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trucks, which in turn dumps the material into previously mined quarry areas. The same process is used <br />to extract sandstone and limestone except the material is mined via loader and dumped into an impact <br />crusher. The overburden and limestone are each mined in two benches for a total of four benches. The <br />following equipment is used in the mining operations: <br />1- Liebhen• Shovel <br />1 -Caterpillar 992G Loader <br />1 -Caterpillar 992D Loader <br />1 -Caterpillar D9R Dozer <br />5 -Caterpillar 785D Haul Trucks <br />1- 20,000-gallon Water Truck <br />1 - Caterpillaz 16H Motor Grader. <br />Holcim (US) Inc. is currently mining limestone west of Bear Creek in Cut 1 (Exhibit C, Figure C-2) <br />and overburden on the east side of Bear Creek in Cut 2 and 3. It is expected that limestone extraction <br />east of Bear Creek will begin in 2003. As depicted in the cut sequence shown on the Mining Plan <br />Map, mining will continue to the north for the next 36 years, working west to east in each of the cuts. <br />Table D-1 shows the estimated timetable, tonnage of material to be mined, the approximate size of <br />each of the cuts (in acres), and sequence of mining that will occur over the next 40 years. <br />The eastern boundary of the Beaz Creek mining area is adjacent to "L" Street and a number of <br />residences. When blasting neaz constructed facilities airblast and ground vibrations induced by <br />blasting will be minimized. Minimizing the amount of explosives or charge weight detonating at any <br />one time will reduce ground vibrations. This is accomplished by altering the blast design and/or <br />detonation sequence of the blast. It is recommended that the peak particle velocity (PPV) stay below <br />0.5 inches per second. The following equation, developed by the Bureau of Mines, can be used to <br />estimate PPV under normal co~nement conditions: <br />-1.6 <br />PPV =160 ~ o.s <br />Where: <br />PPV - Peak Particle Velocity (inches per second) <br />D - Distance to structure (ft) <br />W - Charge Weight in lbs. <br />Normal Confinement is defined as a blast having a free face. <br />This equation is used only to estimate predicted PPV based on a particular blast design. Test blasts at <br />the site will be conducted and the resulting vibrations measured. Actual site vibrations for a particular <br />6 of 34 <br />