Workers have begun paving the twin roadways inside the Port of Miami Tunnel under Biscayne Bay, the Miami Herald reported. They also have begun constructing the massive tunnel portals, with 50-ton metal gates that will close in case of a hurricane to prevent flooding.
A giant tunnel boring machine began digging the eastbound tube in November 2011 from the MacArthur Causeway at Watson Island to the port. The tunnel boring machine, nicknamed Harriet, completed digging the westbound tube back to Watson Island in May 2013.