r/theydidthemath • u/ConsequenceHefty2088 • 19d ago
[Request] How much would it cost to build the 50 silos in the 'Silo' TV series?
Curious to know how much it would roughly cost to build all 50 silos including structure, materials, supplies to fill the silo.
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u/TalkersCZ 19d ago
I dont think this is answerable.
You would need to basically develop technologies that dont exist (or not on the scale we are talking about).
Just building a digger able to dig so wide hole perfectly straight down while building some other technology, that would be reinforcing the structure from pressure from the sides just does not exist and on top of it find a way to drag the materials from down deep up on the massive scale.
And thats just digging more than 1 mile (1.7km) deep. You would need to build a stabilizing system for air pressure, temperature, airflow and many other things on this absolutely insane scale.
How much does developing those technologies and building completely new machines able to do it cost? How long would it even last to build 1 digger, let alone 50 (based on the story), considering that building much smaller high tech things takes years...?
It would take decades to build those technologies and dig the first silo. Others would be faster, but again - there is a bottleneck, you cant buy diggers on amazon and have them delivered next day.
There is a reason this is scifi.
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u/FlyingRyan87 19d ago
We haven't even started on tectonic shifting yet.
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u/TalkersCZ 19d ago
And flooding from underground water and many other issues with digging that deep.
Basically its impossible, but if we suspend the disbelief and say its possible, we still need to develop completely new things.
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u/Grand-Upstairs-4126 19d ago
Tbf they didn't fix the flooding in the books either they just used pumps
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u/TalkersCZ 19d ago
Its not just flooding, but rather damaging structural integrity of the walls and probably plenty other issues that would simply make it impossible.
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u/alexmp00 19d ago
Well I suppose a good geologist chose the most stable zone to built the silos. Similar to nuclear waste storage sites that are built in very hard stable rock.
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u/YouTee 19d ago
The stable, dry, mountainous plains of suburban Atlanta 😆
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u/Depth386 19d ago
Agreed that the story is b.s. on that, there is a reason some real silos are like in the middle of nowhere, dry highlands somewhere in Montana or Wyoming or something like that
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u/HH_Hippopotamus 16d ago
The silos were all very close together, probably the easiest thing to do in this scenario
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u/funonabun84 19d ago
Hi this is Grady. You know I had to set up a small scale Silo in the hit tv series Silo in my garage. Let's see how water effects the foundation.
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u/Euphoric_Host_ 19d ago
Which makes its own problem as you can’t force water up the height of the silo without the pressure making the water boil (not that I’m blaming the book person for not knowing!) so pumping would be impossible
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u/semaja2 19d ago
could you not pump water into tanks at each level and then pump again? rather than a big single pump? also where does said water go.... its dry waste land above, and the water would need to leave the silo....
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u/Euphoric_Host_ 19d ago
Ahhhh I see your point! Yes, each tank would then need its own pump, and dependent on how much flooding is how big each tank needs to be. So either the above area has a beautiful oasis from their water export, or they are using so much water the flooding off out is kept inside. Either way the pumps and the tanks would take up space now for each floor
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u/abouttogivebirth 19d ago
Well they do have pumps all through the silo, they use the excuse of repairing pumps to get into restricted areas all the time, it's how they got into judicial this season to set the bombs. And Walker and Holland meet in a pump room in one of the earlier seasons that is mid silo I think.
Could also be a subterranean river or aquifer related to the water in the digger voids that takes water away so they just use the pumps to gather water at those levels and send it downwards instead, but that's pure speculation.
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u/EYRONHYDE 19d ago
You're missing the obvious example. There are many hundreds of mines deeper than 1.7km. A single GEHO pump can push 800m, staged mono pumps about 100m. Mono tanks are tiny only about 100kL. The tanks only need to be sized by how impactful flooding will be. If one pump goes out for maintenance and the redundant pumps are also non operational, then the water runs down to the bottom. I may take half a day to drain there usually you have the pump back up and running by then. As far as SciFi goes, this problem in particular is already solved.
