Airport newsletter October 2017

Posted on October 5, 2017

October 31 — Construction activity resumed at the airport on Monday, October 30, with the washing and cleaning of the large conveyor belt and rock processing equipment used to make the aggregate subbase. Most of the processing equipment was removed on October 31. Also on October 31, the runway subbase placement began with contractor employees following the newly mandated safety practices. All workers outside of vehicles in the regulated area are using disposable coveralls and half-face respirators. Additional air samples are being performed as the work changes to monitor performance. County staff is in discussions with the contractor regarding extending the working hours to up to 12 hours a day.

October 24 — For the most recent status update on the Airport Runway Rehabilitation Project, please view this PDF.

October 18 — A partnership meeting was held today (Wednesday, October 18) between County staff, the construction manager/design engineer and the construction contractor for the Gnoss Field runway rehabilitation project. All parties are working towards a solution to reopen the runway as soon as possible.

A critical factor is the determination that the subgrade material contains naturally occurring asbestos above certain regulatory levels. This substance is also found in the onsite stockpiled material which will be reused as the runway subbase, and then covered by base rock and asphalt. The next few days and all of next week will be focused on worker training, submitting a work plan to the Bay Area Air Quality Control Board and receiving approval of the work plan. Additional ambient air monitoring will also begin at the airport to verify and document acceptable air quality levels. With these measures and approvals construction work will continue on the runway.

Additional updates will be provided as details and new information develops. Thank you for your patience and understanding during this process.

October 13 — It is unfortunate to report that construction progress for the week October 9th stopped. The material produced from grinding the runway by the contractor the prior week, and intended by the contractor to be used as the runway subbase material, did not meet all of the material specifications for all of the material produced. County staff and our construction manager have been working with the contractor and with the Federal Aviation Administration (FAA) to develop a viable solution that allows the project to move forward. A workable solution has so far not been determined. The runway reopening date has now been delayed by a minimum of one week.

In addition, the contractor tested material below the asphalt runway and found low levels of naturally occurring asbestos containing material, likely from the existing base material. The county has hired an environmental consulting firm which has verified the results and is preparing response plan that safeguards the environment, contract employees and the general public.

We will provide further updates as information becomes available.

October 9 — Please be aware that the fires in Sonoma and Napa have not impacted Gnoss Field airport. We hope for the safety of all people involved in this horrible emergency, and for a successful containment and quick resolution of the fires.

October 5 — Work continues on the runway rehabilitation project. The grinding of all the existing runway asphalt was completed on Tuesday, October 3. Grade and leveling survey points are being set prior to start of importation of the subbase material, which is the next major construction phase. The placement of geogrids (plastic grid meshes) began on Wednesday, October 4, in areas needing subsurface strengthening. A test asphalt pavement strip is expected to be done at the San Rafael Rock Quarry next week to evaluate pavement quality.
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