Assessment of gas and dust explosion hazards in oil shale mining using ANFO

Experimental mine testing has shown that hot combustion products generated from a detonating explosive can result in a secondary dust or gas explosion. The common blasting agent ANFO (ammonium nitrate--6 pct fuel oil) has been shown in the Bruceton experimental mine (BEM) tests to readily ignite pre-existing explosive concentrations of oil shale dust and/or methane gas when detonated unstemmed. Tests also show that these ignitions can be curtailed with the use of an inert stemming material. Current data on background methane emission studies at two western U.S. oil shale mines are also presented.