Hundreds of thousands of cubic metres of waste water have leaked since Sunday, some flowing out of the mine area into the surrounding nature.
The leak has been partially repaired, so that waste water is no longer flowing northward out of the plant area. However there is still a southbound flow.
“The leak in the southern direction has been significantly reduced,” CEO Harri Natunen told Yle.
On Thursday Environment Minister and Greens chair Ville Niinistö visits the site. The previous afternoon he issued a sharply-worded criticism of how the crisis has been handled by the company and local officials, calling it "a serious environmental crime".
Ministry chief seeks shutdown
On Wednesday evening, the Permanent Secretary at the Ministry of Employment and the Economy, Erkki Virtanen, said that the company's operations cannot continue before further studies are completed.
The top civil servant at the ministry was interviewed on Yle TV1's current-affairs programme, A-studio.
He said that the readings now being found from waste water indicate that the environmental permits issued were incorrect for its current operations.
For instance, he says, sulphate levels are much higher than those stipulated by the mine’s environmental permits.
Virtanen added that the firm's behaviour has seriously damaged the reputation of the mining industry, which is seen as crucial to Finland's economy as the telecoms sector slumps.
