Port of Miami Tunnel Project Gears Up to Go ~

State of Florida environmental regulators have given the go-ahead for an ambitious four-year, billion-dollar project to connect Port of Miami facilities with highway access through a 23-foot-in-diameter tunnel under Biscayne Bay, the Miami Herald reports (“ Florida gives green light to Port of Miami tunnel ,” by Andres Viglucci). Major components of the project, including a plan to retain, purify, and re-use water from the tunnel-boring project and a proposal to clean and use spoil dirt for beautification and eco-system recovery on degraded or over-developed islands, have received Florida Department of Environmental Protection approval, allowing issuance of the permit. To dig the tunnel, a consortium of construction companies called MAT Concessionaire, LLC , has acquired a giant custom-built 2,500-ton boring machine longer than a football field, with a huge, 23-foot disc-shaped grinding head that weighs 530,000 pounds (above). The machine was delivered back in June; now, the grinding head has been assembled and a concrete entry ramp built on Watson Key, an artificial island, CBS Miami reports (“ Critical Day In $1B Port Of Miami Tunnel Project ”). Drilling is set to start as early as this month. The boring machine has been nicknamed “Harriet,” reports the Herald (“ Massive machine comes together to dig port tunnel ,” by Andres Viglucci). “The cutting head and the circular engine section will pull a train-like assemblage, including a two-story gantry resembling a high-tech locomotive, that will contain electrical and hydraulic systems, a manned command center, mechanic’s shop, brake room and a chamber that can be sealed to protect 16 people in case of fire or other emergencies,” the paper reports. “The entire machine will be powered through a connection to the electrical grid.” As it tunnels under the bay at a rate of about four feet per hour, the giant machine will inject sealant grout into the porous limestone rock, and set curved pre-cast concrete panels in place to form the tunnel wall’s permanent structure. Upon reaching the other side of the bay, engineers will disassemble the beast, reassemble it, and cut a return tunnel — completing the work, if all goes as planned, sometime in 2014. Then, say Florida Department of Transportation officials, the tunnel will begin decades of service life, ensuring long-term access to the port (see video, below).