La capacité de rétention d'eau des résidus de désencrage utilisés comme matériau de recouvrement des sites miniers producteurs du DMA

Abstract

The Eustis mine site is located in a touristic area 10 km from Sherbrooke in the Eastern Townships, Québec. For many years, the abandoned sites of Eustis, Albert and Capel have been generating AMD, which affect bodies of water as the Massawippi River and the Eustis creek. A capillary barrier constituted of deinking residues was placed over a 1.6 hectare experimental cell at the Eustis site. Piezometers and lysimeters were also installed. Profiles of oxygen were measured through the deinking residues to verify the efficiency of the cover as an oxygen barrier. Field data show that the oxygen concentration decrease rapidly and is below the detection limit at the interface of the tailings.The field investigation is completed by a laboratory program.The suction of the deinking residues of the Eustis site was measured using the axis translation technique and the filter paper method in order to determine the characteristic curve. A pressure plate apparatus was created in the laboratory of environmental geotechnics of the University of Sherbrooke in order to measure the volume changes in the samples during the testing period.The results show that characteristics of the samples tested vary according to the date of production. However, the filter paper method needs to be improved.The suction of the samples tested with the axis translation technique was also measured with the filter paper method but the results do not always match.