Laserfiche WebLink
2.0 INCLINED MINE ENTRY SEAL AND BACKFILL <br />2.1 Description <br />This specification covers all material and work required to construct a steel <br />backstop and concrete block wall or bulkhead seal within the open inclined <br />mine entry at the Sunlight mine, and to backfill the portion of the mine <br />opening remaining between the constructed seal and the surface. <br />2,2 Materials <br />The concrete masonry units to be furnished by the CONTRACTOR shall consist of <br />solid 8"x8"x16" concrete blocks of the standard type used in active <br />underground coal mine operations for bulkhead seals, An example of the type <br />of concrete block to be used will be shown to prospective bidders at the <br />on-site pre-bid meeting, Mortar snail be ASTM C210, Type S consisting of one <br />(1) part Portland cement, 0, 5, part lime putty, 3,5 to 4,5 Darts sand, and <br />water sufficient to produce a stiff plastic mixture. Structural steel for the <br />backstop shall consist of straight steel I-Beam material at a minimum size of <br />W4x13 or straight sections of railroad track taken form the floor of the <br />inclined mine entry. Any steel material to be used other than the existing <br />rail track must be approved by the PROJECT MANAGER prior to use, Grout shall <br />conform to ASTM C476, and aggregate shall conform to ASTM C404, <br />2.3 Execution <br />1, Backstop - The CONTRACTOR shall construct a steel I-Beam or rail track <br />backstop for the concrete block wall in the configuration shown on <br />drawing sheet 6 of 9. The backstop shall consist of four (41 vertical <br />posts positioned as shown on the drawing. The based of each vertical <br />post shall be keyed a minimum of 12" into competent rock along the floor <br />of the incline. The posts shall extend up to the rock roof line <br />presently supported by timbers. It will be necessary to remove a 1.5 ft. <br />to 2.0 ft. section of the existing roof and wall timbers to provide 100% <br />contact between the backstop posts, the concrete block wall, and the rock <br />floor, walls, and roof of the incline. Two (2) of the vertical posts <br />positioned adjacent to the existing rail line shall be supported by <br />welding a straight section of rail or I-Beam at an angle to each of the <br />two vertical posts and to each of the two existing rail tracks which must <br />remain in place behind the position of the block wall for a minimum <br />distance of 2U ft. as shown on the attached drawing sheet 6 of 9. The <br />base of each of the two angled posts shall extend a minimum of 6" into <br />competent floor rock. A steel stop block shall be welded to each of the <br />two vertical I-Beam posts and to the top of each of the two angled posts <br />as shown on drawing sheet 6 of 9. <br />- 5- <br />