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~' <br />REQIIEST FOR RELIEF <br />TOTAL SIISPENDED SOLIDS AND TOTAL IRON <br />FACILITY NUMBER COG-850017 <br />Colowyo Coal Company L.P, formally requests relief from <br />permit limitations for total suspended solids (TSS) and total iron <br />due to a discharge caused by a rainfall precipitation event, within <br />a 24-hour period, greater than the 10-year, 24-hour precipitation <br />event. This discharge occurred at Discharge Point 007 on the <br />afternoon of July 14, 1995 in response to a very high intensity, <br />short duration, thunderstorm rainfall event that was localized over <br />a relatively small part of the mine area that drains to the <br />sediment pond associated with Discharge Point 007. The period of <br />discharge lasted for only 3 or 4 hours, and occurred well within 48 <br />hours after measurable precipitation had stopped as verified by <br />numerous Colowyo personnel. <br />Since the volume of the discharge exceeded the required <br />capacity of Discharge Point 007 sediment pond, Colowyo had no <br />control over the discharge which passed through both the principal <br />and emergency spillways. All discharge points are sediment ponds <br />which are regularly inspected and maintained in top working <br />condition to help mitigate any adverse effect from a noncompliance <br />discharge caused by a naturally occurring and unpreventable <br />thunderstorm event. <br />