On June 20, Southland/Tutor Perini JV began tunnel excavation from the Irvington Portal in Fremont. The contractor will advance the tunnel using a road header (a tracked tunnel excavator) and controlled detonation if necessary depending on the rock conditions. Other construction support equipment will load and haul the excavation spoils from the site to a disposal area on Calaveras Road in the Sunol Valley.
If the road header encounters harder than anticipated rock conditions underground, the use of controlled detonations may be necessary. This involves the use of small amounts of explosives to fracture the rock material so that it can be removed by the tunnel machinery. Safety horns would be sounded a set period of time before each event. We will monitor to ensure that controlled detonations comply with all local, state and federal safety, noise, and vibration requirements. Controlled detonations are only allowed to occur Monday through Friday between 7:00 AM and 7:00PM and on Saturday between 8:00 AM and 5:00 PM. No more than two controlled detonations are anticipated per day on the days that controlled detonations are needed. But most of the excavation is anticipated to be successful by the road header alone.
Due to the nature of tunneling, it is challenging to predict far in advance when controlled detonations would be necessary. The SFPUC will provide residents with advanced e-mail notification of controlled detonations as early as possible (24 hours minimum). To receive e-mail notifications of controlled detonations, please send a message to firstname.lastname@example.org.
Residential Construction Surveys
Many residents exercised their option to have photographic and video surveys of their property prior to construction. These surveys document existing cosmetic and structural cracks for each property and are used as basis for evaluating claims of new damage caused by construction activities. If you have not had a survey conducted please contact the SFPUC as soon as possible, we may conduct surveys until July 6, 2011. Please call 866.973.1476 and reference the New Irvington Tunnel Project or e-mail email@example.com to schedule a photographic and video survey.
Please call our 24-Hour Answer Line at 866.973.1476.