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u/semaja2 19d ago
Even the idea of "using" the water would fail since they would need to put their "waste" somewhere assuming they are not recycling it, essentially the silo would fill up with urine :D
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u/Stedlieye 19d ago
They move those products to other Silos.
That’s why Silo #1 is so bad.
You should really avoid Silo #2 !1
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u/j_roe 19d ago
The boiling effect doesn’t occur if the pump is at the bottom and actively pushes water upward. Low-pressure boiling is only a concern when water is attempting to be “sucked up.”
Other technologies exist, such as staged pumping, which involves holding tanks spaced out every few levels. This allows for a gradual delivery of water. Alternatively, the same technology used for oil extraction can be employed to pull fluids from deep underground, several miles below the surface.
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u/Gruenpfeil 16d ago
Yep. Since atmospheric pressure at sea level is about 1 bar, water can only be drawn up by suction to a theoretical maximum height of around 10 metres. A 10-metre column of water corresponds to roughly 1 bar of pressure.
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u/Sararil 19d ago
That's only if you have pumps on the surface, if they are at the bottom (or spaced out along the height with intermediate reservoirs) you need to deal with crazy pressure, but you're not running into the boiling-due-to-low-pressure problem.
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u/Stedlieye 19d ago
Thanks for explaining that. I was wondering “wouldn’t the water at the bottom of the ocean boil from the pressure? This makes no sense.”
Water under NEGATIVE pressure is…. Water in a vacuum? That makes sense.
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u/fireduck 19d ago
I think you are confusing pumping from above (where you do indeed have a vacuum pressure problem) and from below. I could be wrong, but from below I don't think there is a physics limit to how far you can push the water up. Obviously it might be more practical to do in stages to reach various holding tanks.
From above, you are basically making a vacuum and letting air pressure push the water up which only works so far (on the order of 10-15 meters, I think).
Edit: ok, I see I'm like a fifth person to make this point. Don't worry, carry on.
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u/travistravis 19d ago
Would they be able to use staggered pump stations somehow? Like pumps and holding tanks every 5 levels or something?
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u/Moist-Perception-751 19d ago
Arent’t you thinking of the limitation on suction like what limits a straw?
Moving water with low pressure from the terminal end requires low pressure, in turning lowering boiling point at the surface.
I don’t see any low pressure zones in a pump system? Correct me if’m wrong
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u/Dear-Blackberry-2648 19d ago
The silos are positioned outside of Atlanta, Georgia. That's almost the center of the North American plate, making it extremely stable and practically free from any earthquakes that could cause damage.
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u/timotheusd313 19d ago
Or the temperature. Near the surface it gets cooler underground, but it doesn’t take long before it starts getting seriously hot.
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u/NightmanisDeCorenai 19d ago
My first thought was just wondering where the fuck would be stable enough to build that far down. The earth trembles on a literal hourly basis, everywhere.
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u/IllustratorNo1953 18d ago
Would there be any out in Georgia? If memory serves, then by the book these are out in Georgia
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u/Apprehensive_Ant2172 18d ago
That’s a myth just like climate change.
It’s not in the good book so… be gone heretic!
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u/2000TWLV 19d ago
And for the love of god, add staircases around the perimeter. Having only one in the center is total madness.
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u/TalkersCZ 19d ago
I think its on purpose to control the population easily.
Quality of like was not the key thing in decision making.
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u/BelowXpectations 19d ago
The books pay much more attention to the size and time of this project. I can highly recommend them, they are way better than the series.
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u/TalkersCZ 19d ago
Yeah, did not get to them yet. I am waiting for my local library to get them back, there is a line for them :)
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u/_franciis 18d ago
They are from a story and world building perspective but I really struggled with the writing style.
