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3~3 nRIL,LING 3.3.1 Tvg¢s of DrjLli_~ AC TcappRr kin¢ them are thr@e types Of drilling~ blast hole dsilli~;g, ex~2o~a- tion tlrilling and development drillin8• Blast hole flrilliRg oscC,rs only t•zrkia the p@rmi_t area and Ls tegVizad For the b1asC,ing operatiq~. ThQ hele,r are reeaed fot pl_acPmeht of °-xplosive~ th ftagtaent overburden„ ihterburdep a>v eoa2. Hors sliest depths and spacings vary eCcordigg to the thic~~ess ~.od naa>rg o€ the material to be blasted. Because ttte holes are dulled just ahead nF, ~; ~ii~;in an ad4antiing pit, they are removed by stripbing or mLning within eeyorl} hunths or less. Eor taore_ da_tail Rn blaycing> see Section 3.~. Exploration drilling occur" outside th@ permit qre:~ and is te9uirEd to determ;.ne the ekteht of the coal resarvns and to provide inf7rmation On coal depth, Ybir-k- ness and quality, A11 ekploration dril.liRg 1s conduCted ih ComAliaoce wjrb applihable U.S, Bureau of Land Aianagement add Stage 4f ColOrago regulaCio>LS and will he handled by separatR p@rmits, Devehtpm¢nt drilling ix, required c,o proWid® d$ta for plagnigg pit dimension,,, sequehcing activities and equipment scheduling. Typically, development dtitling is conducted at Gr heat the projected coal cropline anti the ecohomic 6tzippiog liynit ahead, of advagcing l,it~ ahd wheYe new pits are planned within, the ;nertnit area. Drilling depths needed to further define the cropline are usua114 Daly to the coal in g4es[ioR• Depending upon th@ info~atioh obtained, drilling >nay be conducted defining Che cropline to within 25 feet 11or{zontally. The economic stripping Limit is defined in mach the same magnet except it is not necessarily located as accurately as the cropline. Prior to stripping, cha overburien is dri,llbd and blasted. Overburden drilling and blasting precedes stripping by one to five Pit wiry[h5• Before the overburden is drilled and blasted, the topsoil is Yemoved. Topsgil removal is conducted dyring the fair Weathet months of May [h rough ~OctobQr. Therefore, each year's ~_z~ ~{t"i{~514f~ JR~t°RA!'~~ L14?•F .2 1~ 9~~.. /nz ~ ~ y R~vys~D FEB 1 a'8a