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2.2 Blasting Activities <br />Following the completion of topsoil stripping in Co 1t Pit, overburden blasting <br />will commence. Blasting procedures as outlined in Section 3.4 of Trapper's <br />Mining and Reclamation Permit will be followed. <br />Most of the area to be blasted in 1987 will occur within a horizontal distance <br />of 500 fee[ from [he underground workings of Empire Energy Corporation's Eagle <br />No. 5 Mine. Map PR1-1 shows the area to be blasted and Empire's underground <br />workings that lie within the 500-ft horizontal distance of [he blasting area. <br />The underground workings shown are mostly abandoned room and pillar areas for <br />which an estimated 852 extraction was accomplished. No currently active head- <br />ings fall within the 500 horizontal feet of the planned blasting area. <br />Trapper is requesting a variance from the 500 horizontal foot limit for sur- <br />face coal mining over an active or abandoned underground mine. Safety of the <br />underground workers will no[ be compromised as more than 800 vertical fee[ <br />shall separate [he two mines. <br />Trapper will blast within 500 horizontal feet of Empire's East Main Extension, <br />~ 4th East Panel, 1st Left Panel and 2nd Left Panel, Afap PR1-1. Pillar strength <br />• calculations as shown in Empire Energy's Eagle No. 5 Mine Permit show minimum <br />pillar sizes required for a 1.5 to 2.0 safety factor [o be 40-f[ x 40-ft <br />pillars in the East Main Extension and 42-ft x 42-ft pillars in 4th East <br />Panel, 1st Left Panel and 2nd Left Panel. <br />Minimal pillar sizes left in place for Che Main East Extension are 50-ft x <br />50-ft, resulting in a cross-sectional pillar area of 900 additional feet of <br />pillar, 56 percent more pillar than required for a safety factor of 1.5 or <br />2.0. <br />Minimum pillar sizes left in place for the 4th East Panel are 50-f[ x 50-ft, <br />resulting in a cross-sectional pillar area of 736 additional feet of pillar, <br />42 percent more pillar than required for a safety factor of 1.5 or 2.0. <br />Pillar retreat mining methods have been used in the ls[ Left Panel, thus most <br />pillars have been removed and the area caved. <br />Minimum pillar sizes left in place for the 2nd Left Panel are 30-ft x 120-ft, <br />resulting in a cross-sectional pillar area of 1,836 additional feet of pillar, <br />104 percent more pillar than required for a safety factor of 1.5 to 2.0. <br />C~ <br /> <br />