A Novel Process for Decolmatation of Wells During In Situ Leach Mining of Uranium

The objective of this research is to enhance the efficiency of geotechnical wells by using a low-toxicity ammonium fluoride substance in neutral, acidic, and alkaline environments to dissolve colmatants. The research methodology includes X-ray spectral analysis, semi-quantitative X-ray phase analysis of the colmatants, laboratory experiments, and pilot-scale tests. The study results indicate that the use of ammonium fluoride combined with soda increases the dissolution of colmatants, particularly quartz, thereby improving the flow rate and extending the inter-repair cycle of process wells. When ammonium fluoride is used with sulfuric acid, it leads to a decrease in the oxidation-reduction potential (ORP), whereas its combination with soda ash increases the ORP, both of which positively affect the efficiency of in situ leaching technology for uranium mining. The practical significance and novelty of this work lie in the development of an effective and environmentally friendly decolmatation technology using a low-toxicity reagent —ammonium fluoride in combination with soda. For the first time, this research established the dependence of the degree of quartz colmatant dissolution on the concentration of ammonium fluoride in both acidic and alkaline environments, along with observed changes in ORP and pH values over time during treatment with alkaline and acidic solutions of ammonium fluoride.