Montepuez Ruby Mining, a subsidiary of London-based Gemfields group, said in a statement that the 11 were buried in its disused mine following heavy rains late on Monday while they were illegally mining for rubies.
The firm blamed corruption among government officials for the thriving illegal mining of rubies.
“These tragic deaths are linked to the ability of certain foreign buyers to conduct their illegal ruby purchase operations apparently in cities like Montepuez without the authorities taking the necessary measures,” the company’s corporate affairs manager Raime Raimundo said.
In northern Mozambique, informal and illegal ruby mining is a lucrative business that has attracted thousands of itinerant workers despite strenuous crackdowns by police and private guards.
Ruby deposits, which were discovered about a decade ago, are easily accessible near the surface, triggering the sudden birth of a frantic wildcat mining industry.