US EPA

3729075 

Journal Article 

Key Mineralogical Characteristics of the New South Tortkuduk Uranium Roll-Front Deposits, Kazakhstan 

Mathieu, R; Deschamps, Y; Selezneva, V; Pouradier, A; Brouand, M; Deloule, E; Boulesteix, T 

2015 

1835-1838 

WOS:000374801300419 

The South Tortkuduk uranium roll-front type deposits belong to the Shu-Saryssu basin, where world class epigenetic uranium deposits are controlled by stacked oxidation-reduction (redox) fronts within permeable sandy formations of the Mesozoic-Cenozoic sedimentary pile. South Tortkuduk uranium mineralization is hosted in two Lower to Middle Eocene horizons, from bottom to top, namely: (i) the Uyuk horizon, consisting of a widespread 20-40m thick sand reservoir, composed of sand channel accumulations in a coastal environment, and (ii) the Ikansk horizon, composed of non equigranular sands with abundant interbedded layers of siltstones and clays. Clayey to sandy formations vary within a large granulometric range, but with relatively simple arenitic to arkosic mineralogical compositions. Mineralization is dominantly expressed as granules of Ca-P-rich coffinite; a systematic association between sulphides, organic matter and uranium mineralization is noticed. Potentially penalizing minerals for uranium recovery in ISR are mainly smectite and carbonates, which act as impermeable screens and as acid consumers. Disequilibrium occurs mostly at the borders of the sandy reservoir and downstream of the roll front. The main radium carrier minerals currently identified are the ilmenite alteration products. 

Uranium; roll-front; ISR; coffinite; smectite; lignite; carbonates; ilmenite; disequilibrium; Kazakhstan