Advocate staff writer
August 27, 2012
Drilling on an observational well to be used for exploring a salt cavern suspected of causing a massive sinkhole in northern Assumption Parish is expected to resume sometime Sunday, a spokesman for the well owner said Saturday.
Drilling paused Wednesday to enable crews with Riceland Drilling Co. of Lafayette to install metal casing 16 inches in diameter inside the 20-inch casing that already had been driven into the ground, said Sonny Cranch, a spokesman for Texas Brine Co. LLC of Houston.
Workers have since filled the space between the two sets of casing with cement, Cranch said.
Once the cement has dried properly, workers will resume drilling through the 325-foot thick caprock and into the Napoleonville Salt Dome deposit that contains the possibly failed cavern, Cranch said.
The sinkhole, found early Aug. 3, swallowed up swamp between the Bayou Corne and Grand Bayou areas south of La. 70 South.
Scientists from the Louisiana Department of Natural Resources believe the cavern failed, released its brine contents and caused the sinkhole.
DNR ordered Texas Brine to drill the observational well to examine the cavern.
A gas-detecting plane from the U.S. Environmental Protection Agency flew over the sinkhole Saturday afternoon before returning to the organization’s regional office in Dallas to analyze test results, Assumption Parish Sheriff Mike Waguespack said.
Those results should be available in a couple of days, Waguespack said.
John Boudreaux, director of the Assumption Parish Office of Homeland Security and Emergency Preparedness, said he and other officials flew over the sinkhole Saturday morning and saw no changes in the slurry area’s size.
“It hasn’t done anything since a week ago Friday,” Boudreaux said.
Authorities have examined diesel found on the surface of the sinkhole and have determined it “contained and poses no threat to the environment,” Cranch said. However, authorities will continue to monitor the diesel, Cranch said.
The Napoleonville Salt Dome, one of many large underground salt formations along the Gulf Coast, was pushed up vertically from ancient sea beds and, for decades, industry has used the dome for brine production. The perimeter also has been the focus of intensive oil and gas exploration.
In a show of appreciation, a group of Assumption Parish residents surprised site workers Saturday morning with a pickup truck loaded with food and beverages along with a thank-you card, Cranch said.
The card, which Cranch circulated among news media outlets, is signed, “Residents for a positive Assumption Parish.”
“It was a very nice gesture,” Cranch said.