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Slope Evaluation and Remediation <br />West Elk Mine <br />Somerset, Colorado <br />good working condition, generally caused by the presence of cobble, boulders and <br />shallow groundwater. <br />Groundwater was encountered during subsurface exploration at depths as shallow as <br />approximately 16 feet below the existing grades. Groundwater levels will fluctuate due <br />to a variety of factors, and may be several feet higher than reported herein. The <br />contractor should anticipate encountering water at or above the depths at which it was <br />encountered in our test holes, and be prepared to work in the presence of groundwater. <br />Good surface drainage should be provided around temporary excavation slopes to direct <br />surface runoff away from the slope faces. A properly designed drainage Swale should <br />be provided at the top of the excavations. In no case should water be allowed to pond at <br />the site. Slopes should also be protected against erosion. Erosion along the slopes will <br />result in sloughing and could lead to a slope failure. In addition, plowed snow should <br />not be "side cast" onto the slope repair area. <br />Excavations in which personnel will be working must comply with all OSHA Standards <br />and Regulations. The contractor's "responsible person" should evaluate the soil <br />exposed in the excavations as part of the contractor's safety procedures. GROUND has <br />provided the information above solely as a service to Mountain Coal Company, LLC, and <br />is not assuming responsibility for construction site safety or the contractor's activities. <br />Earthwork Specifications Prior to earthwork construction, existing vegetation and <br />other deleterious materials should be removed and disposed of properly. <br />Use of On -Site Materials as Fill Site soils, free of trash, organic material, and other <br />deleterious materials, and that exhibit an angle of internal friction ( 0 ) of at least 30 <br />degrees are suitable, in general, for placement as compacted fill. Testing will be <br />required to evaluate the angle of internal friction for the various soils excavated or <br />otherwise available for use to construct the buttress fill. We anticipate, however, that the <br />majority of the site soils will be suitable for use as compacted fill in the buttress. If the <br />majority of the site soils exhibit an angle of internal friction less than 30 degrees, the fill <br />configuration can be modified accordingly. <br />Cobbles and fragments of inert construction debris (e.g., concrete or asphalt) larger than <br />6 inches in maximum dimension will require special handling to be incorporated into <br />project fills. In no case should these fragments be placed within 3 feet of finished grade. <br />Job No. 11 -6014 GROUND Engineering Consultants, Inc. Page 10 <br />