Swedish mining company Boliden will spend 5 billion Swedish crowns, or US$350 million, on improving the tailings dam at the Aitik copper mine in Sweden.
The company plans to spend 1 billion Swedish crowns, or US$105.5 million, this year.
Aitik produces 2 million tonnes of copper annually.
"Ongoing geotechnical investigations in Aitik show the need to eventually change to a new dam construction method to ensure long-term disposal of tailings," the company said in a statement.
Boliden also wants to strengthen Aitik's current dam to meet best industry standards, the company said.
The Swedish miner has identified areas of poorer soil conditions, and has suspended plans for dam heightening and tailings deposits in these areas.
Boliden will now strengthen existing dam structures and will move some infrastructure, a process which the company estimates will take two years.
The company will resume work on heightening the dams and depositing tailings after this work is completed.
Production at Aitik is not expected to be affected. Boliden will need to wait for the receipt of environmental permits, but will be able to begin some aspects of the process before the permitting process is completed.
The mining industry is expected to comply with new global tailings standards, drafted by the International Council on Mining and Metals (ICMM) and the UN Environment Programme (UNEP).
Tailings disasters at Mount Polley and at Vale's operations in Brazil led to increasing calls for improved maintenance and standards of the structures.
