A U.S. shipping firm is suing Alcoa for $300 million saying it suffered losses after the aluminium maker breached a contract with the Guinean government concerning bauxite shipments... Nanko Shipping and its president Mori Diane filed a civil complaint in the U.S. district court...saying it had been harmed by Alcoa's refusal to honour the terms of the 1963 joint-venture mining deal with the Guinean government.  That agreement established the Compagnie des Bauxites de Guinee (CBG) [now joint venture Alcoa, Govt. of Guinea, Rio Tinto & Dadco]...and gave the government the right to choose a company to ship half of its production... Alcoa spokeswoman Christa Bowers said... "...we can confirm that we do not have, and never have had, a contractual relationship with Nanko Shipping"... Bowers declined to comment on whether Alcoa had refused a request from the Guinean government to allow Nanko to handle the shipment... If Nanko's case were successful it would mark a step forward for African nations seeking to wrest greater control of their natural resources from international companies. Guinean officials said the government had signed a deal with Nanko in August 2011 to transport its share of the CBG's production... Tidiane Traore, transport minister at the time of the deal,...[said] "We signed this deal with Nanko Shipping because we want Guinea to benefit from its share of the minerals, especially in transport"... Diane, a black U.S. citizen of Guinean origin, also accused Alcoa of racial discrimination... [also refers to Halco Mining (joint venture Alcoa, Rio Tinto & Dadco Alumina & Chemicals)]