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• <br />3.0 FIELD INVESTIGATION <br />The field investigation for this study consisted of surface <br />mapping investigations by personnel of Rocky Mountain <br />Geotechnical, Inc. and subsurface investigations performed by <br />Atlantic Richfield and Anchor Mining Company. <br />3.1 SURFACE MAPPING <br />The surface mapping on-site consisted of the detailed mapping of <br />surficial landslide deposits within and adjoining the permit area <br />and bordering on the Northfork of the Gunnison River. This <br />mapping included the location and identification of areas of <br />recent and past movement and their relative ages and the <br />• approximate depth of failure. This was accomplished through both <br />field reconnaissance and measurement, and air photo <br />reconnaissance and interpretation. Air photos used were natural <br />color photos taken in 1975 by InterSearch of Denver and more <br />recent air photos taken in the spring of 1986 by Rocky Mountain <br />Geotechnical, Inc. The results of this mapping are shown on the <br />Slope Failure Map, Figure B1, found in Appendix B. <br />3.2 PREVIOUS SUBSURFACE INVESTIGATIONS <br />Five holes were drilled within the permit boundary as shown in <br />Figure Bl. Three of these were drilled by Atlantic Richfield in <br />1968 and two were drilled by Anchor Coal Company in 1978. Each of <br />the holes with the exception of SOM12 was electrically logged and <br />• their E-logs obtained for this study. Drillers' logs were <br />7 <br />