A pit collapse has killed at least 16 people at the Democratic Republic of Congo’s largest coltan mine, controlled by the Rwanda-backed M23 militia, local sources told AFP on Friday.

Since its resurgence in 2021, the M23 has taken vast tracts of the DRC’s resource-rich east, capturing the Rubaya mine in North Kivu province in April 2024 with Rwanda’s help.

Its advance has intensified the more than three-decades-long conflict which has ravaged the eastern DRC, where dozens of rival armed groups and foreign powers have long vied for control of the region’s rich veins of valuable minerals.

The Rubaya mine produces 15 to 30 percent of the world’s supply of coltan, which is key to the making of electronics including laptops and mobile phones.

At the time of the landslide on Thursday morning, around 131 diggers were on site, according to Emmanuel Ndizeye, a local official appointed by the M23.

Of those, 111 were rescued, while 16 bodies were recovered and four more were still missing, the M23’s administrator for the Masisi territory where the mine is located told AFP.

According to United Nations experts, the M23 has set up an administration in parallel to the Congolese state to regulate the operation of the Rubaya mine since Its capture.

The experts estimate that the M23 makes around $800,000 a month from the mine thanks to a seven-dollars-a-kilo tax on the production and sale of coltan.

However, that amount represents only a fraction of the M23’s revenue from the levies it imposes on trade in the regions under its control.

The UN experts also accuse Rwanda — which denies providing the M23 with military support — of using the militia to syphon off the DRC’s mineral riches.

Besides containing between 60 to 80 percent of the world’s coltan, the wider eastern DRC is also home to vast reserves of gold and tin.

Several international mining firms have temporarily halted their operations in the east as a result of the M23’s advance. (AFP)

•Onlookers peer down at a crane excavating the site of a waterlogged gold mine, which collapsed in a landslide. Image source, Getty Images