Cleanup of sinkhole halted; workers rescued
"We’re not ready to abandon efforts to clean up the sinkhole at this time. We think that work can continue and continue safely as the sinkhole continues to stabilize.” Sonny Cranch, Texas Brine spokesman
Texas Brine Co. LLC suspended cleanup work at a large sinkhole in northern Assumption Parish after the southwestern edge of the slurry area collapsed Thursday morning, company and parish officials said.
Two workers with Texas Brine’s cleanup contractor, Clean Harbors of Norwell, Mass., were rescued from their small aluminum boat by a co-worker in an airboat shortly before the workers’ boat sank into the sinkhole along with the collapsing earth, the officials said.
Assumption Parish Sheriff Mike Waguespack said the boat was tied to a leaning tree on the shoreline. The workers saw the tree begin to move and managed to get out the way, escaping with their equipment at about 8:30 a.m., the officials said.
Waguespack said an area of earth collapsed that extended from the shoreline to about 50 feet inland. The sheriff said bubbling in the sinkhole intensified after the collapse.
The sinkhole was discovered Aug. 3 about 200 feet from the well pad of a plugged and abandoned Texas Brine salt cavern in an area between Bayou Corne and Grand Bayou and south of La. 70 South. The collapse Thursday was on the well pad side of the sinkhole.
Louisiana Department of Natural Resources scientists suspect the cavern failed, released its brine contents and caused the sinkhole, which swallowed up forested swamps.
A mandatory evacuation order has remained in place since the evening of Aug. 3 for the Bayou Corne and Grand Bayou areas. Parish officials have said the order affects about 150 residences.
DNR officials have ordered Texas Brine of Houston to drill a relief well to get a better understanding of what is happening with the cavern, a process that could take at least 40 days.
Other developments also emerged from news statements Thursday and in recent interviews:
- Texas Brine Co. LLC contractor Worley Catastrophe Response will begin distributing weekly housing assistance checks for $875 at 10:30 a.m. Friday at the Sheriff’s Office substation, 4024 La. 70 S., Pierre Part, to households affected by the evacuation order.
- DNR and Louisiana Department of Environmental Quality officials said Thursday that a Crosstex Energy LP of Dallas salt cavern containing 940,000 barrels of liquid butane poses “little to no threat” to populations near the slurry hole.
Sonny Cranch, Texas Brine spokesman, said company officials expected that the edges of the sinkhole would continue gradually to fall in, or slough off, making the sinkhole bigger and shallower.
In an updated estimate of the hole’s size Wednesday evening — before the Thursday collapse — state officials said the sinkhole was expanding at the edges, though still much smaller than the maximum size estimated by DNR scientists.
The statement said the sinkhole was 476 feet from the northeast to the southwest sides and 640 feet from the northwest to the southeast.
“This natural growth of the sinkhole was expected and could continue,” the Wednesday statement said.
On Thursday after the collapse, Cranch said company officials will re-evaluate the sinkhole Monday to see if it has stabilized and will deploy more oil retardant boom.
“But (workers) will not continue physical cleanup activities until they evaluate the sinkhole on Monday,” he said.
Workers with Clean Harbors have been collecting vegetation floating in the sinkhole in preparation for vacuuming diesel on the water’s surface.
Cranch said the cleanup will move forward even though the sloughing process is continuing.
“We’re not ready to abandon efforts to clean up the sinkhole at this time,” Cranch said. “We think that work can continue and continue safely as the sinkhole continues to stabilize.”
Despite the setback on cleanup, Cranch said the delivery of drilling rig parts to Texas Brine’s facility continued Thursday and assembly is underway. Drilling work could start late Friday or early Saturday, Cranch said.
Worley Catastrophe Response, which will coordinate and manage the “Bayou Corne Incident Evacuee Fund” for Texas Brine, plans to issue checks to the representative of each household affected by the evacuation order, Texas Brine officials said.
The representative will have to display a Louisiana driver’s license or “other reasonably acceptable photo identification confirming residence in the evacuation zone,” company officials said in a news release.
The original permit for the Texas Brine cavern requires the operator to provide assistance to residents in areas deemed to be at immediate potential risk, state officials have said.
The requirement is triggered in the event of a sinkhole and evacuation, state officials said.
Crosstex also submitted a revised worst-case scenario analysis in its risk management plan Wednesday at the request of DEQ Secretary Peggy Hatch.
In a statement Thursday, DEQ officials noted that the cavern, which is a half-mile underground and far below the bottom of the sinkhole, cannot release its liquid butane contents without water being pumped into the cavern to push out the butane. The butane is also being held in the absence of oxygen.
“While it is easy to simply convert the known quantity of butane into a blast scenario, that does not mean this scenario is possible,” DEQ officials said in a statement.
Crosstex’s other nearby cavern, which has the capacity to hold 1.7 million barrels, has no hydrocarbons inside and is filled with brine at present, company officials said in their letter.
The sinkhole’s emergence followed more than two months of earth tremors and mysterious natural gas releases in Bayou Corne, Grand Bayou and water wells.
The gas bubbling has continued since the sinkhole emerged. Tremors ceased the day before the sinkhole was found.
The Texas Brine salt cavern was carved out of the 1-mile by 3-mile Napoleonville Dome, a large underground salt deposit.
The cavern, which was used to produce brine for industry and never for natural gas storage, was plugged and abandoned in June 2011 after company officials ran into trouble trying to expand the cavern.