Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2015

[Emily]

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

http://www.lsureveille.com/news/professor-addresses-bayou-corne-sinkhole-issues-at-science-caf/article_eb1a860e-2583-11e3-a5e4-001a4bcf6878.html

Professor addresses Bayou Corne sinkhole issues at Science Caf?
Posted: Tuesday, September 24, 2013 8:43 pm | Updated: 2:28 am, Wed Sep 25, 2013.

Jonathan Olivier | 0 comments

Posted on September 24, 2013

Jonathan Olivier

by Jonathan Olivier

The steadily growing sinkhole at Bayou Corne was discussed Tuesday at the monthly LSU Science Caf? at Chelsea?s Caf? wth guest speaker Jeffrey Nunn, University Ernest and Alice Neal Professor of Geology.
...
While most sinkholes get shallower and wider, this particular one is getting deeper and wider, he said, and currently it encompasses 25 acres, is 750 ft. deep and is continuously emitting natural gas from the subsurface to the atmosphere.

He seems to be agreeing John Boudreaux's measurements there. :tiphat:

But below there appears to be a backing away from a position held in 12/2012:

An audience member asked Nunn about placing blame on a particular department or company, but, Nunn said, the event is so unprecedented and the affected area lies so far underground that it is hard to tell what caused the sinkhole.

Here is the 12/2012 Advocate article reporting his earlier opinion:

http://theadvocate.com/home/4685215-125/geologist-details-failure-factors

Geologist details failure factors
Company officials reject explanation of sinkhole?s formation
BY DAVID J. MITCHELL
River Parishes bureau
December 26, 2012

The sidewall of a Texas Brine Co. LLC salt cavern inside the Napoleonville Dome was dissolved through the dome?s outer edge, bringing the cavern into contact with surrounding sediment layers outside the dome before the cavern failed, an LSU geologist said Friday.

The assessment by Jeffrey Nunn, Ernest and Alice Neal professor of geology and geophysics and Pereboom professor of science, was a step beyond what other officials and scientists working on the sinkhole response have presented in public meetings and appeared to more closely lay the blame with Texas Brine, which mined the cavern by dissolving the salt...

If there is a a dynamic going on here that is not understood, maybe all extraction and mining in this dome should cease until it is understood.

http://pg.geoscienceworld.org/content/1/2/179.short

B. C. Vendeville, Hongxing Ge and M. P. A. Jackson
Scale models of salt tectonics during basement-involved extension
Petroleum Geoscience(May 1995), 1(2):179-183
Scaled experiments, whose design was based on recently published low values for the viscosity of natural rocksalt, suggest that under typically low geological extension rates, a salt layer 500 m thick or thicker decouples the brittle overburden from the faulted basement. Because of its low viscosity, salt cannot transmit the large differential stresses necessary for basement faults to propagate upward as faults or abrupt forced folds into the brittle overburden, unless the salt layer is thin or has been depleted...

That's what I wonder about here. Salt domes sound like they can operate as shock absorbers, protecting the overburden from basement layer seismic movements. Has this whole dome been over-mined?

 

[mixin]

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

I read a recent Texas Brine report in which they state:

** Sinkhole surface waters show elevated levels of hydrocarbons and salinity; no impact off-site.
**Deep sinkhole waters contain elevated levels of hydrocarbons and salinity.

http://www.texasbrine.com/response/TBC_Monitoring-Factsheet-FINAL-090513.pdf

As many diagrams as I've seen of the dome, sinkhole and everything that surrounds them, I still can't seem to get a thorough understanding of it all. Is there any way that fresh water could be getting into the cavern? If the sinkhole is filled with the original salt, shouldn't it be losing some of its salinity?

After looking at the picture Nunn was displaying, I find it kind of hard to believe the salt and hydrocarbons have no impact off site.

 

[mixin]

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

http://assumptionla.wordpress.com/

October 4, 2013
3:15 p.m. Tropical Storm Karen, Press Release #1

Press Release #1
Friday, October 04, 2013
3:00 p.m.

For Immediate Release
Tropical Storm Karen

The Assumption Parish Office of Homeland Security and Emergency Preparedness will continue to monitor Tropical Storm Karen and advise accordingly. At this time, the parish, in a precautionary measure, has declared a State of Emergency. Currently, no evacuations have been ordered and the Emergency Operations Center will not be activated.

OEP Staff will continue to work with state agencies and the National Weather Service to remain updates on any changing activities.

