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.
Iraq investigates attack on military base
A huge blast at a military base in Iraq early on Saturday killed a member of an Iraqi security force.
India begins voting in election as Modi seeks historic third term
India began voting on Friday in the world's largest election as Prime Minister Narendra Modi seeks a historic third term in office on the back of growth, welfare, his personal popularity and Hindu nationalism.
Teenager charged with terrorism over Sydney bishop stabbing
A 16-year-old boy has been charged with a terrorism offence for allegedly stabbing an Assyrian church bishop in Sydney during a church service, Australian police said on Friday, as investigations continued into a riot after the knife attack.
Kenya's military chief among 10 killed in helicopter crash
Kenya's military chief, General Francis Ogolla, was among 10 people killed when their military helicopter crashed shortly after take-off on Thursday.
Security Council to vote on Palestinian UN membership
The UN Security Council is due to vote on Thursday on a Palestinian bid for full UN membership.
