Laserfiche WebLink
West Elk Mine <br />Main Entries & Sub-Main Entries <br />At West Elk Mine, from five to nine entries currently aze mined as main entries. The number of <br />entries depends on mining conditions, and ventilation and access requirements. As few as three <br />entries could be driven in special circumstances. The entries are used for intake and return air <br />ventilation, coal haulage, and men and material transportation. The entries are driven parallel to <br />each other on 60 to 100 foot centers. Crosscuts aze on 100 to 200 foot centers. The entries are <br />also separated as necessary by stoppings. <br />Room and Pillar Panels <br />In general, the F Seam room and pillar panels consisted of 6 to 8 entries driven parallel to each <br />other on 60- to 100-foot centers. Crosscuts were on 60 to 120 foot centers. Room and pillaz <br />panel entries consisted of intake and return ventilation, conveyor belt, haulage, and escape-ways, <br />sepazated as necessary by stoppings. During secondary mining of the room and pillar panels, <br />additional rooms may have been developed on one or both sides of the initial development. <br />Sufficient barrier pillars were left to protect the main entries and bleeder entries (if separate <br />bleeders were utilized). During secondary mining, partial or full pillar extraction was used, <br />depending on conditions in the panel. <br />Longwall Gate-Roads <br />. Room and pillar methods aze used to develop gate-road entries for the longwall mining <br />equipment. Generally, two to five parallel entries aze driven on from 55 to 120 foot centers. <br />Currently, athree-entry yield abutment design is typically used. The size and configuration of <br />longwall gate pillazs is based on the regional geology, and depth of cover. Different <br />configurations are now used in the eastern portion of the B Seam reserve. Longwall panel <br />barrier pillazs will be left to protect main entries and bleeder entries. <br />Bleeder Entries <br />Bleeder entries aze typically developed to ventilate active and previously mined longwall <br />areas until those azeas can be permanently sealed. Bleeder eritries are connected to the main <br />return air ventilation system. Continued use of bleeder entries is currently being evaluated. <br />Preliminary plans for the E Seam include a "bleederless" ventilation system resulting in <br />each panel being progressively and/or completely sealed upon completion of mining a <br />particular panel. This alternative may be implemented in the B Seam as well. <br />Barrier Pillars <br />A barrier pillar is a lazge block of solid coal left in place to protect active mine workings. Barrier <br />pillazs are left, as necessary, between longwall panels and main entries, between submains and <br />longwall panels, or in other azeas, as needed. Barrier pillars vary in size, and designs are based <br />primarily on life-expectancy and degree of protection required for the barrier. Design <br />criteria include depth of overburden, horizontal stresses, etc: In all cases, the dimensions of <br />2.05-8 Revised November 2004 PRII <br />