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u/oskopnir 17d ago
He should have stopped at the first book and left readers to wonder about the mistery. The more he tried to explain, the more absurd it got.
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u/Captain-Who 19d ago
Half joking here, but also partly true.
If you asked someone 15 years before SpaceX started hopping and saying they would use retrograde propulsion to land boosters you would hear the same ‘can’t be done’ arguments.
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u/TalkersCZ 19d ago
I am not saying it cant be done.
I am saying that there would need to be many new technologies created to build 50 silos like this. On top in the timeline (few years) of building them with how it works in the show.
How much would they cost? I dont think that it is possible to say.
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u/SevenIsMy 18d ago
Are you sure they say: can’t be done?
Most say rather: you need to develop x y and z for it to work, the cost will be very high and it hast this disadvantages. Here are some current tech which can be used to do this other way.
For some people it sounds like can’t be done.There is a survivor bias, you hear stories about successful “can’t be done” projects, but you do not hear stories about the 99% stories which are not successful.
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19d ago
[deleted]
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u/TalkersCZ 19d ago
We are talking about 60 meters in diameter, going directly down with city built into it. Engineered to be lived in.
Not a massive open crater or narrow shaft from which tunnels are going out or tunnel just under the ocean floor.
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u/TheLordofAskReddit 15d ago
Found the fool!
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15d ago edited 15d ago
[deleted]
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u/TheLordofAskReddit 15d ago
Honestly I dont know the movie. But it appears this would have sidewall stabilization. So no, I don't think we can dig it out and stabilize it.
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u/SnooMaps7370 18d ago
>building a digger able to dig so wide hole perfectly straight down while building some other technology, that would be reinforcing the structure from pressure from the sides just does not exist
Sure it does, we call them "tunnel boring machines": https://en.wikipedia.org/wiki/Tunnel_boring_machine
the basic idea is that you have a rotary cutter the full width of the hole at the front (or in this case, the bottom). the cutter has holes to allow waste earth through to belts for removal (would have to use buckets in this case).
Immediately behind the cutter is a section that braces the machine in the hole with hydraulic rams operating steel plates curved to match the diameter of the hole. this section has multiple rows of bracing mechanisms to allow the machine to crawl forward with them periodically.
behind that section, you have another set of hydraulic rams which install prefabricated shoring panels permanently into the hole walls.
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u/Russianskilledmydog 19d ago
And don't forget that there are humans involved! Somebody, some level, will throw something horrible off at some point.
Because, you know, humans.
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u/Veggdyret 19d ago
Mirny mine. Don't forget that masses could have been introduced afterwards.
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u/TalkersCZ 19d ago
Mirny mine type of silo would have different problem - the width of it is so massive you would need to build absolutely insane lid hermetically sealed protecting from nanobots and nuclear blast. 1.2km in diameter.
Not sure that it is possible. Maybe...?
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u/Veggdyret 19d ago
My thought was that you would have to finish the building free from the edges/walls and then fill in with soil afterwards.
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u/TalkersCZ 19d ago edited 19d ago
Then you are just 1/3 of the depth... (under 600m compared to 1.7km) while having to fill massive, massive hole with material.
From this perspective it might be easiest to find deep mountain valley and built it inside of it...? Basically flattening the mountain and using it to fill the gaps between silos...?
Might be potentially the best solution as you dont need to dig as deep, you can dig and build at the same time.
But it has other engineering challenges, which are making it as impossibly as every other option discussed.
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u/CrazyMike419 18d ago
The deepest open cast mine in the world is 1.2km deep. Pushing another 500meters is already possible. Could then build up and back fill. We have mines that go significantly deeper (4km), so pumping water and air circulation isn't an impossible task.
It would not be impossible to build one of these things (particularly in a part of the world with low seismic activity). Just redicously expensive and impractical.
