Sinkhole commissioners to brief public Wednesday night

A majority of the 13-member Blue Ribbon Commission investigating the Assumption Parish sinkhole plans to attend a community meeting at 6 p.m. Wednesday in Napoleonville to deliver a public briefing on the panel’s work to date, state regulators said Tuesday.

Appointed in March in response to the 13-acre swampland sinkhole emergency near the Bayou Corne community, all but one of the commission members visited the site and Bayou Corne during a four-hour tour Monday, state and parish officials said.

The group has been closeted in private work sessions since that visit, on Monday afternoon and evening and again Tuesday, at the state Department of Natural Resources offices in Baton Rouge, said Patrick Courreges, DNR spokesman.

“They are looking at different things and just trying to figure out what is it we need to know,” Courreges said in summing up the commission’s deliberations. “What do we already have going into it and what are we still going to need to look at this or that?”

He said the group plans another work session Wednesday during the day before the meeting with residents Wednesday night in the Assumption Parish Community Center, 4910 La. 308, Napoleonville.

The commissioners have been asked to set the criteria upon which a recommendation can be made about the long-term stability of the area and when evacuated residents can return home.

Residents in Bayou Corne and Grand Bayou have been under evacuation orders for nearly nine months.

The sinkhole was discovered Aug. 3.

John Boudreaux, director of the Assumption Parish Office of Homeland Security and Emergency Preparedness, said he led the commissioners’ tour Monday.

Members went on flights over the sinkhole; visited well pads on Texas Brine’s site, including one next to the sinkhole; saw vent wells being used to remove gas trapped under the area; saw the sinkhole containment berm now under construction; and drove through the Bayou Corne community.

Courreges said the commissioners, who already had been given a briefing on the sinkhole, remarked Monday that seeing the scale of the sinkhole up close and learning of the extensive responses to it were “eye-opening.”

He reiterated DNR’s and several outside scientists’ belief that a cavern failure of the kind that happened in Bayou Corne, as well as the sinkhole that resulted, have never happened in the collective experience of mining salt dome caverns with freshwater.

“Nobody has ever seen anything like this before,” Courreges said.

He said the commissioner who did not visit the sinkhole Monday had been there a few weeks ago and was able to assess the situation.

The sinkhole formed last year when a Texas Brine Co. cavern carved from an underground salt dome, the Napoleonville Dome, failed when the cavern was mined too closely to the dome’s outer face through a process called solution mining, scientists believe.

The resulting sidewall failure resulted in periodic tremors and unleashed crude oil and gas from deep underground, scientists say.

Natural gas still bubbles up in area bayous and is caught in an aquifer under the area, parish officials said.

The panel is focused on three areas as a basis for creating criteria to evaluate the sinkhole’s long-term stability: levels of shallow gas in the aquifer, the stability on the western side of Napoleonville Dome and the management and containment of the sinkhole itself.