Geo-probes planned for land near sinkhole

BAYOU CORNE — Assumption Parish authorities dealing with a growing, 4-acre sinkhole in the Bayou Corne area scheduled a community meeting at 10 a.m. Saturday to provide information on planned natural gas venting and positioning of geo-probes on private property.

John Boudreaux, director of the parish Office of Homeland Security and Emergency Preparedness, said Thursday officials hope to show the public a photograph of such probes, which he said do take up some space.

The probes, which are polyvinyl chloride pipes driven about 50 to 60 feet into the ground with landowners’ consent, are being used to monitor for subsurface natural gas in the vicinity of Bayou Corne.

“We’re going to try to cover everything, but we’re probably going to focus on that,” Boudreaux said.

Indications of natural gas have been found in an aquifer beneath the Bayou Corne area northwest of the Napoleonville Dome. The aquifer is located in strata overlying the top of the dome. Natural gas, in addition to its presence in the aquifer, also has been found in caprock crowning the dome, a solid salt deposit.

The Louisiana Department of Natural Resources has ordered the Napoleonville Dome’s seven operators to find and vent off any gas. The agency also is working with contractor Shaw Environmental on observation wells northwest of the dome that could be used to eventually vent off the gas.

The sinkhole was discovered early on Aug. 3 in swamps between the Bayou Corne and Grand Bayou areas on property owned by Texas Brine Co., parish officials said in a blog post.

The sinkhole, which DNR officials think was caused by a failed Texas Brine salt cavern, has forced the evacuation of residents in 150 households in those areas.

The cavern was hollowed out of the 1-mile by 3-mile Napoleonville Dome after nearly three decades of use for brine production. The dome is a solid salt formation that emerged from deeper deposits left by ancient seas and has been used for oil and gas exploration, brine production and hydrocarbon storage for decades.

The sinkhole is not directly over the cavern, but offset to the northwest about 200 feet.

The community meeting will be held outdoors under a tent at the Sportsman’s Landing boat launch on La. 70 South in Bayou Corne, barring inclement weather.

Boudreaux said parish officials would designate a new meeting location on the parish blog, if the weather requires it, at http://assumptionla.wordpress.com/.

During a meeting earlier this week and after calls from activists for weekly meetings, Assumption Parish President Martin “Marty” Triche promised to hold weekly community meetings to update residents on what has been happening with the sinkhole and related matters.

Officials also are trying to determine the sources of natural gas releases in area bayous as well as tremors that preceded and have followed the sinkhole’s emergence.