Miners buried in DR Congo

DR Congo is home to 80% of the world's coltan reserves

A mine has collapsed in eastern Democratic Republic of Congo, killing at least 30 people.

Three bodies have been recovered from the mine but as many as 36 others are still buried under the debris, a week after the collapse.

The Bibapama 2 coltan mine, 60 km south-west of Goma, is under the control of the Rally for Congolese Democracy (RCD) rebels.

Coltan is used in the manufacture of mobile phones and many Congolese have switched from farming to work in the far more lucrative coltan mines.

Journalist Jules Ngala Ngoma told BBC News Online that many of the victims were traders, selling food and other supplies to the miners.

He said that the mine had collapsed following heavy rains.

Store energy

The RCD authorities have stopped all mining activity in Bibapama 2 but Mr Ngoma says that people are so desperate for money that they are still working on the nearby mines of Bibapama 1 and 3.

Coltan is used to make pinhead capacitors, which regulate voltage and store energy in mobile phones.

Many farmers switched to become coltan miners

The spread of mobile phones across the world in recent years has led to a coltan boom in eastern DR Congo, home to 80% of the world's coltan reserves.

Some human rights activists have said the coltan boom has been one reason for the three-year conflict in DR Congo, as the rebels are reluctant to lose their control of the industry.

They have launched a "No blood on my cell-phone" campaign in Europe, hoping to persuade people not to buy phones which incorporate coltan.