Artisanal diamond miners work at Tumbodu, north of the town of Koidu in eastern Sierra Leone, March 3, 2012. Low technology artisanal mining goes on alongside Koidu Holdings' kimberlite operation in Kono District. Koidu Holdings is selling gems in outlets such as U.S. jeweller Tiffany & Co. and considering a possible public listing, which could raise hundreds of millions of dollars to fund expansion. Picture taken March 3, 2012. To match feature SIERRALEONE-DIAMONDS/ REUTERS/Simon Akam (SIERRA LEONE - Tags: ENVIRONMENT BUSINESS CONFLICT CIVIL UNREST EMPLOYMENT)