Assumption sinkhole gets bigger Tuesday

The sinkhole in northern Assumption Parish got a little larger on Tuesday.

Parish officials reported roughly 5,000 square feet of land sloughed off into the sinkhole Tuesday morning and that by Tuesday afternoon, the land-loss had grown to an estimated 7,500 square feet, said John Boudreaux, director of the Assumption Parish Office of Homeland Security.

Boudreaux said he hadn’t remeasured the sinkhole, which was last determined to be 8.6 acres at its surface, but it possibly could cover as many as 9 acres after the 75-foot-by-100-foot parcel of land crumbled and fell into the slurry hole on Tuesday.

“I think this was expected,” Boudreaux said, “because the scientists have estimated that the hole will grow. It was just reported because it did grow.”

The sinkhole, located between the Bayou Corne and Grand Bayou communities, was discovered south of La. 70 on Aug. 3, causing more than 150 residences in the area to be evacuated due to safety concerns.

Scientists have said the sinkhole formed following the failure of an underground cavern in the Napoleonville Dome owned by Texas Brine Co. LLC. The sinkhole has increased in size gradually during the past six months while also releasing methane, natural gas and crude oil underground.

Sonny Cranch, a spokesman for Texas Brine, agreed with Boudreaux’s assessment that Tuesday’s slough was expected, calling it “part of the process of the sinkhole stabilizing.”

The most recent sloughing event, the first to happen in several weeks, officials said, also pulled several trees down into the sinkhole.

“That’s been typical of the occurrence of these slough-ins,” Cranch said. “As the sands and earthen material is exposed, it becomes supersaturated, especially with the rains on top and the moisture that’s able to permeate the areas beneath the root structure of the trees. It’s kind of a load-bearing section, and the weight of the trees allows for a slough-in.”

The positive news, Boudreaux and Cranch said, is that the growth in the sinkhole continues to be on the southwest portion, which is farthest away from La. 70 and the homes in Bayou Corne.

Cranch said Texas Brine workers continue drilling relief vent wells, designed to flare out gas trapped underneath the ground due to the collapsed salt cavern. Boudreaux said he expects that Texas Brine will have four additional vent wells working by Wednesday.