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Trapper Mine <br />Records of Blasting <br />Page 2 <br />October 21, 2014 <br />2. Rule 4.08.5(7) requires sketches of the blast pattern including the depiction of the number of <br />holes, burden, spacing and delay pattern. Rule 4.08.5(8) requires the blasting sketch to show <br />decking, if holes are decked to achieve different delay times within a hole. Trapper's current <br />blasting summary log provides a sketch of the blast pattern; however, many of the sketches are <br />difficult to understand; particularly the delay pattern which is necessary to determine <br />compliance with Rule 4.08.5(11). Also, the current blasting summary form and sketch do not <br />appear to account for down hole delays in the blast pattern. Trapper lists the delays used under <br />the "Materials Used" section of the log. This portion of the form is filled out inconsistently <br />and it is difficult to translate the information to the blast pattern sketched. Based on the <br />Division's conversation with Tom Paulson and Kraig Copeland, Trapper is evaluating how to <br />improve the blasting sketch to make it easier to understand these issues. We appreciate this. <br />The Division agrees the sketch could be improved and also believes the delay information <br />provided under the "Materials Used" section should be clarified. <br />3. Rule 4.08.5(l 1) requires the total weight of explosives used per hole and the maximum weight <br />of explosives used per 8- millisecond period. Trapper's letter dated August 29, 2014 provides a <br />description of how Trapper determines the number of holes that explode within each 8- <br />millisecond period, the total number of 8- millisecond delay periods and the pounds per 8- <br />millisecond delay period recorded. Based on the information provided in the letter, Trapper <br />reports the maximum potential pounds of explosive that could explode within an 8- millisecond <br />period for each blast. The Division understands that Trapper determines the maximum number <br />of holes going off during an 8- millisecond period and multiplies that number by the largest <br />amount of explosives placed within a blast hole. While the Division agrees this is a <br />conservative reporting method to ensure the number of pounds being exploded is below the <br />maximum pounds allowed under the scale distance threshold based on Rule 4.08.4(10), it does <br />not comply with the reporting requirements of Rule 4.08.5(l 1) which requires the maximum <br />weight of explosives used per 8- millisecond period be recorded. Given this, please report the <br />actual maximum weight of explosives used per 8- millisecond period on the blasting summary <br />log. Until the form is revised, please provide this information on the blasting summary log. <br />4. Rules 4.08.5(12), (13) and (15) require the initiation system, type and length of stemming and <br />the type of delay detonator and delay period used be reported for the blast. As acknowledged <br />in Trapper's August 29, 2014 letter, this information is being provided in the notes section of <br />the blasting summary log. The letter also indicates that Trapper will add spaces for the items <br />on the blasting summary log so they are not inadvertently left off. The Division agrees with <br />this plan. Until the approval of the revision to update the blasting summary log, please <br />continue to provide this information on the current form. <br />5. A separate report from the blasting summary log records the results of airblast monitoring at <br />the site. However, Rule 4.08.5(17)(b) requires the distance of the blast to the airblast <br />monitoring instrument be recorded. As this distance will fluctuate from blast to blast, this <br />information will need to be provided on the blasting summary log. For all future blast records, <br />