This project describes the design and testing of large face ventilation systems for oil shale mining. A design data base was generated by reviewing general industry practice, oil shale industry planning, and technical literature. Conceptual designs for seven different systems were developed and evaluated for suitability. A large, freestanding, jet fan and reversible fan with rigid duct were selected for fabrication and testing. The two systems were field tested in a dead-end heading 55 ft wide by 30 ft high and 320 ft long. System performance was optimized using measurements of airflow direction and air velocity. Total system performance was then measured using sf6 tracer gas released to simulate blast fumes, hot diesel exhaust, methane layering, and methane from a blasted muckpile. Field testing indicated that both systems delivered similar performance. The jet fan offered some clear advantages because of its mobility, ease of operation, and lower power requirement. It also offered some functional advantages in ventilating for methane because of its high average velocity.