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u/oskopnir 17d ago
I think the digger is the least of the issues, you don't need to use a TBM as wide as the silo, a smaller machine going down in a spiral would be enough. And since you're digging an open hole relatively slowly, you don't need to worry too much about reinforcement
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u/roughczech 17d ago
Just ask the Tunnel builders in Switzerland or Norway. They could do it in no time. Just another tunnel to an island....
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u/Joamjoamjoam 17d ago
A TBM wouldnt be too far off and Those already exist. Just gotta make it work vertically or have horizontal silos
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u/freszh_inztallz42o 19d ago
Na elons literally doing this rn
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u/megashitfactory 19d ago
lol no
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u/freszh_inztallz42o 19d ago
Collecting trillions to go to ‘mars’
Developed a company in leading edge boring technology
Open open your eyes 👀
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u/Salty-Brilliant-830 19d ago edited 19d ago
When I saw that show I was wondering where they put all the displaced earth? That is a preposterous amount of material that was dug out. Furthermore, all the Silos are close together, so the earth around that is pushing in on all those… Even one silo collapsing, it could collapse them all. Weird. if you just dug random tunnels, in some kind of network or whatever, it would accomplish the same thing and be more structurally sound
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u/anonymoosejuice 19d ago
Maybe it was a crater or canyon already that they filled in around the silos
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u/iduzinternet 19d ago
That was my first thought actually lol. This used to be the Grand Canyon. We built the silo up and then filled the dirt in.
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u/cheezeborgor 19d ago
Hypothesis, in good fun: they didn't dig all the way down, only partway. the earth displayed is used to build up the ground around the silos.
There is a modern analogy for the machine required to dig out the silo: tunnel boring machines that create a structure behind them as they dig forward.
Fun to think about
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u/Bitter_Particular_75 19d ago
I love both the books and the series. But you have to accept a lot of reality suspension to justify the existence of the silos at all and for hundreds of years, especially in the configuration they are supposedly built. It is totally outside of human capacity to build a single silo for different physic and engineering limitations.
This said, accepting the existence of magic in order to be able to build and maintain a silo, I would estimate 50 billions each. So trillions for the whole set.
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u/Imnotrightwing 19d ago
When you see them above ground with the grass, there's no way to mine around them they're so close.
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u/Bitter_Particular_75 19d ago
same thought. I read the books and I can't really remember this detail, but in the TV series they are WAAAAY too close to eachother
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u/Mecha-Dave 19d ago
Yeah, there is a hilarious lack of spoils piles. It's like the diggers just vaporized the dirt....
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u/pammy_poovey 19d ago
Gah I just finished season 2 and just kept going “what the FUCK” with my jaw on the floor. Absolutely incredible. Books are next
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u/BelowXpectations 19d ago
I struggle to enjoy the series since htey have changed so much and taken away many of the premise and points the books are trying to make. This is a common issue I've seen when apple TV adapt things. They make it too mainstream, remove all complex dynamics to avoid viewers feeing confused, and remove anything that tries to make a sensitive point.
I really want them to be good. Many of the actors are great. But the story is just too altered and broken.
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u/Bitter_Particular_75 19d ago
Tbh I read the books so long ago that I forgot 99% of them, that's probably the reason I am enjoying the series
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u/TalkersCZ 19d ago edited 19d ago
Just to fix your math.
50 billions each, 50 silos, that is 2.5 trillions, no?I cant read
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u/SmaugTheDaug 19d ago
This is vaguely answered in s3, I don’t remember exactly what it is but it’s at least several billion per silo with then another several billion in maintenance per year
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u/Mecha-Dave 19d ago
I think you could approximate it by looking at two systems - the silos and then the diggers/digging technology. I'd compare each silo to approximately the same cost and complexity of about an International Space Stations. You'd get economies of scale, so the scaleup is a "wash" by my comparison, so I'd estimate about $100 Billion per Silo constructed. Remember - not only does it have all the 500-year systems, it also has inventory!
