Recovery of diamonds with anomalous luminescence kinetics: results of experimental studies

The paper presents the results of experimental studies to recover diamonds with anomalous luminescence kinetics from deposits in Western Yakutia. The characteristics of diamond luminescence are analyzed and a new algorithm for detecting Type IIa diamonds is implemented. Calculations were carried out to select the optimum X-ray tube settings for fluorescence excitation. The results of upgrading the existing equipment and introducing newly manufactured X-ray luminescence separators by equipping them with an optional upgrade kit at ALROSA's concentration facilities are presented. Upgrading with minimal capital investment, i.e. software modification, made it possible to promptly implement recovery of the high-value anomalous diamonds. Pilot technological workflows for extraction of Type IIa diamonds showed presence of these diamonds in the deposits developed by the Aikhal, Nyurba, Udachny and Lomonosov mining and processing plants. The Udachny site was found to have particularly valuable diamond specimens. Monitoring of recovery of Type IIa diamonds greater than 5 mm in size has shown that the increase in marketable products is estimated at about USD 5 million annually.