2016-10-12_PERMIT FILE - M2016010

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Rationale for Recommendation to Approve 10 September 29, 2016 for Monday through Friday. Blasting schedules will be maintained and made available to the public. The primary notification regarding planned dates and times for blasting will be signs posted at each entrance to the property. There will be a total of five signs, posted 24 hours before a blast, which will be updated as necessary if the blast is delayed. These signs will also communicate the blasting audible signal guide, including length of signal relating to the timeline before and after the blast. Prior to a blast being initiated,access corridors will be secured for the length of time needed to successfully complete the blast.Blast guards will be posted at all entrances to the property to ensure the access corridors through the active mining area are secure during the blast process. Pre-blast procedures will include audible blast signals, originating from a vehicle mounted siren that will be utilized according to the following schedule: two minutes before the blast — 15 second audible siren; and 30 seconds before the blast— 30 second audible siren. Federal regulations [30 CFR 816.66(b)] require such signals be audible within a range of one-half(1/2) mile from the point of the blast. Blast guards will be in contact with the lead blaster via CB radio on a channel to be determined at the time the site begins construction. Blast guards will have the authority to stop the blast at any time,up to the time when the blast is initiated. In the case of an emergency, blast guards will notify the lead blaster and stop the blast until the emergency situation is resolved. A typical length of time for a blast is less than 30 minutes. At the completion of the blast, access corridors will be released for normal use. Once the blaster has checked the blast site and determined the area to be safe, an all-clear audible signal of three short siren blasts will be sounded. Afterward, blast guards will release their blocks, and the access corridors will be re-opened for travel. Although misfires rarely occur, in the event of a misfire, the access corridors may be secured for longer than 30 minutes. If a misfire were to occur, the lead blaster, at his discretion, can choose to open Little Turkey Creek Road and allow traffic to proceed until the cause of the misfire has been identified. Thereafter, the lead blaster may secure the access road again for successful completion of the blast. All blasts will be monitored. The blast monitoring procedures will include seismic monitoring to measure ground vibration and peak particle velocity. The proposed maximum peak particle velocity will be one- half (1/2) inch per second, measured at the seismic instrument set up nearest to the closest structure. Particle velocities will be maintained below the proposed maximum allowable limits. Microphones will be used to measure air over pressure (air blast) and noise. The proposed maximum decibel level for air blasts will be 130 decibels, measured at the seismic instrument set up nearest to the closest structure. The industry standard for air blast level is 133 decibels.Air blast levels will be maintained below the maximum allowable limits. All blasts will be monitored with three separate monitoring units made up of a seismograph, a geophone (seismic unit), and a microphone. One stationary unit will be located at the western edge of the property near the western gate off of Little Turkey Creek Road. The second unit will be located on the eastern edge of the property, adjacent to the eastern gate along Little Turkey Creek Road, or on the quarry access road. The location of this unit will be determined based on the closest structure to the blast. The final unit will be placed perpendicular to each blast at or near the nearest property line. All monitoring will be performed by a blasting consulting firm, and records for all blasts will be maintained on site. A third party blasting contractor will prepare a paper record of each blast completed at the quarry. Copies of each blast report will be kept on file in the scale house/office building for pF_Cp�O 1313 Sherman SUee'_ pone 215, Denver, CO 8::203 P 303,866.3567 F 3-,,M32.8106 hlt : " , ninc,state.co :r, John,W, H1Cne,1. opc', Govermw I 'N. Randall, Fr°'Cu*:; D ioccoi i V r'Jt Bra.inan. Ditect0 *l pJ