PERMFILE134108 - Laserfiche WebLink

Home Browse Search

Mountain Coal Com pany, L.L.C. Exhibit 51 West Elk Mine ~ Lower Refuse Pile • The «•ate: level in the piezometerswas allowed to drop for a minimum period of 16 minutes or until a static water level had been obtained. The results of the Callin¢ head permeability tests are presented in Section 5.4.1. Baseline water quality data from the wells drilled [o monitor groundwa[erdepthgnd quality are contained in MCC's Quarterly Hydrology Reports beginning in August of 198. Hydrology data for the wells are contained in MCC's subsequent Annual Hydrology Reports. 5.2 Laboratory Results ••, The laboratory tests performed on samples retrieved from the soil boring program included gradation tests, natural moisture content determination, Atterberg limits, and triaxial shear tests. Analyses were performed at Rockv Mountain Geotechnical. Colorado State Universih's soil laboratory, and Garco Laboratories in Salt Lake City, Utah. All tests used the appropriate ASTM procedures. The Shelby tube soil samples which were tested to determine the shear strengths of the debris flow materials primarily consisted of clayey soil. Due to the gravely nature of [he soils in the area, additional Shelby tubes could not be obtained. The results of the shear tests are shown in Table ~. The moisture contents are shown on [he boring logs found in Appendix E. while the gradations of the various soils can be found in Appendix G. Table4- LaboratorvAnalysisSummarv Soil Sample SB-3 (15.5') Soil Sample SB-9 (15.2') Thinwall Samnle Information Dry Unit Weight(pcf) 113.7 105.5 Moisture Content (%) 15.8 14. I Liquid Limit 24 21 Plastic Limit 17 17 Triaxial Testing Information Dry Unit Weight (pcf) 1 13.7 105.0 Degree of Saturation (%) 90.E 64.5 Initial Void Ratio .46 ~8 Final Moisture Content (%) I3.5 12.6 Specific Gravity 2.67 '_.66 Triaxial Cell Pressure (psi) 20, 60, 100 20.60. 100 Drained Friction Angle (degrees) 34 33.7 Cohesion Value (psf) 0 0 5.3 Geolaw Geology and engineering geoloe} of the site has been provided by Ray Junge of the Colorado Geological Survey on maps published in 1978. These maps show, and Rocky Mountain Geotechnical agrees, that the LRP is located in an older debris Flow environment. The debris fan appears to be an older stabilized feature. The major drainage across its surface is deeply entrenched. The vegetation on its surface is well established and does not appear to have been disturbed in the recent past. A thick organic horizon ranging in thickness from 6 inches to 6 feet has developed on the surface of the fan. Average thickness of topsoil • was estimated to he approximately 18 inches. Logs of test pits at two locations on the face have shown I?