By Andres Schipani
BBC News, Potosi
Watching children and young adolescents push loaded wheelbarrows out of the dark corridors of the tin, zinc and silver mines of the Bolivian town of Potosi, it is clear that the harsh reality of adulthood comes far too early.
Ramiro, 12, works as a driller in the high-altitude mines of Potosi
"I work out of necessity," explains 12-year-old driller Ramiro, helmet in hand, as he stands at the entrance of one of the mines that honeycomb the Cerro Rico - meaning Rich Hill - that towers above the town.
He feels bad because he knows that working in the mine puts his health at risk, he says, and "that is what every single one of the children that works inside feels; sometimes some die, some survive".
Wiping his sweaty forehead, which is covered in dark dust, he adds: "For us, who work inside the mine, it is not good; the mine brings a lot of disease, a lot of death."
It is prolonged exposure to that dust that gives the average miner a life expectancy of only 40 years. The culprit is what they call the "mal de mina", the lung disease silicosis.
At the entrance to one of the mines, surrounded by grey piles of mineral waste, men can be seen alongside children, chewing coca leaves as a way to stay awake, carrying picks, mattocks and shovels.
It seems that childhood is a luxury the poorest residents of this mining area, located 4,300m (14,100ft) above sea level, cannot afford.
Although Potosi was the financial epicentre of the Spanish colonies more than 400 years ago, due to its vast silver reserves, today it is inhabited by many families that are on the edge of survival; families in which every member, no matter how young, has to work.
The Spanish conquistadores took vast amounts of silver from Cerro Rico
And although child labour is illegal, Bolivian mines employ thousands of children who need to work to ensure their families' as well as their own survival.
In the case of the western region of Bolivia, mining is still the source of jobs and entire families work in the exploitation of minerals.
Today most Bolivian mines are co-operatives that operate using risky methods. It is the increase in the international price of minerals that has led many families to look at mining as an option to improve their income in South America's poorest country, even if it may involve sending their children to work.
"We thought with the increase in these prices, child labour was going to decrease as families were going to have higher incomes - but reality shows the complete opposite," explains Maria Elena Reyes, who heads the division of child labour at the International Labour Organisation in the country's administrative capital, La Paz.
"The situation and the see-no-evil attitude of many sectors are quite worrying."
'No way out'
Bolivia's birth as a republic was tied to mining, and here, for many years, indigenous people have been joining the mining work force, bringing themselves, their families and community values rooted in the Andean cultural identity, where children help adults in their labours as part of their process of growing up.
Child miners chew coca leaves like their elders to help them stay awake
But that is not the main or only reason most children are here.
For Felipe, a veteran miner and father of Ramiro, there is no other option. "Children work to help me support the family. If they do not work, families here won't make it...
"What am I going to do with my children if they don't work? There's no way out of the mine; that is why we all work, the whole family works."
Many of these child and adolescent miners work at night, between eight and 12 hours a day. They do not have a contract and work under the control of contracted workers, which makes it difficult to count their number exactly, but according to the UN children's charity, Unicef, about 10% of all Bolivia's miners are under-age.
Earning an average of £3 ($6) a day, they generally work as drilling assistants, wheelbarrow pushers, pick-miners and sweepers.
Dreams of study
Girls also go underground. Abigail, who is 10 years old, works inside the mine, loading minerals into the wagons, and sometimes outside, cleaning the mineral mills with her four-year-old sister.
Abigail works above and below ground, sometimes helped by her sister
They lost their father last year to silicosis, so prevalent among miners. Abigail works eight hours every night, then goes to bed at dawn and anxiously wakes up to go to school at noon.
"I've started to work because of lack of money, because my family had no money, we had nothing to eat," she explains.
"It's hard, I feel like I am already a mother or something because I am working this hard, but I don't want my mother to work because she might also get silicosis or some other disease, something similar to what killed my dad."
Cupping a small piece of shiny mineral rock in her hands, she says: "My dream is to study, to have a profession and work in something else, basically, to get out of the mine."
Throwing the rock away, she adds: "The mine summons death and I am too young to be called yet."