I remember Journey to the Center of Earth and wonder: What is the deepest in the Earth surface or below sea level we have traveled either by foot, sub, drill or camera?

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    Also of interest to many may be Can we really travel through earth's core? – JeopardyTempest May 16 at 15:47
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    Now that you've changed what you're asking, the answer is surely the Mariana Trench, almost 11km below sea level. – curiousdannii May 17 at 7:41
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    In fact. I come from asking my father and he appoints. The caving sportmanship is not going "on foot" he uses ropes, so the answer to previous question migth be 5 billion people at beaches! Note "on foot" has been deleted from the ask if following the live comments – Universal_learner May 17 at 14:17
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    Oh come on. This question started off asking how far below the earth's surface people had gone on foot. Then it became how far below sea level on foot. Now it's just below sea level. Each time people have answered the question, and had their answer become wrong because the question has changed. PLEASE DO NOT DO THIS. – Semidiurnal Simon May 18 at 8:34
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    @muze But you are drastically changing the criteria of the answer, making assessing the quality of an answer impossible. just ask a new question if you are going to change it that much. Right now the Kola superdeep would be perfectly valid answer even though it is only 9 inches across. – John May 19 at 19:41
up vote 27 down vote accepted

Probably a bit over 4 km, in this South African mine: https://en.wikipedia.org/wiki/Mponeng_Gold_Mine But as the link mentions, the mine operators go to considerable lengths to reduce the mine temperature to endurable levels from the 66°C/151°F of the surrounding rock.

Note: This answer is for the original question, where the OP asked for the deepest depth below the surface. It's since been changed to ask for depth below sea level.

enter image description here


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    How far below the surface is the natural water table at the mine? Because once the mine is eventually abandoned, when the recoverable gold has been mined, the pumps will be turned off & the mine will flood, which will reduce the depth that anyone could have access to while breathing air. – Fred May 16 at 8:38
  • @Fred: But if it's abandoned, nobody will be down there anyway. – Lightness Races in Orbit May 16 at 16:46
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    @LightnessRacesinOrbit: Not necessarily. It may be abandoned by large mining companies for mining purposes but it could be re-purposed. Smaill scale illegal miners could attempt scavenging operations or it could be used for scientific purposes such as the former [Homestake Mine ](en.wikipedia.org/wiki/Homestake_experiment) which is housing an experiment to detect neutrinos produced by the Sun. – Fred May 16 at 17:38
  • @Fred: Not if it's flooded ;) – Lightness Races in Orbit May 16 at 17:39
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    The usable depth depends on the water table & how much of the mine is flooded. – Fred May 16 at 17:41

Since you termed it based on sea level, the gold mines in South Africa are not the deepest, they begin at an elevation of ~1500 m, meaning their 4 km depth is only 2.5 km below sea level.

The Kidd mine in Canada is 2.9 km deep and is located at an elevation of only ~250 m above sea level making it's depth 2.65 km below sea level.


Also if you don't care about the underground part and only care about below sea level, the undersea exploration of Challenger Deep wins by a lot, they went ~12 km below sea level.

  • Ha. I don't think OP had open pit mines in mind. But their answer would be boring. :) – Mazura May 16 at 17:20
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    Correction, the Kidd mine is an underground mine, not open pit, but has a smaller open pit mine on the same site – Josh King May 16 at 18:42
  • The reference point for measurements makes a big difference in the results in questions like this. Depth below surface vs depth below sea level vs distance from Earth's centre. Thus, Chimborazo in Ecuador is higher than Mount Everest using the latter definition. – Vince O'Sullivan May 17 at 7:00
  • I suppose you could think of Challenger Deep as a really ambitious open pit mine as well... – Cort Ammon May 21 at 19:16

I think originally you seeking the answer for the absolute record in depth from the surface. This is not the same as from sea level. There is also a huge difference if you say "on foot" or not.

You generated multiple questions, I am going to list some of them. People can disagree with any of my answers, I made the estimations quickly.

I recommend you try not to modify the title of a question, better if you do to add something in the text saying *edited and the date of the add.

1.Record depth in the rocks from the surface a person has reached.

Based on your original question, jamesqf's answer of the mine in South Africa may be the deepest.

2.Record depth in the rocks from the surface a person has reached -see level is the reference-.

Based upon "under sea level", Josh King's answer of the Canadian mine should probably be the correct one.

3.Record absolute inches under sea level a person has reached, including underwater immersion.

Challenger Deep wins, as Josh King noted. It is the deepest point on Earth's seabed.

4.Record closest a human has come to Earth's center.

