A Houston-based brine company agreed Saturday to make a “significant contribution” to a fund for residents ordered to evacuate their homes after a sinkhole formed in Assumption Parish, La., that may be connected to one of the company’s salt caverns.
Texas Brine Co. LLC’s original permit for the cavern requires the operator to provide assistance to residents in areas deemed to be at immediate potential risk, in the event of development of a sinkhole and an evacuation, the Governor’s Office of Homeland Security and Emergency Preparedness said Saturday.
Assumption Parish officials ordered an evacuation Aug. 3, the day the sinkhole was found.
Company officials said Friday it will be at least 40 days before they get definitive answers about the sinkhole.
Mark Cartwright, president of United Brine Services, a subsidiary of Texas Brine Co., said Friday the company spent the last week “intensely focused” on an emergency response as they try to figure out the cause behind a sinkhole near Bayou Corne.
Cartwright said they’ll be drilling a relief well to investigate a brine cavern they own, which is housed within the Napoleonville salt dome. It will take at least 40 days to drill the well, and scientists have speculated that the 372-foot-wide and 422-foot-deep sinkhole might be related to structural problems within the cavern, he said.
“Our efforts are going to be more focused on diagnostics, and looking into what caused this event,” Cartwright said at a press conference in Gonzales.
The company told the state Saturday that it planned Monday to submit its permit application for the drilling of a new well into the abandoned cavern to determine the stability of the cavern structure and what pressures, brine or natural gas, it contains.
Commissioner of Conservation Jim Welsh had ordered the company to drill a well and investigate the salt cavern and “further evaluate potential causes of the subsidence near its well site,” as well as obtain samples of cavern content.
Cartwright said the company was just as shocked as anyone else when the sinkhole erupted, swallowing up an acre of bald cypress trees and leaving diesel fumes and slurry water in its wake.
The sinkhole sits on top of an underground mountain of salt and residents of Bayou Corne have been reporting tremors and gas bubbles for weeks. Despite a battery of diagnostic tests from federal, state and local officials, no one has been able to pinpoint the source of either occurrence.
When the sinkhole expanded, the owners of three natural gas pipelines at the edge of the liquefied area were asked to flare off and depressurize their pipelines as a precaution. Louisiana Highway 70 was temporarily closed and Gov. Bobby Jindal declared a state of emergency in Assumption Parish. At least 150 homes and several businesses were ordered to evacuate.
Cartwright said they never thought their salt cavern, which was plugged and abandoned in 2011 and isn’t used to store natural gas, would be behind the gas bubbles and tremors. But seismic readings from the U.S. Geological Survey were able to narrow down the concentration of the earthquakes to the western edge of the dome, which is where the Texas Brine salt cavern lies.