Heavy rain in the Mabayi commune in northwest Burundi on Friday sent torrents of water from a swollen river gushing into a pit mine were they were digging, said Nicodeme Ndahabonyimana, the municipal administrator.
The 14 miners "did not have time to get out of the holes," Ndahabonyimana said.
Efforts were underway to pump water from the mine shafts to recover the bodies of the trapped miners, he said, but "there is no longer any chance of finding them alive."
Burundi is rich in gold, precious minerals and rare earths but many mines are unregulated.
Four miners were killed in Mabayi working at an unregulated mine just last year, Ndahabonyimana said.
In May 2019, nine miners were killed and another 20 injured when an unregulated coltan mine collapsed following torrential rains in northern Burundi.
Such incidents occur regularly across the country but local authorities are discouraged from reporting them, civil society activists say.
In 2021, Burundi's government announced it was suspending the operations of several international mining companies, complaining that it was not getting its fair share of income from the country's mineral wealth.