Nirupa Bhatt, longtime head of Rio Tinto’s India office, is leaving her post at the end of this month.

Announcing the shift, Rio Tinto Diamonds‘ general manager of marketing, Jean-Marc Lieberherr, said, “I would like to emphasize at this point Rio Tinto Diamonds’ firm commitment to its association with the Indian diamond community and that the local office remains operational. I shall announce the new head of the Mumbai representative office in due course.”

Even so, the move raised speculation. There are persistent rumors that Rio Tinto is about to sell its Argyle Mine, the Australian producer of smaller stones that caters to the Indian industry. PolishedPrices.com recently reported that Rio Tinto has hired Gresham Partners, an equity firm, to sell the mine. Rio Tinto did not respond to requests from JCK for comment on the report.

According to knowledgeable sources, Argyle’s underground expansion has proved more costly than expected because of rising steel and manpower costs, the result of a mining boom in Australia.