CONTRA COSTA COUNTY (KRON) — A worker who was hit by loose rock inside of the mines at the Black Diamond Mines Regional Preserve was airlifted to the hospital with chest injuries.

around 11:14 a.m., fire crews were called to one of the mines after getting a report of a person who might be hurt inside the mine.

According to Contra Costa County Fire Inspector Steve Aubert, the worker was stabilizing the mine while standing on scaffolding about 200 feet inside the Hazel-Atlas Mine when a large rock came loose and hit him in the chest.

Aubert said the man’s colleagues were able to bring him up to the top of the mine using a backboard before emergency responders got there.

The East Bay Regional Park District regularly does work inside the mines to ensure that it is safe for visitors, EBRPD spokeswoman Carolyn Jones said. The mines are closed to the public except during weekend tours, which Jones said have been going on “for decades.”

“(The mines) are checked every day either by our staff or contractors or engineers for loose rocks and other safety issues,” Jones said. “There’s a bunch of old coal mines and sand mines there dating back from the 1800s that the park district maintains as a way for the public to learn about mining history in the area and how glass is made.”

EBRPD acquired the 6,000-acre park in the early 1970s and regularly hosts tours, which take participants hundreds of feet inside the mines, Jones said.

The man was able to communicate with first responders, complaining of chest pain and shortness of breath. “”We’re also concerned about internal injuries,” Aubert said.

The injured worker was taken to the hospital with serious injuries.

At this stage, Aubert said that it’s unclear whether the man was wearing a hard hat or other protective gear.

“It sounds like they were taking the proper precautions with the scaffolding,” Aubert said. “It’s hard to place what the workplace mishap was without being down there.”

“It’s extremely rare to have an injury out there,” Jones said. She said she didn’t know which company was working inside the mine.

Fire Marshal Robert Marshall said the California Division of Occupational Safety and Health would be notified of the workplace accident. “At some point, they will be involved,” Marshall said.