Mining giant Rio Tinto's majority-owned diamond company operating in Zimbabwe, Murowa Diamonds, is upset with that country's mining policies, saying the amount of money they take from firms is too high, Rough and Polished reports.

In comments made to a Zimbabwean newspaper, Murowa's communications and external relations manager Lovemore Chimuka asserted that local mines ran the risk of being closed down because high royalty rates were making mining activities far less profitable.

Chimuka said that Murowa was first told that it would be charged a royalty rate of 10%, but that this was then jacked up to 15%, which Chimuka says is financially oppressive, according to Rough and Polished. Chimuka says the mandated $3,000 per hectare ground rental fee is illogical, because it would amount to an annual payment of $109 million, while the company only conducts $60 million worth of business in a year.