Submitted by Charlton Stanley (aka Otteray Scribe), Guest Blogger
There are gigantic salt deposits under the state of Louisiana. Geologists tell us the salt dome under Assumption Parish is about the same size as Mt. Everest. Some of the deposits are as deep as 35,000 feet as shown in this not-to-scale drawing. In fact, huge salt deposits are under large patches of the North American continent along the Mississippi River valley all the way up to Lake Erie. The city of Cleveland is sitting on top of a large salt deposit.
Salt settled out of the water when these areas were part of the ocean as the continent of North America was forming. We have all seen what happens if you dissolve salt in water. It reaches a saturation point, where no more salt can be dissolved. At that point, the excess salt settles to the bottom. That process is still going on at the surface in places like the Great Salt Lake and the Dead Sea. Once the water evaporates, it leaves behind places like the famed Bonneville Salt Flats. The excess salt in the water in those formative years of this continent settled out into enormous deposits. The primary deposits of salt are deep underground, as far as ten thousand feet or more. However, like glacier ice, solid crystal salt becomes somewhat plastic under great pressure. At ten thousand feet, the overburden of rock and sediment creates pressures of thousands of pounds per square inch. Salt deposits find weak places in the rock, and start squeezing upward in plumes, called “salt domes.” These extrusions come nearer the surface, making the salt more accessible so it can be mined. When I lived in Louisiana as a kid, I remember the salt mines being an everyday topic of conversation. The salt is not only used for food, but has many industrial uses as well. During World War Two, the salt mines provided essential minerals used in the manufacture of ammunition and high explosives. Salt mining in Louisiana has been going on since before the Civil War. Some of the mine shafts go down as much as ten thousand feet, and some of the salt caverns that have been mined are enormous.
Some of those salt dome mine caverns have been used for storing things, such as butane and natural gas under pressure. Let’s see now. We have a salt dome near the sea holding about one and a half million gallons of liquified gas under pressure at 1,000 pounds per square inch. What could possibly go wrong? Add to that an abundance of oil deposits. Drilling for oil and gas is big business along the Louisiana Gulf Coast. Drills have a bad habit of punching holes in things. The Lake Peigneur Disaster of November 20, 1980 was the result of a simple miscalculation on the part of engineers responsible for telling the drill crew where to drill.
When the salt is not fractured, it retains its integrity as a vault. However, geological and human activity can cause fracturing. Additionally, mining creates a cavity, and the sidewalls must be thick and strong enough to resist side pressure from underground oil, gas and rocks. Like a crack in the foundation of a house, water can get into cracks. Water pressure at 5,000 feet is 2,165 pounds per square inch. At 10,000 feet, water pressure is 4,350 pounds per square inch. It does not take much of a crack for water to get in. At those pressures, a leak the size of a straight pin has the penetrating power of a cannon shell.
Assumption Parish is south of Baton Rouge, the state capitol. A parish is the Louisiana equivalent of a county. Parish governments are supervised by a Police Jury, a body of elected citizens somewhat similar to County Commissions in other states. The Parish has a web site, a blog and a YouTube channel. Over a year ago, bubbles were observed coming from the general area of the salt dome. At first the bubbles were a mystery. Then crude oil began appearing. At that point, geologists realized the integrity of the salt dome sidewall had been breached. A sinkhole began to appear in Bayou Corne in Assumption Parish. It has grown steadily since last year, and by this past week, was about 26 acres in size. The sinkhole is due to the collapse of a salt dome like the illustration at the top of this story. Some experts on the scene make a difference between a sinkhole and a salt dome collapse, saying the latter is a far worse environmental and geological disaster than a sinkhole. Because a true sinkhole is due to erosion of rock and sand, it can only get a few hundred feet deep at most. On the other hand, a salt dome collapse has the potential to end up more than two miles deep. No matter what it is called, the hole is getting larger by the day, and after the most recent sloughing this week, workers were pulled back from the berms and service roads surrounding the sinkhole. The increased rate of sloughing off edges of the hole was making it too dangerous to stay there.
An incident last week illustrated how the edges of the sinkhole are eroding away. Watch this short video made by work crews as the underwater edge of the sinkhole creeps toward a stand of 100 foot tall Cypress trees. The floating booms seen in the video were for containing the crude oil floating on the pond. Seeing these giant trees sink is not the most disturbing thing about this sinkhole. Despite the fact it is about twenty five miles from the nearest open water, the sinkhole has been exhibiting tidal wave action. That means it is probably somehow connected to the Gulf of Mexico deep underground, either through old mine shafts or cracks. Water pumping back and forth will cause more scouring than stagnant water. An unlimited water supply also means more salt can dissolve because the water will not become over-saturated with salt.
