Thursday, November 20, 2008

A town rips up

I just wanted to share with you an article I read in the German magazine Spiegel because I found it as spooky as fascinating. It is in German, so here is a rough and partial translation. For those of you who speak German, the full original article can be found at

and photos are here.


After Geothermal Drilling: A town rips up

Exemplary into disaster: The idea was to heat the town-hall in Staufen with geothermal energy. But briefly after the drilling the horror began. Everywhere in the town, cracks and crevices started to appear. Nobody knows what else is to expect - and who is to blame.

Staufen in Breisgau: A small, quiet town near the Black Forest. 7800 people live here, where the world is still all right. More precisely: Where the world was still all right. Then last fall, the disaster started to happen...

It started with a worthily idea. One wanted to heat the historical town hall with climate-friendly geothermal heat. An Austrian company was hired, seven drillings were made below the town-hall, 140 meters deep.

Briefly after this, the first cracks appeared in the historical building. At first one was not really worried. Mayor Michael Benitz spoke of “cosmetic damage”. “In the beginning the movement was in the millimeter range,” he says. But it didn't stay that way: Millimeters grew to centimeters, and the cosmetic damage grew to a catastrophe. These are at least the words Mayor Benitz uses when he talks about the uncanny events in his town.

The cracks in the town-hall began to grow, spread to the surrounding houses, and became longer and deeper. Like monster from inside the earth, they gnaw on the town. After only one year, more than a hundred houses show cracks. Sometimes they are so deep you can reach into them.

Something is going on below Staufen. The whole town has raised. And that on scales that are enormous in a geological context. We are talking about several centimeters per month.

What is going on?

Geologists were asked for advice. They should clarify if - and if so, how - the mysterious cracks were caused by the drilling. Scientists from the Technical University (TU) Darmstadt have a theory. Ingo Sass, geological engineer at the TU Darmstadt and expert for geothermal drilling, suspects [...] that the following happened: “One started drilling below the town-hall and broke through the gypsum-keuper-layer, under which there is groundwater under high pressure.”

Keuper is an anhydride, a calcium sulfat. In contact with water, if forms gypsum. And that gypsum expands. When the groundwater layer below the Keuper was drilled into, water rose through the drilling and came in contact with the anhydrite. This caused a chemical reaction. The volume growth in this process can be up to 60 percent. [For details, see e.g. this paper.]

The people in Staufen are desperate [...] Presently it is checked whether it is still save to enter the town-hall at all [...]

Sass further says: “This can go on like this for years, depending on how fast the water raises.” He is even afraid the worst is yet to come. The plaster could partly resolve again the water, causing hollow spaces below the city. “I can not exclude this situation won't become dangerous.” Because then, there could be sudden collapses. “Something needs to be done urgently,” Sass says. “The water contact needs to be stopped." But that will be expensive.

[...]

But as long as the question of responsibility is not clarified, no insurance company will pay. A report was alread conducted to bring clarity.

Geotechnicians took temperature profiles in the drilling holes and at 30 other places in the city center, and measured the vertical motion. In the end however, nothing could be said with clarity. The drilling might have caused the problem. Or maybe not. It could also have a natural cause.

“Staufen is a tectonically active area,” says Sass. “Of course it is possible that the layers moved tectonically against each other which changed the water flow and caused the reaction.” But: He doesn't consider this to be very probable.

That the start of the events coincides with the drilling is a strong indicator against natural causes. Why would this weird raise of the ground start now, so briefly after the drilling. Most of the inhabitants of Staufen do not believe in theoretically possible natural geological processes [...]

13 comments:

Uncle Al said...

Anhydrite is calcium not copper sulfate. Visit Chemistry for a bottle of Drierite (less the blue/pink moisture indicator). Cf: the mud volcanoe outside Surabaya City, Indonesia.

http://en.wikipedia.org/wiki/Sidoarjo_mud_flow
Mr. Grenade is grumpy after his pin is pulled.

The Enviro-whiner trinity is expensive, shoddy, deadly. Staufen in Breisgau already enjoys two of three. The first recycled wool in the Industrial Revolution was called shoddy. How well do you think that worked?

Bee said...

Oops, thanks. I've corrected the typo. (My typo, it is correct in the German article.)

It is puzzling to me though that the swelling ability of anhydrite seems to be a fairly well known problem, so one would have thought that they wouldn't just go an blindly drill holes somewhere. Just think of all the families who might have lived there for generations, what a tragedy. If I'd live there, I would move out of town asap.

Phil Warnell said...

Hi Bee,

It seems these folks in Staufen have got themselves into a bit of a pickle in their attempt to utilize nature’s power in the spirit of saving the environment. I must say although I am truly sympathetic to their plight, yet at the same time it has one mindful there is more to utilizing a technology then what first presents to be a good idea superficially.

