A boy playing with friends around a gravel bin got trapped inside when a conveyer system started and buried the 9-year-old under the rocks. He was rescued without serious injuries about an hour later.

"We had communication with the kid the moment we rolled up," said Tipton Fire Chief Jeff Ogden. "He was covered up, but in the position to talk."

Police were investigating whether Justin Harshman fell or climbed into the 20-inch opening of the rock bin Monday afternoon at Irving Materials Inc., which makes concrete.

Andrew Smith, 12, ran to get help, while his 10-year-old brother, Dakota, jumped into the bin to pull the rocks off their friend.

Employees heard the boys' screams and shut the conveyor off, police said.

Only Justin's hand was visible, said plant manager Butch May, who tried to remove gravel from the boy's face so he could breathe.

But gravity continued to pull the gravel, about a half-inch to three-quarters of an inch in diameter, and the boy toward the bottom of the bin that funnels the rock to the conveyer system.

"The more I threw out, the more came back in. ... The longer he was in there, the further down he went," May said. "I didn't know what to do."

Rescue crews stabilize the flow of gravel underneath the bin to hold Justin up as workers used buckets and a sewer vacuum to haul rocks out from the top, Ogden said.

On Tuesday, Justin was sore but had no broken bones and was recovering at his home about 35 miles north of Indianapolis, said Indiana State Police Sgt. Tony Slocum.