No one knows for sure when the sinkhole will stop growing. Depending on who you talk to, some geologists are pessimistic about these new developments, and want to post evacuation warnings as far as 25 to 100 miles from the sinkhole. There is another concern as well. No one knows exactly how all this geo/hydraulic activity in south Louisiana will affect the maze of fault lines along the Mississippi River valley up into the Great Lakes. The most famous of these fault systems is the New Madrid Seismic Zone. If it proves to be true the side walls of the dome were breached, the situation becomes unsalvagable. Maps show that a substantial portion of Louisiana could end up underwater unless the hole stops growing.The video below shows that unusual wave action.
A few days ago, Governor Bobby Jindal, with Attorney General Buddy Caldwell beside him, held a press conference in which he said the state is going to sue the salt mining company, Texas Brine. He didn’t say anything about suing any of the oil companies, such as BP.
The floor is open for discussion.
Thad Daly 1, September 2, 2013 at 1:29 pm
There is a limit to the size of the sinkhole
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Irrelevant. Everything finite is that way but we are not talking about everything.
We are talking about a first-of … a dome collapse …
This is said to be a unique event and it is back up with actual data:
The collapse of the dome is unique, the tidal movement in the water, and the not-yet-plumbed depth belie your assertion.
Width is also an issue.
How wide is it?
Just some off the cuff thoughts —
Concerning Thad Daly’s much appreciated comments: Does it matter that this may be a salt dome wall collapse, and not a salt dome sinkhole? Why would the amount of incoming water necessarily be limited to the cavern –what of the new fissures in the strata caused by the collapse?
As far as incoming fresh water floating on the brine, what of OS comments: “Despite the fact it is about twenty five miles from the nearest open water, the sinkhole has been exhibiting tidal wave action. That means it is probably somehow connected to the Gulf of Mexico deep underground, either through old mine shafts or cracks. Water pumping back and forth will cause more scouring than stagnant water. An unlimited water supply also means more salt can dissolve because the water will not become over-saturated with salt.”
Concerning salt saturation of water, “the average salinity of the ocean is 35 parts per thousand (ppt); most of the Gulf of Mexico averages 28 to 32 ppt. However, some areas of the Gulf of Mexico average 36 ppt.”
http://www.create.cett.msstate.edu/cosee/cosee-lplan_view.asp?articleid=74
I recall form HS chemistry that 36 ppt is the sea level saturation point of sodium chloride at room temperature. Of course the salinity of Gulf water near the mouth of the Mississippi would probably be lower than 36ppt.
If there is a tidal connection to Gulf water of less than 36ppt salinity, why wouldn’t all the salt be dissolved?
My greater concern than earthquakes is hydrocarbon pollution and unimaginable flooding of Louisiana. “That was crude oil and natural gas bubbling up from below ground. It was a mystery at first, but now authorities say an abandoned salt cavern collapsed, shifting the rock and salt formations deep below, causing the sinkhole above and unleashing hydrocarbons into the groundwater aquifer up to two miles from the site.”
http://www.npr.org/2013/03/20/174853576/massive-sinkhole-in-louisiana-baffles-officials
Is it possible that a wall collapse of a salt dome tidally connected to the Gulf, not necessarily this one, might drain an adjacent O&G reservoir into the Gulf?
As far as flooding, don’t forget climate change – from a summary of the leaked IPCC’s recent draft report: “Long-term, sea level rise could be 5 to 10 meters.” Tides, of course, could be even higher. Oh, 5 meters (the low end of the projection), is a bit more than 16 feet 4 inches.
And we might as well take a long view of things since “much of the carbon we’ve emitted will stay in the atmosphere for a millennium…even after we’ve stopped emitting it.”
http://www.motherjones.com/environment/2013/08/five-terrifying-statements-ipcc-report
raff,
Yes, people in nearby homes were evacuated a long time ago. Some engineers and managers were talking earlier this week about expanding the evacuation area anywhere from 25 miles to 100 miles from Bayou Corne. I suppose it depends on developments.
I am taking Thad Daly’s word for it the depth limit is about 5,600 feet. Hypothetically, if we assume the area sinks even a few hundred feet, it does not take much imagination to see what could possibly happen to the course of the Mississippi River. I have the USGS open in another tab, although I don’t really need to look at maps. Been there. The highest elevations in Assumption Parish are only about 20 feet above sea level, which is true of most of that area of the state. The Bayou Corne community is only about seven feet +/- above sea level.
Thad Daly,
Thanks for weighing in. While I am a scientist, I am not a geologist and never played one on TV. In researching this piece, I talked to people and dug up everything I could find on the Internet. Google Scholar can be your best friend or worst enemy, depending on what data are relied on.
