A gold mine collapsed in southern Sudan, killing at least 60 small-scale miners, two survivors told AFP on Wednesday, while many more are missing.

Shafts began collapsing in the Al Zaraa mine near the town of Al Nahud in West Kordofan on Tuesday, and by the following morning 60 bodies had been retrieved.

"We don't know how many more are still inside," one of the survivors, Khair Al Sayyed Jabara, told AFP after an all-night rescue operation with fellow miners, using the same rudimentary tools they use to mine.

"Everyone's working very hard to retrieve the bodies or any survivors, but it's difficult. We need heavy machinery to clear the rock and soil."

Employs more than two million people

Artisanal and small-scale mining, which takes place in decommissioned mines or unofficial zones like Al Zaraa, accounts for the majority of gold extracted in Sudan.

Al Amin Suleiman, another miner who was working at the rim of Al Zaraa on Tuesday, told AFP that "the shafts here are all close together, if one collapses, it brings down all the ones next to it."

"This is what happened here. So far, 60 bodies have been pulled out, but there are people still trapped underground since yesterday."

Artisanal mining employs more than two million people in Sudan, according to industry figures.

Sudan is one of Africa's leading gold producers and recorded a "five-year high" of 70 tonnes of production last year, it said. But officials say most of the gold is smuggled across Sudan's borders.