Re-drilling begins on south Carlsbad brine well

CARLSBAD — Work has begun on re-drilling the I&W brine well that officials believe may collapse under the south end of town.

The well was ordered sealed in concrete in 2008 by the state Oil Conservation Division after two similar wells collapsed that year, creating enormous sinkholes in the desert floor. Friday's re-drilling is in preparation for sonar equipment to be lowered into the underground salt cavern to better determine the size, shape and location of the void, a news release from the city of Carlsbad stated.

"It's a critical first step in characterizing what that underground structure is," said Ned Elkins, Brine Well Working Group technical subcommittee member. "This is the most significant step we've taken so far."

Elkins said the study would ultimately lead to a solution. He said it would be difficult to properly fill in the cavern without knowing the volume, shape and location of the cavern. Many believe the cavern is shaped like an inverted lollypop, he said, but it is likely more irregular in shape.

"Why don't we fill it up? Because we don't know what 'it' is," he said. "Do we intend to fill it? Yes we do."

Determining the volume of the cavern would also be helpful from a public safety perspective, Elkins said, because it would determine the extent of a crater in the event of a collapse.