***************

Sept 30, Oct 1, 3, 4,
Sinkhole Activity Code 2 ? elevated ? increase in number of Very Long Profile seismic activity, generally associated with movement of gas/fluid below sinkhole, in area of sinkhole/Oxy 3 cavern ? requires halting all work directly on sinkhole.


***************

October 3, 2013
8:25 a.m. September Sinkhole Survey

Click here to access the sinkhole survey from September.
http://classic.edsuite.com/proposals/proposals_280/september_2013_sinkhole_survey_fi_709.pdf

Please note that low water and safety restrictions did not allow surveying in the eastern portion of the sinkhole.

***************

October 2, 2013
10:45 a.m. Flaring Possibility @ Crosstex

Crosstex has reported to us that there is a possibility of flaring at their facility today. Maintenance of pumps and lines continue there and although unlikely, the possibility of flaring does exist.

 

[mixin]

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

http://assumptionla.wordpress.com/

Monday, Oct. 21 work-

Sinkhole Activity Code 2 – indicating no work is allowed directly on sinkhole, elevated due to seismic monitoring indicating trend of increased MEQ (micro-earthquake) activity near sinkhole/Oxy 3 in the past few days

Texas Brine advised that the tagging of Cavern 3 is at 4,097′ which is 75′ lower than last week’s tag. As information becomes available, it will be shared here.

October 18:
Texas Brine advised that the tagging of Cavern 3 is at 4,022′ which is 72′ higher than last week’s tag. As information becomes available, it will be shared here.

***********

I wonder how many total cubic feet is in that 72 feet that rises and falls. More info on that would be interesting.

Some of the seismic monitors have been moved in an ongoing effort to monitor for tremors and pinpoint tremor locations with greater accuracy. Here's a screen cap of the new locations, as well as the link to the monitors:

http://folkworm.ceri.memphis.edu/heli_temp/



http://classic.edsuite.com/proposals/proposals_280/seismic_monitor_map_10182013_fi_712.pdf

 

[Emily]

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

Thanks for posting the updated monitor map, mixin! There certainly seemed to be intense activity recently - especially at LA 17. I can't evaluate that, but do wonder what is happening when I see activity in the middle of the night.

After looking at the picture Nunn was displaying, I find it kind of hard to believe the salt and hydrocarbons have no impact off site.

LEAN just published test data from a soil sample taken this summer:

http://leanweb.org/our-work/communi...testing-results-from-the-bayou-corne-sinkhole

Hopefully that is from within the bermed area, (which has increased over time.) Whatever the case, the MRAA, (Mississippi River Alluvial Aquifer) is compromised:

Gary Hecox, CBI, Slide Presentation 2/19

Large amounts of gas and some crude oil migrating through Disturbed
Rock Zone (DRZ)
? Flowing into aquifer with gas footprint over 2 square miles
? Brine and hydrocarbon contamination in sinkhole and potentially in MRAA
? Estimate of gas in MRAA >50 million cubic feet in place
? Vent wells have flared ~10 million cubic feet to date
? Known gas bubble vent rate from MRAA estimated at 20 mcfd
? Depth and volume of gas reservoirs is currently unknown

The Parish blog reports that TB is drilling a relief well on the west side of Bayou Corne now.

 

[mixin]

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

You are very welcome.

There certainly a lot of things to wonder about when it comes to this salt dome. I wonder if the seismic activity coincides with the rise and fall of material in the cavern or if it's due to the release of gas and oil or if it's all tied together.

I see Crosstex has finally gotten Well #2 down to ~10,000 bbls.
http://dnr.louisiana.gov/index.cfm?md=pagebuilder&tmp=home&pid=969

I still haven't watched the videos from the last meeting. Maybe some of our answers are there :magnify:

The picture of the oil covered sinkhole in your LEAN link is really depressing.

 

[Emily]

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

I see Crosstex has finally gotten Well #2 down to ~10,000 bbls.

That's good to know that is progressing since yesterday they moved up to a Code 3 alert.

http://assumptionla.wordpress.com/2013/10/24/255-update-from-the-office-of-conservation/

October 24, 2013
2:55 Update from the Office of Conservation

Bayou Corne/Grand Bayou Response Activity

Thursday, Oct. 24 work-

Sinkhole Activity Code 3 – indicating no work is allowed directly on sinkhole or on containment berms, elevated due to seismic monitoring indicating further increase in MEQ (micro-earthquake) activity near sinkhole/Oxy 3

 

[mixin]

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

Emily,
Thank you for catching my error. Can I use the excuse I got caught in a time warp? The level as of 10/20 is 162,127, as you discovered.

