By Charles Lavery
Their bodies caked in dirt from the river beds they are forced to work in, African children are enslaved in lethal mines to power our love affair with the mobile phone.
The child miners of the Democratic Republic of Congo (DRC) risk death to dig for a highly dangerous ore used in mobiles, laptops and games consoles.
The massive demand for coltan - short for columbite-tantalite - has fuelled a desperate and bloody battle to seize the river beds where it can be mined.
Coltan smuggling is big business throughout Africa and is a major source of income for warring militias.
The valuable ore is sold for £300 a kilo but the young slaves risking death to mine it get just £1.50 a week.
For that paltry sum they work in narrow tunnels dug into river-beds which are at constant risk of collapse. Thousands have already died.
Coltan, which is highly toxic, is also blamed for birth defects in the areaswhere it is mined.
Glenn Lesak, who heads Save The Children's relief programme in Congo, estimates that between 5000 and 6000 child slaves are forced to work in the mines.
He said: "This is an industry which is concentrated on forced labour and child labour. It's horrific.
"Their working conditions are inhuman and have accelerated now because it's the dry season and the river beds are dry.
"Children are essential to the process because they can get into smaller holes dug in the river beds."
An elite few have made a fortune from coltan but their wealth does not reach those desperately scraping the ore from makeshift mines. Lesak added: "There are a handful of very rich people and the rest get nothing.
"The end users - the phone and computer companies - say they don't take anything from Congo but there are ways around that for the militia and the people selling it.
"They simply take it to another country - Rwanda, Uganda or South Africa - and ship it from there.
"There is no way to regulate an industry that can be started with one forced worker who needs as little a spade to get started."
US journalist Sara Turner, who won a Pulitzer award after writing about child labour, reported: "I wonder how many times someone looks at their laptop or their cell phone and thinks, 'there is coltan mined by children in this product'.
"These children die because of disease, starvation and unsafe working conditions. They die because the military abuse and murder them to hush their crimes."
Over 80 per cent of all coltan is mined from DRC, one of the world's poorest countries.
More than four million children in Congo are not in school and a third of those under the age of five are underweight.
Life expectancy is only 44 years and 80 per cent of the population lives on less than a dollar a day.
The discovery of such a valuable resouce has led neighbouring states to plunder coltan from within Congo's borders.
The UN Security Council believe profits from DRC coltan has funded wars in Rwanda and other African Sates. Rwanda made Û250million in 18 months from selling coltan, even though they have very little within their borders. Their soldiers stole it from Congo by forcing women and children to mine it.
Save The Children have been working to help the child miners of DRC since the 1990s.
A spokesman said: "DRC is rich in minerals such as diamonds, copper and coltan however the struggle to control these resources is fuelling the fighting which continues in the east of Congo.
"We started work in DRC in 1994, helping children who had fled the genocide in Rwanda.
"We then began to work with Congolese children. We are still here but we need more awareness."
Coltan's journey from Congo to your mobile is a complicated one involving militias, arms dealers and finally big business in the west.
The UN Security Council has cited 85 international companies for their purchases of natural resources from warring factions in the country, though the firms claim they are "unaware" where their coltan is mined.
The UN list includes household names such as Compaq, Dell, IBM, Nokia and Siemens.
The US-based Carlisle Group, a global private equity investment firm fronted by George Bush Snr, made a fortune from coltan.
Their board of directors includes ex-US Secretary of State James Baker, ex-US Defence Secretary Frank C. Carlucci, former UK Prime Minister John Major and until October 2001 was the home to a £1million investment from the bin Laden family.
DRC hopes to set up a scheme to certify coltan produced within its borders next year which should help trace illegal exports.
It will be similar to the global Kimberley Process set up to end the trade in "blood diamonds" from warzones.