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Deep Cut LLC Permit# M-2017-032 <br /> 22 West Pit April 30, 2018 <br /> GEOTECHNICAL STABILITY EXHIBIT <br /> This information is presented to address the plan to mine <br /> within 200 feet of the structures listed in Exhibit S . The <br /> factors of safety are based on non-site specific data for the <br /> material being mine . In the past, Mr. Alan Sorenson reviewed <br /> Slope Stability Reports prepared for the mines in Colorado and he <br /> suggested that an appropriate friction angle could be found in <br /> Table 1 of a Federal Highway Administration paper Rock Slopes: <br /> Design, Excavation and Stabilization, Publication No. FHWA-TS-89-045, Table 1 <br /> - Typical Soil and Rock Properties and used when non-site-specific <br /> information was available of a gravel deposit . So for this <br /> analysis a 35' friction angle and a near vertical mining face of <br /> %: 1 is used for the pre reclamation calculations . For the <br /> reclamation calculation a 3 : 1 slope was used. <br /> TABLE A <br /> DRY UNIT MOIST WEIGHT SATURATED WT COHESION FRICTION <br /> WEIGHT (LBS/CFT) (LBS/CFT) FACTOR ANGLE <br /> (LBS/CFT) <br /> 119 129 130 0 35 <br /> There are two adjoining structure owners that did not return <br /> the structure waiver agreements to Deep Cut, LLC so this analysis <br /> contains specific factors of safety from the closest structure <br /> they own to where actual mining activities will take place, An <br /> additional analysis was done for the closest structure south of <br /> the peninsula areas first to be mined and for the closest struc- <br /> ture, CR 22 on the eastern limit of the mine . The mine depth <br /> closest to any structure is shown on the cross section for that <br /> structure and varies for 10 to 20 feet . For the peninsula area <br /> the mining face is shown as 3h to lv. In the remaining 3 it is <br /> calculated for the working face and the finished slope . This is <br /> a wet mining operation so water is associated with the mine so <br /> the friction angle used was the lowest in the range for the type <br /> of material . <br /> The two structure owners for which there was no damage <br /> agreement received are the City of Aurora and for Donald Memeda . <br /> The closest structure to the active mining face Memeda owns is a <br /> chainlink fence on this north property line . For Aurora it is <br /> the irrigation return flow ditch along the northeast part of the <br /> mine . I also point out here that along the entire south side <br /> none of the structures are located within 200 feet of the mining <br />