2020-12-28_GENERAL DOCUMENTS - M1977300 (23)

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Colorado Legacy Land Former Schwartzwalder Mine North Waste Rock Pile Diversion Channel b. Sheet overlaps should be sufficient to facilitate seam peel testing, typically 4 in. for extrusion seams and 6 in. for fusion seams. C. For double track fusion welds,the outer flap shall be wide enough to facilitate peel testing. d. Welding shall not be done in strong winds, during precipitation, and during lightning storms,nor where there is standing water on the subgrade. e. The surfaces to be bonded shall be dry and clean for fusion welding. Dry with a clean cloth, or carefully with a hot air gun. Clean with a cloth or carefully with isopropyl alcohol and water. f. Reinforcement yarns shall not be exposed during grinding/abrasion, and all abrasion debris shall be removed. g. Welding shall be done within 30 minutes of surface preparation. h. Welding shall continue to the edge of the liner in the anchor trench. i. Fishmouths in reinforced materials shall be cut along the peak, overlapped, laid flat, and extrusion welded along the full length. A minimum 6 in. diameter patch will be placed over the end of the cut. A keyhole shall be made at the end of the cut and the remainder of the overlap patched. The keyhole will minimize the potential for further propagation of the cut. j. At the end of every weld write on the liner: (1) Initials of operator (2) Number of welding machine (3) Machine speed,temperature,pressure settings (4) Date (5) Time started 4. Nondestructive Testing a. Two test methods are available: (1) center air channel pressure testing for double track fusion seams (2) vacuum box testing for single track fusion and extrusion seams b. Air Channel Testing (1) Clamp or otherwise seal both ends of the seam to be tested— distance not to exceed 450 ft. Section 026617-Geomembrane Page 9