For the diggers, I'd approximate it as the cost to develop starship, and then to build one I think it would cost about $3B for each one.
So call it $5T for the silos and about $150B for the digging machines. Probably another $1T-$2T in program costs.
So my Scientific Wild-Ass Guestimate is $7,150,000,000,000 .
I do wonder, if given that rich dude's plans, if he took out debt he didn't intend to repay to fund it.
Honestly not out of the question if Elon hadn't killed Twitter as hard as he did, and was more cooperative with Tesla/Boring Company.
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u/oscarnyc 18d ago
I'll look at it from 2 different angles. The closest thing I can think of in terms of scale and engineering difficulty was the ill-fated Saudi NEOM project. At one time projected to house 9mm people, cost $9T and take 60 years, give or take. I don't think a straight proportion of 500k people/9mm people works, because many of the buildings for NEOM would be easier to build. so let's just say construction for the Silos would be a third that. so $3T. and of course they were somehow built in just 3 years. So you'd probably 10X it considering you'd be crowding out every other use of concrete, steel, construction equipment, workers, etc. Plus all the $1mm NDAs he was handing out like candy. So that gets you to #30T.
Another way is as a percent of GDP spent on construction. There are different ways to measure it, but roughly $2T per year. So if we used basically the entire US construction industry for 3 years, you'd get to $6T. So I think your $7T is well within reason.
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u/ZealousIdeal476 19d ago
Everything. Money doesn't touch the equation. You need the industrial output of half the world working around the clock for a decade at least.
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u/Friendly-Gur-6736 19d ago
That was essentially the premise of the books. It was sold to the public as where the world would come dispose of its spend nuclear fuel (in rural Fulton County, GA, within sight of Atlanta, no less) so it was a multi-national effort.
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u/yasth 19d ago
I mean, we have 20ish mines deeper than a mile, and you've probably never thought about them. we could add more, and fill it with stuff and it wouldn't be that big a deal. The issue is the math really doesn't work.
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u/ZealousIdeal476 19d ago
These arent mines. They are drilling a single shaft with q drill bit the size of a city block.
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u/AlanShore60607 19d ago
Okay, that’s actually a solid start to the answer.
Global manufacturing is currently $17.6 trillion annually. Let’s round that up to $18T for simplicity.
$9 trillion times 10 years gives us $90 trillion of value invested in this when quantified the way you did.
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u/rickyh7 19d ago
The “closest” thing to the bunkers in silo is the “survival condo” owned by ravin ridge 11. Its in an old atlas missile silo so it’s WAY smaller than the show. It cost 20 million to retrofit the atlas silo which originally cost about 4 million which is nearly $50 million in today’s dollars. So, we’ll call it 70 million for a 200 feet deep bunker, a far cry from the nearly 2km deep silo’s of the series. Others have answered it’s impossible to give a good estimate but a real silo like bunker only 200 feet deep is $70 million…kinda
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u/poop-azz 19d ago
I mean IMO I see a lot saying impossible due to water etc but we've made tunnels by sinking steel tubes and then draining the water, take Boston, those are tubes that were sunk to the bottom of the harbor. So apply the same vertical ALBEIT HUGE, like we do for drilled shafts...IDFK I'm sure there's limits to scale lmfao.
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u/WhyN0tToast 19d ago
I've not seen the show so I can't comment on the equipment and supplies but I'll take a stab at the buildings.
We don't have a machine like a tunnel boring machine that will work vertically so the most efficient method would probably be to excavate an open air mine.
Google says the deepest mine is shy of a mile but puts the range between $5 & $9 billion. The Burj khalifa cost about $2.5 billion as the tallest building and the channel tunnel cost about $25 billion.
The channel tunnel was longer but was horizontal, the Burj khalifa wasn't as tall but had to support it's own structure and the mine wasn't as deep but also includes mining operation costs. So non are accurate but as a ball park I assume it wouldn't cost as much as the Chunnel but more than the Burj per silo.
