INSPEC03669

• Permit No: C1980007
• IBM Index Class Name: Inspection
• Doc Date: 12/12/2005
• Doc Name: Spill Monitoring Report
• From: Hydro-Geo Inc
• To: Mountain Coal Company, LLC
• Inspection Date: 11/15/2005
• Media Type: D
• Archive: No

Technical Memo - SII,V-EX Spill Monitorine Report Paee 4
mgQ, compared to the detection limit of 0.10 mg/1) are present in Upper Minnesota Creek. The
presence of ammonia is likely due to recent livestock activity in the area. Sodium concentrations were
also elevated in Lower Dry Fork, ranging from 61.8 at MC-1 to 72.4 mg/l at MC-2, compared to
Minnesota Creek which had values ranging from 23.2 at MC-5 to 34.6 at MC-14. Elevated sodium
concentrations are typical in the waters of Lower Dry Fork and the average baseline concentration was
69 mg/l as measured at the Lower Dry Fork Flume monitoring station (FIydroGeo, 2005). A
summary of the laboratory data is presented in Table 2 and the complete lab report is presented in
Appendix B.
Table 2
Summary of Laboratory Data
~~I !e

MG1A, 1B ~'

1526 `-`ple°

17/2/2005 -" ape-

9:20

8.17 i

0.11 i

fi1.8 I it
9
<0.010

ry or ume

MC-2A, 2B
1527
17/2/2005
9:40
8.10
0.14
72.4
<0.010 ry or a innesota
Creek.

MG3A, 3B
1528
12/2/2005
9:45
8.34
0.11
26.4
<p.010 innesota ree ve
Confluence of Dry Fork

MC-4A, 4B
1529
12/2/2005
10:00
7.68
0.12
24
<0.010 innesoa ree eow
Confluence of Dry Fark
MC-SA, 50 1530 12/2/2005 10:35 8.07 0.11 23.2 <0.010 innesota ree
MC-6A, 60 1531 12/2/2005 11:15 7.89 <0.10 29.fi <0.010 innesota ree
MC-7A, 7B 1532 12/2/2005 71:40 7.87 <0.10 27.4 <0.010 innesota ree
MC-eA, OB 1533 17/2/2005 11:50 7.83 <0.10 25.6 <0.010 innesota ree
MC-9A, 98 1534 12/2/2005 12:20 7.9fi <0.10 28 <0.010 innesota rae
MG10A, 10B 1535 12/2/2005 12:40 8.03 <0.10 26.6 <0.010 innesota ree
MC-11 A, 11B 1536 12/2/2005 1315 7.98 <0.10 26.2 <0.010 innesoa ree
MC-12A, 12B 1537 12/2/2005 13:35 8.12 <0.10 31.4 <0.010 innesota ree
MC-13A, 13B 1538 12/2/2005 14:00 8.06 <0.10 33.4 <0.010 innesota rae

MG14A, 140
1539
12/2/2005
14:25
7.99
<0.10
34.6
<0.010 innesota ree at ppe
Valley Park
Sily-Ex in Bucket 1540 12/2/2005 8.13 181,864.00 9,010.0 68.2% by volume
Adapted from Enviro-Chem Analytical, Inc. (2005).
2.2 Summary of the Toxicity Analysis
SILV-EX is rated as a slight hazard and may cause skin or eye irritation, but is non-toxic according to
the Ansul Material Safety Data Sheet (Ansul, 2001). Mixing calculations performed by Wright Water
Engineers (W WE 2005) indicate that the concentrations of SILV-EX (Butyl Carbitol) released into
Dry Fork and Minnesota Creek were 13.5 parts per million (ppm) and 0.8 ppm, respectively. At these
estimated concentrations of Butyl Carbitol, an unrealistic amount of Minnesota Creek water would
have to be ingested in a small amount of time to cause adverse health effects in humans or other
mammals. For example, to reach the LDSO level for dogs would require a 146 gallon release into Dry
Fork (W WE, 2005). In addition, the estimated concentrations of Butyl Carbitol were also below the
LCsp (96-hour, >500 mg/I) limit for fathead minnows. The validity of this estimate is further
supported by the observation of no fish kill as reported in the Incident Report (MCC, 2005).