Dust formed during drilling in natural stone quarries

Dust mass concentration and concentration decrease was studied in two natural stone quarries in Finland. The dust mass concentrations produced during drilling was measured at several distances with short time interval (5 s) sampling. The variation of concentration was high and wind direction had a crucial effect on dust dispersion. The impact of weather conditions, like temperature and relative humidity, on dust concentration were inconsistent. The dust produced during drilling was mainly coarse-grained and it settled quickly. The background mass concentration was attained from 55 to 105 m at the downwind direction from the drill. The fine particle mass concentrations were low during the measurements. The fine particles originated mainly from other, remote, sources and from the machinery used in the quarries. Local dust sources, like hauling, had a significant impact on dust mass concentrations even inside the quarry. The drilling capacity effected on dust mass concentration near the drill, but the impact vanished quickly with increasing distance.