Technology of underground block leaching at underground mines of “VostGOK”

Abstract

The article is aimed at enhancement of the uranium ore mining technology at underground mines of the state enterprise “VostGOK”. The investigation task consists in determining impacts of various factors on the crown stability when mining uranium ore deposits by vertical double blocks applying underground block leaching. In the course of the investigation there is used mathematical modelling of the stress-strain state of crowns applying the finite-element technique, analytical study of the degree of crown disturbance caused by mining and laboratory study of uranium ore strength under impacts of block leaching reagents. To cut costs for final products, vertical double blocks are suggested for underground mining of uranium ores by block leaching. There are determined impacts of deposit dips and workings on the stress-strain state of crowns. Correction of crown thickness is suggested taking into account the above factors and applying corresponding coefficients. There is also determined the degree of impact of acid solutions used in underground leaching on uranium ore strength depending on the exposing time. The determined dependencies enable correcting the crown thickness when mining uranium deposits by vertical double blocks applying the underground block leaching technology and therefore provides safety of works.