On 7/21/13, they were down to 2,073 barrels of lpg mix (which makes me think they had finally emptied the cavern). Crosstex stayed at 10,011 barrels for some days near the end of July, then began to go up again.

 

[Emily]

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

Thank you for catching my error. Can I use the excuse I got caught in a time warp?

You would have bumped into me if you were caught in that place, mixin. I've been confused about what was going on at Crosstex - at least #2 looks like it has had a significant reduction in butane stored there. Thanks for finding all those reports so we could try to sort through them.

I've been meaning to share this video posted by a Bayou Corne resident about the fate of cats that live there. The cats are beautifully photographed, but the story is very sad. There are some good people trying to help the survivors, but it sounds overwhelming. I was hoping Occidental might help out, considering how busy TB is in dealing with day-to-day operations, but so far any help will come from volunteers.

<object width="420" height="315"><param name="movie" value="//www.youtube.com/v/MMPgnUhcQnc?hl=en_US&version=3"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="//www.youtube.com/v/MMPgnUhcQnc?hl=en_US&version=3" type="application/x-shockwave-flash" width="420" height="315" allowscriptaccess="always" allowfullscreen="true"></embed></object>
Bayou Cornes Feral Cats Need Help~
Posted on Youtube by rainbeaudais

Published on Oct 5, 2013

Mobile device users can watch it on VIMEO. Click here: https://vimeo.com/76260014 or google rainbeaudais on vimeo.

There are 2 main colonies of cats on the north side of Hwy 70 of Bayou Corne, and others scattered around. One year ago, there was probably an easy 100 cats. That number has dwindled down to around 50-60, as they have started roaming looking for food, and possibly poisoned by non cat people that consider them nuisances.

Both colonies were being fed by residents, but those residents have now evacuated, and some have left forever and are only able to come once or twice a week to feed them. One day, I was driving around late in the day, and was shocked to see how many were gathered at one evacuated residence, just waiting to be fed. That's how I started feeding them, and began this journey to save them.

Although these cats have always been a part of this community, now that the community is basically void of people living there, the cats are more noticeable as they roam, hunting for food, and are being threatened. People are under the impression that if fed, cats will no longer hunt for mice, rats, snakes, etc. That is a myth.

It is my goal to keep them fed, hoping they will roam less until we can get them all through the TNR program, and possibly relocated, and maybe some adopted out. In just a few weeks, I am able to now pick up two, and pet several others. Sadly, many of these cats have also become dependent on human interaction. The people that were feeding them, and slowly having them TNRd, also loved these cats.

Seems it's okay for chickens to roam free, and spread their wealth all over the community, but not these cats that have been there much much longer. Funny how that works.

Please share this video and Contact the local parish officials, and the Humane Society, and ask them why it's okay for chickens to be roaming free in the neighborhood, but not cats. Demand that these cats be protected, and the harassment of those trying to care for them, be stopped.

http://www.assumptionla.com/Parish-Go...

http://www.humanesociety.org/issues/f...

 

[mixin]

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

Poor kitties; I hope their plight touches enough hearts to find a good solution for them.

People are under the impression that if fed, cats will no longer hunt for mice, rats, snakes, etc. That is a myth.

I see this attitude all the time from farmers around here; I'm glad she pointed that out.

Here's the latest update on the sinkhole:

October 26, 2013
2:30 p.m. Update

A crack has developed on the South Berm, south/southwest of pad 3. There is also increased seismic activity occurring. We will continue to monitor the south berm and sinkhole for any changes and will update accordingly.
http://assumptionla.wordpress.com/

Link to the seismic monitors:
http://folkworm.ceri.memphis.edu/heli_temp/

Here's a link to Texas Brine's Oct 24 update on their seismic monitoring:
http://www.texasbrine.com/response/TBC_Passive_Seismic_Monitoring _2_ Factsheet_FINAL-102413.pdf

 

[mixin]

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

October 30, 2013
4:55 p.m. Second Crack in Berm Discovered
A second crack has been discovered on the South Berm toward the western corner. Although this crack doesn?t go all the way across the berm, we will continue to monitor all these areas for continued changes.

