VIENNA (Reuters) - Iran, which the United States accuses of secretly pursuing nuclear weapons, has a stake in the world's biggest open-pit uranium mine in the African state of Namibia, the mine's owner told Reuters. Rossing Uranium Limited, which is majority owned by Anglo-Australian firm Rio Tinto, sells its uranium to nuclear power plants in the United States, Japan, South Korea and Sweden. Graham Davidson, the general manager for operations at Rossing, said in a letter to Reuters that the company's board of directors only permits the sale of uranium for use in generating electricity. "The government of Iran has...