[en] The purpose of this research project is to develop efficient leaching processes for the extraction of uranium from low-grade ores and for the removal of long half-life radionuclides (radium and thorium) from the leach residue in order to produce innocuous tailings. The present investigation is the first part of a three-year project. It provides kinetic information not heretofore available for uranium leaching by hydrochloric and sulfuric acid solutions and preliminary data for the removal of radionuclides from the leach residues by KCl-solutions. This study has demonstrated that uranium extractions as high as almost 100% can be realized with either HCl or H₂SO₄ leach solutions. Initial radium concentration of 245 pCi g^-1 originally in the ore was reduced to 70 and 23 pCi g^-1 in the final tailings of hydrochloric and sulfuric acid leachings