October 30, 2013
3:45 p.m. Update
Statement from Texas Brine:
RECENT SEISMIC ACTIVITY
There has been a recent increase in seismic activity detected on the Texas Brine seismic instrumentation over the last ten days. These occurrences consist primarily of minor tremors or ?micro-earthquakes? (MEQ?s) and not extended events or very long period (VLP) tremors. Additional monitoring and interpretation of the data from the newly installed borehole seismic array is being performed in order to better understand the location and magnitude of the seismic activity. This monitoring and analyses is performed by industry specialists, along with government and university experts, which has been the case from the very beginning of the response.

Texas Brine, in coordination with DNR and APOEP, recently relocated sensors and added additional resources to the passive seismic monitoring system already in place. This is all part of a coordinated effort to better monitor for tremors and pinpoint tremor locations with greater accuracy. Response personnel are closely watching this situation and if additional information becomes available about the source and location of the activity, the community will be updated.

October 30, 2013
3:10 p.m. Update from the Office of Conservation
Bayou Corne/Grand Bayou Response Activity
Wednesday, Oct. 30 work-
Sinkhole Activity Code 3 ? indicating no work is allowed directly on sinkhole or on containment berms, due to seismic monitoring indicating ongoing elevated MEQ (micro-earthquake) activity near sinkhole/Oxy 3

October 30, 2013
9:05 a.m. Update
Statement from Texas Brine:
As reported on the Parish Blog, some cracking was observed over the weekend on portions of the South Berm. Currently there is one main crack that is approximately 3.5″ wide that crosses the South Berm with some additional smaller cracks also appearing in proximity to this location. The Geotextile liner and clay cap remain unbroken ensuring the barrier between the sinkhole and outside environment remains intact.

It?s unclear at this time if the increased seismic activity detected over the past week is related to this cracking. Additional interpretation of the data from the newly installed seismic arrays is being performed in order to better understand the location and magnitude of this seismic activity along with any connection it may have to the cracking.

Response personnel will continue to monitor for any further expansion or movement of the soil and southern berm and plans are already in place to repair the berm once the seismic activity level around the sinkhole subsides and it is deemed safe to work. Additional updates and information will be provided as necessary.

October 29, 2013
10:40 a.m. Update from the Office of Conservation
Bayou Corne/Grand Bayou Response Activity
Tuesday, Oct. 29 work-
Sinkhole Activity Code 3 ? indicating no work is allowed directly on sinkhole or on containment berms, due to seismic monitoring indicating ongoing elevated MEQ (micro-earthquake) activity near sinkhole/Oxy 3

October 28, 2013
1:40 p.m. Update from the Office of Conservation
Monday, Oct. 28 work-
Sinkhole Activity Code 3 ? indicating no work is allowed directly on sinkhole or on containment berms, due to seismic monitoring indicating ongoing elevated MEQ (micro-earthquake) activity near sinkhole/Oxy 3

 

[mixin]

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

There was a flyover posted on Oct 28
http://www.youtube.com/watch?v=rpA2F0wSbaw&feature=c4-overview&list=UURi6D8S8okOdYsJ-39YOvJw

<iframe width="560" height="315" src="//www.youtube.com/embed/rpA2F0wSbaw?list=UURi6D8S8okOdYsJ-39YOvJw" frameborder="0" allowfullscreen></iframe>


October 29, 2013
11:05 a.m. Maps Presented at Texas Brine Meeting

The links below access the maps that were presented at a meeting held by Texas Brine last week (10/24).

Cone Pentrometer Test (CPT) Boring Locations
http://classic.edsuite.com/proposal...g_locations_and_gas_zones_10-23-13_fi_716.pdf

Proposed Observation Relief Wells & Mississippi River Alluvial Aquifer (MRAA) Contours
http://classic.edsuite.com/proposal..._and_mraa_contours_aerial_10-24-13_fi_717.pdf

MRAA Gas Zone Thickness in Bayou Corne
http://classic.edsuite.com/proposals/proposals_280/figure_2_gas_zone_thickness_a1_fi_718.pdf

Elevation of MRAA
http://classic.edsuite.com/proposals/proposals_280/elevation_of_the_mraa_20131021_fi_719.pdf

 

[Emily]

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

There's some good closeups of the new berm crack here at WAFB's page, mixin:

http://www.wafb.com/story/23824174/crack-in-bayou-corne-sinkhole-berm-concerns-residents

The video at the link reports on the anguish residents are experiencing. Also John Boudreaux says that tremors have increased from 10-14 a day to 326 on Saturaday at the site.

 

[Pathfinder]

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

Work halted at Assumption Sinkhole after containment berm cracks

wwltv.com
Posted on October 31, 2013 at 10:31 PM
Updated yesterday at 11:00 PM
Katie Moore / Eyewitness News

BAYOU CORNE, La. -- Work around the Assumption Parish sinkhole is at a standstill now, after two cracks in the containment berms around it appeared.

