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Bob :.fdCle -?- Jmie 30, 1981 <br />waste Material and Smi1 <br />The applieati.on has several deficiencies in regard to the disposition of <br />~derground waste materials and overburden spoils. The application rhould <br />specifically discuss the underground waste rmterial placement and compaction <br />_ -" speci~ieations to be utilized. Plans and cross-sections of :he backfillQd <br />pit to receive waste ..~I.erial should be includod within for appliear~nn. <br />The applicant present3 the opinion that the permanent overburden spoil pile <br />located in Section 24 predates the permanent regulatory programs inception <br />and is,thesefore , exempt. if the applicant does net redisturb that pile, <br />as the application proposes, I agree. The applicant should topsoil and re- <br />vegeuste that pile as scan as possible in a tsmely manner. <br />The application alao states the applicant's opinion that the regulatory <br />requirements of Rule 4.09 do not apply to temporary spoil ailes, two of <br />which are contained within the application, The Ili. vision disagsaes with this <br />opinion. The application should be amended to include Qiscrsptions of the <br />consrruetian specifications as utilized during material placement within the <br />two piles, as well as cross-sections and plans for these temporary piles <br />located within Section 12. The applicant should eonfosm with the requiremen s <br />of Rule 4. U9. Osvtsaon po.ticy has born to uur~iuei .aria.:ra ?ras !ne raauirnd <br />long-term static safety factor'reguireswnts,.if the applicant is not intending <br />redistuzb the piles. Sf continued disturbance is proposed, the Division will <br />investigate the possibility of achieving conformance by sale=rive placement <br />of additional material to reconfigure the slopes n_ the existing temporary <br />piles. Pe_^ioc'ic iapections in keeping with Rule 4.09 wi?1 also be required <br />to assure mainrenance of a safe condition during the piles life saes. <br />Subsidence <br />The stbsidence evaluation within the app':catien has several major deFiciencies <br />~ which mist be eliminated by the applicant. Pirst, the applicant's subsidence <br />pre3iction (exhibit l5) projects subsidence based uoon extrapolation =rom <br />empirical graphs contained within a publication by Sud Peng, The epalicant. <br />utilizes this graphical information to proiect subsidence beneath "area ;," <br />rqu:;vElen= t0 7$ of the eXCTdCLed Seam tl~iCY.ness. "Area S" contains Faidel <br />and Middle Creeks. T:is presentation is inadeauete. She ap,:.licant should <br />amend the application to include aiilar stability ground control calculatio_^s, <br />which are described at lenc`...h in the same p:i^licatien by Suc Peng ("Coal Y.ine <br />Grot:nd Control", 1978), _rom which the Graphical tec;siques were exoe_^nted. <br />Any one of the normellu acceptable te_n.^=sues for roa° s~a~ility calcLlatian <br />may be applied to the task by the applicant. <br />Secondly, the applicant describes the existence of an approximately 2DD ft. <br />ndde :salt zone, which eonstit~res the eastern bo.:ndary of the Middle reek <br />tmdergrormd mice plan. Faults comrmnly ir..luence file character of Ground <br />subsidence above un~?erprounri wnrkin.^s. A horngeaei:y es5:::p :iPns implicit <br />i~ the no_-ae1 gra_arsical and mathematical subsidence projection tec:.niques <br />often do not apply in fates tad s-tuations. subsidence can occur along ezietin_I <br />shear Plains within .he vaulted zone, increasing the possiblity of d::screte <br />