More rock blasting to affect U.S. Highway 189 in Provo Canyon

OREN, Utah — The wet, cold weather that has continued into this spring has caused unusual problems for the Utah Department of Transportation.

Two weeks ago, large rocks, two to three feet in diameter, started tumbling from a cliff face onto U.S. 189.

UDOT shut the ramp from 800 North to U.S. 189 at the mouth of Provo Canyon on Tuesday and used explosives to bring down an unstable rock shelf.

More rock blasting to affect U.S. Highway 189 in Provo Canyon

At 1 p.m. UDOT detonated the charges after shutting down traffic in Provo Canyon.  The charges blasted an 80-foot section of rock shelf about five feet tall and 10 feet deep onto the dirt road. The rock and dirt weighed several tons.

“Some of this rock cliff gave way, creating a shelf that was hanging over the road,” Geoff Dupaix, region communications manager for UDOT said. 

The idea was to bring that rock shelf straight down onto the road where it would be cleared away.

“So that we can bring down that rock and work towards getting this ramp open by the end of the week,” Dupaix said. 

The shale on the rock face has been crumbly before. But the exceptional amount of moisture this winter intensified the freeze-and-thaw cycle that breaks up the rock. 

“It has eroded away and into the fissures and cracks and expanded those cracks,” Dupaix said. “It’s a sizable amount of rock that we need to bring down in order to make this road safe for motorists.”

After they blasted that rock shelf, they originally thought they would do another blast Tuesday.  Instead, UDOT spent the rest of the afternoon cleaning up the rock and getting ready to do another blast Wednesday.