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Review of Blasting Operations at Denver Brick Company's Golden Mine <br /> Range of PPV Curves(Oriard) <br /> 10.00 <br /> (254) V=K(DJW,2 j- �--K 1�1 =eas <br /> K Metrc(S 1.)=4318 <br /> E K Wwerd-242 <br /> v K Metic(S 1►= 1726 <br /> IA �'tdr� <br /> 1.00 <br /> (25.4) r <br /> K InVerW =24 IA' O <br /> K Metric(S 1.)- 171 <ry <br /> 0.10 NOTES: <br /> oe s <br /> F� r <br /> R (2.54) ATTENUATION SLOPE: ti� ' tiy <br /> d. -1.6 is typical but slope may vary qs� <br /> Y depending on crave types ' <br /> aand other modifying factors. <br /> Slopes usually vary between-1.0 and-1.9 <br /> 0.01 <br /> (0.25)1(0.45) 10(4.52) 100(45.2) 1000(452) <br /> Scaled Distance - ft/lb"n (m/kg1f2) <br /> Figure 2.3 -Oriard Blast Vibration Prediction Curves <br /> The Colorado Division of Labor blasting regulations require blasters to use a minimum scaled <br /> distance (SD) of 55 ft/lb'"2when calculating maximum charge weights. Charges determined with <br /> this formula are designed to ensure that ground motion does not approach levels that might <br /> cause even cosmetic damage (0.5 in/sec in homes with plaster walls).The intensity of vibration <br /> is reduced when scaled distance is increased. <br /> For Blasting at the Golden Mine, the maximum charge per delay could be limited to 50 pounds <br /> per delay.At this limit, the scaled distance to the nearest occupied residential structure 800 feet <br /> from the blasting area, is 113 ft/Ib'r2. <br /> SD = 850 = 113 ft/lb1/2 <br /> At this scaled distance, using conservative response constants in the vibration prediction <br /> formula shown in equation 2.1, the ground motion at the nearest structure would be around 0.15 <br /> in/sec. <br /> PPV = 300013)" = 0. 15 in /sec <br /> 10 <br />