Environmental surveillance in mining, milling and processing of thorium mineral monazite -radiological aspects

The paper presents the results of the ongoing environmental radiological surveillance related to beach sand minerals mining, separation and monazite/thorium processing and assesses the radiological environmental impact. Mining and mineral separation activities resulted in a net reduction of the external exposures by factors ranging from 2 to 12 at the natural high background radiation area (NHBRA). The activity content of the solid tailings and liquid effluents in mining and mineral separation is comparable to that of soil and water concentrations of NHBRAs. In the case of chemical processing of monazite, source control measures by engineered safety systems like liquid effluent treatment, controlled release of gaseous effluents and safe storage of solid wastes coupled with constant surveillance ensure that the environmental impact of monazite processing operations by the way of solid, liquid or gaseous discharges and active material storages are insignificant. (author)