REP26488

• Permit No: M1977215
• IBM Index Class Name: Report
• Doc Date: 10/11/2005
• Doc Name: Windy Gulch Water Quality Monitoring Report
• From: Homestake Mining Company
• To: DMG
• Media Type: D
• Archive: No

Mr. G. Becenti,
October 7, 2005
Table 2 2004 Windy Gulch water quality
Upper Weir Lower Weir
Parameter 326/04 4/20/04 5/16/04 32N04 4@0/04 5/t6/04

luminum total (mg/q 2.74 3.43 2.43 <0.03 1.02 1.01
enic dissolved (mg/q 0.0023 0.0018 0.0029 0.0087 O.O146 0.0149
enic total (mg/p 0.005 0.0025 0.0029 0.008 0.0147 0.0175
admium dissolved (mg/q <0.005 <0.005 <0.005 0.035 <0.005 O.OI1
admium total (mg/p <0.005 <0.005 <0.005 0,033 0.008 0.007
opper dissolved (mg/p <0.01 x0.01 <0.01 <O.OI <0.05 <0.01
opper total (mgfl) <0.01 <0.01 <O.OI <0.01 0.01 0.01
Uon dissolved (mg/p 0.22 O.19 0.1 B <0.01 0.23 0.1
Uon total (mg/1) 2.14 1.77 1.27 <0.01 0.48 0.54
anganese dissolved (mg/I) 0.061 0.009 0.019 0.028 0.008 0.089
anganese total (mg/p 0.161 0.038 0.024 0.028 0.012 0.087
ercury dissolved (mg/p <0.001 <0.0002 <0.0002 <O.OOI <0.0002 <0.0002
ercury total (mg/l) <0.0002 <0,0002 <0.0002 <0.0002 <0.0002 <0.0002
inc dissolved (mg/1) <0.01 <0.01 <0.01 8.42 1.68 1,46
inc total (mg/p 0.01 <0.01 <0.01 8.22 L75 1,46
H (units) 7.3 7.3 7.4 7.1 7 7.1
onductivity (mcnhos/cm) 72 44 50 1020 163 162
S (m~/1) l00 100 110 890 170 140
SS (mg/p 8 <5 c5 GS <5 <5
ulfa[e (mg/q 20 l0 20 450 80 60
3
The April 20, 2005 sampling event is on the rising limb of the runoff hydrograph and indicates that
continued flushing of some sediments from the Windy Gulch streambed is occurring, resulting in
higher concentrations than in the subsequent samples. The concentrations during this flushing period
are significantly less than the flushing that occurred during the 2004 spring runoff period. As
discussed in our August 2004 update, this may continue for several years as accumulated materials in
Windy Gulch are gradually removed during the high flow period in Spring.
The April 20 & May 16, 2004 and May 10 & May 25, 2005 sample sets at the lower weir meet all
agricultural standard• goals established for Windy Gulch. Data to date shows an improvement in
conditions with the 2005 sample set generally representing an improvement over the 2004 sample set.
Cadmium was 0.008 and 0.007 mg/l in April and May of 2004 and is now near the detection limit
(<0.005 mg/1) for 2005. Zinc was 1.75 and 1.46 mg/1 in April and May of 2004 and varied from 1.00
to 0.96 mg/1 in May 2005. Sulfate was 80 and 60 mg/1 in April and May of 2004 and subsequently
was only 40 mg/l for both sample sets in May of 2005. TDS has also continued to decrease with
levels of 170 and 140 mg/1 observed during April and May 2004 compared with 100 and 130 mg/1
during the two samples taken in May 2005.