Soil-bentonite liner for the JEB Tailings Management Facility optimization - Part 1: design

Hung Vu, Greg Misfeldt, Vincent Laniece, Jeff Stone

In the proceedings of: GeoRegina 2014: 67th Canadian Geotechnical Conference

Session: Uranium Tailings Management

ABSTRACT: ntonite liner for the JEB Tailings Management Facility Optimization Part 1: design Hung Vu1, Greg Misfeldt1, Vincent Laniece2 & Jeff Stone1 1Golder Associates Ltd., Saskatoon, Saskatchewan, Canada 2AREVA Resources Canada Inc., Saskatoon, Saskatchewan, Canada ABSTRACT The JEB Tailings Management Facility (TMF) is the repository for tailings generated from processing uranium ore at the McClean Lake Operation, a uranium mine and mill complex operated by AREVA Resources Canada Inc., in northern Saskatchewan. The TMF needs to be optimized to provide full approved tailings storage capacity. A key component of the JEB TMF optimization is the soil-bentonite liner to be placed around the TMF till slope to contain the operating pond throughout operation. The design and construction of the soil-bentonite liner for JEB TMF optimization project is presented in two parts; Part 1 (this paper), associated with the liner design, and Part 2 associated with the construction of the soil-bentonite liner. The design in Part 1 provides an overview of the design of the liner, including the characterization of the liner base material, the characterization and design of soil-bentonite mix, and a numerical evaluation of the soil-bentonite liner. RÉSUMÉ L'installation de gestion des résidus (IGR) de JEB est le stockage des résidus générés par le traitement du minerai d'uranium à l'usine de McClean Lake, une mine d'uranium et complexe de l'usine exploitée par AREVA Resources Canada Inc. dans le nord de la Saskatchewan. L'IGR de JEB doit être optimisée pour fournir la capacité des résidus totaux approuvés. Un élément clé de l'optimisation est le revêtement de sol-bentonite à être placé autour de la pente de l'IGR de JEB pour contenir d'exploitation tout au long de l'opération. Le dessin et la construction du sol-bentonite pour le projet d'optimisation de l'IGR de JEB est présenté en deux partie; Partie 1 (ce document), associé au dessin du revêtement, et Partie 2, associé à la construction du revêtement de sol-bentonite. Le dessin de la Partie 1, donne un aperçu du dessin de la garniture, y compris la caractérisation de la matière de base du revêtement, la caractérisation et le dessin de mélange de sol-bentonite et une évaluation numérique du revêtement de sol-bentonite. 1 INTRODUCTION The JEB TMF has operated since 1999 and the final design needs to be optimized to fully realize the approved tailings storage capacity. The TMF optimization plan will provide an additional 0.5 million m3 of tailings storage volume. The current licensed elevation of consolidated tailings is at the sandstone/till contact following cover placement after closure. As part of the optimization plan the operating pond above the tailings will be raised to allow subaqueous tailings deposition above the sandstone/till contact elevation. A key component of the JEB TMF optimization plan is the compacted soil-bentonite liner which will be placed around the TMF till slope to contain the operating pond throughout operation. The soil-bentonite liner has been successfully designed and constructed for the initial stage of the optimization project, which was completed in 2013. The soil-bentonite base material is either screened till or crushed sandstone waste rock that can be produced on site. An untreated Wyoming sodium bentonite is used for the soil-bentonite mixture, which contain 5% bentonite by weight. This paper, (Part 1: Design), provides an overview of the design of the liner including the characterization of the liner base material, characterization and the design of soil-bentonite mix, and a numerical evaluation of the soil-bentonite liner. The construction of the soil-bentonite liner is presented in the Part 2 paper submitted to this conference, (Vu et al., 2014). 2 BACKGROUND Topography in the area of JEB TMF is defined as muskeg-covered, poorly drained terrain. The original ground surface varies from 443 metres above sea level (m ASL) on the west side to 470 m ASL on the northeast and southeast of the TMF. The general stratigraphy encountered in the JEB TMF area, in descending order, includes the following units: i) till, ii) upper sandstone, iii) lower sandstone, iv) basement regolith, and v) intact basement. The depth of the till in the area of the JEB TMF ranges between 10 and 28 m. The till/sandstone contact daylights between elevations 433 and 442 mASL in the pit slopes. The till of the JEB TMF area has been characterized into three stratigraphic units (Christiansen 1995). The three units identified, in ascending order were named Units 1, 2, and 3 which are thought to represent three separate and distinct glaciations. Unit 1 is composed of up to 9 m of sandy till and sand inter-beds. Unit 2 is composed of up to 15 m of silty till and silt inter-beds. Unit 3 is composed of less than 2 m to 15 m of sandy till that becomes siltier with depth. All three till units are dense to very dense and non-plastic. Christiansen (1995) suggested that the lithology (or physical characteristics) of the till units are not significantly different. A schematic of the JEB tailings disposal system is presented in Figure 1. The JEB TMF was designed with a natural surround concept, which relies on tailings with a low hydraulic conductivity to divert groundwater flow

RÉSUMÉ: -bentonite liner for the JEB Tailings Management Facility Optimization

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Hung Vu; Greg Misfeldt; Vincent Laniece; Jeff Stone (2014) Soil-bentonite liner for the JEB Tailings Management Facility optimization - Part 1: design in GEO2014. Ottawa, Ontario: Canadian Geotechnical Society.

@article{GeoRegina14Paper373,author = Hung Vu; Greg Misfeldt; Vincent Laniece; Jeff Stone,title = Soil-bentonite liner for the JEB Tailings Management Facility optimization - Part 1: design,year = 2014}