The Solbec tailings pond was active from 1962 to 1977. Over 2.5M cubic meters of sulfide waste were deposited at the site, and sporadic sampling performed between 1972 and 1980 confirmed the presence of acid mine drainage (AMD). A 1987 characterization report of the tailings pond tabled proposed flooding of the
tailings as the most appropriate solution to the problem. It was at this time that Cambior became involved through its acquisition of the Sullivan Group, owner of the Solbec mine.

A series of experiments and studies followed from 1989 to 1993 to test the efficiency and viability of the flooding as a solution. The work required to achieve flooding was carried out in 1994. Since then, as part of the MEND program, a project has been conducted to monitor the quality of the water cover and groundwater associated with the tailings pond. The monitoring program also includes an evaluation of the oxydizing micro-organisms viability, their activity level activity in the flooded pond and of the hydrology and wave impact on site.

After twelve sampling and analysis campaigns of over 50 samples and ten parameters each, the solution now seems to be effective. The pH is now near neutral and the anomalous concentrations of iron, zinc and copper are resorbing. In addition, the basin retains enough water to keep the tailings submerged and thus prevent harmful wave action consequences. The effectiveness of the solution is supported by a decrease in the oxidizing microbial population, the cessation of its oxidizing activity and especially the appearance of sulfate-reducing bacteria. These bacteria contribute to the inverse oxidation process by reducing sulfate ions to sulfide ions, which reprecipitate metals in the more stable form of metal sulfides.