ABSTRACT
Blasters are one of the highest exposed work groups to diesel particulate matter (DPM) in underground metal/nonmetal mining. They can spend a good portion of their day under a canopy in a basket loading blastholes with explosives. Therefore, one way of potentially reducing their exposures to DPM is to place a canopy air curtain (CAC) on the basket of the ANFO loader. This paper describes the testing of a CAC that was redesigned to fit an ANFO loader and mitigate exposures to DPM as well as respirable dust. Laboratory measurements demonstrated reductions of submicron particles that relate to the percent reductions of DPM. The CAC provided substantial protection of mine workers to DPM (78 % reductions), from within 15.24 cm (6 inches) of the edge of the plenum using a 7.62-cm (3-inch) lip. As the mine worker approaches the edges of the plenum, the percent reduction starts to reduce to the 7%–53% range. The mine worker achieves the best results when within 15.24 cm (6 inches) from the edge of the plenum. In addition, the breathing zone of the mine worker should be 25.4–50.8 cm (10–20 inches) below the plenum.
