Archaeologists have unearthed a Chinese coin minted between 1667 and 1671 at a planned mine site in the Yukon, suggesting early trade with Canada's far north, the mining company announced.

The 340-year-old Chinese coin was found during a dig in June within the Selkirk First Nation's traditional territory on the historic Dyea to Fort Selkirk trade route.

Information stamped on the money indicates it was minted in China's Zhili province.

"The coin adds to the body of evidence that the Chinese market connected with Yukon First Nations through Russian and coastal Tlingit (aboriginal) trade intermediaries during the late 17th and 18th centuries and perhaps as early as the 15th century," said James Mooney, who led the expedition for Western Copper and Gold Corporation.

The discovery was made during a heritage impact assessment required as part of the approval process for the company's proposed Casino copper-gold-molybdenum mine, some 300 kilometers (185 miles) northwest of Whitehorse.

"I was less than a meter from our archaeologist Kirby Booker when she turned over the first shovel of topsoil and I caught sight of something dangling from the turf," Mooney said in a statement.

"It was the coin -- the neatest discovery I've ever been part of."

Research shows that ancient Chinese coins were common along the Northwest coast of North America, brought back by Russian fur traders.

But only three of the circular coins with a square hole in the centre have previously been found in the Yukon. The oldest, discovered in 1993, dates back to the 15th century.

The Tlingit tightly controlled trade with inland aboriginals by controlling access to the Chilkoot Pass, one of the few entry points through the coastal mountains to the interior of the continent.

The coin was found on a promontory overlooking a river and creek tributary -- a likely place for a resting place for travelers, Mooney said.