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Ms Carla Lensky <br />NOTIFICATION FOR MAY 3,1999 DISCHARGE <br />May 10,1999 <br />At 7:00 a. m. May 4,1999 two pieces of equipment were allocated for the repair of the <br />treatment cell. A maintenance plan was developed for the repair of the failure and <br />mobilization of the equipment began at 7:45 a.m. after the equipment operators were briefed of <br />the situation. Approximately 240 cubic yards of native silty clay material was applied to the <br />area to gain access, and spread and compact over the failure area with a Caterpillar D6 <br />bulldozer. The failure and resulting tension cracks emanating from the failure were repaired. <br />By 11:00 a.m. May 4,1999 the flow of water from the seeps had measurably slowed. A <br />survey of the treatment cell was performed to determine the volume of water, which <br />discharged from the treatment cell, and water level markers were placed on the embankment of <br />the cell. A sample of water from the treatment cell was obtained.' The equipment operator <br />continued to maintain and monitor the failure area until 1:00 p.m. May 4,1999. Subsequent <br />inspections of the treatment cell were made and the water level remained unchanged suggesting <br />the breach was repaired <br />At approximately 6:30 a.m. May 4,1999, the Blasting Crew had begun loading with 28 blast <br />holes with explosives located in the bottom of the West Pit. Adjacent to those 28 blast holes <br />was a temporary holding pond containing excess snowmel[ and rain, which had entered the <br />West Pit. The holding pond was full and would orily be in place until the scheduled 4 p.m. <br />blast on May 4,1999. A contractor was on-site and was filling the blast holes with a mixture <br />of emulsion and ammonium nitrate used as the explosive. <br />Colowyo was unable to ittimediately redirect the flow of water from the treatment cell into the <br />West Pit due to the serious safety concerns associated with the explosive loaded holes in the <br />bottom of the West Pit. Loaded blast holes that have been inundated with water raise serious <br />safety concerns because of the possibility of the explosives not detonating and remaining in the <br />material being blasted, presenting a potential danger to mine personnel. Consequently, waters <br />from the treatment cell that were draining from the spoil material were directed into the West <br />Pit after the blasting was completed at 4:00 p.m., and the safety hazards eliminated. <br />Observations of the treatment cell and spoil material were conducted on May 5. Seepage from <br />the spoil material continued to diminish throughout the day. No noticeable change of water <br />elevation within the treatment cell was observed. When access to the area of the East Taylor <br />Pond improved water quality samples were obtained from the Outfall of East Taylor Pond, <br />Outfall OlOA, May 5, 1999 at 7:0(}~m~-- <br />2,3. Analytical results from the sampling events are included at the end of this letter. <br />3 <br />