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<br />be <br /> <br />0982 <br />very thin and <br /> <br />. <br /> <br />. <br /> <br />would offer considerable frictional resistance <br /> <br />to large leakage. <br /> <br />The only other path of leakage would have to be through the <br /> <br />evaporite. To investigate this possibility, the physical character <br /> <br />of the evaporite and the possible paths it might offer for water to <br /> <br />escape from the basin have been checked carefully. <br /> <br />Within the Ruedi basin the evaporite exhibits a very forbidding <br /> <br />aspect. The outcrops are twisted and broken with rare areas of re- <br /> <br />cognizable bedding structure. In places it has a deeply eroded, bad <br /> <br />lands appearance and occasional sink holes and sink hole reman ants can <br /> <br />be found. A person looking surficially at the evaporite would be in- <br /> <br />clined to believe that it is very porous and subject to transmission <br /> <br />of large quantities of water. Since this possibility also occurred to <br /> <br />the geologists investigating the site, extra effort was made to explore <br /> <br />and test the evaporite and to understand its physical character. Holes <br /> <br />were drilled into the evaporite in excess of 600 feet. One hole was <br /> <br />drilled into the center of an old sink hole scar to a depth of 310 feet. <br /> <br />A prominent sink hole known as the "glory hole" was tested by turning <br /> <br />a nearby stream into it. Water losses during drilling were recorded <br /> <br />and static water levels were measured at various stages and after com- <br /> <br />pletion of drilling. Data were examined relative to the solubility and <br /> <br />flowage characteristics of the gypsum, anhydrite and halite. The data <br /> <br />on these studies indicate that these salts will flow under rock loads <br /> <br />less than those now lying above the evaporite around the edges of the <br /> <br />reservoir basin. Examination was also made of a prospect tunnel and a <br /> <br />- lO - <br />