Abstract The radium content of a representative sandstone type of uranium ore was found to be distributed uniformly according to particle size before leaching, but in sulfuric acid-leached tailings was found predominantly in the −325 mesh fraction. The radium leaching characteristics from both ore and sulfate-leached tailings were investigated. Several 1 M salt solutions showed poor to moderate RaSO 4 dissolution from “slimes solids” tailings, while 3 M HNO 3 or HCl solutions dissolved approximately 95% of the radium content of either ore or tailings. Tests are reported in which −325 mesh sand particles were coated with alkaline-earth sulfates by a special technique to simulate slime solids tailings. The dissolution of RaSO 4 from these coated sands was decreased by the presence of BaSO 4, but increased by the presence of CaSO 4. The interrelationships in the dissolution of mixtures of CaSO 4, SrSO 4, BaSO 4, and RASO 4 are shown, and a generalized equation for the estimation of the dissolution of a minor component is presented.