E. P. Slavsky PIMCU, Krasnokamensk, Russia:

A. S. Bodrov, Chief Engineer at Central Research Laboratory, Candidate of Engineering Sciences, info@ppgho.ru

Mitigation of the environmental impact due to placement of radioactive waste of uranium hydrometallurgy in liquid-type tailings storages on ground surface is an urgent scientific and practical issue at E. P. Slavsky PIMCU. In this connection, in 2000–2003 and in 2012–2021, the Company investigated suitability of hydrometallurgy waste in different physical states as components of cemented paste backfill. Based on the permeability/impermeability classifications and testing results, the test samples of backfill mixtures, subject to their formulations, in the testing intervals to 180 days are characterized as impermeable to weakly permeable and as extremely weakly permeable to weakly permeable. The implemented research allows concluding that a cemented paste backfill with a relatively compact-grained structure, and composed of hydrometallurgical tailings and inert aggregates possesses low gas permeability for radon to flow to underground openings through the hardened fill mass. Emanation of Rn from the hardened backfill depends on many factors: dosage of tailings in the backfill composition; uranium content and radioactive equilibrium of initial ore; cement consumption, curing time and strength; volume of filled voids; method of undermining and exposed area of the backfill mass. In case of large volume of voids filled with the mixture composed of hydrometallurgical tailings, for the minimization of radiation exposure of personnel and for the maintenance of radiation safety of mine air, additional activities to combat radon emission are required to be undertaken.

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