East Lyme ― The flashing lights of multi-agency contingents of crash trucks and police cruisers brought traffic to a gradual stop Thursday morning on both sides of Interstate 95 while East Lyme police Lt. Mike Macek brought up the rear on the southbound side.

His Motorola radio, on loan from project contractor Manafort Brothers crackled inside his cruiser. It was go-time for one more daily detonation intended to blast away 300 feet of ledge along the right lane on the northbound side of the highway.

Originally estimated as a six- to eight-week project, the blasting effort represents one of the first critical phases of the four-year, $148 million reconstruction of the highway. Resident Engineer Robert Obey of Glastonbury-based GM2 said crews could be looking at an extra month of blasting because an especially challenging section of ledge has resulted in longer closures and fewer detonations than project officials anticipated.

Each blasting period requires the complete closure of the highway between exits 74 and 75. The goal is to get it open again within 20 minutes, though project data shows there were more closures lasting over 20 minutes than under.

A voice came through Macek’s radio again after two Manafort pickup trucks swept the area for stragglers or disabled vehicles and took their place on either end of the cleared highway.

“Manafort is in position,” the voice said. “Maine Drilling, the highway is yours.”

Foreshadowed by a “fire in the hole” call from the blasting operator, charges loaded into machine-drilled holes 30 to 40 feet deep exploded beneath massive blast mats designed to contain the debris.

About 10 mats, each one made of 12,000 pounds of recycled tires and stacked to overlap, lurched in a cloud of dust upon detonation. The mats dulled the sound so that it wasn’t audible 1,000 feet from the blast.

Obey said daily efforts to monitor vibrations and movement at the nearby Smilow Cancer Hospital Care Center in Waterford, where sophisticated but delicate instrumentation can be sensitive to blasts, has shown no disturbance down the road.

It turned out to be what Obey would classify as a “good blast.” That’s the kind of explosion that doesn't end up with blast mats on the highway and concrete barriers pushed into the road.

Traffic was moving again on the southbound side in the time it took the foreman to check the expanse for debris before exiting the highway and reentering on the northbound side to help with cleanup closer to the blast site.

Nine minutes after the 11:05 a.m. detonation, the northbound lane was open too. The quickest turnaround to date, it was a stark contrast to detonations on Monday and Thursday of last week that resulted in the longest closures since blasting began on Aug. 1. In both cases, stopped traffic was detoured off the highway along Routes 161 and 1 before the lanes opened up again 46 minutes later.

State Department of Transportation project engineer Andrew Millovitsch said last Thursday’s delays were exacerbated when the reopened highway had to be closed again after inspection of the blast site revealed rock remnants on top that could potentially cause problems if dislodged.

“So we went ahead and made the judgment call that we’d need to do the second closure to go ahead and surgically remove some of the bigger rocks off the top so they didn’t decide to tumble down against the barrier at midnight when we’re all home in bed,” Millovitsch said.

Obey, a former district engineer for the DOT, emphasized the balancing act that comes from trying to keep the highway open while ensuring public safety.

“We have to sleep at night,” he said. “So we have to make sure that if there’s even a chance that something could fall and go into the highway, that it doesn’t happen.”

An original plan to conduct two separate blasts per day – both within the 9 a.m. to 1:30 p.m. time frame – has been on hold while Obey waits for closures to consistently come in below the 20-minute maximum. Up until Wednesday, he hadn’t seen times within the acceptable window since Aug. 9.

“At two blasts a day, this was estimated to take two months,” he said. “And we haven’t done a two-blast yet. So we’re adding a month.”

After Thursday’s nine-minute closure, he was optimistic “a two-blast day is in the future.”

Difficult terrain

Standing on the ledge about 30 feet over the highway and 15 feet from the edge of the road where peak traffic can bring 80,000 cars a day, Obey said the blast site is one of the closest to the highway that he’s encountered.

That makes it especially difficult and time-consuming to keep debris off the adjacent northbound side of the highway, though the southbound side has remained clear.

Millovitsch acknowledged summer construction comes with peak traffic volumes and carloads of frustrated drivers.

“We have to maintain two lanes of traffic in both directions at every minute possible,” he said. “We know the pain that it causes.”

Obey said the four-and-a-half-year project schedule makes it that much more imperative not to allow any more holdups. That means sticking to under 20 minutes for each closure so crews can move to two blasts per day.

“I can’t have the construction schedule be delayed,” he said. “The public is expecting us to figure it out.”

For information and updates, and to sign up for text alerts about upcoming blasts, visit the project website at i-95eastlyme.com.

e.regan@theday.com