Solid Energy has won praise from conservationists for moves to clean-up a Buller river polluted by the Stockton opencast coal mine.
The company has constructed a $14 million sump to hold and treat acidic mine water before it's discharged into the Mangatini stream, which feeds the Ngakawau River.
Buller conservationist Pete Lusk says there's a good chance the ecology of the waterways can now be restored after years of run-off from the mine.
He says conservationists will monitor Solid Energy's clean-up plan, which the company says has already cost $40 million in three years.
