Vast Resources is this week expected to sign an agreement with Zimbabwe's state diamond mining firm to prospect and mine diamonds in Marange, according to media reports.
Vast recently formed a company, Katanga Mining, with the Chiadzwa community.
That company will sign a joint venture mining agreement with Zimbabwe Consolidated Diamond Company which holds the mining rights, said mines minister Winston Chitando.
He said financial details will be revealed at the signing of the agreement.
Zimbabwe also allowed Russia's Alrosa and the unlisted Chinese firm Anjin Investments to prospect and mine diamonds in the country.
Anjin returned to Marange having been forced out from the diamond fields in 2016 along with other miners.
The government of the late president Robert Mugabe refused to renew their licences saying the miners were smuggling diamonds.
Meanwhile, President Emmerson Mnangagwa is expected to launch on Monday an ambitious plan to increase investment in mining and raise the sector's export earnings to $12-billion by 2023 from $3.2-billion last year.