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<br />Mr. Martin Azcarraga <br />June 7, 2000 <br />Page 3 of 4 <br />Overburden removal at the site consists of a silty-clay material approximately 12-ft in <br />depth. The silty clay soils in [he Appleton Wash and Canning Factory Drain, located <br />north of the proposed site, provide a good indication of the expected slope stability of the <br />silty clay material. These drainages have numerous azeas of near vertical faces and no <br />azeas of slope failures were observed, except for a localized failure in the Canning <br />Factory Drain, located near the northeast corner of the site. A slope failure occurring at <br />this location appears to be the result of a crushed drainagelirrigation culvert. Water <br />draining through this culvert has leaked out into the surrounding bank area and saturating <br />it to a point where small-localized failures along the bank are present. <br />All of the overburden is anticipated to be located above the groundwater table. A <br />slope/landslide failure of this 12-ft highwall area large enough to damage any offsite <br />man-made structure is unlikely. <br />However, slope failures large enough to damage the catch basin structwe could occur if <br />the mined sand and gravel undercuts the overburden highwall. This condition should not <br />be allowed at the site under any scenario. Not only is there a risk to damage offsite <br />structures, but also a risk to all personnel mining in the immediate area. <br />Groundwater Impacts: <br />Impacts from pumping out groundwater from the sand and gravel dewatering operations <br />are not expected to impact any structure. <br />Because of the high salinity levels in the groundwater, the water is not suitable for <br />drinking or irrigation purposes. A search conducted [he Office of the State Engineer, <br />Colorado Division of Water Resources indicates there are no wells within 600 feet of the <br />proposed site (reference permit # 053886-F). <br />Groundwater removed during the mining operations will be pumped into a settlement <br />pond, and into the Canning Factory Drain ditch owned by the Grand Junction Drainage <br />District (GJDD). The GJDD has approved the discharge of the water into their drainage <br />facilities (Reference Exhibit G of 112 Permit #: M-2000-032). <br />Drainaee Impacts: <br />Drainage from the sand and gravel mine are not expected to impact offsite man-made <br />structures. <br />