Prolonged exposure to high concentrations of respirable coal mine dust causes coal workers' pneumoconiosis and silicosis. Roof bolter operators in underground coal mines have a higher risk of coal dust overexposure. The canopy air curtain (CAC) was developed by NIOSH to protect roof bolter operators from excessive coal dust exposure. The CAC dispenses streams of airflow over the breathing zone of the operator to provide an impenetrable air curtain which prevents coal dust from entering the breathing zone of the operator. However, current CAC generation has an efficiency of 46% due to non-uniform airflow distribution across the plenum indicating rooms to improve the design. This study therefore redesigns the CAC using a two-level manifold system with optimized flow distribution that effectively protects roof bolters from coal dust exposures. The Simplex Evolutionary Operation (EVOP) optimization algorithm and Computational fluid dynamics (CFD) simulations are used to optimize the uniformity of airflow distribution across the plenum to achieve the optimum uniformity. A physical model of the optimized design is built, and lab tested in an experiment to validate the results from the CFD simulations. The improved CAC design is capable of keeping roof bolter operators' dust exposure levels below permissible limits.
