Three new bubbling locations have emerged in waterways near a large sinkhole in Assumption Parish and near other bubbling sites where natural gas has been percolating up from the water, parish officials said Tuesday.
The new bubbling spots were found on Bayou Corne, Grand Bayou and Triche Canal south of La. 70 South, parish officials said in a blog post.
The bubbling has been ongoing in the bayous since late May, about two months before the sinkhole was discovered Aug. 3 in swamps between Bayou Corne and Grand Bayou and the communities that carry the same names.
As a result of the sinkhole, residents in about 150 homes were evacuated. Residents affected by the evacuation order have been eligible for weekly housing assistance checks of $875 each. Texas Brine Co. LLC of Houston, the company that owns an abandoned salt cavern suspected as a cause of the sinkhole and the bubble sites, is a major contributor to the fund from where the checks are disbursed.
Parish officials said the Louisiana Department of Environmental Quality is expected to test the new bubbling sites and the results will be posted online.
“We plan to pull samples today, and if not today, then tomorrow,” said John Boudreaux, director of the Assumption Parish Office of Homeland Security and Emergency Preparedness .
He said the samples will be tested in DEQ’s Mobile Air Monitoring Laboratory.
The air monitoring lab has returned to the command post area in the Bayou Corne community along with other state and parish agencies monitoring the sinkhole that had left with the approach of Hurricane Isaac last week.
The new sites come in addition to a new bubbling location found Aug. 20 in Grand Bayou between two other previously noted bubble sites, parish officials have said.
The Triche Canal is a dead-end oil field access canal that runs roughly parallel to and south of Bayou Corne and north of Lake Verret, parish officials said.
The total number of bubble sites in area waterways around Bayou Corne and Grand Bayou has reached 22, parish officials said. Additional sites have also been found around water wells on land.
Boudreaux noted that some of the prior bubble sites over a major pipeline corridor under Bayou Corne have lessened in their activity some, saying they still bubble but do not have the boiling action as in the past.
Boudreaux said the sinkhole does not appear to have changed size but plans are to take new measurements later this week.
In other developments Tuesday, Texas Brine officials announced the company is making progress on a well aimed at looking inside the cavern.
The Louisiana Department of Natural Resources has ordered Texas Brine to drill the investigatory well into the cavern, which is a few hundred feet from the sinkhole.
The hollowed-out cavern is inside the 1-mile-by-3-mile Napoleonville Dome, a solid underground salt deposit pushed up in geologic history from ancient sea beds.
For nearly three decades, the cavern had been used for solution mining with water to produce brine for industry, and it has been gradually widened into the shape of an narrow, upside-down vase, 150 feet across at the top, 310 feet across at the bottom.
Sonny Cranch, Texas Brine spokesman, said drillers finished installing a 10¾-inch diameter casing and cemented it into place on Tuesday.
Cranch said the cement is expected to dry by Wednesday evening and drilling can start again.
He said drillers stopped the well between 900 and 1,000 feet underground to set the casing.
From that point, the drillers will angle the bore hole diagonally to a point 400 feet above the top of the Texas Brine cavern, which sits at 3,400 feet underground.
The drillers then plan to drill straight down into the cavern after which Texas Brine will conduct diagnostic tests on the cavern.
Texas Brine said in a statement on Saturday that drillers had broken through tough caprock on top of the salt dome and into the salt dome itself, which starts at 700 feet.