Thursday, June 11, 2009

Lake Peigneur: d’oh on a scale that’s hard to imagine

Think about salt for a moment. In recent years it’s gone from the standard fine-crystal iodized stuff that came in cardboard canisters and was not generally considered a subject for rhapsody to a whole new world of artisanal seasonings: much like bread, salt has become fashionable, and salt snots now argue with one another over the relative benefits of flake salt, fleur du sel, French grey salt, Hawaiian pink salt, or Indian black salt (“an unrefined mineral salt. It is actually a pearly pinkish gray rather than black, and has a strong, sulfuric flavor. Uses: Use in authentic Indian cooking”).

Before there was, you got your salt from industrial salt mines. Rock salt, or halite, the stuff that rots the undercarriage of your car in winter, represents ancient salt deposited in marine basins as water evapourated. Over time, the salt beds were covered with layers of sediment and compressed. Salt is less dense than the surrounding rock, and it has a tendency to push upward in blobby formations called salt domes (topographical modeling of these formations looks a lot like the bottom of a lava lamp as it warms up). These domes can be absolutely massive, shouldering aside mountains as they bubble to the surface.

As the salt domes squash and displace strata around and above them, pockets are formed between salt and rock where oil and natural gas can collect. Salt mining operations, therefore, are often found right next to oil/gas drilling operations–including under the Gulf Coast. Mostly this does not present a problem. Mostly.

Imagine a salt mine that is busily chipping away at a salt dome that happens to be directly under a shallow lake. The miners know perfectly well where they can and cannot dig; the tunnels extend far below the lake itself, and the mine is producing a healthy crop of salt for the Diamond Crystal Salt Company. It’s November 21, 1980, and the most bizarre man-made natural disaster in decades is about to occur.

The area of New Iberia, Louisiana, is dotted with oil wells. Texaco is having a whale of a time poking holes in the ground and seeing what they hit; one of these probing wells is located three hundred yards offshore in 11-foot-deep Lake Peigneur. The presence of salt domes in the area makes it likely that they’ll find pockets of oil beneath the lake, and the presence of the salt mine in the area has made Texaco do some careful calculations so as not to infringe on Diamond Crystal’s territory.

Somebody apparently forgot to carry the three.

On the morning of November 21, the men on the exploratory rig in Lake Peigneur were happily drilling away in the hopes of striking it rich. Over a thousand feet below the surface, the drill bit was chewing its way through rock when it hit something with a considerably different texture and seized up; as the men tried to free it, wondering what was going on, the rig itself suddenly tilted alarmingly toward the water, and they heard some strange and ominous popping sounds.

Wisely, the operators cut loose their barges and got the hell out of it, and watched from the shore as their whole rig continued to tilt and collapse beneath the surface. They knew the lake was only about eleven feet deep, so the disappearance of five million dollars’ worth of equipment was impossible.

So was the fact that a massive whirlpool developed over their drill site.

In the Diamond Crystal mine, something like 1,230 feet below the surface, water was roaring down the Texaco drillshaft into a mine gallery through a hole fourteen inches wide--a hole which rapidly became much larger as the blasting stream of water dissolved the salt. I don’t know the calculations to work out exactly how forceful the initial jet of water would have been, given the width of the drillshaft, the diameter of the opening, and the distance from the surface, but I think it can be safely assumed to be intense.

An electrician in the mine was the first to see the flood approaching, and sounded the alarm: incredibly, all of the miners managed to escape as the water dissolved away supports and collapsed shafts, swirled and frothed and roared in the darkness of the tunnels, driving air before it with such force as to blow the heads off the mineshafts and then send geysers shooting four hundred feet into the air. Excellent emergency planning and mine-evacuation drills were credited with the survival of the miners. Others attribute it to divine providence.

On the surface, onlookers watched in fascinated horror at the demonstration of what happens when you pull the plug at the bottom of a lake. By now the whirlpool was massive, a quarter-mile across, powerful enough to reverse the Delcambre Canal leading to the Gulf of Mexico and suck eleven barges helplessly down into the drowned caverns of the mine. Another drilling platform, quite a lot of an island, and a nearby parking lot vanished as well. As the lake drained away (with what must have been the loudest sucking sound ever heard) the water from the canal poured 164 feet into the lakebed, creating the tallest waterfall in Louisiana.

As children, most people have watched bathwater swirl away down the plughole and wondered on some level whether it would suck them down too; what child hasn’t anxiously asked its parent what would happen if someone pulled the plug on the ocean? I don’t envy the children who were around to watch Lake Peigneur go down the drain. If that can happen, what else have the grownups lied about?

The lake water took about three hours to drain into the mine. After that, water from the Gulf of Mexico via the Delcambre Canal continued to flow into the crater that had been the lakebed, filling up vast and unknown caverns under the earth, replacing freshwater with salt, moving silently through the holes where men had dug and joked and cursed. It took two days before the water level finally rose to the point where the pressure equalized and the suction eased off: nine of the eleven sunken barges resurfaced, leaving the tug and the Texaco rig somewhere in the flooded mine workings.

There are no obvious reports to be found on the internets about investigation into the accident, and–-hilariously–-no official responsibility could be taken, as there was no longer any actual evidence of the Texaco drill shaft breaking through into the salt mine. Texaco paid Diamond Crystal and a neighboring business several million in out-of-court settlements anyway, but the disaster itself erased the evidence required to legally convict its perpetrators.

I have to wonder who was responsible for the miscalculation that sent the drill bit into the mine. I have to wonder what he or she thought when the lake started to go down the drain. This is not just “d’oh,” this is “d’oh” on a scale that changes ecosystems.

Remember, boys and girls, double-checking one’s sums can save a lot of hassle. Next time you’re deciding between pink, black, brown, smoked, kosher, or grey salt to put on your purple Chinese space potato fries, remember how lucky you are not to have to rely on boring old mined rock salt, and the hazards associated with salt mining.

(It’s okay to laugh at Lake Peigneur. It’s a little difficult not to.)

Information for this post was taken from Wiki (yes, I know) and the excellent Damn Interesting article on it. Unfortunately I can't get my hands on any official reports.


  1. That is a good one... with no loss of human life, and all. I don't recall ever hearing of it - I would have been a freshman or sophomore in high school at the time.

  2. There is video of this, and it is awesome: