How deep can you dig an open pit mine?
Hypothetically, if you have a very large area and can go very wide, and have special equipment like heat shielded or remote controlled eart moving equipment, water pumps ect.
What happens if you break through the crust?
Do you get killed by hot gasses or molten rock or what?
You get earth aids
eventually it gets too hot to dig any deeper
you could get killed by gasses/molten rock too but that's basically the same thing as "it gets too hot to dig deeper"
so...you are saying...it gets too hot?
>you could get killed by gasses/molten rock
yeah this is way you don't dig directly under your feet in Minecraft
>eventually it gets too hot to dig any deeper
But if you are digging a huge open pit then the top layer of magma can be frozen by pumping seawater all over the place. If your pit is hitting magma it is probably quite deep.
nou
>orange
ignore this moron
Current record is 2.5 kilometers
https://en.wikipedia.org/wiki/Mponeng_Gold_Mine
One of the biggest issues is the heat.
Thats not an open pit. Why are you so stupid?
The problem is the same whether it's a pit mine or a drill hole. The heat.
I take this as further evidence that you are stupid
So only 2.5km is already unbearably hot? Then why are caves so cold? WHat the frick?? Serious question please answer
Because its closed, an open pit would be much cooler
No it wouldn't. Adiabatic heating should amount to about 10 degrees/km. It would be very hot.
Writing adiabatic isnt making your post scientific
The air gets pressurized by its own weight as it flows into the pit.
>The air gets pressurized by its own weight as it flows into the pit.
Completely negligible in an open mine where the rate of excavation will be m^3/min not km^3/s. The window for when the fluid can do work on itself is very small.
An object under static pressure doesn't warm continuously. Work is only done during the compression phase where the pressure is changing
Yeah I'm dumb
didn't understand what he meant
>Adiabatic heating
lmao. are some chemical reactions happening or something?
You really should just lookup elementary earth science/geology, or you're going to have a lot of questions.
As air moves vertically, the change in air pressure makes it expand (upwards) or contract (downwards). Expanding gas cools, contracting gas heats. This is the main reason why temperature varies with altitude within the troposphere. Meteorologists will talk about the "dry adiabatic lapse rate".
For a fluid that makes sense but I thought you were talking about heat moving through the crust, nevermind.
>No it wouldn't. Adiabatic heating should amount to about 10 degrees/km.
And what part of an open pit, i.e. an open system, do you think adiabatic applies?
ur diabetic
I won't swear to what that anon was thinking, but it would apply to the air within the pit. As air drops into the newly excavated pit, it would compress and heat up.
>it would compress and heat up.
>Adiabatic heating should amount to about 10 degrees/km.
>Expanding gas cools, contracting gas heats.
No. Just because the air is at a higher pressure because the total fluid column is 2.5km longer than at sea level does not mean it is going to be hotter. There is no work being done.
Yes, there is. Unless you are magically manufacturing the air in situ.
>Unless you are magically manufacturing the air in situ.
What flow rate of air are you expecting to fill the void from mining activities?
okay but CLOSED caves are cold, why?
The deepest cave ever found is "only" 2.2km deep, and they are usually full of water.
so 2.2km deep is cold as frick but 2.5km deep is hot as frick?
Have you tried dropping a glass of water in your 2.5km hole?
Caves have stable temperature year round i dont know if they have to be cold. They might be colder than the average daytime temperatures when you visit that are not the average 24 hour temps, you can see the same effect on large buildings
Caves aren't deep, deep caves are hot.
how deep?
also is the lava inside Earth the reason that wells work even during the winter?
The deep underground has a constant temperature, by deep i mean 10 meters underground. Same thing at sea, only the surface water changes temperature with the seasons
Caves relatively near the surface have a temperature close to that of the annual average temperature of the air at the surface. Go down far enough and you start to encounter heat coming up from the interior of the Earth.
The temperature gradient is about 25°C per km of depth.
the deepest cave in the world is only 2.2km deep and it's way above sea level. The drills at the kola borehole were reaching rock that was hot enough and under enough pressure that it acted like really heavy toothpaste.
