Thursday, Jul. 10, 2008

Large 'wired' rock gets blasted in Sonora

Suspicious wires coming from a hole in a large rock in Sonora caught the attention of authorities Tuesday and led to an "extremely large explosion" when officials detonated the rock.

About 4:30 p.m., Sonora police officers responded to a report about the strange rock on Truckenmiller Road near Mono Way. The hole and wires appeared to be related to blasting efforts, officials said.

The bomb unit from Calaveras County decided to detonate the rock for safety reasons, according to Sonora police Lt. Mark Stinson. After the explosion, the bomb team determined that the hole had been filled with explosive gel and a working blasting cap.

Miners used to drill holes into large areas of solid rock, then fill the holes with explosives to break up the area, Stinson said.

"With this rock, they drilled a hole, packed it with the explosive gel and didn't fire it off for some reason," he said. "Once the rock was blown off the face of a bigger rock, they hauled it into the city and unloaded it. It was used as a barrier to help hold the hillside up. Then someone walking around last night noticed it and said, 'Hey, that's interesting.' "

The rock was pushed against a hillside during the late 1990s. Then it was taken to Truckenmiller Road, where it sat undiscovered.

Before the blast, officers knocked on doors to warn residents about the detonation. One man told them he had blasting caps in his garage. The officer told the man police would help him dispose of the caps after detonating the rock.

Soon after, the man walked up to the bomb unit carrying a can of blasting caps, Stinson said. The bomb unit told him to stop, put down the can and back away from it. There were numerous old, unstable copper blasting caps in the can. These also were detonated because of their "extremely sensitive condition."

The Sonora Police Department says blasting devices should be handled only by trained professionals. Anyone who finds such devices should call local law enforcement officers. Many blasting items in the foothills are from the late 1800s and early 1900s and are extremely unstable.

Bee staff writer Emilie Raguso can be reached at eraguso@modbee.com or 578-2235.