Laserfiche WebLink
These consisted of: <br />• 1. Foundation materials saturated; <br />2. Phreatic surface located 10 feet above the existing <br />foundation and exiting at the toe; <br />3. Phreatic surface located 10 feet above the existing <br />foundation and exiting 5 feet above the toe. <br />4. Extreme phreatic surface conditions (Refuse Pile No. 2 <br />only). <br />The strength properties for the coal waste material were based on <br />the previous laboratory test on the refuse material. A copy of <br />this test is located in Appendix B of this report. The strength <br />properties for the foundation materials were based on triaxial <br />• shear tests performed by Colorado State University. These tests <br />are summarized in Table 1.0 of this report. The strength <br />parameters for the bedrock material were based on previous <br />experience for this type of material. <br />6.6 RESULTS OF ANALYSIS <br />The CMLRD requires a factor of safety 1.5 to be considered <br />acceptable for long-term stability of coal refuse piles. The <br />slope stability for the different cases indicated that the <br />proposed mine refuse pile will have a factor of safety greater <br />than 1.5. These cases were analyzed assuming an underdrain will <br />not be built as originally planned. A summary of the slope <br />• stability analysis with the slope stability failure circles are <br />shown on Figures 4 and 5. <br />13 <br />