Rio Tinto's (RIO.L: Quote)(RIO.AX: Quote) Zimbabwe's diamond unit Murowa produced a record 260,000 carats last year compared to 145,000 carats in 2007, the company's managing director said on Thursday.

Niels Kristensen, the managing director of Murowa, which is 78-percent owned by mining group Rio Tinto Plc (RIO.L: Quote), said the local business environment had improved lately, but urged the government to do more to attract investors.

We achieved record production in 2008. Production was in the region of 260,000 carats in 2008 and there is potential to increase that substantially, Kristensen told Reuters in an interview on the sidelines of a mining conference.

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