Nitric acid leaching of representative uranium ores and mill tailings from the western U.S. mining districts removes up to 98% of the 226Ra and 230Th, yielding a residue con¬taining 17 to 60 pCi of radium per gram. At best, this is an order of magnitude greater than that in surrounding soils, but about the same level as a standard proposed for building materials in the United Kingdom. Data are also presented on the water penetration and leaching of tailings, the solubility of BaS04, and radon emanation coefficients of ores, tailings, and nitric acid-leached residues.
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