A human-rights lawsuit against a Canadian mining company can be heard in British Columbia, even though it involves events in Africa, the Supreme Court of Canada says.

The high court ruled Friday against B.C.-based Nevsun Resources (TSX:NSU), which had argued the claim should not proceed because a Canadian court could not decide the legality of acts by foreign states.

Three refugees from Eritrea in eastern Africa allege they were forced to work at a gold, copper and zinc mine owned and operated by the Bisha Mining Share Company, which is controlled by Nevsun.

They contend construction of the mine flouted international legal provisions against forced labour, slavery and torture — accusations that have not been tested in court.

Nevsun denies that the company or its subsidiary enlisted the Eritrean military to build the mine or supply labour, and says the refugees behind the court action were not mistreated.

B.C. courts dismissed Nevsun's attempts to make Eritrea the forum for any lawsuit.

In its decision, the Supreme Court rejected the company's argument that Canadian courts are precluded from assessing the sovereign acts of a foreign government, including Eritrea's national military service program.

The court also noted that customary international law — the common law of the international legal system — embraces fundamental norms, including prohibitions against slavery, forced labour and cruel, inhuman or degrading treatment.

Customary international law is part of Canadian law, Justice Rosalie Abella wrote on behalf of a majority of the court.

"Nevsun is a company bound by Canadian law. It is not 'plain and obvious' to me that the Eritrean workers' claims against Nevsun based on breaches of customary international law cannot succeed. Those claims should therefore be allowed to proceed."

Nevsun said in a statement Friday it expects a trial of the plaintiffs' claims and those of other, similar claimants will take place in the B.C. Supreme Court in September of next year.

Nevsun said it intends to "vigorously defend itself in court," adding it expects the Bisha Mining Share Co. will continue to operate the mine according to high standards of governance, workplace conditions, health, safety and proper protection of human rights.