Rehabilitation of the Barzava Uranium Mine Tailings

Results are presented and discussed concerning the radiometric survey of the Barzava uranium mine tailings (Arad District, Romania), a 20,000 m3 sterile dump, before and after rehabilitation. Before rehabilitation, gamma dose rates in the air over the tailings varied between 200 and 2,400 nSv u h-1, at 3 cm and between 190 and 1,580 nSv u h-1 at 1 m above the soil, dropping to 114 nSv u h-1 at boundaries, close to 110 nSv u h-1 multiannual background for Arad County. The rehabilitation consisted of terracing, followed by covering with 1.5 m of pebbles, sand, clay, and fresh, uncontaminated soil. After rehabilitation, the gamma dose rate was reduced to background all over the tailings, excepting some points where the cautionary threshold of 250 nSv u h-1 was surpassed. Outside tailings, in sediments and in the waters of the Barzava stream, no signs of radioactive contamination were observed. Moreover, all estimations of dose rates from the experimental gamma spectra were in good agreement with the experimental ones within a limit of approximately 15%. (C) 2013 American Society of Civil Engineers.