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Colorado Legacy Land Former Schwartzwalder Mine <br /> North Waste Rock Pile Diversion Channel <br /> a. Trial welding will be done at the start of every 4 hr. (approx.) shift, after <br /> the machine has been turned off and restarted,and when the <br /> geomembrane changes temperature by more than 25°C. <br /> b. Trial welds,at least 4 ft. long, shall be made on scraps of the same <br /> material as will be installed. <br /> C. Welds will be made with sheet in the same orientation(flat floor, slope, <br /> wall etc.)and on the same substrate as the planned production welds. <br /> Trial welding conditions shall not be optimized. <br /> d. Five specimens shall be tested in peel mode according to the parameters <br /> below. The minimum geomembrane tab elongation of 50% allows for <br /> scrim break but the polymer layers must not break. <br /> e. Trial Seam Peel Test Parameters: <br /> (1) Width Specimen: 1 inch <br /> (2) Number of Specimens: 5 <br /> (3) Grip/Specimen Distance: 1 inch <br /> (4) Crosshead Speed: 2 inches/min <br /> (5) Elongation: 50%min. <br /> (6) Separation: 0% <br /> f. If three trial weld attempts fail,the equipment shall be put aside and <br /> repaired. When used again,two passing trial welds shall be made before <br /> that equipment can be used for production welding. <br /> g. The cross sections of welds shall be examined for symmetry, lack of <br /> crimping(overheating), and the presence of voids and foreign <br /> particulates. If voids and particulates are present the weld will be <br /> rejected, even if the weld passes a peel test. <br /> h. When geomembrane temperatures during welding are below 40OF or <br /> above 100°F 5 peel specimens will be tested for unreinforced material <br /> seams. All must pass. <br /> 3. Field Welding <br /> a. Two types of weld geometry are acceptable: <br /> (1) Double track fusion welding for long straight seams with free <br /> flaps on each side of the weld for peel and shear testing <br /> (2) Extrusion welding for patches with a flap on the underside. <br /> Section 026617-Geomembrane Page 8 <br />