INGUISHERS, FLAME PROPAGATION, POTASSIUM COMPOUNDS, CARBONATES, PRESSURE*COAL DUST, COAL MINES, SYSTEMS ANALYSIS, MINE SAFETY, POTASSIUM CARBONATESA program for the Bureau of Mines to develop a system to suppress coal mine dust explosives has achieved certain notable results at the end of the first year. After extensive study of coal dust explosion phenomena a project plan was developed, a test facility built and several suppression devices tested. The facility is a 4.5 foot diameter shock tube, 317 feet in length, and to date 53 tests have been carried out with methane-air and methane/coal dust-air as the explosive mixtures. Suppression of slowly propagating (up to 300 ft/sec) flame fronts has been successfully carried out on two tests using the dry chemical extinguishing agent Purple K. Delivery of the material directly into the flame front seems to be required if effective suppression is to be accomplished. (Author).