BUTTE, MT — A massive boulder blocking the westbound lane of Interstate 90 near Homestake Pass has proven to be a formidable obstacle for the Montana Department of Transportation crew tasked with clearing it.
The dump truck-sized rock fell onto the highway earlier this year, presenting a challenge too big for conventional equipment. According to Jim Pesanti, Butte District Maintenance Chief, the crew initially attempted to break the boulder apart using an excavator equipped with a jackhammer attachment, but the rock’s hardness quickly wore down the equipment.
“This one is way bigger than we can handle,” Pesanti said.
Faced with limited options, the crew turned to a technique known as “Boulder Buster,” which employs controlled explosions to split large rocks. The process involves drilling deep holes into the boulder, filling them with specialized explosive shells, and detonating them to generate hydraulic pressure capable of fracturing the stone.
Four explosive shells are inserted into water-filled holes drilled in the rock. Once primed and detonated, the blast’s hydraulic force is intended to crack the boulder into manageable pieces.
The Montana DOT crew hopes this innovative approach will finally clear the obstruction and restore safe passage on this crucial stretch of highway.
