2nd U.S. Mine Ventilation Symposium, Reno, Nevada, 23–25 September 1985 Authors: C. E. Brechtel, M. E. Adam, and J. F. T. Agapito (AAI), and E. D. Thimons (USBM) The performance of two large-capacity face ventilation systems was measured using sulfur hexaflouride tracer gas tests in a large dead-end heading at the Colony shale oil mine. The test room was 17-m wide by 9-m high and 98-m long. Testing compared the effectiveness of a free-standing, jet fan and a reversible fan with rigid duct. The jet fan performance was similar to the ducted system while using less power. Tracer gas was used to simulate the production of mine air pollutants including blasting fumes, hot diesel emissions, free methane from surrounding strata, and methane desorbing from rubblized shale. The tests showed both systems could provide effective ventilation during oil shale mining.