Feb. 23 (Bloomberg) -- De Beers halted production at its diamond mine venture in Botswana since the start of the year because sales slumped, the Financial Times said.

The mines, the source of half of De Beers’ supply of rough diamonds and almost a quarter of the world’s by value, sold no diamonds in November and “very little” in the following two months, the report said, citing Sheila Khama, chief executive officer of the company’s Botswana business.

Khama couldn’t say when the mines will resume production, adding that demand may recover in 2010 and costs are being cut, the report said. The Botswana mining venture has yet to reduce its 6,300 staff, the newspaper said.

To contact the reporter on this story: Kyunghee Park in Hong Kong at kpark3@bloomberg.net

Last Updated: February 22, 2009 19:52 EST