>rock that was hot enough and under enough pressure that it acted like really heavy toothpaste.
I really want to see this. The toothpaste behaviour will be from the pressure, not heat, and you will only see this in material with a huge column of material above it. You won't see this in an open pit with sloped walls, certainly not at 2.2km
I calculated the maximum height of solid steel to be ~2600m, at which point the material at the bottom plane will start yielding plastically.
I did this calculation too, althought i dont remember if that was the limit. Something about the maximum height of a skyscrapper. 500 megapascals and steel flows like liquid? That would be around 50.000 tons per square meter or 4000 meters tall, but i mean maybe steel is weaker than 500 megapascals.
I used 200 MPa for the strength of steel, cheap generic carbon steel.
like 90% of the posts here keep ignoring "open pit" if you look at satellite pics if the biggest mines they all stop whem they hit the water table.
Just dig somewhere that doesn't have an aquifer, then.
its always a logistical problem...all this theoretical nonsense means nothing in reality...if there is no aquifer that's a huge logistical problem of it's own.
Temperature plays also a very important role. From a certain depth rock behave like a non linear viscous fluid with a power law dependency on temperature. Look up dislocation creep if you are interested in the exact formulation
>dislocation creep
Interesting stuff
>10000 years
>So it can be pretty much ignored in this case
Optimistically we should be dramatically decreasing this timeframe. If I'm gonig to be digging the world's biggest hole, I'd like something to break quick enough for me to see it.
What is it about Yellowstone that makes it so dangerously explosive? Is it because a fault line is very very long rather than particularly high pressure magma?
non-meme answer: there’s two heat sources, the sun and the earth’s core. you keep getting further away from one as you dig down (the sun) and closer to the other (the core). you reach a point where it’s very cold, but as you go further down, you gradually get closer to the earth’s core, and it begins to warm up, until it’s unbearable
2.5 burger units*
4km
by making a big open pit you would basically make a volcano
dig down until all the dirt is gone and lava keeps filling back up
Can't you pour water onto the lava to make obsidian which you can use on the walls?
Says lava is 100km away. When you dig down won't that make the crust deeper as you go? How much energy do you need to remove in order to freeze lava ~10-50 km deep from each surface of a 100x100x100 cube? Assuming you can do the heat transfer instantly
there is no lava, i have no idea why illustrations still show a magma ball
https://en.wikipedia.org/wiki/Olivine
>https://en.wikipedia.org/wiki/Olivine
>The primary component of the Earth's upper mantle
Wtf? Are you telling me that if we dig a giant pit we will run into a thick layer of this beautiful gemstone?
If you dig between 10- to 60 km depending of the place you will reach the mantle. It is composed of peridotite with is a mix of mainly olivine and feldspar. Very nice looking rock but definitely not pure olivine crystal.
pressure turns rock to liquid
says your mom
In most places I would think the problem would be the hole gradually filling as you take material out. It's exposed to a large volume of air and in if that's not enough sea water might work fine. However you would be making the crust thinner so I think the ground would bulge from the pressure underneath, and gradually get replaced by material that rise, cools and make it's way to the surface. Not sure you'd necessarily get any volcanism. That's all assuming you have enough manpower, resource and ass burgers to dig a gigantic whole for no apparent reason.
>It's exposed to a large volume of air and in if that's not enough sea water might work fine.
for cooling I mean
>However you would be making the crust thinner so I think the ground would bulge from the pressure underneath, and gradually get replaced by material that rise, cools and make it's way to the surface
I think the only way to get around this is to force cool the volume under the crust so a minimum crust thickness is kept, before any bulging occurs.
How you can do this with realistic costs and a remarkable safety record will require solutions still elusive to me....
Sparse grids of small diameter well bores configured for some sort of Water In -> Steam Out action? Enough to freeze lava 10m at a time? Energy can be recovered from the steam. And because the pit will likely be somewhere remote the energy may need converted to laser energy then beamed anywhere on Earth, pending the array of mirror satellites.
