BONDAD – A contractor hired by the Colorado Department of Transportation on Tuesday brought down a huge chunk of the landmark rock formation on Bondad Hill along U.S. Highway 550 just north of the New Mexico state line.
The blasting was prompted by the fall of a large slab of the outcropping Oct. 26 that reached the shoulder of the highway in a habitual trouble spot.
“There won’t be any flying rocks,” Kent Baxstrom, a CDOT maintenance supervisor, said as he watched the last of 40 holes being packed with dynamite just before the blast. “The rock will just break and fall.”
So it was. From a vantage point a half-mile away on the west side of the Animas River, the explosion announced itself with a burst of dust and smoke – followed a second later by a muffled boom.
Traffic, which was single-lane for a time early Tuesday, was halted before, during and after the blast for safety reasons and to allow CDOT to clear debris.
It took a week of preparation by a crew from Yenter Cos. of Arvada to reach that point. Yenter is a longtime contractor for CDOT projects beyond the scope of CDOT maintenance crews, agency spokeswoman Nancy Shanks said.
The crew drilled 40 holes from 4 feet to 12 feet deep into the hillside to hold two to four sticks of dynamite each, Baxstrom said. Each stick weighed one-half pound.
The section of hillside brought down was about 80 feet long, 20 feet high and 15 to 20 feet deep, Baxstrom said.
Katie Mitchell and children Cooper, 5, and Kinley, 3, watched the operation from across the river in their bronze-colored SUV. They live on the Paxton Ranch, about a mile to the east and directly behind the site of the safety project.
“We watched them working for the past week as we drove by,” Mitchell said. “We’d see them hanging down from ropes to drill holes.”
Cooper summed up the finale: “It’s so cool.”
CDOT monitors roadside hillsides for dangerous rock areas. The Bondad Hill stretch of Highway 550 and Colorado State Highway 3 across the Animas River opposite Bodo Industrial Park are among areas where danger is greatest. Highway 550 around Molas and Coal Bank passes north of Durango also have problematical stretches.
Previous rock work on Bondad Hill occurred in March 2008, April 2010 and April 2011.
In August 2009, a boulder fell from a cliff on Colorado Highway 3 and struck a pickup. The driver was seriously injured, but her 6-year-old son in a car seat in the rear was not hurt.
The next month, CDOT hired a firm to scale off sections of the Pictured Cliffs sandstone that borders a short stretch of the highway there.
In 1996, CDOT established a Rockfall Hazard Rating System to determine priority for funding mitigation work on 756 dangerous sites statewide, Shanks said. The Bondad area is ranked 131, well up on the list.
The estimated cost of the current work is $10,000 to $15,000, Shanks said.
daler@durangoherald.com