Seismic activity has been increasing over the past week, an indication that it may be getting ready to swallow more land.

The sinkhole is an unprecedented disaster that still has 150 homes under a mandatory evacuation order.

It continues to grow and change, and just when the company that many blame for causing it starts to think they have a handle on it, it sucks more land and trees in.
...
Texas Brine said new technology is giving them a better idea where pockets of gas are underground, so they're starting to install two new vent wells in one of the Bayou Corne neighborhoods. ?The indications are right now that there's not a large volume of material that is sinking at depth. So, we think we may be close to stability,? Cartwright said.
...
One of the initial concerns with the stability of the area was an old mining cavern that is used to store the potentially-explosive chemical butane. It's 1500 feet from the sinkhole, and the company that operates the cavern, Crosstex, removed much of the butane as a precaution when they first suspected a cavern collapse in 2012.

The company has consistently maintained the collapse is not a threat to the butane cavern because at the depth in which it?s stored, the pressure puts it in liquid form. They insist something would have to propel it out of a damaged well head in order to cause a flashover, or explosion, according to records maintained by the Department of Environmental Quality.
...
Scientists from all over the world have been studying it, but no one seems to know what is really going on underground. While they make presentations to the community every so often, the state's scientists with contractor CB&I and even an expert at LSU wouldn't do an interview with us about it.

?Unfortunately with an unprecedented event, there's no book to open to see what the end will be,? said Boudreaux.
...
Full text:
http://www.wwltv.com/news/workhaltedatassumptionsinkhole-230103111.html

 

[Pathfinder]

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

New containment berm cracks form around Assumption sinkhole

wwltv.com
Posted on November 6, 2013 at 6:16 PM
Updated yesterday at 6:21 PM
Katie Moore / Eyewitness News

BAYOU CORNE, La. -- New cracks formed in the containment berm around the Assumption Parish sinkhole as seismic activity increased for a prolonged period.

Because of that increase in activity, which typically precipitates a ?burp? where more land is swallowed, work has been at a standstill at the site.

More...
http://www.wwltv.com/news/companyblamedforsinkholesued-230898661.html

 

[Emily]

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

http://theadvocate.com/home/7502547-125/insurer-claims-texas-brine-ignored

Insurer claims Texas Brine ignored warnings
by David J. Mitchell
November 06, 2013
...
Liberty?s lawsuit also quotes internal documents portraying Texas Brine as pushing back against suggestions from the one-time well owner, Vulcan Materials Co., to mine the cavern at a shallower depth than had been planned to avoid the deeper trouble areas.

By 1998, the suit claims, Texas Brine was evaluating which way to proceed: continue mining at 5,700 feet deep despite concerns about being too close to the edge of the salt dome or mine at far shallower depths and raise the widely known risk of a cavern roof cave-in that could cause disastrous damage to nearby caverns...

Maybe this is why TB was leery of taking Vulcan's advice back in 1998:

http://articles.chicagotribune.com/2011-06-27/news/ct-met-end-of-road-20110627_1_traffic-snarls-idot-route

Commuters, businesses bedeviled by suburban road closing might soon get relief
Shifting earth means stretch will likely never reopen, but IDOT mulls upgrades elsewhere
June 27, 2011|By Gerry Smith, Tribune reporter

Nearly 50 years ago, John Saban Sr. opened a restaurant, feeding hungry motorists along a bustling thoroughfare linking Chicago's southwestern suburbs ? a stretch of the fabled Route 66.

But then the earth began to move, turning the road outside his McCook restaurant into a dead end for motorists and slowing business to a trickle.
...
He was not the only one affected. The 1998 shutdown of a milelong stretch of Joliet Road sparked a nine-year legal battle between the state and the quarry owner, widespread road rage and a struggle for survival among some local businesses...

I happened to run across that article the other day reading up on quarries in the Chicago suburbs near the site of the big blast. It was sad & shocking to read about the iconic Route 66's continuity being destroyed along with the livelihoods of business owners who got dead-ended, but when I got to this part of the article that described what happened to the poor mother and her little tot and 4 month old infant, I was horrified beyond words. I even looked up the accident site on Google Street View and saw another quiet, beautiful community impacted tragically by mining gone wild.

Tobolski blamed their deaths on a driver frustrated by the detour.

