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Scaled cloud model for released toxic fumes.
Proceedings of the 10th Annual High-Tech Blasting Seminar, Nashville, TN, July 22-26, 2001. Allentown, PA: Blasting Analysis International, Inc., 2001 Jun; :1-18
Recognizing the dynamic nature and possible range of toxic concentrations in the impending fume cloud prior to undertaking explosive blasting can reduce potential hazards and mitigate related incidents. The scaled cloud model was formulated to predict the relevant (major) toxic components in fume clouds released by nonideal mining explosives used for surface blasting. Natural turbulence unceasingly disperses the toxic molecules, widening (inflating) the fume cloud while diluting the concentrations, ultimately rendering nonhazardous conditions. The threshold cloud size depends upon the type and quantity of total explosives used and the cloud's thermodynamic condition. Though the scaled theory works for fume clouds with irregular (odd) shape, and equivalent upright cylindrical form is useful for rendering simple risk/hazard scenarios. The cylinder's projection downward on the underlying terrain yields a circular 'shadow' marking the region threatened, thereby permitting a rough estimation of the potential hazards, were the cloud to settle down there. Wind causes the cloud to drift while it expands, so the shadow travels while it grows, until the risk/hazard process is truncated at the nonhazardous threshold.
Surface-mining; Mining-industry; Explosives; Explosive-hazards; Explosive-gases; Explosive-dusts; Toxic-gases; Toxic-vapors
NIOSH Pittsburgh Research Laboratory, P.O. Box 18070, Pittsburgh, PA 15236
Proceedings of the 10th Annual High-Tech Blasting Seminar, Nashville, TN, July 22-26, 2001
Page last reviewed: April 12, 2019
Content source: National Institute for Occupational Safety and Health Education and Information Division