Miami Tunnel about to head under Government Cut -- what was that? a drip?

Port of Miami tunnel boring machine approaching Government Cut
By Alfonso Chardy 
 

El Nuevo Herald Staff
Port of Miami tunnel boring machine approaches Government Cut
Photos

The machine boring the tunnel to the Port of Miami is approaching an important milestone on its underground journey from Watson Island.
After four months of excavation from the median of the MacArthur Causeway, the machine on Wednesday approached the water’s edge, where it will begin burrowing under Government Cut, the channel used by cruise ships to dock at port terminals.
“We’re a quarter of the way into the tunnel,” said Chris Hodgkins, vice president of Miami Access Tunnel, the multinational firm building the $1 billion facility. “We’ve gone underneath the MacArthur Causeway and we’re heading over to Government Cut.”
Harriet, as the boring machine is called, operates 20 hours a day, stopping for maintenance between 7 and 11 a.m.
The machine, which drills at a rate of 20 feet per day, began boring Nov. 11 and has completed 1,245 feet of tunnel. It is expected to finish the first 4,200-foot tunnel tube over the summer. Then it will be turned around and take another six months to bore the second tube back to Watson Island.
Each tube will house a two-lane underground highway that project officials hope will draw a majority of the cargo trucks that now meander through downtown streets to reach the port. The tunnel will provide the first direct link to the port from area expressways such as Interstate 95 and State Road 836, which connect with the MacArthur Causeway.
During a 3 a.m. tour Wednesday, sitting in the control room before an array of television and computer screens was Richard Henson, a 28-year-old tunnel boring machine pilot from Bemidji, Minn.
As the machine’s giant cutter head sliced through rock and soil, it turned the spoils into a mixture with the consistency of toothpaste. That mixture was then carried out of the machine on a conveyor belt and taken to dump trucks. Hodgkins said spoils extracted between Tuesday and early Wednesday would fill 279 truckloads.
As the machine bored, only a slight vibration coursed through the control room. The noise, however, was deafening — not from boring, but from electric motors and air compressors that made it feel like being inside a jet engine.
A little before 4 a.m., the machine stopped so a team of workers could finish installation of one of the concrete ring segments that make up the tunnel’s oval wall. The tunnel boring machine not only excavates but it also builds the wall.
The tunnel is expected to be completed by 2014.

Read more here: http://www.miamiherald.com/2012/03/14/2693620/port-of-miami-tunnel-boring-machine.html#storylink=cpy