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<br /> <br />Figure 3. Alternative blasting level criteria. (Source Modified from figure B-1. Bureau of Mines R18507) <br /> <br />5.2 Limits on airblast <br />Air overpressure shall not exceed the maximum limit of 136 decibel (0.124 Kpa) at the location of any <br />building or structures within one half mile of the blast area. <br /> <br />5.3 Methods used to control adverse effects of blasting <br /> <br />For the adverse control effects of blasting, we propose the recommendations from ISEE, International <br />Society of Explosives Engineers: <br /> <br />Flyrock Control Issues <br />Issue Comment <br />Explosive Column <br />Length <br />Column length should never been longer than design to such and extend that estimated maximum flyrock <br />projections can exceed ½ to 2/3 of the distance to sensitive receivers. <br />Explosives Loaded <br />density <br />Loaded density should not be significantly higher than design-through incorrect gassing of emulsion <br />product, errors in the size high density base charges, reduction in size of air decks, or the use of larger <br />diameter cartridge products than was proposed in the design (where an air deck is specified, but the hole <br />is full of water, then calculations of effective density should ignore the air/ware/deck) <br />Stemming columns Stemming columns must be continues, and bridging of the stemming columns must avoid - best achieved <br />through the use of uncontaminated, well-graded aggregate material, and loaded so as to avoid bridging <br />Protocols for <br />exception reporting <br />Errors will happen, and adjustments to procedures can be made providing that the error is reported and <br />tools are available to provide reliable estimates of worst-case outcomes. <br />Table 2. Flyrock control issues. <br /> <br /> <br />