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ll,rl 1'/7) Srrrrco (-an/CnrnPunr ` 1~umt Iliur Serlnnnr6rl:an PouApl' Smbi/rq :-Irm/nrr ~ 3 <br />• <br />TABLES <br />STABILITI'RESULTS <br />Eh1BANKh1ENT hATERIAL BASE MATERIAL BISHOP SF <br />Sandy Clav Sliehdv Sandy Clav 1.86 <br />As indicated by Rule 4.0.6 (1 I) Q) or (k) all surface water impoundment structures must be constructed <br />with a SF not less than 1.3 f I.~ under IJ)). As shown m Table 4, the Sedimentation Pond 012 design meets <br />the applicable stability criteria. In order to assure that the embankment is constructed in accordance with <br />the design parameters. the following construction control measures are recommended: <br />3.0 RECOMMENDATIONS <br />In order to assure consistency with the design parameters, the following procedures are recommended for <br />foundation preparation and construction of the sedimentation pond embankment. <br />I) Following soil material removal and excavation of the embankment keyway, a Registered <br />Professional Engineer ur qualified Soils Scientist should verify that sub-grade material <br />characteristics are consistent with material type assumptions made in this stability analysis <br />and that no unanticipated adverse foundation conditions' (such as saturated soils. clay layers. <br />organic materials, etc.) exist. <br />2) Similarly, verify that the characteristics of materials to be used, as embankment tills are <br />consistent with material type assumptions made in [his stability analysis prior to construction. <br />3) Construct embankment in maximum 2-foot horizontal lifts. <br />4) Compac[ each individual lift l0 9590 of standard Proctor density using available equipment. <br />5) Maintain upstream and downstream slopes no steeper than 3H: I V. <br />• <br /> <br />4.0 REFERENCES <br />Huang, Yang H. (1983). Srnbi(in~ Annh~sis of Enrrh Slopes. University of Kentucky. Van Nostrand <br />Reinhold Company, New York. NY. <br />Leidich, Tom (1999). Proposed Pond 012 Design. E.rhibir 13-12.2. Yoasr Perrrrit. Prepared for Seneca <br />Coal Company. <br />NCRS (1999 drafll. Soi! Survey jor Rouu Corurn~. NCRS. Craig, Colorado. <br />Northwest Colorado Consultants (July, 1994). "Georechnicnl /n vesrigntion, Hnulrnads Y-A & Y-8 nrrd <br />Sedinrentorion Pond 0/0, Yoasr Mine Aren, Roeut Counn~, Colorado". Prepared for Seneca Coal <br />Company. <br />Northwest Colorado Consultants (August. 1996). "Georechnicnl lui~esrigatiorr/Sunmmn~ Reporr Pond 010 <br />Embnnkment -Permir C-9-1-08? Yoasr Mirre, Rourt Count, Colorado". Prepared for Seneca Coal <br />Company. <br />Nyenhuis, Jim (1993-a). Yoasr Mine Resenrch Soil.4nalysis. CSU Soil Testing Laboratory. Performed tar <br />Seneca Coal Company. <br />Nyenhuis. Jim (1993-b). "Soil Types and Soil Salvage Map". E.rhibit 9-/, Yoasr Permir. CSU Soil Testing <br />Laboratory. Performed for Seneca Coal Company. <br />.tlomtgumep~ Il~otrwr .-tntenmt. Inc /Gi Sauth L4rion Bou/erord, Suttr a70 "Lukrwoad, ColoroAo 60?'8' (303J iG3-5/~0 <br />): \y i 1 \mrvin\rnnd' 1 rt.rGrl~ <br />7i/1i179 n1, <br />