Joel, a 13 year old child miner readies the plastic lamp strapped to his forehead .
He is one of hundreds of children and young people working at the Nobsin mines, about an hour's drive from Burkina Faso's capital Ouagadougou, who every day risk their lives in the search for gold in the impoverished west African nation.
Child mining has become a growing problem in Burkina Faso, where 60 percent of the population is under 25. A mining boom in recent years has made the country Africa's fourth-largest gold producer, where exports of the yellow metal account for almost a fifth of economic output.
Joel, who started working at the mines two years ago, makes a meagre income from the backbreaking work. Sometimes it's 5,000 CFA francs (7.6 euros, $10.5), on a good day twice that, but often nothing at all.
"Down there, it's really damp," he said, scratching a filthy arm. He hopes one day to find "less painful work" but "mostly, I think about what I could earn".
Burkina Faso's government estimates a tonne of gold was brought out of the ground by small-scale miners last year -- official estimates say it could be double that -- compared to the 32 tonnes mined legally.
Part of that was dug by children. The UN Children's Fund estimates that between half a million and 700,000 adolescents and youngsters are caught up in the mining sector in the nation of some 17 million people.
- 'Sometimes it's scary' -
At the illegal mine, even breathing is hard in the windy, arid landscape.
Children, many barefoot, scramble into small rectangular holes between 20 to 30 metres (65 to 100 feet) deep to pound away at the rock face.
Thuds and muffled voices drift up to the surface, where fellow workers take turns to haul up broken stones in plastic cans. Other teams further pounded the stones, sifting and hoping to find gold.
At 15, Hamidou is a short stripling of a lad, wincing and weary as he wrenches a splinter out of his foot. But he says that mining is still better than working in the nearby village where he lives.
There "they cultivate the land, but they don't earn anything," he says, adding that he is "not afraid" of working in the mines.
Some youngsters invoke spirits to help them in their search for gold. "If you don't go to see the sorcerers, you won't find anything," said 19-year-old Issiaka, who has been sifting for three years.
Children at the mines dream of a local El Dorado, but mining is dangerous. Five people were injured at Nobsin the day before AFP visited, according to a 50-year-old "elder" at the site Ouinin Ouedraogo, while a landslide killed 14 and injured another 14 at a different dig in Western Burkina Faso last year.
Younger children, who are small enough to get to the bottom of the mine shafts, are often the first accident victims. David Kerespars, whose children's charity Terre des Hommes works at a dozen illicit sites in Burkina Faso, says up to a quarter of youngsters are hurt working at the mines.
"Here the ground is solid, but sometimes the earth is very fragile. You can feel it when you probe. Cracks appear in the hole and that's scary," said Frederic Tindiebeogo, 23, whose T-shirt bears the slogan: "It's only funny when someone gets hurt".
- 'Despair' lures them here -
Ouedraogo, the elder at Nobsin, says it is "despair" that brings so many kids to the mines, where they are exposed to sexual abuse, alcohol and drug use.
The effect on their futures is catastrophic. The young gold-diggers receive no schooling and mostly work "more than 10 hours a day" and often "in the full glare of the sun", according to UNICEF's representative in Burkina Faso, Marc Rubin.
Living and working near dangerous chemicals such as cyanide and mercury, both used in the extraction of gold, also poses a serious risk to their health, Rubin said.
"We need a national effort" to keep them away from the mines, he added.
Some are already trying. Last year Terre des Hommes managed to withdraw 2,000 children from Burkina Faso's mines and provide them with schooling or training for jobs, Kerespars said.
Minister of Mines Salif Kabore says a new unit will be created to "oversee the security (at some 600) mining sites" and crack down on child labour. "It would be utopian to say that we'll ban it. But we must try to provide a framework."
But despite these efforts, and the 21,000 youngsters UNICEF estimates were brought out of the mines between 2010 and 2013, the charity says Burkina Faso's child miners are still an "enormous" problem.