It appears these geologists have a good idea as to what has happened and as to why. It’s somewhat clear to me (as you yourself suggest) that this type of advice was never sought out before the plan was enacted upon. I also find it somewhat ironic that perhaps those who might deem a nuclear power plant installed nearby as being an unwarranted risk, would without much concern as by way of forethought allow deep holes be bored under their town to have it now threaten its very existence. Perhaps more thought should be given to what amounts to defining risk beyond simply what is considered as being its source.

Best,

Phil

stefan said...

Dear Bee,

wow, thanks for preparing the translation! I had seen this story last week and pu ton my mental list of "bloggy stuff", but couldn't find an English version...

Cheers, Stefan

Chitragupta said...

As Phil said.

This was, for the townspeople, one of the unknown unknowns -- they did not know that there was something to be known -- and it seems it is fatal to the future of the town.

That is true for so much of the new technology we have, too. The negative impacts of asbestos were known only after a generation. Who knows what being 40 years in a perpetual WiFi radio bath will do?

Bee said...

I can understand the town-people didn't know that, but the company who did the drilling should have known. One would think there must be means to do some preliminary tests to exclude such disasters.

Georg said...

Hello Bee,
some hints to this "chemical" reaction.
"Keuper is an anhydrite, a calcium sulfat. In contact with water, if forms gypsum. And that gypsum expands."
Keuper contains anhydride (there is one
and only one anhydrite)
In contact with water below 101.45 °C it
forms gypsum, this transformation
is accompanied by volume increase.
(The Gypsum does not swell)
And: this is physics, no chemical bonds broken or
formed. :=(
The question of responsibility is somewhat complex, normally drilling
in such depths needs a permission of
the "Bergamt" (Mining Authority), but details
depend on laws in the different states.
This "Bergamt" is the institution who
should know the riscs.
Maybe nobody asked them, maybe the city
was not obliged to ask (only 140 meters).
Moreover, the valley of the Rhine is extremely
complicated geologically.
It is a rupture in the continental plate, some 3000 to 4000 meters deep,
filled with the debris of the adjacent
mountain areas.
Close to the continental crust on both sides (Black forest in Staufen) the
situation is extremely complicated.
So, maybe even the Bergamt did not know.
Here in the town I live (about 150 km north, similar place), there is a
hot water drill (3400 m) for geothermal
water of 155 °C running since last year.
So what did they hope in Staufen for
in a depth of 140 m? Strange.
In general, anhydrite and Gypsum are very
common deposits in Germany, often found in connection with salt (domes).
The risk of holes by dissolution of the
anhydrite or gypsum is not acute ,
this will take thousands of years because
that depends on streaming water, which carries away the dissolved matter.
The swelling of the mass is contrary to that, because this swelling blocks the
percolation by the water. But on long terms something has to be done.
Best Regards
Georg

Bee said...

Hi George,

Thanks for the correction, I got confused with the translation of the chemicals because my dictionary wasn't helpful in this regard. Regarding the volume increase: is there a difference between anhydride and the anhydrite? Best,

B.

Georg said...

Hello Bee,
menwhile I read the comlete Spiegel story,
so I know that these are the typical journalists
errors. Your translation was perfect.
Anhydride is a chemical expression.
The meaning is "any chemical compound
drepraved of water".
Exapmles: Sulfur trioxide is the anhydride
of sulfuric acid, calcium oxide is the anhydride of calcium hydroxide, CaSO4
(Anhydrite) is the anhydrous Gypsum CaSO4*2H2O .
Anhydrite is a mineralogists name for
the anhydrous gypsum. The "ite" ending
comes from greek lithos (stone).
Best Regards
Georg

Phil Warnell said...

Hi Georg,

“ maybe even the Bergamt did not know.”

I think it simply boils down to a case where the inductive aspect of reasoning has played too large a role. What I mean is perhaps there are no other instances where such an outcome has been realized since what has been undertaken is not often done. That’s why deduction must also play a role in decision making; otherwise what one essentially ends up with is trail and error. One would still have to imagine that if good science had been utilized this could have been avoided.

Best,

Phil

Georg said...

Hello Phil,
excuse my lack of precision.
What I wanted to say is, maybe the
"Bergamt" did not know that anhydrite
lies under Staufen.
What You find there is varying within
some hundred meters often.
The phenomenon of anhydrite swelling is rather wellknown to mining people, I think.
Anhydrite deposits are rather common,
often atop of potash salt mines.
Georg

Phil Warnell said...

Hi Georg,

Yes I can accept what you are saying, yet in the process of drilling it is quite often usual practice (and not difficult)to take as to analyze core samples as one goes along. If this had truly been a recognized possibility and concern one would think it would have been identified at this juncture. For that matter this whole business of what the geologists suspect now as being the problem could be made more certain by drilling only one more hole in the immediate area; that is stopping of course before reaching the hot water depth. It still seems to me to point more to the lack of forethought in general as being what was missing here.

Best,

Phil

Kaleberg said...

Drilling does have its hazards. Look at that mud volcano in Indonesia (http://www.cbc.ca/technology/story/2008/11/03/mud-drilling.html)

At least no one has reported any invasions by mole men.