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Bulldog Mountain Operation Operating Plan Page 2 Initial Investigation and Containment Efforts Following discovery of the seepage in 1978 a hydrogeologic and geotechnical reconnaissance was performed in order to locate the paths of seepage and define the magnitude of the problem. In late 1978 and 1979 a series of piezometers were installed to measure hydraulic gradient through the dam structure to the upwelling seepage area below the dam toe. Soil samples were taken and the holes were logged. In addition to monitoring the numerous piezometric wells in 1979, the discharge of mill tailings was moved from the inside dam face to new areas in order to establish more uniform lining with tailings slime. In 1980, a series of seven wells, 12-inch diameter were drilled below the dam and a network of submersible pumps were installed for return of the seepage back to the pond. The pumpback system failed because of excessive pump wear and pump failure from sanding resulting in abandonment of the wells early in 1981. In 1981, additional field investigation was made with six borings in the vicinity of the dam to better define the paths of seepage, identify pervious zones, measure additional piezometric pressures, and provide water quality sampling to "trace" seepage. A seventh boring was completed late in 1981 at a distance downstream from the dam to identify pervious formations at depth. Proposed Remedial Measures As a result of the aforementioned investigations, the pathways of seepage beneath the dam have been generally defined indicating flow preddminantly through rock under the center portion of the dam. Detailed information about soil and rock conditions, permeabilities, and the groundwater pressures was evaulated and the following remedial measures have been identified as a program for seepage containment. Grout-off the seepage flow under tailings dam. The current flow, estimated at 200-230 gpm, is located at the deepest fill point near the center of the dam and is caused primarily by the presence of an old stream channel. Furthermore, it is believed the old stream channel, located under the base of the dam, follows a fracture system caused by faulting that has minor displacement. Because the under flow increases more each year as the pond is filled and water level rises, there is concern that piping may eventually occur, resulting in dam failure.