This investigation was originally to evaluate, through underground tests, water spray systems for controlling respirable dust at the face of a longwall plow. After encountering several difficulties, the investigation was modified to evaluate five factors believed to affect respirable dust levels in the dust tunnel facility. A 60- foot-long plow face mockup was constructed in the tunnel, a facility with controlled airflow and dust concentration. Six types of nozzles were tested with the following parameters: two nozzle orientations, two levels of water pressure, two levels of airflow, and with and without simulated airflow through the gob. Of these factors, the most significant in reducing respirable dust levels was nozzle orientation, where the nozzle directed 45 deg downstream resulted in 27 percent lower dust levels than those directed 45 deg upstream (against airflow). All nozzles tested resulted in similar dust reduction, that is, the type of nozzle was the least significant factor.