During work on a future light-rail station in Pointe-Saint-Charles, archeologists have discovered what could be the bones of Irish immigrants who died after fleeing the Great Famine more than a century-and-a-half ago.

The dig site is a stone's throw from the Black Rock — a three-metre-tall boulder that, erected in 1859, marks the site where some 6,000 people are buried.

Workers on the Réseau express métropolitain (REM) are digging a hole to to install a concrete support pillar for its trains.

As part of the survey, they sent in a team of archeologists who discovered the bones of 12 to 15 people.

Archeologists were lowered by crane into the ground and have been working to excavate the remains by hand.

Bone fragments have been discovered belonging to at least 15 different people believed to have died during the typhus epidemic in the mid-1800s. (REM)

In 1847 some 6,000 Irish famine refugees died of typhus in Pointe-Saint-Charles. It's believed they were buried in a mass grave.

"We made sure that the work here would be done with respect," said Elizabeth Boivin, the REM's deputy director of environment.

Wood that may be from coffins has also been unearthed in the dig.

The yellow, cylindrical basket fits perfectly into the hole so experts can carefully comb through the dirt in search of bone fragments and other artifacts. (CBC)

Before crews began digging in June, a ceremony was held in collaboration with the Irish community.

Largest Irish grave site outside of Ireland

Because the dig affects less than one per cent of the site, the project will leave many other graves undisturbed, Boivin said.

Still, finding evidence of as many as 15 bodies in such a small area demonstrates just how many people are buried there — giving credence to the claim that it is the largest Irish grave site outside of Ireland, said Fergus Keyes.

He has been co-leading a push for a memorial park near the site for the last decade.

Fergus Keyes has been pushing for a memorial park near the Black Rock site for a decade. ( Simon Nakonechny/CBC)

"We always knew that, in that area, 6,000 Irish were buried," Keyes said. "Nobody has ever dug into that earth since the mid-1800s, as far as we know."

The hope is that lab tests will provide more information about who they were, how they lived and how they died, Keyes said.

Then they'll be put back close to where they where found.

"We will re-inter them in a very nice, proper ceremony at some point near the Black Rock," he said.