New Irvington Tunnel Roadheaders Get Well-Deserved Break

They worked an average of 20 hours a day, 5 days a week for two and a half years; grinding away at rock hundreds  of feet underground. And now, they’re finally getting the rest they deserve.

The three road headers that helped excavate the New Irvington Tunnel were removed from the tunnel last month after we holed through from tunnel headings and they are now out in the fresh air and resting after completing the excavation of the three and half mile-long tunnel.  The largest of the group is a Mitsui Miike which weighs in at 57 tons. The two Antraquip roadheaders each weigh 36 tons. 

What lies ahead for our three tunnel veterans? All three machines could be refurbished for use at future jobs. 

While the workhorses await their future fate, work continues to complete the New Irvington Tunnel. Crews will begin installing the steel lining soon. The entire project is expected to be complete in 2015.

KTVU Video: New Irvington Tunnel Project Underway

Want to take an exclusive look at the New Irvington Tunnel? Check out KTVU Channel 2's sneak peak at the construction taking place to seismically upgrade the aging Hetch Hetchy Water System.

http://www.ktvu.com/video/27877116/index.html

Tunneling Begins

On Friday, March 11, the AQM 150-HR Roadheader began grinding its way west and has reached a distance of 25 feet. Tunneling will pause for approximately a week to complete the installation of the portal yard, ventilation and permanent power. Railroad tracks will also be installed behind the road header. The tracks are needed because as spoils generated they are collected on a conveyor belt and loaded onto rail cars for transport outside of the tunnel.

When tunneling resumes the roadheader will travel an average of 22 feet per day until it reaches the Vargas Shaft (14,300 feet away). A sister roadheader headed in the opposite direction will rendezvous with the machine sometime in 2013.

The roadheader’s boom-mounted cutting head that hacks away at rock face.

The boom-mounted cutting head is capable of excavating the 13-foot horseshoe shaped dimensions of the tunnel.

The Roadheader starts its journey from the Alameda West Portal

Spoils generated are collected on a conveyor belt attached to the roadheader and loaded onto rail cars for transport outside of the tunnel.

Packing a Punch: The AQM 150-HR Roadheader

How do you punch through 3.5 miles of dirt and rock? You start with an AQM 150-HR Roadheader which arrived on President’s Day after a weeklong trip from Maryland. A roadheader is a tracked piece of tunneling equipment used in conventional mining. In front is a boom-mounted cutting head that hacks away at rock face. The spoils generated are collected on a conveyor belt and loaded onto rail cars for transport outside of the tunnel.

This roadheader will start its journey at the Alameda West Portal (AWP) which is one of the primary tunneling sites for the New Irvington Tunnel. From there, the roadheader will tunnel west towards the Vargas Shaft and meet with a sister roadheader headed in the opposite direction. The roadheader rendezvous is expected to take place sometime in 2013.

The roadheader is more than 26 feet long, 7 feet wide and weighs 36 tons. The boom-mounted cutting head is capable of excavating the 13-foot horseshoe shaped dimensions of the tunnel. This roadheader also has a probe attachment used to drill a 2-inch hole 150 feet ahead of the rock to investigate ground conditions and groundwater inflow.

Look for continued images and updates of our progress at New Irvington Tunnel.