NIOSHTIC-2 No. 20025149


Removing Booster Influences From Toxic Fumes

1999

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This report investigates whether it is tractable and thereupon reasonable to remove the booster influences when ranking the toxic fumes for non-cap-sensitive mining explosives. The hazard potential is represented by relative fume toxicity RFT, the resultant influence computed from a formulated rule with a restricted set (tally) of fume components and multiplying constants. The RFT result is compared to the rule criterion that represents the worst case tolerable toxicity stipulated by regulations or otherwise. The typical nonstoichiometric booster composition can render notable unwanted influence on the RFT ranking results. Historically, the remedy was to shoot the booster separately and reduce the trial concentrations by the relevant subtractions. Unreal negative concentration results were noted on rare occasions, revealing the faulty nature of the reduction procedure. With thermodynamic reaction chemistry codes TDRC, on the other hand, the booster ingredients can be retained in or removed from the reactant tabulation, yielding reduction factors taken as the concentration ratios for the two circumstances. The underlying presumption regarding reduction factors is that the ratios of component concentrations with and without the booster ingredients when resolved theoretically ought to equal those rendered experimentally, when tractable. Upon rearranging the presumed relationship, the unadjusted fume concentrations divided by theoretical reduction factors yield the wanted readjusted fume concentrations, thereby removing the booster influence without generating unreal negative concentrations.

Author(s):Wieland-MS
Reference:Proc 25th Ann Conf Explos Blasting Tech. Cleveland, OH: Intl Society of Explosives Engineers, 1999; :11-28

   rbiftf (PDF, 7800 KB)


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Page last updated: September 17, 2008
Content Source: National Institute for Occupational Safety and Health (NIOSH) Mining Division