Some New Characteristic Properties of Certain Industrial Dusts

Abstract

WITH the assistance and encouragement of the Institution of Mining and Metallurgy and the Medical Research Council, we have continued an investigation, initiated four years ago under the auspices of the Institute of Chemistry, upon the chemical nature of dusts causing silicosis. Using the salicylic acid dust filters described in a recent communication1, we have now obtained, probably for the first time, analysable samples of mine dust as breathed by the miner. The dust was produced by wet drilling and blasting of granite in a Cornish mine. On beginning the analyses of these samples, we immediately found that the loss on ignition, determined on the material dried at 105° C, was between 8.0 and 9.0 per cent, whereas the corresponding figure for the powdered granite rock was 0.6 per cent. Further analyses showed that the high loss on ignition was probably due to hydration of the dust, since it increased progressively from 3.7 to 5.7 and 8.5 per cent in samples taken at 10 ft., 20 ft. and 40 ft. from the working face.