Rio Tinto is pumping another US$175m (£110m) into it Simandou iron ore project in Guinea to cover mine, rail and port infrastructure work.The miner, which finalised a joint venture deal for the project with Chinese state-owned miner Chinalco last week, has already spent $650m on exploration, community development and evaluation studies.Though Guinea may consider an export route through Liberia, current plans are for construction of a mine at Simandou with an annual capacity of 95m tonnes, a 650km dedicated industrial railroad passing through 21 km of tunnels traversing Guinea to the coast.The new money will pay for initial work on upgrading the national road network, building the construction wharf at the port and building project facilities.