Unusual geological event / Assumption Parish / Louisiana

The 24-acre Assumption Parish sinkhole underwent a periodic burp early Friday, the second in two days and the fourth in the past 21/2 weeks, parish officials said. The most recent burp was accompanied by an increase in tremors early Friday, along with other effects often connected with burps, including water movement and so-called “rain drop” bubbles on the lake-like hole’s surface indicating a gas release. John Boudreaux, director of the parish Office of Homeland Security and Emergency Preparedness, said the tremors began to ease by Friday afternoon as they typically do once a burp event has eased. “I went out there (to the sinkhole), and it was almost like glass out there,” he said. The increased tremors led to a halt in activity on the sinkhole Friday but Boudreaux said some work could resume Saturday morning. Also on Friday, Conservation Commissioner James Welsh ordered Texas Brine Co. to cease a type of earth-probing test aimed at seeing where gas is in the shallow rock under Bayou Corne.

Welsh ordered the company to provide by 5 p.m. Monday plans on the construction and abandonment of the test holes and other details, including how Texas Brine seals the holes. Scientists suspect the sinkhole was caused by the failure of a Texas Brine salt dome cavern. The cavern failure set in motion subterranean rock movements that set loose gas from natural pockets and created the sinkhole. It was found Aug. 3 in cypress swamp between the Bayou Corne and Grand Bayou communities. The one-time area of 350 people has been under evacuation orders since. In addition to the sinkhole, gas is being released from bubbling sites in area bayous and is thought to be gathered in an aquifer and even in shallower rock under the communities. Welsh’s order follows Boudreaux’s cease and desist order to Texas Brine earlier this week after residents complained about a plugged probe site leaking gas in front of homes on Sauce Piquante Lane. Boudreaux said he tested the hole and found leaking gas at a concentration that was approaching an explosive level. Sonny Cranch, spokesman for Texas Brine, said 41 of the holes were drilled in the community and only one leaked.

“Our ultimate goal is to remove the gas from the shallow aquifer and to know where it is,” Cranch said, “and this was the technology we were employing to identify the location of that gas.” The test involves driving a metal probe into the ground about 125 feet to check for gas. Once the test is finished, the hole is capped, Boudreaux said. The testing was the subject of complaints during a Tuesday community meeting in Napoleonville. The repairs completed by Texas Brine on Friday caused further irritation.

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