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Under most conditions the subsurface hydrogeologic conditions <br />• would also be affected by the development of this zone. However, <br />in the case of this particular site, formations are dry and no <br />significant long-term effect on the hydrogeology is anticipated. <br />6.4 POST-SUBSIDENCE CONDITIONS <br />Cross-sections AA' and BB' were also used to analyze the post- <br />subsidence stability with regard to deep-seated bedrock failures. <br />In this case, Formations 11 through 16 were assumed to be <br />rubblized and, therefore, were assigned reduced strength <br />parameters. For the rubblized zone an angle of friction of 38 <br />degrees and a cohesion intercept of 0 were used. Both circular <br />and wedge failures were analyzed and the results are shown in <br />• Table 4. The critical failure surface is also shown on the <br />cross-sections. The factors of safety calculated ranged from <br />1.71 to 2.80 for the typical strength parameters and from 1.91 to <br />2.15 for the conservative strength parameters (a reduction of <br />five to six percent for the critical sections). <br />In addition, several analyses were run assuming that the <br />rubblized zone extended to include Formations 9 and 10 and that <br />Formation 8 was the first to be able to span the rubblization. <br />Results of this analysis are also shown in Table 5. Calculated <br />factors of safety ranged from 1.62 to 2.47 for the typical <br />strength parameters and from 1.37 to 2.04 for the conservative <br />• strength parameters (a reduction of seven to eleven percent for <br />the critical sections). <br />27 <br />