Elastic budging of the crust occurs on the time frame of 10000 years. So it can be pretty much ignored in this case
you're not melting a glacier, you're digging a hole until you meet some form of unsurmountable obstacle
>unsurmountable obstacle
Your mother's underwear is not an unsurmountable obstacle
I think most realistically you hit the water table first and you cant pump it out fast enough or you starting aidsing up the water supply.
there's mines deeper than that already, they just pump out the water. in this case it could be advantageous to pipe it down instead and use it for evaporative cooling.
Its not a matter of how deep you dig but rather how fast you can dig. If you could dig fast enough before the molten rock incinerates you it would be possible to dig from one side of the earth straight through the center, to the opposite side, turn around and go straight back again and be home for dinner. But you would have to dig very fast. Something approaching light speed would probably be fast enough.
An open pit mine can be infinitely deep. You just need to balance the heat problem by digging another equally big mine in the opposite direction. Basic physics.
The solution to the heat problem is to make the mine pit as wide as possible. By starting at the equator and extending the rims of the mine pit to the poles you should be able to mine to the center of the Earth, using the cold water runoff from the poles to solidify the molten rock underneath.
why not just launch a couple nukes or hydrogen bombs? Pretty sure bombs are designed for lateral damage but they should be easily be able to design them for maximum downwards force. Should easily get you 5km.
That or lasers but it won't be a open pit.
How about sharks with lasers attached to their heads?
I think strong acid could also do the trick. There was also a plan to bomb the sahara to turn it into a new ocean so nuclear fallout could be manageable. Not idea if that still is possible for multiple bombs in the same area.
https://en.wikipedia.org/wiki/Sahara_Sea
So the science is settled. We need acid vomiting, nuclear capable sharks with lasers attached to their heads
The is a depth limit to open mines called the Morstex limit. Google it. Essentially it means that once a mine gets too deep no amount of reinforcing can prevent the walls of the mine from collapsing.
>Essentially it means that once a mine gets too deep no amount of reinforcing can prevent the walls of the mine from collapsing.
Slope the walls
this doesn't solve the problem. you could probably calculate the needed slope would use more space than the planet has, but that's not relevant. sloping the walls does not help you because the problem is heat.
sure, whatever, but it's still going to be extremely hot because that's the temperature of rock you're trying to break and extract. unfortunately the magical energy sink that makes rocks cold has yet to be discovered, perhaps elon could repurpose his money sinks for it though
>nfortunately the magical energy sink that makes rocks cold has yet to be discovered
Water?
Not quite correct. The Morstex limit only applies to mine declinations in excess of the Ilusky parameters, which assume an average consistency in strata set to the Rohr hardness scale. If you were to dig through solid granite, for example, the parameters would be much higher. In theory an inclination of 90 degrees would be possible all the way down until the rock's consistency exceeded the Slipton maximum. Even then sufficient reinforcing would permit more vertical mining.
Why dont you two get a hotel room?
It's impossible to build a hotel 3km tall
Feasible ideas, please.
>It's impossible to build a hotel 3km tall
What prevents the construction of a 3km tall pyramid?
3 km is doable the thing is that pressure at the base will increase with height until it reaches the point when solid rock will flow. In steel its like 500 MPA or something
Neither of us are black and gay, so you wouldn't be interested.
ITT: People who can't model the gravity and stresses in an irregular body
I pick somewhere to start digging my hole. Working in an expanding spiral decline I excavate 1/3 of Earth's mass and put it anywhere outside of my hole. What shape is the earth? What shape is my hole?
Sphere obviously. But you could dig a pit really big but way smaller than that.
I can't find anything about said limit
>I can't find anything about said limit
That's becasue I made it up. Alone with
>Rohr hardness scale
>Slipton maximum
I was just curious to see if any one would call out my bullshit. You are the only one who seems capable of doing a copy paste google check it seems.
