The urgency of the discussed issue is caused by the need to develop the technology of industrial processing of persistent uranium ores. The main aim of the study: to research the activation of persistent uranium ores by ammonium bifluoride solutions. The methods used in the study: neutron activation analysis, photocolorimetric analysis and X-ray diffraction analysis. The results: preliminary processing of grinded uranium ore of Elkon uranium district by ammonium bifluoride solutions allows loosening and even disrupting ("activate") persistent structure of minerals such as feldspar, quartz, other silicates containing brannerite, due to the removal part of silicates to a soluble form, making uranium minerals more accessible to leaching by acids. The uranium leaching degree from activated ore increased from 50…70 to 96 %.