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RULE 4 PERFORMANCE STANDARDS <br />schedule and inform them of the meaning of the signals. Colowyo will also maintain signs in <br />accordance with Section 4.02. <br />A resident or owner of a dwelling or structure that is located within one-half mile of the location of the <br />blast, as described in the annual blasting schedule, shall be notified no less than 24 hours prior to any <br />surface blasting or less frequently as each resident occupant in such areas shall approve in writing to the <br />Division. <br />Colowyo will regulate access into the area possibly subject to flyrock from blasting to protect the public <br />and livestock. Fences are in place to keep livestock out of the mining areas. The permit area will be <br />identified by signs on the access road restricting entry to authorized personnel. Signs will also be posted <br />identifying the area as a blasting area and describe the warning and all -clear signals. Immediate access to <br />the area of blasting will be cleared and controlled by qualified mine personnel prior to any blast. <br />Colowyo will control air blast from its blasting operations within the permit area so it does not exceed <br />the values specified by the chart set forth in Rule 4.08.4(6). The same design factors utilized to control <br />the seismic effects of blasting (i.e.: the use of numerous surface delays to "spread" the shots out over <br />time, particularly near residences) is also very effective in controlling airblast. Additionally, to keep <br />airblast to a minimum Colowyo also routinely 1) utilizes reduced weight (12 grain Zap) surface primer <br />cord, 2) uses proper stemming material, 3) uses a proper stemming weight, 4) avoids overdigging the <br />front row of holes and 5) avoids overloading the front row of holes. <br />Colowyo does perform event triggered monitoring. However, Colowyo will not commit to daily <br />monitoring due to unforeseen circumstances where the seismograph monitoring unit may be getting <br />repaired or calibrated. Colowyo employs an Instantel Inc. Minimate Plus seismograph/microphone <br />with a low frequency limit of 2 Hz which corresponds to an airblast standard of 133 dB (peak). <br />Records of airblast monitoring will contain the information required by Rule 4.08.5(17). This <br />information will include either a recording of the calibration signal of the monitoring instrument's gain <br />setting at the time of each blast, or certifications of the instrument's annual calibration. <br />Colowyo will conduct blasting to prevent injury to persons and damage to public or private property <br />outside the permit area. Colowyo will insure that the maximum peak particle velocity will not exceed the <br />criteria as prescribed by utilizing the equation found in Rule 4.08.4(10) (b) (i) when conducting blasting <br />operations that could affect any dwelling, public building, school, church, or commercial or institutional <br />building. As shown in the Blasting Analysis Map (Map 26) Colowyo has determined the maximum <br />pounds of explosives per 8ms period of time for variable distance from any such structures. <br />The number of blast holes detonated per 8ms period will be calculated according to the equation in Rule <br />4.08.4(10)(c)(i) in order to determine the maximum weight of explosive that can be detonated within any <br />eight ms period. <br />4.08.5 Records of Surface Blasting Activities <br />Colowyo will record all blasts including coal, overburden, and overburden pre -split blasts in a format as <br />shown in Section 2.05, Figure 2.05-2, Blasting Report, which conforms to the requirements of 4.08.5. <br />Conducting blasting operations in accordance with the equation in 4.08.4(10)(c)(i) deems peak particle <br />velocities from blasting to be within the regulatory limits described in 4.08.4(10). Periodic airblast <br />monitoring occurs at Colowyo. The monitor is located along Moffat County Highway 13 at the <br />Durham/Ott Ranch. Records of airblast monitoring described on page 2.05-30 will contain the <br />information required by Rule 4.08.5(17). This information will include either a recording of the <br />calibration signal of the monitoring instrument's gain setting at the time of each blast, or certifications of <br />the instrument's annual calibration. <br />Rule 4 Performance Standards 4-29 Revision Date: 1/31/18 <br />Revision No.: TR -119 <br />