207.3(e) 207.3(f) 207 – 6 • The Contractor is liable for all injuries or deaths of persons and/or farm/domestic animals, and any damage to property caused by blasting.
specified in Section 207.3(e), and with the following :
• Conduct initial test blast section as one presplit blast pattern using variable spacing of 18 inches over 18 feet, 24 inches over 24 feet, 30 inches over 30 feet, and 36 inches over 36 feet using a maximum lift of 30 feet.
• Maintain h ole to hole spacing requirements for 18 -inch and 24 -inch presplit patterns within 75 to 125 percent of the intended spacing. For 30 -inch and 36 -inch presplit patterns, hole to hole spacing must be within 6 inches of the intended spacing. Maintain h ole to hole spacing throughout presplitting. If the deviation of presplit blastholes exceeds the allowable tolerance, provide the Representative alternative drilling methods in a revised Blasting Plan to reduce deviation within the above specified tolerances. Obtain Department acceptance of the revised Blasting Plan before proceeding. Do not exceed 110 feet for t estse ctions.
• Ensure t he test section demonstrates the suitability of the proposed blast plan relative to fragmentation requirements, over break control, flyrock control, adequacy of stemming, and other appropriate or necessary factors.
• When results of the drill logs are unusual (i.e., encountering zones of soft or weathered rock, mud or clay pockets, voids; rate of penetration; and the color and character of drill cuttings), revise the Blasting Plan as necessary and obtain Department acc eptance of the revised Blasting Plan before proceeding.
• When rock of different characteristics is encountered, perform a blasting test section.
• Excavate the blasted test section to fully expose the presplit face and provide the means to access the face so that the Representative can examine and evaluate the results of the blasted test sections. The Representative will examine the completed test section and select the blasthole spacing that demonstrates the best presplit face quality. If no acceptable conditions are found by the Representative upon examination of the test section, revise and submit to the Representative a new Blasting Plan for review and acceptance. Suspend d rilling and blasting until the Blasting Plan is accepted. At no additional cost, conduct additional test sections at the same blasthole diameter and spacing used for the previous test section and adjust the explosive load until desired/acceptable results a re obtained without exceeding the established PPV as specified in Section 207.3(j). Unsatisfactory results include, but are not limited to, excessive fragmentation beyond the indicated lines and grade, excessive flyrock, and poor timing delay