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3.2.3 BLASTING METHODS <br />• Blasting will be conducted to minimize the peak particle velocity for each shot. <br />The equation W = [D/60]2, where W is the weight of explosive in pounds and D is the <br />distance to nearest dwelling in feet, will be used to calculate the pounds per delay <br />period. The minimum delay period will be 8 milliseconds. Delays will be placed in <br />a shot in accordance with the preceding formula. Hole spacing and powder columns <br />will be adjusted as necessary for compliance with airblast and flyrock regulations. No <br />monitoring of these parameters is anticipated while using the scale distonce formula <br />of 60 as stated above. <br />All blasting will be accomplished using commercially available explosives which <br />are suitable for surface mining operations. These will usually consist of bulk or <br />bagged ANFO, cast primers and slurry. Detonation cord and blasting caps will also <br />be used. <br />A typical overburden hole loading pattern and detonation scheme are shown in <br />Exhibit 3.2-5. A Typical interburden and coal loading pattern and detonating scheme <br />are shown in Exhibit 3.2-6. <br />3.2.4 PRE-BLAST SURVEYS <br />Upon request by the Regulatory Authority or landowner, pre-blast surveys will <br />be made in a timely fashion. We anticipate using Travelers Insurance to perform and <br />report these surveys in compliance with the applicable laws. Travelers has been used <br />in the past by Pittsburg 8~ Midway to perform This Type of evaluation. Reports of <br />findings will be filed with the Regulatory Authority and the subject of the pre-blast <br />survey. <br />• <br />Revised 7-81 3.2-5 <br />