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Corrective Actions: November 10, 2010 - Upon discovery of the depressurized packer, the <br />packer was immediately re-pressurized and the flow was stopped. Site <br />personnel were instructed to closely monitor packer system pressure <br />readings until further mitigation measures could be assessed and <br />implemented. <br />November 11, 2010 - The packer was removed from the core hole and a <br />mechanical expansion plug was installed at the end of the PVC pipe. <br />Site personnel were instructed to pull the end of the PVC pipe out of the <br />pond every morning in order to physically inspect plug integrity. <br />November 12, 2010 - A 90-degree elbow was glued to the end of the <br />PVC pipe and a flexible (more freeze-resistant) hose was attached to the <br />elbow. The flexible hose was then raised up the pond embankment to <br />an elevation sufficient to stop flow. A plug was placed at the end of the <br />flexible hose as a secondary containment measure. <br />Pendin - Cotter will soon submit plans to DRMS for permanent <br />sealing of the exploratory core hole by a professional grouting <br />contractor. The goal is to permanently seal the core hole before the <br />pond freezes due to the onset of winter weather. <br />Quantity: Estimated 56,000 gallons (to the old emergency pond area). <br />Material: Groundwater from an unknown source (approximately 25 mg/L <br />uranium, 1.5 pCi/L Ra-226). Although believed to be in hydraulic <br />connection to the flooded mine workings, the chemistry of this <br />groundwater is different than that of water in the flooded mine workings <br />(approximately 34 mg/L uranium, 245 pCi/L Ra-226). <br />Retrospective Assessment and Preventative Measures <br />Remedial Investigations with Potential for Unplanned Releases <br />On July 20, 2010 water was discovered to be leaking at 1.59 gpm from a 2-inch HDPE pipe <br />protruding from the alluvial fill adjacent to the former emergency overflow pond. The leak <br />was stopped by raising the end of the pipe. The uranium concentration of water from the <br />pipe was elevated (about 25 mg/L), but was not the same as that of the mine pool (about 34 <br />mg/L). Radium-226 activity level in the pipe water (1.5 pCi/L) was several orders of <br />magnitude lower than that of the mine pool (245 pCi/L). <br />Regardless of differences in water chemistry, Cotter attempted to determine the source of the <br />water from the pipe in an effort to understand and permanently eliminate any potential for <br />releases from this source. A company was hired to insert a special camera into the pipe to <br />find out where the pipe water was coming from, but an obstruction encountered at about 40 <br />feet prevented further penetration. It was subsequently decided to excavate the pipe in an <br />attempt to help determine its origin. During this effort, a pipe joint separated underground <br />and the subsurface end of the pipe could not be located for eight days, partly because it was