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specifications for these two instruments can be seen in Attachment 2.05.3(6)(a)-3. These <br />instruments will measure peak particle velocity in three mutually perpendicular directions. They <br />will be typically placed at the closed structures to the actual blast site. They will provide a <br />recorded readout of peak particle velocity and potential air blast after each blast event. The peak <br />velocity value and other instrumentation data will be printed out as shown in Attachment <br />2.05.3(6)(a)-4. The recorded digital seismic data will be downloaded and kept on file, along with <br />the blast report from the contractor, at the mine office. <br />Production <br />Bagged, slurry or dry ANFO explosive will be used at different times to properly fracture the <br />overburden at the New Horizon Mine. Powder factors will vary with each shot due to ever <br />changing geologic rock formations. Powder factors for each shot will be selected after the <br />following criteria have been taken into consideration: <br />a. Examining the highwall for geologic rock formation thickness and rock type. <br />b. Consult with the blast-hole drill operator for hardness of the rock and thickness within <br />the proposed blast area. <br />c. Consult with the overburden shovel operator for size of blasted rock and ease of <br />digging. <br />d. Location of shot in relationship to dwellings and other structures. <br />e. Reviewing previous seismic blast records for peak particle velocity. Peak particle <br />velocities for each shot will be closely monitored by seismic recorders and will be kept <br />below the 1 in/sec limit at any inhabited structure off the mine property. WFC will make <br />every attempt to keep the PPV as low as practical but still get the overburden fractured <br />to our satisfaction. <br />)xeoisea 12-07-99) 2.05.3(6)(a) 4 <br />