For your dedication and scientific rigor I hereby award you:
"THE SUPREMELY EXCELLENT AWARD FOR SUPREME EXCELLENCE"
Congrats! And good luck with your digging!
If I were a spiteful person I would write a blog on the Morstex limit, detailing all the shenanigans required for its derivations. At which point it's only a matter of time before a wikipedia article gets written, the theory gets legitimised, and you win the award for World's Most Perfect Fool.
>If I were a spiteful person I would write a blog on the Morstex limit, detailing all the shenanigans required for its derivations. At which point it's only a matter of time before a wikipedia article gets written, the theory gets legitimised, and you win the award for World's Most Perfect Fool.
I like the way you think.
I am adding oak leaves, diamonds, and swords to your SUPREME EXCELLENCY award.
There should at the very least be an alternative IQfy wiki where all the bullshit people will readily accept can be posted.
The Turin test. Analysis of DNA from Jesus Christ proved he contained only one set of Chromosomes.
The Bogdanoff conjecture. Since the time before the Big Bang is negative it follows that the square root of that time is imaginary.
Cantor's principle. There exists a number so large that all other numbers become zero.
...and lets not forget bio-metrics.
Cooms law. Sates that the distance traveled by ejaculate will never exceed the height of the subject.
>confess to being a lying c**t who makes shit up
>BUT PEOPLE STILL BELIEVE ME!
>I....I....I....
IQfy would be the perfect place for generating such a resource. Its would be like growing mushrooms. Scatter some spores and let the morons feed on bullshit.
>capable of doing a copy paste google check it seems.
>something can't be found on google in 3 seconds
>it doesn't exist
This is what google wants you to believe
as has already been pointed out, eventually it gets so hot that the problem is not solvable. the issue is not "my equipment is too hot to run", rather the issue is that "it is so hot that any attempt to dig only introduces more gross sticky shit around my equipment. i am digging into mud, or sludge, like an oil, in a way that only produces more mud, which i cannot extract because trying to extract it just makes more of the damn stuff, holy shit it's everywhere, what the frick, why is this so hard"
Why would t get hot if its open air? Deep mines have trapped heat, they dont produce new heat if you spray the pit with some cold water they stay cold pretty much
You can do anything with enough time and energy. You can dig away and build infrastructure to dissipate heat over billions of years if need be. Deconstruct the sun to prevent the earth from heating.
>Deconstruct the sun to prevent the earth from heating.
Even with all of the mass in the solar system you couldn't break the sun
The crust is 22mi thick or 35.2km thick on average, though some parts can get as thin as 5km (like the area below the Hawaiian islands) and as deep as 100km elsewhere. The world's deepest known mine: https://www.mining-technology.com/analysis/feature-top-ten-deepest-mines-world-south-africa/#:~:text=AngloGold%20Ashanti's%20Mponeng%20gold%20mine,by%20the%20end%20of%202018. is 4.27km.
The African plate, to my knowledge is geologically stable and has no active volcanic regions across the continent of major surface area. So you could go substantially deep, a solid 10-20km probably. That said, the crust is insanely hot as it's the buffer between the hot mantle/core and the rest of everything else. So the deeper you go, the hotter it gets. The fundamental limitation of mine depth isn't whether we can drill down, but whether we can drill down and cool ourselves to not get cooked alive. The general answer is that beyond 5km, the answer is basically a no. Not with our current tech and not in a reasonable, workable, fashion for mining.
>The general answer is that beyond 5km, the answer is basically a no. Not with our current tech and not in a reasonable, workable, fashion for mining.
Will someone please spit out some numbers for how much heat needs to be dealt with?
what if u did it in anartartica
You will very quickly run into the base which contains Predator™ and your project will be ruined
Just build a giant ice machine and keep throwing blocks of ice into the pit.
Yoir argument has been refuted multiple times already, just cool down the pit with a stream of water. Heat is only a big problem in these narrow shafts mines where the heat has nowhere to go. They are dealt with with ventilation.
