Many have called it 'Canada's worst mining disaster' and its right here in northeastern Ontario. 

For the past 17 years, the province has been working to undo a half century worth of environmental damage by a copper and zinc mine just west of Timmins.

Stan Kaczmarek and Brian McMahon have been responsible for rehabilitating the tailings disaster surrounding the Kam Kotia Mine.

"This is certainly our biggest project," said Brian McMahon, Kam Kotia site rehabilitation manager.

"Both from an effort and from a cost perspective, so for Ontario, it's our biggest reclamation project."

Kam Kotia's story begins in the 1940s with the Hollinger Mine; answering the call from the U.S. for copper and zinc, to help with the war effort.

When costs ran high, the project was cancelled, trading hands for two decades.

"The mine ran until 1972, when it was finally closed and of course, we all know all of the issues that revolved around that and the kind of mess that was involved," said Karen Bachmann, Timmins Museum curator

The highly acidic and alkali-heavy tailings water scorched the area for years.

"We have the physical stability issues, the chemical issues and it's the ongoing maintenance, but we're making progress," said Stan Kaczmarek, a mine rehabilitation specialist.

The progress involves relocating toxic tailings dumps to a central area, sealing that off from the surrounding environment and slowly capping it off.

"That process started in about 2000, it's ongoing to date and we've invested about 75 million dollars," McMahon said.

Reclaiming this area is often a game of chess with Mother Nature; containment dams burst and attempts to regrow vegetation fail.

"It's encouraging to see some successes,” said McMahon.

“When you look back and see that it's improved, it feels good."

The project will last more than a lifetime.

The pumping station on site will run for 50 to 100 years, but for the first time in recent memory, the water exiting the area into the Little Kamiskotia River is cleaner than it's ever been.