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church, or community or institutional building outside the permit area except at such structures <br />owned by WFC. <br />Ground Vibration. WFC may use seismograph monitors for homes located within 1000' of the <br />proposed blast location, if additional data collection is needed to help perfect WFC's blast <br />modeling program, or at a resident's request, to record the ground vibrations (in /sec) in the <br />three planes (Longitudinal, Transverse, and Vertical). Where appropriate, these same <br />seismographs will also record the air pressure change (dbL) caused by the blast at the same <br />locations. After each blast, the seismographs are downloaded and the information is printed and <br />analyzed. The information is then used to formulate a new blast scale distance factor as well as <br />to judge the shot as being in /out of compliance. For this permit, WFC will use the Maximum <br />Peak Particle Velocity (PPV) vs. distance table located in Table 2.05.3(6)(a) -1 to judge the <br />ground vibrations for compliance purposes. The maximum allowable air blast limits WFC will <br />use for compliance judgment can also be viewed in Table 2.05.3(6)(a) -1. <br />Fly -Rock. Stemming is loaded into blast -holes prior to detonation to substantially reduce the <br />occurrence of fly rock. The depth of stemming will be designed such that the fly rock, which <br />may result from blasting operations, shall not be cast from the blasting site more than one -half <br />the distance to the nearest dwelling or other occupied structure, and in no case beyond the area <br />of control or beyond the line of property owned or leased by WFC. WFC uses crushed rock for <br />stemming to control vertical displacement of fly rock. The horizontally displaced spoil however, <br />is allowed to move within the previous pit area and into position against the existing spoil pile. <br />Blasting within 500 feet of Pipeline. Under the approved MR -82 for the New Horizon Mine <br />Permit, a segment of the CCC Ditch will be located within 500 feet of blasting activities <br />proposed for the New Horizon North Mine. Rule 4.08.4(7)(b) prohibits blasting activities within <br />500 feet of a pipeline unless approved by DRMS. WFC requests DRMS that this requirement be <br />waived in the NHN permit. The pipe material is heavy duty polyethylene (HDPE). It has <br />adequately resisted blast vibrations at the New Horizon Mine West Lateral Ditch. Blasting has <br />taken place as close to as 147 feet from the pipeline in the New Horizon Mine without any <br />adverse consequence. The pipe carries only water. Should there be any damage to the pipe <br />due to blasting, it will be promptly repaired. No adverse consequence will take place. The <br />pipeline maintenance is also a requirement under the agreement between WFC and CCC Ditch <br />Company. See Appendix 2.05.3(4) -5. <br />Section 2.05.3(6)(a) <br />Page 7 <br />February 2012 <br />