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3 _3 DRILLING <br />3.3.1 Tvpes of Drillin}a <br />,kt Tcapp@r Mine ttterw are three types Of drilling: blast hole erillid;g, exP2o<-a- <br />tion grilling and development drilling. Blast hole crtlling oscvrs only rizkia <br />the p@rmit srea aRd Ls tegVirad tor the blasting operation. The holes a1-e meeaed <br />tot Aace_m&ht of 0xplosive% to fragme%C oVezburgen„ ihterbut-dep a)?j coa2. Holes <br />sizes, depths and spacings vary a¢cordigg to the thicl.?ess wt naz,)rg of the <br />material to be blasted. Because the holes are drilled just ahead D.€, w Lii?;za <br />an adbanciog pit, they are removed by st'p4yi.ng or mLning vitl?in Geyor4l r,un,,hs <br />or Ie%s. For mor@ detail on bla„ting, see Section 3.4. <br />Exploration drilling occur% outside tht permit Ares and is re9uire6 rD dete?n nQ <br />the ekteht cf the cosl reserves and to provide inf,.)rmation on coal depth, thick- <br />ness and quality, All exploration drilling is conducted ih Romhliance w;rb <br />applihable U.S. Bureau of Land Alanagement and Stage of Colorado reSulakiovs and <br />will be handled by separate permits. <br />Development drilling ix required to proWid® delta for planning pit dimensions, <br />sequehcing activities and equipment scheduling- Typically, develupment drilling <br />is conducted at rr hear the projected coal cropline anal tie economic sttippio8 <br />lijnit ahead at advartcing pitk and whe?e new pits are planned within, the ;permit <br />area. Drilling aspGhs needed to further define the cropline are usually ooly so <br />the coal in question- Depending upon tht informahioh obtaYned, drilling tray be <br />cot-,ducted defining khe cropline to within 35 feet horizontally, The economic <br />stripping limit is defi.ned it, mach the same magnet except It is not necessarily <br />located as accurately as the cropline. <br />Prior to stripping, the overburden is drllltd and blasted. Overburden drilling <br />and blasting precedes strippi.hg by one to fiVe Pit wi0th4. Before the overburden <br />is drilled and blasted, the topsoil is removed. Topsgil reikoval is conducted <br />dgYing the fair %veathet months of May through October. Therefore, each year's <br />a-za ?APRA!'?d <br />D+4 <br />/»iz ? to y <br />REVISED fEnD 1 o