Venting of gas from the area of a sinkhole that has been bubbling in Assumption Parish, LA, since August could begin as early as Thursday, according to press reports, as residents in the area worry about rising pressures in the abandoned brine cavern blamed for the sinkhole.

Vent wells were being dug in the four acres of slurry to release an unknown gas. An Assumption Parish Office of Emergency Preparedness official told news media that the clay layer containing the gas might not hold if pressures were to rise above 75-85 psi.

Bubbles were first seen in the area in August, forcing some residents from their homes and necessitating the shut in of some natural gas pipeline infrastructure running through the area (see Daily GPI, Sept. 18).

Jill McMillan, spokeswoman for Crosstex Energy LP, one of the companies with infrastructure affected, said Monday there were no updates since the company made piping changes at its two salt dome natural gas liquids facilities in the area in order to move stored product farther from the sinkhole site.

Early last week Louisiana Commissioner of Conservation James Welsh placed new requirements on Texas Brine Co. LLC, owner of the brine cavern in the Napoleonville Salt Dome, for providing data and analysis to the Office of Conservation. The move followed a statement by the company that its cavern had been breached due to seismic activity in the area, a finding that regulators had neither reviewed or approved.

According to the U.S. Geological Survey, seismic activity in the area is a consequence of the cavern collapse, not the cause of it, the Office of Conservation said.

“Texas Brine has elected to let its own interests guide a premature conclusion lacking sufficient supporting analysis — breaking away from the ongoing cooperative effort to apply scientific principles to determine causes and impacts, guided by the need for accurate data and analysis to best protect public safety,” Welsh said. “The investigation and the remediation for environmental damages will be driven by the best science available and carried out to standards set by the state of Louisiana to ensure the safety of the Bayou Corne community — and will not be driven by Texas Brine’s timetable or concerns about corporate liability.”

Texas Brine is providing daily updates on the status of the sinkhole operations on its website. The Office of Conservation also is providing routine updates on its website.

Welsh said he has also directed his office’s contractor to perform an independent root cause analysis of the cavern failure. The Office of Conservation is also continuing the work, through its contractor, on establishing locations to drill water wells near the Bayou Corne community to assess the presence of natural gas and ensure it is removed, it said.

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