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f° <br />• the slide of April 12, 1993 were between 1.0 and the 1.255 <br />indicated for the peak strength condition. <br />The RMG report also included a sensitivity analysis which <br />identified the most important factors with respect to the stability <br />model and that factors impact on stability. The conclusion of the <br />sensitivity analysis was that the stability conditions on this <br />particular site are relatively insensitive to the existence of a <br />piezometric surface (groundwater level) and highly sensitive to <br />variations in shear strength parameters. <br />In the spring of 1986, a series of landslides occurred in the <br />mine site area. The largest of which originated on the slope above <br />the fan house and access road eventually destroying the fan. At <br />this time another report was produced by RMG titled, Inspection <br />Report April 1986 Landsliding Bear No. 3. The RMG inspection <br />report concluded that the previously stable slope, failed due to <br />heavier than normal amounts of precipitation prior to the failure. <br />• EXPLORATORY PROGRAM <br />Four test borings were drilled on the slide site using a <br />conventional auger drilling rig. Three of the borings were placed <br />at the top of the slide and the fourth boring was placed below the <br />toe of the slide. Test borings were advanced with a power-driven <br />rotary drilling rig to refusal with depth ranging from 16 to 48 <br />feet. Samples were obtained using a 2 inch OD split-barrel <br />sampler. Shelby tube sampling was taken in two of the borings <br />where significant cohesive materials were encountered. However, <br />due to the similar physical characteristics and correlations of the <br />samples obtained and the description presented in the RMG report, <br />no lab analysis was done on the samples obtained. <br />Locations of the test borings are shown on drawing number 21- <br />3. Test borings No. 1 through No. 3 were placed along the center <br />of the portal access road on the bench at the slide crest which had <br />settled due to the past slope failure. Test boring No. 4 was <br />• placed in the portal access road below the toe of the slide. <br />21-4 <br />