The difference between equatorial and polar radius is 22 km, so you might search for the answer at the Poles. I would not recommend the traveler to chose Antarctica, as it has an average elevation around 2000 meters. And I would say he would fails again at North Pole against James Cameron's Marianas dives -he goes "on foot", he is not a submariner :)-. Perhaps a military submarine that is traveling around the Arctic Ocean may be the winner. You will need to make some calculations to determine if the Arctic Seabed is closer to Earth's Center than the Marianas Trench.

5.Record depth from the surface a person has reached "on foot".

If you consider miners that take an elevator to still be going "on foot", the South Africa ones should have that record. If not, a spelunker.

6.Record absolute depth under sea level a person has reached "on foot".

If you consider Cameron to have been "on foot" when in the Challenger Deep, he wins again. If not, and you consider miners going to their jobs as being "on foot", then it would be the Canadian miners (2.65 km below see level). If you are strict against both, then maybe port workers (note a submariner won't win in this case neither), or maybe a spelunker.

7.Record absolute depth under surface by drilling.

Sending machines from the surface (by borehole) rather than humans, the Kola Superdeep Borehole is the deepest (12km).

8.Record closest drill to Earth's Center.

The Ocean Drilling Program could have this record, but I cannot determine where. Average seabed deep rounds -4.000 m. and the Arctic Ocean is not a deep ocean in comparison with the Pacific and Atlantic. So the Kola Borehole may well have this record too.

"Deepest drillings. The Kola Superdeep Borehole on the Kola peninsula of Russia reached 12,262 metres (40,230 ft) and is the deepest penetration of the Earth's solid surface. The German Continental Deep Drilling Program at 9.1 kilometres (5.7 mi) has shown the earth crust to be mostly porous. Drillings as deep as 2.1 kilometres (1.3 mi) into the seafloor were achieved at DSDP/ODP/IODP Hole 504B.[citation needed] Because the continental crust is about 45 km thick on average, whereas oceanic crust is 6-7 km thick, deep drillings have penetrated only the upper 25-30% of both crusts.

source: wikipedia

enter image description here

Closest projects to Earth's Core

*Distorted scale. You can take a look at this image to have an idea how thick the crust is at Earth scale.

Sources of the images: miner,submarine, boat

Here is some information about a Japanese plan to reach the mantle.

There was a proposal by geophysician David J. Stevenson that was supposed to go to the Earth's core, but it was controversial. It was published on Nature on 2003.

I encourage students to try to solve the question raised in option 4 to determine:
Which is closer to Earth's Center, the Marianas Trench or the North Pole's seabed?

Related posts:

Can we really travel through earth's core?

Farthest point from the center of the Earth

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    Also... do you have more details/reference to the New Zealand project you mention? Otherwise it sounds like it might have just been an idle daydream or something, and we have no idea how serious they took it :) That's more the kind of stuff I speak of when I suggest the importance of references and details. If you don't have a full source, perhaps tell us more about where you heard about it at least?? – JeopardyTempest May 18 at 9:36
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    Two things chagned semanticaly. My bad english+it was technical. I will ask you to change Earth's core to Earth's Core in order to leave clear I have not that english level and I need help. Thank you very much. I don' t find any link but I am sure it was published on spanish press there was a project at NZ to drill to go to the Core – Universal_learner May 18 at 13:54
  • There was no project to go to the core, because it can't be done. Going to Earth's core is as likely as walking barefoot on the surface of the sun. – Gimelist May 19 at 12:12
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    @Universal_learner I'm surprised that Nature published this nonsense. If you want, you can start a new question about whether or not this will work. I will be happy to answer. – Gimelist May 20 at 11:24
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    @Muze: I did what I could. I needed to paint the contour as I am not so skilled at inkscape. I think anyhow clarifies a bit my answer, while it is sure they are not the best graphs you will see. – Universal_learner May 24 at 11:08

The book "Blind Descent" by James M. Tabor details this answer and I found it a terrific read. I can't recall the exact depth, but what stuck in my mind was one particular explanation where the author said that we (humans) have gone as far below sea-level as above it. That is, roughly equivalent to the height of Everest - well over 8km.

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    As it stands I think this is quite a poor answer, but if you have the time to find the book and look up the details, it might be quite interesting! – Semidiurnal Simon May 17 at 13:04
  • Indeed, the exact details would help, but seems a fair answer. However, of course that isn't including flight/rocketry, which seems unfair. – JeopardyTempest May 18 at 2:39
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    IMO any answer is a good answer. Don't be discouraged from here. I got massacred before I started to write good posts/answers/questions and still miss often.Try some of the other SE sites as well. – Muze May 18 at 12:56
  • That book may say something interesting about original question and may show surprises for minning answers – Universal_learner May 28 at 0:27

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