Reducing Bag Operator's Dust Exposure in Mineral Processing Plants

Abstract The Bureau of Mines has been investigating various techniques to reduce dust exposures of workers at mineral processing plants. A major problem has been the exposure of the bag operator who loads mineral product into 50- or 100-pound bags at a fill station. In many cases, this worker has the highest dust exposure of the entire plant. In the past few years, the Bureau has investigated several approaches that can significantly lower bag operator dust exposure. These include bag valve modification, dual bag nozzle system, overhead air supply island (OASIS), and control of background dust sources. Five commercially available bag-filling valves were evaluated to determine their dust reduction capabilities. An extended polyethylene valve was found to be the most effective, resulting in a 62 percent reduction in operator dust exposure as compared to the standard paper valve. A dual bag nozzle system was developed that decreases product loss and significantly lowers the operator's exposure. With this sys...