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detonate during any 8 -millisecond delay. We compared several of these to the associated sketch <br />diagram delay patterns and did not find discrepancies. <br />CCC employs a very conservative approach to calculating the maximum amount of explosives <br />detonated within any one 8 -millisecond delay period. CCC reports the maximum single -hole <br />load multiplied by the maximum number of holes to be detonated within any 8 -millisecond <br />delay. Although this regularly results in CCC reporting more explosives than actually detonated <br />within any particular 8 -millisecond delay, CCC's reported blasting activities still fall within the <br />maximum weight limit per distance from the nearest structure calculated under the equation in <br />Rule 4.08.4(10)(c). <br />CCC employs the formula at Rule 4.08.4(10)(c) to determine the maximum amount of <br />explosives that may detonate during any one 8 -millisecond delay. Under Rule 4.08.6, when using <br />this equation to determine the maximum amount of explosives per delay, and initial seismic <br />monitoring reports are taken and incorporated into the permit (see permit section 4.08.6), seismic <br />monitoring is not required for each blast. However, CCC runs event -triggered seismographs at <br />all times when the machines are not taken off-line for annual calibration or to download monthly <br />data. CCC's seismic monitoring program would record blast events that were close or large <br />enough to trigger the seismographs even if such seismic monitoring were not explicitly required <br />under the approved permit. <br />Seismographs are placed by both nearby dwellings. These properties have changed hands, <br />leading to some confusion in the records. The property formerly owned by Sweeny is now <br />owned by the Cannon Family Partnership and the property formerly owned by Durham is now <br />owned by the Ott's. Mine staff is very familiar with these properties and can correctly identify <br />which structure is referred to on any record, but care should be taken to correctly identify the <br />current landowners. <br />During this inspection, Mr. Blunt brought both seismographs into the office and downloaded the <br />internally recorded data from the month of May. These seismographs are triggered by ground <br />movement or acoustic events. They are not only used to record during blasting activities and <br />will regularly record non -blasting events such as large vehicles traveling on nearby roads. Blast <br />records may be identified by both the time of recording (must be between sunrise and sunset per <br />the approved and advertised blasting schedule, and CCC typically blasts around 12:00 or 4:00 <br />pm) and/or a seismic blast pattern signature. No seismic recordings corresponded with blast <br />times for any of the evaluated blasting records although the seismographs were regularly <br />triggered by other events. <br />The seismographs are calibrated annually and were most recently calibrated on January 23, 2015. <br />The type of instrument and annual calibration certification were included in the seismograph <br />record file. Each individual event record, which may be a blast or any other event that triggers <br />the machine, includes the location of the instrument identified by homeowner name (always <br />placed in the same protected structures / locations), the date and time of the event, and the <br />vibration and airblast level recorded. The distance from the blast to the nearest structure and <br />exact blast location are noted on the blast record rather than the seismograph printout. The <br />records do not indicate the name of the person and firm taking or analyzing the record because <br />5 � Page <br />