By Micah Gammons, Maintenance Manager I
and Heidi Crawford, Public Information Officer
Whether it’s from Mud Creek to Rat Creek or Big Sur on State Route 1 in Monterey County, the Montecito Mudslide in Santa Barbara County, or the brushfires in Santa Cruz County, or near Gaviota in Santa Barbara County, the District 5 Blasting Crew has had a very busy and challenging few years.
In the past, the team would average three to five blasts per year, which has increased to 60 to 70 blasts per year and counting. Our current crew consists of five: Maintenance Manager I Micah Gammons, Maintenance Area Superintendent Cody Collins, Maintenance Supervisor Gilbert Cruz, and Maintenance Leadworkers Cory Simmons and Lucas Weeks.
They travel throughout District 5 and at times adjacent districts, to reduce large boulders and secure unstable slopes to reopen highways and make them safe for the traveling public as well as our own Maintenance, Construction and Geotechnical crews. Our team has assisted District 7 on State Routes 33 and 150 near the Pacific Coast Highway in Malibu, and all the way up in District 4 on State Route 152 over the Pacheco Pass.
This group attends annual training in Kingvale at Donner Pass to stay current on existing regulations, safety policies, blasting methods, and the latest equipment, so they can continue to work safely and to the best of their ability.
The crew is trained to assess the size and type of rock they are challenged with, calculate necessary reduction sizes, and identify equipment capable of moving and hauling the material away safely. They first measure and drill 1.5-inch holes with pneumatic rock drills approximately two-thirds into the boulders, which have been as large as 20 feet in diameter.
Next, the area is cleared before carefully preparing and loading the explosives. Then they back the holes (filling the holes with small angular rock to lock the explosives inside the hole) with stemming and run the trunk line out to a safe distance away.
The blasting signals are activated with an air horn, which consists of a five-minute warning to clear the area, a one-minute warning prior to the blast, and a 20-second countdown before ignition.
After the successful blast, the licensed blaster inspects the area and gives the “all clear” before personnel may enter to begin clearing the area.
Blasting is mostly an unheard-of practice within the department but is an extremely vital part of what Caltrans does to keep the state highway system open. It is just another example of the department’s efficiency; an internal program that trains and develops specialists ready to face any challenge in maintaining our highways and infrastructure throughout the state of California.