The tax regime which include ground rental fees, are significantly affecting the business, the company said.
Murowa Diamond mine managing director Zebra Kasete was quoted by Bloomberg as saying in a letter: "The management team is continuously engaging government and hope for some positive outcome from this process; else the viability of Murowa Diamonds as a going concern will be impacted."
A source familiar with the matter said that the land rental, if implemented, could cost the company around $109m a year.
Rio Tinto owns 78% stake in the Murowa mine, while its former subsidiary RioZim owns the remaining interest. Deutsche Bank valued the mine at $279m in 2013.
Said to be the company’s sole diamond mine in the country, the mine produced 101,000cts of gems in the fourth quarter of 2014.
