There were no immediate reports of any injuries or deaths from the latest dam wall collapse at the dormant diamond mine, which was once owned by De Beers.
One of the world's largest copper mines has suffered recurrent disruptions from indigenous Peruvian communities who say its vast mineral wealth has not translated into better living conditions.
Finland has thus far not collected taxes on minerals but the government now proposes introducing a royalty of 0.6% on the taxable value of metallic minerals.