Known as the ulcer on Mt Te Aroha, the abandoned Tui Mine is deemed one of NZ's worst environmental disasters.
It's taken $22.5 million and a five-year clean-up project to get the area back into what is deemed a safe state for the community.
But locals say, although a positive step forward, it will still be generations before it gets back to its original state.
The mine was opened in 1967 to extract precious metals, but back then under the Mining Act, site rehabilitation was not required, thus in 1975 when the company up and left, a toxic wasteland was left behind.
Acid rain contaminating the adjacent Tunakohiao stream was dangerous, but has today been deemed no longer a threat to human health.
The on-going monitoring and maintenance of the Tui Mine will lie with the Department of Conservation and Matamata-Piako District Council.