Navoi Mining and Metallurgical Combinat, Navoi, Uzbekistan:

R. I. Usmanov, Head of Innovation Center’s group, r.usmanov@ngmk.uz

The article generalizes experience of in-situ uranium leaching from low-watered (including dry) strata enclosing ore bodies inside weakly permeable calcareous, highly carbonate and clayey sandstone. The relevant semi-commercial research was carried out in 1980–1994 during extraction of ore body No. 3 of the Surgaly deposit in Uzbekistan. Mining was implemented by Navoi MMC whereas the research was performed by the Innovation Center of the Combinat (this article author is the head of the Center’s group). The set of programs developed for reaching the research objectives was based on solution of a twodimensional problem on geo-migration and geo-permeation using a mathematical model of mutually permeating and interacting continuums: fluid as the first phase and rock matrix as the second phase. Based on the results of the studies, a two-stage circuit integrating advantages of carbonate- and acidbased technologies was proposed for in-situ uranium leaching. After completion of the extraction, the test site represented a trough cupola which was higher than the average piezo-metric level of the ore basin, and it was considered inexpedient to continue mining of the deposit. At the present time, based on the data of undertaken additional research (1994–2000), this article author proposes to reactivate uranium production from weakly permeable highly carbonate strata with clay and siltstone interbeds by hydraulic fracturing and bicarbonate leaching. To this effect, it is recommended to accomplish optimization of volumes of leaching mass as well as injection and pumping-out solutions using mathematical models, obligatory geo-ecological monitoring of qualitative composition of groundwater and mapping of geochemical envelopes of chemical elements.

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