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l <br />TRI -STATE GENERATION AND TRANSMISSION ASSOCIATION, INC. <br />HEADQUARTERS: P.O. BOX 33695 DENVER, COLORADO 80233 -0695 303 - 452 -6111 <br />June 17, 2013 <br />Ms. Kelly Morgan <br />Water Quality Control Division <br />Colorado Department of Public Health and Environment RECEIVED <br />4300 Cherry Creek Drive South <br />Denver, Colorado 80246 -1530 JUN 18 2013 <br />RE: Upset Condition Report - f ^« ,-n•,AATION <br />New Horizon Mine, CDPS Permit #CO- 0000213 ,,,, <br />Dear Ms. Morgan: <br />On June 12, 2012 at 3:30 pm, Tri -State Generation and Transmission Association, Inc. <br />(Tri- State) verbally reported to you an upset condition for pH at Outfall 007 for the Western <br />Fuels — Colorado, A Limited Liability Company (Western Fuels) New Horizon Mine in Nucla, <br />Colorado. As noted in earlier communication with the Water Quality Control Division, Tri -State <br />is the parent of Western Fuels. The New Horizon Mine discharges under the Colorado <br />Discharge Permit System (CDPS) Permit # CO- 0000213. Outfall 007 has a pH limit of 6.5 -9. <br />The facility measured pH in the outfall on June 10th at 9.22 and on June 12th at 9.38. Tri -State <br />believes that the pH concentrations for these days qualify as "upset conditions ", based on the <br />permit definition in Part II.A. 3.d. We believe the high pH was caused by irrigation return flows <br />and regional high air temperatures without relief from precipitation. The information provided <br />below further supports the "upset condition" affirmative defense as "unintentional and temporary <br />noncompliance with permit effluent limitations because of factors beyond the reasonable control <br />of the permittee ". <br />Pond 007 mainly receives irrigation return flows from the vegetated and fertilized fields <br />located upstream (reclaimed areas that have been revegetated and are awaiting bond release). <br />The fields contain grasses and alfalfa, used for livestock only. The facility sampled the nearby <br />Colorado Cooperative (CC) Ditch for pH in the same time period and found pH measurements of <br />8.82 on June 12, 2013. The CC Ditch is the source water for the irrigation. A map with the <br />ponds and fields is enclosed, showing the sampling locations for Outfall 007 and the CC Ditch. <br />The air temperatures in Nucla, Colorado have been in the high 90s in the last week. The high <br />90s temperatures are unseasonably warm for early June. In addition, the last measurable <br />precipitation was on 5/28/2013 at 0.08 inches. During the month of May, the total precipitation <br />was measured at 0.5 inches at New Horizon Mine. The southwest corner of Colorado, including <br />the Nucla area, is currently under severe - extreme drought conditions due to low snowpack and <br />little precipitation according to the U.S. Drought Monitor (enclosed June 11, 2013 map of <br />Colorado drought conditions). <br />.04 EQUAL Ct = -d C41 Ukl7Y/ �FFl� /fC`t;iiE <'4 i "4C7Pf EeJI LGY Fi <br />A Touchstone Energy' Cooperative <br />CRAIG STATION ESCALANTE STATION NUCLA STATION <br />P.O. BOX 1307 P.O. BOX 577 P.O. BOX 698 <br />CRAIG, CO 81626 -1307 PREWITT, NM 87045 NUCLA, CO 81424 -0698 <br />970 - 824 -4411 505 - 876 -2271 970 -864 -7316 <br />