Armed robbers stole $8.5 million worth of gold from a refinery at a mine in the Mexican state of Sinaloa, a Canadian mining firm says.

Toronto-based and TSX-listed McEwen Mining Inc. says the theft occurred Tuesday at the company's El Gallo 1 mine. Thieves made off with 900 kilograms (almost 2,000 pounds) of gold-bearing concentrate containing approximately 7,000 ounces of gold.

The company said Tuesday that the crime was being investigated by Mexican authorities.

"The Company maintains insurance against these types of incidents and is working closely with its insurance carrier to determine the extent of available coverage," the company said in a media statement. "However, the Company's policy will not be sufficient to cover the entire expected loss."

The Toronto-based company has operations in Mexico, Nevada and Argentina. Based on its current stock price, the company is worth about $364 million.

The company is led by, Rob McEwen, who owns 25 per cent of the shares that bear his name. McEwen is best known as the man who steered Vancouver-based Goldcorp from a collection of smaller companies into the 4th-largest gold mining company in the world