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to areas where water collection sumps return captured water to the water <br />treatment plant for treatment. <br />Corrective Actions: The water level was lowered in the south concrete Barren Pond via <br />transfer to an available storage tank outside of the building and through <br />active evaporation. Leakage is believed to have ceased by about <br />October 15, 2010 though about 8 inches of water still remained in the <br />pond at that time. Cotter currently plans to refurbish the concrete <br />Barrens Ponds to prevent future leaks as soon as existing water is <br />removed and treated through the water treatment plant. Currently, the <br />south concrete Barren Pond is essentially dry and is not being used for <br />water storage. <br />Quantity: Estimated 90,000 gallons (to the alluvium). <br />Material: Mixed groundwater from alluvium and formerly leaking exploration <br />core hole (estimated to have been in the range of 10-15 mg/L uranium). <br />Packer Failure in 2-inch Exploration Core Hole Casing Pipe at Old Emergency Storage <br />Pond <br />Date/Time: November 7-10, 2010 <br />Description: On November 4, 2010, a specialty underwater repair contractor was <br />employed to send a qualified diver into the old emergency storage pond <br />and install a more durable, pressure-rated coupling to the core hole <br />casing and attach the coupling to 40 feet of rigid PVC pipe so that a <br />packer could safely be installed into the core hole at depth. An <br />inflatable packer was installed about 50 feet inside the exploration core <br />hole on November 5, 2010. The objective was to provide a seal not <br />subject to freezing/thawing cycles during the coming winter, and one <br />that could be subsequently removed for proper grouting and <br />abandonment of the core hole the following summer. <br />For unknown reason(s), the packer became depressurized on November <br />7, 2010. This circumstance was not discovered until November 10, <br />2010. The resulting leakage flowed into the excavated portion of the <br />old emergency storage pond at an estimated rate of 13 gpm. The release <br />was contained within the pond, ultimately infiltrating into the alluvium <br />and did not flow overland into Ralston Creek. Based on the earlier <br />release from this same exploratory core hole, within several weeks the <br />released slug of elevated groundwater is expected to begin arriving at <br />groundwater capture/extraction locations (Sumps 1 and 4, MW-9, and <br />newly operational Sumps 5 and 8) where captured water will be pumped <br />back to the water treatment plant for treatment. <br />4