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iii iiiiiiiiiiiiiiii <br />~~ YVCC 999 <br />Yampa Valley Coal Corporation ~ 29588 Routt County Road #27, Oak Creek, CO 80a67 • (303) 879-3800 <br />August 6, 1987 <br />Mr. Dan hiathews <br />Colorado Mined Land Reclamation Division <br />1313 Sherman Street, Room 423 <br />Denver, CO 80203-2273 <br />Dear Mr. Mathews: <br />AU G 101987 <br />tJiINED LAND <br />RECLAMATION DIVISION <br />Re: Annual Hydrologic Monitoring Report for Mine 3, Permit C-84-062 <br />As requested by Brent Anderson, Colorado Yampa Coal Company has <br />addressed the two concerns outlined in his letter of July 13, 1987. <br />MLRD CONCERN: <br />1) The detection limist for cadmium (ground water) and mercury (surface <br />water) are greater than the respective material damage criteria used by <br />the Division. CYCC is requested to improve its detection limit <br />capabilities for cadmium and mercury to concentrations equal to or less <br />than the appropriate material damage concentration. <br />RESPONSE: <br />Colorado Yampa Coal Company has been working with HCZ Laboratories, Inc. to <br />ensure the cadmium detection is at least equal to the material damage <br />criteria limit. Currently, the lab is utilizing methodology which reports a <br />detection limit of 0.0001 mg/1. <br />Concerning mercury, the lab is using the best available testing methodology <br />which attains a detection limit of 0.0002 mg/1. Until an improved mehtod is <br />developed, CYCC will be unable to improve the detection limit capabilities. <br />MLRD CONCERN: <br />2) CYCC is requested to generate a <br />represents the flow at Site <br />under-estimates the discharge at <br />be capable of determining peak <br />submit the new discharge ratin <br />curves to the Division. <br />discharge rating curve that accurately <br />29. The current rating curve <br />g curve and previous <br />this point. The new <br />spring flows. CYCC <br />rating curve must <br />is requested to <br />discharge rating <br />