Studies of radioactive dust in Canadian uranium mines

CIM Bulletin, Vol. 77, No. 869, 1984

J. BIGU and M.G. GRENIER Elliot Lake Laboratory, CANMET, EMR Elliot Lake, Ontario

Dust size distribution and aerosol size distribution measurements have been carried out in several Canadian underground uranium mines. In addition, dust samples have been analyzed for long-lived radioactive products of the U-238 and Th-232 natural decay chains using α-spectroscopy and γ-spectroscopy techniques. From the data collected one may summarize: (a) most airborne particulates are of size below 1 µm and 50% by mass are found above 1 µm; (b) dust clouds are bimodal; (c) preferential deposition of radon (thoron) daughters takes place on airborne particulates in the sub-micron range at about 0.1 µm; (d) deposition of radon (thoron) daughters is proportional to particle surface area; and (e) a-spectroscopy and γ-spectroscopy of dust samples reveals the presence of U-238, Ra-226 and some of their short-lived and long-lived decay products.
Keywords: Radioactive dust, Environmental control, Underground mining, Radiation, Monitoring, Uranium mines