If you put together the 2010 uranium output from mines owned by Rio Tinto (in Namibia and Australia), along with output from BHP Billiton’s Olympic Dam mine in South Australia,  these two London-listed companies rank equally (at 16%)  with  Cameco (Canada) and  Areva  (France)  as the world’s most  important publicy-listed uranium producers.
Kazakstan remains the most significant uranium producing country – by far (thanks to mines owned by the state nuclear company, Kazatomprom, and from smaller mines operated in joint ventures with Cameco, Areva and Uranium One).
ARMZ (the Russian state-owned nuclear conglomerate) – credited with supplying 8% of global uranium requirements last year, is also 100% state owned – and is currently the 51% shareholder in Uranium One, itself the 6th largest uranium producer in 2010. Uranium One has a main listing on the Toronto Stock Exchange and has a secondary listing on the  Johannesburg Stock Exchange. Its assets are located in Kazakhstan, the United States and Australia and it is now the operator of the Mkuju River Project in Tanzania.
(Commentary by Nostromo Research)
See the global uranium summary in ARMZ and the man at http://www.minesandcommunities.org/article.php?a=11115&l=1.