The rooms and tunnels they have dug out are huge, the ceilings 20 metres from the floor.
Trucks load and scurry about, tipping their loads of freshly mined salt into crushers connected to long, fast-moving conveyor belts.
Some 500 people work in this mine in Goderich, Ont., exploiting a massive and almost pure deposit that is the small town's ace in the hole.
"There is salt underground in this seam for 100 years of mining, " said Gerry Rogers, the Compass Minerals executive in charge of the operation. "It will last a long time."
The company says the salt mine in Goderich, a town about 100 kilometres northwest of London, is the largest in the world. And business is good.
Almost all of the salt that comes out of the mine will be used as road salt, spread on highways and sidewalks in cities and towns around the Great Lakes.
Many of those cities have endured two tough winters in a row, which used up their stockpiles of salt.
They are now ordering more, which means the mine is near peak production this summer, trying to keep up with demand.
Ships call regularly at the port in Goderich to be loaded with freshly mined salt.
Derek Hoggarth, a recent hire, is grateful to have a well-paying mining job in a community he has called home "forever."
"We're busy," he said. "It's a mainstay for 500-plus people. It's what is needed to keep the community alive and keep it youthful."
Goderich has had its share of job losses. A big Volvo plant that made road graders shut down in 2008, a move that eliminated 500 manufacturing jobs and damaged the town's economy.
Mayor Keith Morrison said the blow was devastating to Goderich. And when a large manufacturing operation leaves, it can't be replaced.
"What we are finding is the days of the large industry coming to a community like this, it's gone," Morrison said. "You hear the doom and gloom throughout the province, throughout the country."
Goderich still has the mine, however. It is now the town's biggest employer. And it isn't going anywhere.
No other options
But some residents still worry about the future.
At the community ballpark, fans taking in a youth baseball game were lamenting the loss of stores and services in Goderich's beautiful downtown square, (which is actually round).
"The salt mine is OK, but that's the only thing we got," said Jan Kinahan. "We've lost a lot. The square has not recovered. There is no shopping around here for young people. They have to go to the city."
Beside her, Meiva Alves nodded in agreement.
"I have a small motel," she said. "Things are closing, like Volvo and Zellers. Young people have no option."
Still, Goderich is better positioned than most small towns, with an employer that can't leave, producing a product that is needed every winter.
And when bad weather hits, business gets even better.