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3 _3 DRILLING <br />3.3.1 Tvpes of Drillin}a <br />AG Trapp@r Mine ther@ are three types Of drilling~ blast hole dsilli~;g, ax~2ora- <br />tion drilling and developmont drilling. Blast hole ~SrilliRg osct.FS only r,•izkia <br />the p@rmi_t Brea and Ls tedVizad For the b1asC,inS oyeratiQn. ThQ hele$ arE meeaed <br />fot pl_acQmzht of axplosive~ to ftagmenC overburden„ ihterbuPdep a~ eoa2. Hors <br />sizes t depths and spacings vary eCcordigg to the thicl.~ess ~.od nat~rg of the <br />material to be blasted. Because the holes are drilled lust ahead ng, ~: ~.~ai~;zn <br />an adbanring pit, they are removed by stripping or mLning within Geyoxs~l i,unahs <br />or IeSs. For taor@ detail Rn bla„[ing> seo Section 3.~. <br />Explora[3o» drilling occur" outside tht permit hre:t and is te9uired to detp~n.;nQ <br />the ekteht of the coil reshrvns and to provide inf7rmat ion on coal depth, tbirk- <br />ness and quality. All exploration dril.liRg Ss conducted ih ComAliance w;rb <br />applihable U.S, Bureau of Land Alanagemen[ aqd Stage 4f Colorado reSulaCio>LS and <br />will he handled by separatR gRrmits. <br />Develttpmtnt drilling, ix, required 5o proWid® delta for plagniRg pit ditnensioos, <br />sequehcing activities and equipment scheduling• Typically, development drilling <br />is conducted at Gr heaY the projected coal cropline and the ecnhomic stripping <br />limit ahead. o£ advaacing pith ahd wheYe new pits aze planned within the ;oarmii <br />area. Drilling depths needed to further define the cropline are usually oo]y so <br />the coal in questioR• Depend,i.n~ upon the informahioh obtalne8, drilling >nay be <br />conducted $ef%ninp e;he cropline t0 within 35 feet horizontally. The econasic <br />stripping Limit is defined in mach the same magnet except 1t is not necessarily <br />located as accurately as the cropline. <br />Prior to stripping, cha overburiten is dr.lllbd and blasted. Overburden drilling <br />aqd blasting precedes stripping by one to five Pit wiilth5. Before the ovefburden <br />is drilled and blasted, [he topsoil is removed. Topsgil removal is conducted <br />dyYing the fair weather months of May [h rough October. Therefore, each year's <br />~ ~~~ti~~ <br />a-za ~APRA!'~d <br />/»iz ~ to y <br />REVISED f~ ~ ~~~ ' <br />