Geological and geotechnical specifics of uranium production at hydrogenetic deposit Semizbay

Abstract

The article presents a geological and geotechnical comparison of the hydrogenetic uranium deposit Semizbay in North Kazakhstan with deposits of the same type in the southern regions of the country. The Semizbay deposit is characterized by a nonuniform and variable lithological structure, diverse permeability of rocks, and by alternation of permeable and water-resistant rocks in the section. Geotechnically, Semizbay is a very complex deposit for the in-situ leaching (ISL) technology. Depending on the complexity of the geological structure of the deposit, the factors affecting the mining process can often complicate production and increase the cost of the extracted metal. To reduce the influence of negative factors, various methods are used to intensify the ISL processes. The implemented experiments and the proposed technological solutions prove the significant increasability of recovery of the useful component. This article discusses the use of oxidizing agents as a method of intensification. Currently, air oxygen and hydrogen peroxide are used as oxidizing agents, while iron-oxidizing bacteria as well as purified ferric iron in the form of Fe2(SO4)3 are at the stage of testing. One of the potential research intensification trends is the use of sodium nitrite (NaNO2) as an oxidant. As a result of the tests, the increase in the redox potential in leaching solutions is correlated with the concentration of sodium nitrite. The test data on the use of this reagent allow us to conclude that it has a positive effect on uranium production performance at hydrogenetic deposits. The authors express their gratitude to specialists of Semizbay Mine, Semizbay-ULLC, for the data accumulation, and to the laboratory personnel of IVT-Zerde LLC, Semizbay Mine’s branch, for the highquality lab-scale studies at that stage of semi-commercial testing in Semizbay Mine.