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EFFECT OF CEMENTITIOUS AMENDMENT ON THE GEOCHEMICAL BEHAVIOR OF A SURFACE PASTE TAILINGS DISPOSAL
Session: Contamined Sites and Remediation / Sités contaminés et réhabilitation
Ichrak Hadimi, Université du Québec en Abitibi-Témiscamingue (Canada)
Mostafa Benzaazoua, Université du Québec en Abitibi-Témiscamingue (Canada)
Abdelkabir Maqsoud, Université du Québec en Abitibi-Témiscamingue (Canada)
Bruno Bussière, Université du Québec en Abitibi-Témiscamingue (Canada)
Laboratory study of the long term geochemical behavior of paste sulfidic tailings (SPD) and the cement amendment used to the control acid mine drainage (AMD), was performed using an instrumented physical model test. This model was filled initially with nine layers of paste tailings. After 27 months, a 10th layer of cemented tailings (with 2wt.% of cement) was deposited on top of the tailings stack. The tailings were submitted to wetting/drying cycles until the 34th cycle. The collected water during each cycle was analysed for its chemistry and its volume measured. Investigation results showed that the pH of leached collected water remained around neutrality. The evolution of the concentration of metals in the leachates did not change much after the addition of the 10th layer. While the calcium concentrations increased slightly. The projection of the oxidation-neutralization curve of the physical model has shown that the uncemented paste in time becomes AMD generator however the behaviour of the cemented paste is uncertain.
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