Tuesday, February 22, 2011

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.

Thursday, February 10, 2011

Digging Deep: The Vargas Shaft

What is 120-feet deep, 41-feet in diameter and supported by 76 concrete secant piles? If you have been following us for awhile you know this is none other than the Vargas Shaft! For those that are new or just need a refresher here is a run down:

The Vargas Shaft is one of the three locations where tunneling will take place for the New Irvington Tunnel. The shaft is located immediately east of I-680 off of the Vargas Road exit. A road header will be lowered into the shaft where it will tunnel west towards the Irvington Portal. As soon as this tunnel section is complete, the road header will reverse direction and tunnel eastward from Vargas towards Alameda West Portal where it will meet another road header coming from the Alameda West Portal. The tunnel rendezvous is scheduled to take place sometime in 2013.

Excavation of the shaft began in late January and is scheduled for completion by early March. The road header will be most of the way to the Irvington Portal by year's end.

Here's a progress photo of the Vargas Shaft. A yellow railing has been installed for safety. In the background, you can see the steel I-beams that are used for sound barriers.

We will post more pictures as the project moves forward. Feel free to send any photos or videos you have of the project to fzamora@sfwater.org.

Tuesday, February 8, 2011

Water Line Damaged at Irvington Portal

At approximately 10:00 AM, a drill crew installing inclinometers struck and damaged a 24" water line at the Irvington Portal. San Francisco Public Utilities Commission (SFPUC) and contractor personnel responded immediately and were able to stop the flow of water and contain it within the SFPUC's property.

The damaged water line serves the City of Hayward. The SFPUC immediately notified the City of Hayward so that the City can set up secondary pumps and storage measures. No service disruptions are anticipated as a result of the damage.

SFPUC and contractor personnel are currently working to repair the water line. Upon completion the water line will be disinfected and inspected prior to returning to service.