The men are believed to have drowned after water from a burst dam flooded the shafts and underground tunnels they were working in.
Police said rescue teams were trying to pump out the water and search for bodies and any survivors.
According to reports, illegal miners in Battlefields, 175 km west of Harare, had entered shafts on land owned by RioZim and another firm in search of gold.
It added that the two mines, called Silver Moon Mine and Cricket Mine, are run by registered companies.
At least 47 dead in eastern Indonesia after magnitude 7.7 quake
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Kuwait, Bahrain strongly condemn Iranian attack on ADNOC vessels
Kuwait and Bahrain on Saturday expressed their strong condemnation of the Iranian attack against vessels affiliated with the UAE's Abu Dhabi National Oil Company (ADNOC) while transiting the Strait of Hormuz.
Yemen's Mocha port halts operations after Houthi attacks, port director says
Yemen's Mocha port has suspended commercial and maritime operations after being hit by more than 25 missiles in Houthi attacks over recent days, the port's director said on Saturday.
Morocco arrests 111 migrants headed for Spain's Ceuta in security crackdown
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