Underground Controlled Blasting FAQ
What is underground blasting?
Underground controlled blasting is a common infrastructure construction method used to break rock for excavation. Holes are drilled into the rock for placement of the blasting agent. Packed dirt is added to holes and above the rock. A seismograph records blast vibrations to verify they are within specifications.
Is it safe?
Yes. Controlled blasting is highly regulated and conducted using safe methods and procedures by trained professionals. Blasts will be monitored by seismographs to maintain acceptable levels of ground motion in conjunction with vibration controls. Each blasting event will occur only after verification of all safety precautions and the site is deemed cleared and secure by the blaster-in-charge.
What can I expect to hear/see/feel?
Air horn safety signals will sound 5 minutes and 1 minute before the blast and at the conclusion of the blast. In addition to the air horn, those very near to the construction site may feel a vibration comparable to a door slam or a large truck driving down the street.
Dust suppression systems and heavy blasting mats will be in place to minimize vibration and debris.
When will blasting occur?
Blasting activity will likely begin the second or third week of October and continue for approximately six months. Current plans call for a blasting event once a day between 1-1:30 p.m. on Tuesdays and Thursdays. The blasting schedule is subject to change and to the extent weather or project schedule necessitates blasting outside of those times, blasting would occur during daylight hours Monday through Friday. No blasting will be performed weekends or federal holidays.
What should I do to prepare?
Residents living adjacent to the project site may wish to keep windows closed for the brief period of the blasting, between the one-minute signal and the following all-clear signal. If you are near the construction site and hear an air horn, please be aware blasting activity will occur shortly and follow instructions of site personnel or any additional signage that may be posted.