At a depth of about 50 meters the men get out of the bucket and into a tunnel just wide enough for a few men and a couple of wheelbarrows. It is pitch black, save for the lamps on the men's heads, as they start to mine coal with handheld jackhammers.
Mexicans have been mining "pozitos", or little holes, such as this one in the town of Nueva Rosita in much the same way for more than a century. Now, with energy prices sky high and Mexico's electricity needs surging, these rudimentary and dangerous mines are working at full capacity.
Rene Zertuche, the supervisor of the pozito in northern Mexico's Coahuila state, watches as a worker perched on a bolted-down car seat pulls a lever to lift a bucket of coal.
After receiving orders over a two-way radio rigged up to an old telephone, the worker uses the same bucket to haul up two workers. They are both shirtless, covered in grime and drenched with underground water and sweat.
Up to 14 percent of Mexico's electricity comes from coal, with the rest generated using more expensive fuel oil, natural gas and from hydroelectric installations.
At least four more coal-fired plants are being planned and the state electricity commission is considering converting some oil-fired plants to coal.
The electricity industry burns about 16 million tons of coal a year, the vast majority of it from big coal mines. The pozitos supply only a small fraction of that, but with demand rising pozitos are trying to extract as much coal as they can.
Rising energy and commodity prices have boosted informal and dangerous mining techniques in many poor countries around the world, from Honduras to Ghana.
In traditional mining states such as Coahuila there are few options. Risk your life in the mine or slip across the border into Texas to work illegally.
Prices of imports are soaring. Coal reached almost $200 (R1 548) a ton on the European Energy Exchange this month, while the going price for a ton of coal in Coahuila is $64, one reason the Mexican government is clamouring for more.
While more mining means more work and money for people in the rich coal belt of Coahuila, below the US state of Texas, it also means more injuries and more deaths.
Three people died in accidents at pozitos last year and miners say its rare a year goes by without fatalities.
"You die down below when gas can't escape and there's an explosion. There are never any survivors then. Or rocks can fall and kill you, or crush your arm or leg," says Jacobo Rodriguez.
A methane explosion in 2001 and then a flood in 2002 left 25 pozito miners dead, forcing the government to tighten safety controls.
Silverio Valdes, a government official who buys coal from the small miners to sell to the power stations, says the pozitos risk going out of business unless they improve safety standards and upgrade technology to compete with more modern open-pit operations.
And yet the state electricity commission has asked small- and medium coal mines in Coahuila to increase their production by about 50 percent next year.
A quarter of the roughly 100 tiny underground coal mines are not registered with the government and escape regular safety inspections, Mexico's coal producers' union says.
Miners earn between $3 and $6 for each ton of coal they can hack out by hand, more than they could in other occupations.
Some worry the payment system itself leads to accidents. "The more they mine, the more they are paid, so they go into areas that are unsafe where the tunnels can collapse," says Gerardo Cardenas, a manager at the coal producers' union.
"When you see how the pozitos work it's obvious that they are just as dangerous as they have always been," says Elvira Martinez. "But instead of closing them down, you just see more and more popping up in this region."