Thomas Mukoya / Reuters Trucks ferry excavated gold, copper and zinc ore from the main mining pit at the Bisha Mining Share Company in Eritrea, operated by Canadian company Nevsun Resources, on Feb. 17, 2016.

A Vancouver-based mining firm can be sued for slavery, forced labour and crimes against humanity over its operations in Eritrea, the Supreme Court of Canada ruled Friday. Experts say the ruling could change the way Canadian companies do business abroad. The ruling marks the end of efforts by Nevsun Resources to stop a lawsuit that began in 2014, when three Eritrean refugees took the company to court in British Columbia. They alleged the local government forced them to work at a facility jointly owned by Nevsun and the Eritrean government, and sought damages for violations of international law, including slavery. Watch: Escaping modern slavery. Story continues below.

As involuntary conscripts in the military, they claimed that they were forced to work at the Bisha gold, copper and zinc mine under intimidation and threats of torture, sometimes in exposed sunlight at temperatures approaching 50 C. The three plaintiffs told the courts they had respectively spent 17, 14 and 11 years in forced military labour before escaping in 2011, and were forced to work 12-hour days, six or seven days a week, while at the Bisha mine. Since its inception, Eritrea has been a dictatorship run by Isaias Afwerki, a former Marxist guerrilla who fought a war for independence from Ethiopia. He was supported first by the U.S. and later the Soviet Union. Afwerki instituted compulsory military service for all citizens when they turn 18. The service runs for 18 months but can be extended indefinitely. For this and other reasons, the UN and Amnesty International have accused Eritrea of crimes against humanity ― accusations the government rejects.

Nevsun has denied the claims against it, stating in court filings that the Eritrean military has never provided workers to the Bisha mine. “There are contractual commitments in place that strictly prohibit the use of national service employees by Eritrean subsidiary Bisha Mining Share Company’s contractors and subcontractors,” the company said Friday, as quoted at Mining.com. The plaintiffs’ law firms said in a statement that the Supreme Court ruling means “Canada’s first mass tort claim for modern slavery will now proceed to trial.” Camp Fiorante Matthews Mogerman LLP and Siskinds LLP said, “The Court recognized for the first time that a Canadian corporation may be held legally responsible for violations of international law that protect human rights.” Charting a different legal path Legal experts say that sets Canada apart from countries such as the U.S. and Great Britain, where courts have recognized the “act of state doctrine” ― the legal principle that a court in one country shouldn’t pass judgment on the actions of another, sovereign state. That principle has never existed in Canada. “[I]t is not ‘plain and obvious’ that corporations today enjoy a blanket exclusion under customary international law from direct liability for violations of ‘obligatory, definable, and universal norms of international law’, or indirect liability for … ‘complicity offenses’,” Supreme Court Justice Rosalie Abella wrote in the decision reflecting the majority view on the bench.

... the ruling is “a landmark, watershed moment in Canadian law.” Hassan Ahmad, University of Toronto doctoral candidate