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<br />-33- <br />• XVi, Explosives - Pules 2.05.3(bl 'and 4.08 <br /> <br />~vo explosives will be used or stared in conjunction with this operation. hone <br />of the requirements of this section apply. <br />.YVII. BackfiZlinq and Cradinq - Rules 2.05.3(6)(b), 2.05.3(91, 2.05.4(2)(a), <br />2.05.4(2)(c), 4.09, 4.13 and 4.14 <br />Information regarding 6ackfilling and grading of disturbed areas is presented <br />in Sections 2.2.2, 3.1 and 3.3 of volume I and Appendix 0 of volume v of~the <br />application. Details of the waste disposal pile are presented in Sections 2.2.5 <br />and 4.5.3.1.4 of volume I and Appendix .v of Volume J of the application. These <br />materials have been reviewed by the Division for compliance with the Rules and <br />Regulations. <br />The applicant proposes not to backfill the workings to achieve approximate <br />original contour. The application contains a description and cross-sections of <br />proposed backfilling and grading plans for the mine portal bench area and for <br />the haul road. <br />The upper havZ road segment between the confluence of the tfunaer Creek val_'ey and <br />the unnamed tributary to the ;?urger Creek valley (Sta. 0'7+00') to, and including, <br />the mine portal bench area, is characterized by steep slopes, commonly in excess <br />of 200. Under the regulations of the Rule 4.27, Operations on Steep Slopes, <br />the applicant is allowed variance from approximate original contour, if the <br />• approximate original contour donfiguration will not achieve a static slope safety <br />Factor of 1.3, as required by Rule 4.14. Ideally, the entire tv:ghwall shall be <br />backfilled to achieve a safety factor of I.3. In situations in which a static <br />slope safety factor of 1.3 cannot be achieved, the applicant proposes to backfill <br />to that confi wration which will maximize the static slope safety factor of that <br />portion of the backfilled slope. Remaining port one of the exposed cuc slopes <br />will be treated to achieve a surface which is as erosionally and as structurally <br />stable as is possible. <br />In response to Division comrrent, the applicant developed typical backfilled <br />cross-sec ti one, similar to the operational road cross-sections depicted in Figure <br />2.2-23. T.he applicant's detailed backfillino and grading proposals are supported <br />by thorough stability anal uses of the proposed backfill and grading confi w rations <br />.`or the haul road and portal bench areas. The analysis demonstrated that the <br />redesigned reclaimed confieurations' static slope safety factors exceed those <br />of the predisturbance natural slopes. <br />The applicant's original permit application contained several deficiencies :with <br />regard tp the underground de•ieiopment :caste pile, which nave been remedied in <br />supplemental submittals. In response to the Division's PrelLmi.aary Adequacu <br />:Pe view, r,he applicant has prepared and submitted an acceptable geo to chni cal and <br />stability analusis of the proposed 25,000 cubic yard underground development <br />waste pile. This analysis determined that the pile :+iil achieve a ,ni,vmum static <br />slone saretu :actor of _.034, based crcn conservative assumpticns of t5e :+aste <br />mate riai 's stren gt9. .The applicant s also ccnni tted to en inspection and <br />_.._.._=i ca ti on p:roeram which conforns :with the reovire=rents o: 3ule 4.J9.1(11). <br />.':a applicant's plan =cr the disposa: of uncle^~round development waste cf the <br />• 'funcer Canyon J/i ne :,, .n comp _'i arse .ri th t::e rec;i came..^.ts of pv:es 2.05.3;5) <br />and 4.09. <br />