"Everybody is in a hurry to get through and not paying attention to what they're doing," Tobolski said.

The closed roadway sits atop a narrow, pillarlike ridge that divides a deep, century-old limestone quarry operated by Vulcan Materials Co. For years, the quarry has supplied crushed stone and gravel for construction and road projects in the area.

Shallow mining doesn't preclude disasters - in fact, I thought all the trouble with Oxy3 started after TB started trying to mine shallower.

 

[mixin]

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

A new video was posted yesterday; amazing how the sinkhole has gone from a pond to a nice-sized lake.

http://www.youtube.com/watch?v=_Tty0CLH_1s&feature=c4-overview&list=UURi6D8S8okOdYsJ-39YOvJw

<iframe width="560" height="315" src="//www.youtube.com/embed/_Tty0CLH_1s?list=UURi6D8S8okOdYsJ-39YOvJw" frameborder="0" allowfullscreen></iframe>

Sinkhole activity has been at code 1 since Nov 7, so work can resume on the sinkhole and berm.

Nov 5:
Texas Brine advised that the tagging of Cavern 3 is at 4,055′ which is 42′ higher than the tagging performed two weeks ago. As information becomes available, it will be shared here.
http://assumptionla.wordpress.com/

Itasca subsidence estimates:
The study found that normal subsidence levels are projected to be present in the area over the next 30 years. The charts summarizing the initial estimates of potential future subsidence are all based on total cumulative subsidence from the present time to different points in the future ? 1.5 years, 5 years, 10 years and 30 years out ? and do not distinguish between historical subsidence driven by Louisiana?s normal geologic processes and increases in expected subsidence due to the failure of the Oxy Geismar 3 cavern and subsequent development of the disturbed rock zone and sinkhole. For reference, Itasca has used available historic survey data to estimate that normal rates of subsidence in the Bayou Corne area west of the Napoleonville Salt Dome are in a range of .2 to .4 inches per year, or 2 to 4 inches every 10 years.
http://assumptionla.wordpress.com/

Here's the report with illustrations:
http://dnr.louisiana.gov/assets/OC/BC_All_Updates/Itasca.results.1152013.pdf

 

[mixin]

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

As I was reading the last report from Texas Brine, I noticed something I had never seen mentioned before (maybe I just overlooked it):

Since preliminary containment was accomplished in February, water transfers into the sinkhole have been required to maintain level approximately 12"-18" below the swamp level outside the sinkhole berm. Because of this lower water level inside the sinkhole, it s virtually impossible for water in the sinkhole to escape with or without the containment berm.

In this Nov 7 Assumption update, they note that TB is moving water from surrounding swamp to sinkhole. On Nov 8, they note that TB is ceasing moving water from surrounding swamp to sinkhole.

I don't understand the dynamics of the swamp/sinkhole/berm. Why is it important to keep the sinkhole lower than the swamp? Would the pressure of the swamp cause berm problems if the sinkhole water level goes below 18"? Were fluctuating water levels the cause for the recent cracks?

Here's a pic of the berm, taken from the TB report I linked to

 

[Emily]

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

I hadn't noticed that Texas Brine has been adding water to the sinkhole, mixin. It does seem very strange to me - I'd assume the lower the water levels, the better as far as stopping overflow.

I think you are right about the pressure differential being a factor, though. If you think of the sinkhole as an ad hoc containment pond for the failed cavern, then its fluids are providing a buttressing force for the berms.

LESSONS LEARNED FROM AN IMPOUNDMENT SLOPE FAILURE INVOLVING GEOSYNTHETICS

This case history illustrates how several factors can coalesce to result in a slope failure. The four main factors are: (i) constructing a 1V:2H slope instead of a 1V:3H slope, (ii) installing two adjacent layers of a GCL and thus a potential weak surface, (iii) rainfall inducing seepage forces in the protective soil cover material, and (iv) reducing the fluid level in the pond, which reduced the buttressing force on the slope. It is recommended that sedimentation ponds be designed for an emptied condition...

 

[mixin]

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

Re: Louisiana: Assumption Parish Bayou Corne Sinkhole 2012-2013

That's a good study; thanks for finding it.

According to the TB report, the dimensions of the berm are: 30' across the base, 14' across the top and 12' high. It's hard to tell by any of the videos or pictures how high the water levels on the berm are. I wonder if that's what the mid way line (B1) in the diagram indicates.

So every time the sinkhole expands, the water level drops and more water from the swamp has to be added? If it finally stabilizes, then adding water shouldn't be necessary?