It was known as Pit 15, a coal mine 175 fathoms deep under the earth in a valley a few miles outside Glasgow.

More than 300 men worked in the depths, hammering into the core with coal dust as black as pitch mixing with their sweat as the hours went by.

In the years to come, mines like this would all have a little golden bird singing down among the shadows.

A lifeline to the miners, the canaries would be their only protection against the invisible killer carbon monoxide.

If the birds stopped singing, if silence fell, it could mean the final breath for the men they were brought down to protect.

On August 3, 1913, it is not known if there were birds to sing for the men down Cadder Mine.

At 8pm that evening, three hours before their shift was to end, pit fireman William Brown went down to check on the 26 men working back shift that night.

At the bottom of the shaft he found a mass of hot flames – hurrying back up to the service he rushed at once to call the other firemen.

The brigade were miles away in Cambuslang. When they arrived, their hoses weren’t long enough to reach down to quell the fire.

John Marshall, a pit employee, switched off the electric current from the cables. The lights underground went out.

Down in the depths of the mine, the air thick with toxic gas, 22 men died together in the darkness.

“These guys suffered down there, down in the mines. They were suffocating, they couldn’t breathe,” said Paul Troy.

“They had risked their lives without anyone able to save them.”

Troy, a film director and producer, is due to release a history documentary on the Cadder Pit disaster called ‘Vale of Tears’ based on his research of the local community affected by the tragedy.

With no budget and one narrator – actor Brendan O’Donnell – the project has been a labour of love for Troy.

“The whole point was to get people involved in their history and take pride in where they come from,” he said.

“In particular there was a hero of this tragedy, a man whose actions I wanted to highlight.

“His name was Robert Dunbar and he was an experienced miner – he managed to save three other men who were with him down the mine.”

Newspaper reports from the time record that Dunbar, though exhausted himself, dragged another miner to safety.

In many cases the rescuers were overwhelmed by the poisonous atmosphere and had to be dragged back.

Rescuers going back down to the mines, then took canaries with them to help detect gas.

Although there are no written reports of the miners having the birds with them when the fire broke out, thanks to a Rescue and Aid Order issued the previous year, rescuers had access to canaries to take down with them.

Without them, they said, they would not have known when to turn back.

The incident struck a deep chord within the city of Glasgow, with some 50,000 people turning out to show their respect for the men who lost their lives during the funeral procession.

Their coffins were carried on the shoulders of the miners who had worked alongside them.

And even while the funerals were taking place, the fire in the pit still blazed. It would take days for it to finally burn out.

Among the dead were three young brothers. Among the families left behind, there were 13 widows and 44 fatherless children.

Following the Cadder Pit disaster, rescue centres were set up at Kilmarnock in 1913, Edinburgh in 1915 and Coatbridge in 1915.

The latter provided rescue cover and training opportunities for Lanarkshire including Cadder. Men travelling 50 miles to the rescue became a thing of the past.

“There are still people in the community who have relatives or the same names of those who knew the men who went down there,” said Troy.

“I wanted to create a film that showed what the conditions were like for miners at that time.

“There was a significant lack of air vents or training. These men went down risking their lives with no proper health and safety or rescue equipment.

“It’s important that they are not forgotten, and that we continue to remember and learn about what took place that day.”

Troy’s production ‘Vale of Tears’ is due to be released shortly on the Internet & Digital Youtube channel.

View the original article by Laura Piper on the STV web site here.