Portugal's government announced on Wednesday an investment plan worth 4 billion euros ($4.6 billion) to expand and modernise its main ports over the next 10 years, 75% of which will be done by private companies.Infrastructure Minister Miguel Pinto Luz said the investment would be made in six ports, including the port of Sines - the closest deep-water European port to the U.S. coast - where the current terminal is being expanded and a new one will be built…