2011-05-03_HYDROLOGY - C1982056

• Permit No: C1982056
• IBM Index Class Name: HYDROLOGY
• Doc Date: 5/3/2011
• Doc Name: 1st Quarter 2011 DMRS ‎(CO-0036684)‎
• From: Twentymile Coal Company
• To: WQCD
• Permit Index Doc Type: DMR’s
• Email Name: JDM
• Media Type: D
• Archive: No

Aqua-Tox, Inc.
4880 Robb Street, Suite 8

' Wheat Ridge, CO 80033
[phone] aqua-tox.com
ACUTE TOXICITY REPORT
Ceriodaphnia dubia
CLIENT NAME: 20-Mile Coal Company SAMPLE I.D.: 012811-2
50 % MORTALITY TEST: Pass TEST RESULT LC50: >100%
% SURVIVAL IN 100% DILUTION: 80%
SAMPLE DATE: 01-27-11 TIME: 15:30P CLIENT ID: Site 62
ORGANISM: Ceriodaphnia dubia AGE: < 24 hours old
TEST START: 01-28-11 12:20P TEST FINISH: 01-30-11 12:20P
TYPE OF TEST: LC50 48 hours static renewal moderately hard fresh synthetic dilution water.

MODERATELY HARD FRESH SYNTHETIC DILUTION WATER CONSTITUENT
AMMONIA: ND D.O.: 7.07 mg/L
HARDNESS: 98.60 mg/L CHLORINE: ND
ALKALINITY: 59.78 mg/L TEMPERATURE: 20.3 deg C
pH: 7.91
SURVIVAL DATA DILUTIONS (%)
DATE (HOURS) CONTROL 6.25 12.5 25 50 75 100
1/2812011 INITIAL 20 20 20 20 20 20 20
1/29/2011 24 20 20 20 20 20 2- 19
1/3012011 48 20 20 20 20 20 20 16
MORTALITY: 0 0 0 0 0 0 4
% SURVIVAL: 100% 100% 100% 100% 100% 100% 80%
DAILY CHEMISTRY - (MIN/MAX) DILUTIONS (%)
0 6.25 12.5 25 50 75 100
CONDUCTIVITY (micros) 308/319 827/839 1386/1409 1844/1863 2320/2350 3330/3370 4310/4350
D.O. (mg/L) 7.1/7.4 7.1/7.4 7.2/7.4 7.2/7.5 7.3/7.6 7.3/7.7 7.4/7.8
pH 7.9/8.3 7.9/8.3 7.818.4 7.8/8.5 7.8/8.6 7.7/8.7 7.718.8
TEMPERATURE (deg C) 19.9/20.4 19.9120.4 19.9/20.4 19.9/20.4 19.9/20.4 19.9/20.4 19.9/20.4
GENERAL CHEMISTRY - SAMPLE
AMMONIA: 0.06 mg/L D.O.: 7.75 mg/L
HARDNESS: 2,539.10 mg/L CHLORINE: ND
ALKALINITY: 616.92 mg /L TEMPERATURE: 20.3 deg C
pH: 7.68 D.O AFTER AERATION: NA
'wtf ANOEC? titrCALCULATION;METHOD' _ ..,:;,METHOD. REFERENCES
75% SPEARMAN-KARBER EPA -821-R-02-012 October 2002 pg.78
ADDITIONAL COMMENTS:
Analysis
Conducted by:m Reviewed by
Date: Z ?/ Date. ,,