[4] AEC became Encana with legacy mines being moved into the holding of subsidiary EWL Management.

[9] EWL Management Limited owned five decommissioned mines in Ontario:[10][11] The company managed 4,600,000 tonnes of uranium tailings at former mines, which in 2016 represented 2% of all uranium tailings in Canada.

[17] Since two of EWL's mines contaminated local groundwater,[18][19][20][21] EWL were rehabilitating mines to meet provincial water safety standards.

[12][13][20] This included rehabilitating two tailing management areas at Madawaska Mine.

[22][23] The rehabilitation was managed by Golder Associates with the aim to make the site compliant with Canada's Nuclear Safety and Control Act and Ontario's Mining Act.