A 67-year-old man from Townsend has been identified as the worker who died in a rock collapse at a Sterling quarry on Thursday, according to authorities and his company.

A “large chunk” of rock wall collapsed, falling on top of an excavator Brian Derby had been operating “within the safety zone of a 100-foot ledge face,” according to Onyx Corp., a demolition and excavation company that operates the sand and gravel pit.

“Brian was a dedicated 11-year employee of the company and was respected and loved by many,” Onyx Corp., said in a statement Friday. “We will continue to provide support to Brian’s friends and family.  Professional counseling is being provided to everyone at the company while we mourn this tragic loss.”

The Worcester County District Attorney’s Office released Derby’s identity first after “crews worked through the night,” with the District 8 Technical Rescue Team – including assets from eight towns – recovering the body Friday morning.

The state Office of the Medical Examiner took Derby’s body from the scene.

Sterling police dispatchers received a call for the rockslide around 8 a.m. Thursday. Upon arrival, officers and firefighters found a “large chunk of rock wall had slid and fallen on top of an excavator.”

“At that point, the fire department was working our rescue operations … they were unable to find any signs of life,” Police Chief Sean Gaudette told the Select Board during an emergency meeting Thursday.

“Crews used camera equipment to assess the scene of the collapse,” the Worcester County District Attorney’s Office had said in a statement.

Responders pronounced the worker dead at 8:39 a.m. Thursday, the office added.

Sterling, a rural town of roughly 8,000 people, is roughly 40 miles west of Boston.

Demolition and excavation company, Onyx Corp., has operated the quarry site on Chocksett Road, off Route 12 and near Interstate 190, since 2018.

Onyx Corp. posted online it had closed all locations through the weekend, saying it would resume business on Monday, but that came before the Select Board ordered the company to cease operations until an investigation is complete.

“Our hearts are with those involved at this time,” board Chairwoman Kirsten Newman said Thursday. “I also want to thank our local first responders who went into an unknown situation and put their lives at risk to try and recover the trapped worker.

A spokesperson for the U.S. Department of Labor Mine Safety and Health Administration, which inspected the site to determine the safety of moving forward with retrieval efforts, gave no estimate on when the investigation would be done.

“This is a tragic event that none of us really want to be reporting on,” Select Board Vice Chairman David Smith said, “but as the governing body, I believe it is our due diligence to issue a cease-and-desist order.”