Analysis of monolayer covers for the reclamation of acid generating tailings : Column tests and interpretation

This paper presents a study on the reclamation of an acid generating tailings site that has been exposed to natural conditions for decades. One of the goals of this investigation is to assess the behaviour of a monolayer cover placed on the tailings, using laboratory column tests and numerical simulations. The experimental data indicate that the efficiency of the single-layer cover is fairly limited for the imposed conditions. The test results are then compared with simulations conducted with Vadose/W (GeoSlope Inc). Sensitivity analyses are conducted to evaluate the impact of various factors such as water table position, cover thickness and material properties. Alternative configurations are also investigated. RÉSUMÉ Cet article présente les principaux résultats d’une étude portant sur la restauration d’un site minier générateur d’acide exposé aux conditions atmosphériques depuis plusieurs décennies. L’un des objectifs de ce projet est de déterminer, au moyen d’essais en colonne et de simulations numériques, le comportement d’une couverture monocouche installée sur ces résidus. Les données obtenues lors des essais au laboratoire tendent à montrer que l’efficacité de la couverture monocouche est limitée dans les conditions imposées. Ces résultats sont ensuite comparés à des modèles numériques développés avec Vadose/W (GeoSlope Inc.). Des analyses de sensibilité ont été réalisées pour évaluer l’impact de la position de la nappe, de l’épaisseur de la couverture ou des propriétés des matériaux. Des configurations alternatives ont également été testées.

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