have never exceeded the water supply intake standard of 40 pCi/L or 0.059 mg/L (Figure 34) or the
instream aquatic toxicity standards. Although water quality in Ralston Creek changes with distance
downstream of Stations SW-AWD and SW-A001, as the creek flows across the mineralized zone and past
the property, the applicable standards for uranium and trace metals have seldom been exceeded, as shown
in the following table. Dissolved uranium has not exceeded the chronic or acute hardness-based aquatic
toxicity standards in any of 98 samples analyzed. Total mercury exceeded chronic aquatic standards in one
of 51 samples, dissolved iron in one of 60 samples, and total iron in one of 45 samples. Total aluminum
exceeded the chronic aquatic toxicity standard in 9 of 52 samples, while the acute standard was exceeded
only once.

Parameter
Units
Summary Statistics Aquatic Standazds (based on average
hardness at SW-BPL) Number of Exceedences

i
f C
#
# of Sam les # of ND % ND Acute Chronic # of Acute c
O tun
o
16 0 0% 6.5 - 9.0 6.5
~ .0 0
pH
Nitrate Nitrogen s.u.
mg/L
10
3
30%
10 1
5 77
0 0
0
Ammonia, total mg/L 10 3 30% 22.8
250
250
0
0
Sulfate
Chloride m L
mg/L 71
70 0
0 0%
0% 250 250 0
] 0
9*
Aluminum,total mg/L 52 41 0
79/0 0.75 0.087 0
Arsenic, total mg/L 54 54 100% 0.05 O 75 0 0
Boron, total m 3 3
6 100%
100% 0.75
0026
0
0.00061
0 0
Cadmium, dissolved mg/L 6
6
6
100% .
0.016
0.011
0 0
Chromium, dissolved mg/L 1 100% 005
0 0.005 0 0
Cyanide, total mg/L 1
75 63 84% .
0.0213 0.0136 0 0
Co er, dissolved m 0 3 1
Iron, dissolved mg/L 60 40 67% --- 1 ___ 1
Iron, total
l
d
i mg/L
/L
m 45
8 11
8 24%
100%
° ___
0.1095 0.00427 0 0
ve
sso
Lead, d g 54 54 100% 0.1095 0.00427 0 0
Lead, total
dissolved
Manganese m
mg/L 72 62 86% 3.513 1.941 0
0 0
0
,
Manganese, total mg/L 51 36 71% 3.513 1.941
0 1
Mercury, total mg/L 51
8 50
8 98%
100% ---
0.7079 0.0786 0 0
Nickel, dissolved
dissolved
Selenium m L
mg/L 8 8 100% 1.84E-OS 0.0000046 0 0
0
,
dissolved
Silver mg/L 9 9 100% 0.0047 0.00074 0 0
,
Thallium, dissolved mg/L 77 77 100%
80% ---
2174
0 0.015
0.1885 0 0
Zinc, dissolved m 10 8 . 571
2 0 0
dissolved
Uranium mg/L 98 0 0% 4.116 . 0
,
Uranium, suspended mg/L 64 34 53% 4.116 2.571
571
2 0
0 0
Uranium, total mg/L 2 0 0% 4.116 .
5 0 0
Radium-226, dissolved pCi/L 65 14 22% 5 5 0 0
Radium-226, sus nded Ci/L 61 41 67% 5
* Aluminum standard based on total recoverable concentrations
4109B.071116 Whetstone Associates •