Alcoa Aluminio started prospecting at the Juriti bauxite deposit in Para state, north Brazil, part of a planned expansion in bauxite, alumina and aluminium output, a spokeswoman said. "But so far there has been no formal definition of the new bauxite project," said the spokewoman for the Brazilian unit of U.S.-based Alcoa Inc. the world's biggest aluminum producer. Local business newspaper Gazeta Mercantil this week highlighted potential environmental objections to the project, 800 kms west of Belem in Brazil's Amazon rainforest.