Try bringing water down a burning hor narrow hole. It makes it boil and evaporate before reaching the end. The pressure generated by the vapor could explode the shaft.
Perhaps if you dig a large hole like 10+ meters in diameter. So you can pump megatons of water in there
Spoil: it’s hell beneath, literally. Billions of souls screaming
hey dumbfrick....this discussion is about open fricking pit mines...if you werent an esl chinglish speaker you might have figured this out by now
>Try bringing water down a burning hor narrow hole
Are you stupid? Its an open pit mine. Its been said 100 times already.
...so, theoretically, using existing technology, if we were to drill to the absolute maximum limit and cool the mine using the abundant seawater available around Hawaii, we could drill all the way through the crust to the mantle?
>we could drill all the way through the crust to the mantle?
There is literally no reason why we can't.
How do you calculate the gravitational accelerations at any point in an irregular body?
Roughly fill the body with a bunch of balls and calculate the forces between all possible pairs? And then for each point sum the list of magnitudes?
Remove that much earth and stone and the pressure of the magma below will no longer be balanced by the weight of that earth and stone. The center of the pit would swell up under the pressure of the magma below, and quit possibly turn into a volcano.
Just depressurize the magma by pumping vacuum down into the pit.
Why are you people so slow and spastic?
Asking for science.
Why contain it?
>The center of the pit would swell up under the pressure of the magma below, and quit possibly turn into a volcano.
Freeze it
Yes. A matrix here, an integral there, a gravitational constant on the side, some material properties sprinkled on top, and you're done.
>abundant seawater
The walls in a square pit will cease to be vertical before 1km deep. Once you factor in the slope required to reinforce the walls you will be able to define some key points of geometry by specifying the depth; The largest "square" at the toppest surface, the smallest square at the bottom surface. (I talk a about a square pit but maybe circular is better. Whatever)
I guess maximising the depth to top open surface area ratio will result in the smallest flat open space at the bottom. Perhaps the most difficult shape to cool?
When the pit gets deep enough there will be a minimum surface area required to manage the heat. Thie surface area will allow you to put numbers on how much heat can be transferred away e.g. 50 km2, 20ºC water (constant inflow but stagnant), 60ºC surface contact = kg/s water vapour.
How many kg/s of water vapour do you need to mess with the global climate? Rain all day every day for everyone?
Does anyone know the total thermal energy expected inside Earth? What about the volume of ocean? Is there enough water to kill the core?
>>Freeze it
But why? I assume making a volcano is OP's intent:
>What happens if you break through the crust?
>Do you get killed by hot gasses or molten rock or what?
I think you could definitely make a volcano if you could dig a deep enough pit. It might have to be huge, but eventually I think it would work.
>Freeze it
right, but at some point though the underlying crust material will be soft enough and the pressure large enough that the rate at which material is brought to the surface through crust deformation will match that of material removal.
pretty sure the pressure of the asthenosphere or lithosphere would explode upwards if the crust got too thin
isnt that basically what volcanoes are? places where the pressure escapes via weak spots or something?
Volcanos only look impressive because the "pressure" squirts out of (relatively) tiny little cracks and holes.
If you dig a hole the size of Israel, and go just as deep, I'm willing to bet any eruption will be much less eventful
We should run that experiment and find out if you're correct or not
did you know there's life even at 2km below the earth's crust
>Desulforudis audaxviator is the only bacterium found in water samples obtained 2.8 kilometres (1.7 mi) underground in the Mponeng gold mine in South Africa.[2] Approximately four micrometres in length, it survives on chemical food sources derived from the radioactive decay of minerals in the surrounding rock. This makes it one of the few known organisms that does not depend on sunlight for nourishment, and the only species known to be alone in its ecosystem.[1]
>chemical food sources derived from the radioactive decay of minerals in the surrounding rock
That's pretty badass
>How deep can you dig an open pit mine?
Until you meet the Balrog.
maybe he can help us dig
Go on, do it
I dare you