Uranium(IV) Content After 40 d without Oxygen 0% 61% 0% Outer Injection Well Inner Injection Well Inner Extraction Well Outer Extraction Well Sampling Wells NA 30% 17% NA 51% 54% NA 0% 102 101100 Depth 45 ft 40 ft 35 ft - Average geochemical conditions at time of collection pH 6.5, ~ 5 mM sulfide, 1.5 mM HCO 3 -, ~1 mM TOC, ~3 mM SO 4 -, ~100  M Fe 2+ - Reduced uranium detected throughout stimulation zone (except well #100) - No well contains more than ~ 60% U(IV) Isolation Zone Treatment Zone
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