I am uncertain as to absolute limits, since I can’t find any record of anything like this event happening before. The closest seems to be the 1980 disaster at Lake Peigneur At any rate, I am not so much concerned about salinity as I am any fissures that might develop in the salt deposit. That and possible movement of water, whether it be scrubbing from tidal action or the Mississippi River and its scouring action. Whatever is going to happen is not all going to happen at once, maybe not even in the lifetime of anyone living today, but a long view is much better than a short one.
I am well aware of the 26% saturation limit, but seawater is roughly 3.5% salt, and of course the river is pure fresh water. The river flows past that area at around three knots, and carrying +/-600K gal/second. As anyone who grew up around the Mississippi knows, the river can and does meander.
The problem is the great number of unknowns, but I do understand theoretical limits very well. Planning for a worst case scenario has kept me alive more than once, so I prefer to err on the side of Murphy’s Law, and try to anticipate the worst possible thing that could happen.
@ Otteray Scribe –for salt to be dissolved there must be a source of fresh water- not saturated brine. The sinkhole and cavern is full off brine-
Fresh water with Sg 1 is lighter than brine with Sg 1.2 and so floats on top of the brine– how would fresh water get down into the salt dome to dissolve more salt. The bottom of Oxy#3 and the absolute limited for sinkhole depth is 5,600 ft and the only waters in them is brine. No pathway farther down so how does fresh water get through the brine then into the salt.
Bare in mind it takes 3 bbls of fresh water to dissolve 1 bbl of salt.
There is a limit to the size of the sinkhole– that is the volume of Tx Brn’s Oxy#3 cavern. The material from the sinkhole area is going into the cavern when the cavern is full or when no more material can enter
that is the max size of the sink hole–
Amazing stuff OS. The videos are almost disturbing. This is very scary. I do hope the authorities are moving people out of any areas that might be impacted.
OS, Thanks much. Like everyone, I’ve seen sinkhole video and been amazed. But, I was never curious enough to research. If I were a movie producer I would be making a disaster flick about the giant sinkhole that consumed Cleveland. People would definitely attend a sinkhole disaster flick. The awe watching them is primal, as is the fear. Anyone want to start on a screenplay?
Gene,
Salt dome and caves are abundant in Michigan and the Detroit area….. OS you best work today date here in my opinion… Very informative in every aspect…..I’m surprised they didn’t blame Obama….
Evidently this sinkhole event is the first time the sides of a saltmine shaft has collapsed:
(Mining Madness). Something is going on down under the ground that is not promising.
This video was made by a guy who lives about 100 miles from Bayou Corne. He posts updates on environmental issues, especially as it relates to the oil and gas industry. He is also big into end of world theories, but does seem to have a good grasp of the realities on the ground as long as he stays out of conspiracy theory stuff. Note he mentions Radium-226 and Radium-228. I have worked on lawsuit cases involving Ra226 and Ra228. Those are stable isotopes of Radium which are commonly found on drill pipes from that area. This particular video was made last January, so is slightly out of date.
http://www.youtube.com/watch?v=kprEOkRsV1c
This next video was posted two weeks ago, on August 15.
One report had me wondering:
Evidently the radiation being talked about is naturally occurring underground radiation.
But the explosion potential shows the power of these events:
A 36″ (3 feet) pipe is quite strong, so bending it shows lots of energy being generated.
Mr. Ed,
I was aware of that hiccup at the Cargill site and did some research on it. Let’s hope it stays stable. In the story, I only mentioned Cleveland in passing because I wanted to keep focused on the breaking news coming out of Louisiana.
Otteray Scribe 1, September 2, 2013 at 12:50 am
Elaine, the big difference between what is happening in LA that is different from both Kansas and FL, is this sinkhole has the potential to go down anywhere from two to five miles deep. That could put enormous shearing pressure on fault lines further up the river. Also, water acts as a lubricant when forced into faults. That is a Bad Thing. For potential harm, you don’t need to look further than Port Gibson, Mississippi. The Grand Gulf nuclear plant owned by Entergy Corp. is there.
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That is scary.
Most of these plants are Fukushima type designs.
They are not perfectly safe in normal times, much less under the uncertainties presented by these developments.
There are several salt mines under the north shore of Lake Erie. So far, no problem, though the Cargill mine off Cleveland had a tiny roof movement that caused some concern. After a few days, the mine reopened.
Que sera.
My half blind guy had a mother in law from a prior offense (marriage) disappear in a sinkhole in Plaquemine Parish. She was so rough that the sinkhole spit her back up. After that was when half blind guy got divorced. He calls his ex wife “collateral consequences” for some reason. Those sink holes are smart.
Reblogged this on Brittius.com.
And the evidence is at the bottom of the sink hole…how convenient for the oil company. Sound familiar. The government was probably paying directly or indirectly for the “engineering work” that lead to this disaster. We never learn. Do you know that BPs government contracts doubled after the disaster in the Gulf? And fracking is “completely safe”. Our government doesn’t know and doesn’t care.
Thanks for this piece.