HYDRO26540

• Permit No: C1980007
• IBM Index Class Name: Hydrology
• Doc Date: 4/25/2003
• Doc Name: NPDES Biomonitoring ‎(CO-0038776)‎
• From: Mountain Coal Company
• To: WQCD
• Permit Index Doc Type: NPDES
• Media Type: D
• Archive: No

MOUNTAIN COAL
~- COMPANY~.~.~.
A Suhsidiary afArch Wes[em Resources, LLC
RECEIVE®
APR 2 5 2003
West Ells Mine
P O Box 591
5174 Highway 133
Somerset, CO 81434
[phone]
Fax [phone]
Apri122, 2003
Ms. Cazla Lenkey
Division of Minerals and Geology
Colorado Department of Public Health and the Environment
Water Quality Control Division, Enforcement and Compliance Section
4300 Cherry Creek Drive South
Denver, CO 80222-1530
Re: Mountain Coal Company, LLC, (MCC), West Elk Mine, CDPS Permit No. CO-0038776,
Notification, Status Report, and Evaluation of Biomonitoring for Outfa11017.
Deaz Ms. Lenkey:
Referencing my recent telephone conversation with you of April 8, 2003, MCC has passed the second
quarterly biomonitoring Whole Effluent Toxicity (WET) testing as required and defined by MCC's
Permit No. CO-0038776. MCC also passed WET testing for the first quarter 2003.
As you may recall from our previous telephone conversations and meeting of Mazch 12, 2003, MCC
failed the October, 4th Quarter 2002 WET test for Daphnia magna (the fathead minnow Pimephales
promelas test passed). MCC then conducted accelerated toxicity tests. Those tests also resulted in failure
for the Daphnia and established a "pattern of toxicity".
MCC then enlisted the help of Wright Water Engineers (WWE) to determine the factor(s) causing the
pattern of toxicity to Daphnia magna at Outfa11017. MCC conducted sampling and analyses for metals,
inorganics, volatile organics, and semi-volatile organics, and the results did not indicate toxicity from any
of the pazameters measured. MCC sent this information to the WQCD in January 2003 as part of the
NPDES/CDPS reporting requirements for the 4~' Quarter 2002.
MCC completed a Preliminary Toxicity Identification (PTI) in November 2002, the results of which were
inconclusive. At this juncture, MCC elected to complete side-by-side Toxicity Identification Evaluations
(TIE} with two different laboratories (CT&E and SeaCrest}. MCC completed these tests because the
accelerated testing and PTI had shown a pattern of toxicity. An additional series of tests with alkalinity
were also conducted since data indicated that alkalinity could be the cause of the test failures. As
described in more detail in the letter from W WE to myself dated Mazch 7, 2003, the results of these tests
indicated that elevated total dissolved solids (TDS) and alkalinity, in particular, was the cause of the
toxicity to the Daphnia magna.