
What's the Deepest Hole Ever Dug? - mpweiher
https://www.smithsonianmag.com/smithsonian-institution/ask-smithsonian-whats-deepest-hole-ever-dug-180954349/?no-ist
======
lb1lf
Just a bit of pedantry - the story linked (correctly) identifies the Kola
superdeep borehole near Pechenga, Russia as the deepest hole humanity has ever
drilled, at some 12,200m/40,000ft.

However, 'dug' in my book is not the same as drilling; the deepest hole ever
dug (unless you want to go all fundamentalist and claim 'dug' implies shovels
and pickaxes and nothing else!) is the Bingham Canyon open-pit mine in Utah,
at some 1,200m/4,000ft. (They've been at it for more than 100 years!)

The deepest mine? Mponeng and TauTona, two South African gold mines, at
approx. 4,000m/13,000ft. (And counting!)

~~~
growlist
Deepest hand dug well is in Brighton - 1285ft:
[https://www.woodingdeaninbusiness.co.uk/blog/where-is-the-
wo...](https://www.woodingdeaninbusiness.co.uk/blog/where-is-the-woodingdean-
well/)

------
mirimir
> The Kola hole was abandoned in 1992 when drillers encountered higher-than-
> expected temperatures—356 degrees Fahrenheit, not the 212 degrees that had
> been mapped.

That, plus the collapse of the Soviet Union.

Then: [https://www.thevintagenews.com/wp-
content/uploads/2015/11/01...](https://www.thevintagenews.com/wp-
content/uploads/2015/11/0150127f68add612b7ac573ac871.jpg)

Now:
[https://f4.bcbits.com/img/a4184178639_16.jpg](https://f4.bcbits.com/img/a4184178639_16.jpg)

~~~
ccozan
I wonder why not investment goes into tapping the geotermal potential. Is like
having a free reactor ( since both work on transferring heat to water -> steam
)

~~~
sametmax
Educated guess: it's very hard.

A pipe that long would be subject to break down every time the earth moves a
bit. Fixing said leak would requires stopping the use of the pipe completely.

As 300 C is not that a huge temperature, the energy to pump the water may also
cost a lot compare to the energy you get out of it.

I'm not saying we should not try, but it seems a great challenge. And we don't
have the motivation of creating an atomic bomb to drive it.

~~~
lb1lf
With only a very tenous grasp on the basics of fluid mechanics and
thermodynamics, I'd suspect it is simply a lot more cost effective to drive a
significantly larger volume of water through a significantly shallower (hence,
lower temperature - but cheaper to drill, maintain and force water through)
well to reap the same amount of energy.

Assuming reasonable heat exchange efficiencies, you'd do as well with
1000m^3/hour at a 20 degree differential as you would with 100m^3/hour at a
200 degree differential.

Or am I missing something?

~~~
sametmax
Yes, but if you can turn the water into steam you don't have to pump it back
as much. So you leverage gravity in, density out. I have no idea if that evens
out though.

------
bastijn
Previous (recent) HN topic on the same thing:
[https://news.ycombinator.com/item?id=17336315](https://news.ycombinator.com/item?id=17336315)

------
no1youknowz
Real Life Lore Video:
[https://www.youtube.com/watch?v=E39GIysMevQ](https://www.youtube.com/watch?v=E39GIysMevQ)

------
rwmj
Is the transition from crust to mantle a sudden one or gradual? It seems
unlikely that the two could be entirely separate. And how about between the
mantle, outer and inner cores?

Strange drilling fact: When digging the Channel Tunnel, all existing bore
holes (going back a century) had to be mapped and the tunnel avoided them so
that if any of them hadn't been plugged properly it wouldn't create a hole
that caused the tunnel to fill with water.

~~~
Piskvorrr
It's complicated.
[https://en.wikipedia.org/wiki/Transition_zone_(Earth)](https://en.wikipedia.org/wiki/Transition_zone_\(Earth\))

------
dingaling
An interesting article but infuriating in how it translates all dimensions to
Imperial first. Such as stating the depth of the Kola borehole in feet and
adding metres in parentheses; it was drilled using equipment specified in
metres...

~~~
brightball
There are countries that use the metric system and countries that have been to
the moon. :-)

~~~
growlist
The Third Reich? Ah no, it was just their rocket scientists wasn't it.

~~~
perl4ever
Von Braun never was an astronaut, much less traveled to the moon. And, I
presume Nazi Germany used metric.

