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.:.. Subsequent to submittal of the initial design, actual testing <br />, <br />~ <br />(`j:~%` <br />~~,.~' <br />l was performed on the refuse generated at the Raton Creek Mine <br /> Complez to determine its actual physical characteristics <br /> with'reapect to stability. The results of this testing <br /> confirmed that the initial design was conservative. The <br /> following physical pazametere were obtained from the actual <br /> field tenting o! the reiuee material: ' <br /> i. Internal angle o! friction 40° I <br /> 2. Compacted density 96.4 lbe/cu. ft. <br /> 3. Cohesion 10.0 psi. • <br /> Based upon the actual physical properties o! the refuse <br /> material described above, the previous operator performed a <br /> stability analysis on a revised design which was submitted in <br /> 1983. The overall elope and maximum embankment height <br /> utilized in the revised design were 2 horizontal to 1 <br /> vertical and 320 feet respectively. The resultant !actor <br /> safety wan determined utilizing the references described <br /> above to be 2.46. A similar sensitivity analysis to that <br />F;'~~ performed on the initial design was run on the revised <br />~~-'v design. Average slopes were vazied down to 1.5 horizontal to <br /> 1 vertical, cohesions were varied down to 0 psi and the <br /> internal angle of friction was varied down to 30 degrees. The <br /> resultant factors of safety varied from 1.55 to 2.0. ~ <br />As described above, the reiuee disposal embankment contem- <br />plated by thin revision ie nearly identical to that which was <br />presented in the initial design in 1982. Based upon the <br />stability analysis performed on both the initial and <br />previously revised designs, combined with the actual physical <br />parameters of the refuse material, it is clear that the <br />salet7 factor for the reluae embanlment contemplated here <br />under any possible caae• will be much greater than the <br />required 1.5, and most likely in the 2.5 to 3.5 range. I <br />The mechanical testing on the coal refuse material described <br />above was conducted by F.![. Foz Associates, Ise. of <br />~~ ~ plheatri e, Colorado durin earl 1983. This information is <br />~` ~~ dg g 7 <br />470 • <br />Revised S/93 <br />