The National Institute for Occupational Safety and Health (NIOSH) and the Mine Safety and Health Administration (MSHA) conducted joint research to evaluate explosion blast effects on typical U.S. mine ventilation stoppings in the Pittsburgh Research Laboratory (PRL) Lake Lynn Experimental Mine (LLEM). An innovative Australian-designed brattice stopping was also evaluated. After mine explosion accidents, MSHA conducts investigations to determine the cause(s) as a means to prevent future occurrences. As part of these postexplosion investigations, the condition of underground stoppings, including the debris from damaged stoppings, is documented as evidence of the approximate strength and the direction of the explosion forces.