President Thabo Mbeki named one of South Africa's most powerful women on Wednesday to succeed his graft-tainted ex-deputy Jacob Zuma but immediately faced questions about the new number two. Mbeki appointed Minerals and Energy Minister Phumzile Mlambo-Ngcuka a week after he fired Zuma, who was implicated in a corruption trial earlier this month and is to face graft charges in court next week. Mlambo-Ngcuka has distinguished herself as one of Mbeki's most efficient cabinet members and loyalists, according to Reuters.