by Susan Gentle
Large crowd on hand for ground breaking and christening of the tunnel boring machine (TBM ,shown in background).
Construction of the new $1 billion Port of Miami tunnel has taken a giant leap forward now that "Harriet", the largest diameter soft ground tunnel boring machine (TBM) in the United States, is digging the first of two tunnels under Biscayne Bay. On Friday, November 4, 2011, following a worldwide tradition, the TBM was christened with her name: Harriet, selected by the Miami-Dade County Girl Scouts for Harriet Tubman, the founder of the Underground Railroad that helped guide dozens of slaves to freedom. Hundreds from various subcontractor and vendor firms were present at this momentous occasion on a gorgeous South Florida day. Just seven days later, at 4:30 a.m. on Friday, November 11, 2011, Harriet's break-in commenced. The machine, which will build the tunnel walls as it digs, has also begun assembling the segments forming the lip of the tunnel entrance. "This is an exact business. This is engineering at its finest," said Chris Hodgkins, the vice-president of Miami Access Tunnel. As of January 16, 2012, the TBM is more than 400 feet into the ground with more than 70 rings installed. Harriet, which is four stories tall and as long as a football field, will continue boring over the next six months before breaking through on Dodge Island. Harriet will then be partly disassembled, turned around and re-assembled before boring out the separate return tunnel to Watson Island. James Noe, Project Manager for Revere Control Systems, earned this badge for attending the Port of Miami Tunnel Boring Machine Launch Ceremony."
Revere Control Systems designed and built the controls for a conveyor system spanning the eastbound MacArthur Causeway which will remove the paste-like spoils from the tunnel and transport them to a plant on Watson Island where water will be removed. Tons of soil is expected to be excavated for the tunnel. For more information on the tunneling process, visit
http://www.portofmiamitunnel.com/system/js/back/ckfinder/userfiles/files/11-04-11-pomt-fact.pdf. When complete, the tunnel will provide direct access between the Port of Miami and I-395 and I-95. The tunnel is also expected to improve traffic flow in downtown Miami by reducing the number of cargo trucks and cruise related vehicles on congested downtown streets. The tunnel is expected to be open to the public by May of 2014.