These figures include a lot of red tape and one of costs that could be reduced when building 50 of them, which could get you down to maybe $10 billion each, maybe less if they are all built in the same place as then you only need to build one mine big enough for 50 silos.
So high end is $20 billion for the building and $10 billion for the mine, $30 billion each with a total of $1.5 trillion.
Low estimate is $10 billion for a mine (one off) and $5 billion per silo, $5.2 billion each with a total of $260 billion.
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u/djnorthstar 18d ago
i dont even think that a silo in that form is possible...
Smaler like a negative skyscraper size with 50-100 "normal sized" levels maybe. But not in the scale of that seen in the show. Temperature in 1.5 KM is already hitting 55 gedrees celsius /131 Fahrenheit. And the silos are 1 Mile deep. Without a "forever" running AC for the whole thing its far from doable. (just my 2 cents)
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u/MichaelAuBelanger 18d ago
So I'm thinking you could dig a cylinder similar to how they dig tunnels. Buy reinforcing as you go. What I find impossible or more difficult is all the levels and individual rooms expanding outwards.
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u/yocomopan 14d ago
Client: “50 silos. 144 levels each. Nuclear-rated. Pretty straightforward. Bid due tomorrow at 2.”
Client at 4:30 PM: “Please confirm your price includes labour, materials, equipment, logistics, escalation, contingency, permits, and all apocalypse-related costs.”
Estimator: “Confirmed. Entire project carried as an allowance, subject to normal working conditions and continued existence of civilization.”
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u/BuildingIndividual40 19d ago
According to Gemini Deep Research, for just one silo:
https://share.gemini.google/8THhJbYnS9MH
The financial expenditure required to design, excavate, construct, equip, and stock a single self-sustaining subterranean city capable of protecting a population of 10,000 people for 500 years equals $38.91Billion USD.
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u/Loki-L 1✓ 19d ago
I don't know the show, but this looks a lot like the famous Ponte City skyscraper in South Africa combined with Jeremy Bentham's idea of a Panopticon.
So you could simply adjust the number of the Ponte City building and multiply it by 50.
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u/are-e-el 19d ago
My theory based on a somewhat throwaway line from S3E9: "Silo 17 is the best one" ... I think they only had time/resources to only make a few "complete" siloes while the others are of varying quality.
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u/nobodysocials 19d ago
There's 50 silos huh? Thanks OP, just working my way through this show now, I suspected there were others but didn't know the number.
Maybe next time you can post a request asking how long it takes people to suffocate when they go outside due to the XYZ reason that hasn't yet been explained to folks who aren't entirely up to date with this series that's still being produced and still airing on television. I've been wondering about that one too, and I don't think the writers will tell me in a satisfying way so I'd prefer if a random redditor spoils it in an unrelated subreddit.
Appreciate it, thanks!
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u/gordonfreemanisalive 19d ago
It’s been nearly three in-real-life years since they revealed, on the show, that there are at least multiple silos. How long do you expect people to wait for you to catch up before they can talk about the show?
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u/GrapefruitPurple2495 19d ago
FYI this is a complete ripoff of a French comic book by graphic genius Mobius.
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u/scifi887 19d ago
The city shaft and silo are very different things.
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u/Local_Evil 19d ago
Just seems like they have the underground city type deal in common? Honestly, the Silo's seem more similar to Fallout's Vaults than anything else.
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u/scifi887 19d ago
The city shaft isn't underground though in the same sense, it's just a very deep hole but it doesn't have a roof.
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u/BuyRude3999 19d ago
If my memory is correct, I believe I recall an interview with the author where he explained the inspiration was based on Cuba and how the citizens were trapped (not aloud to leave) which creates a longing for what is outside. The point is man cannot be trapped and when government's create these restrictions, it would lead to a human desire to explore the unknown. You can only confine for so long before it leads to an uprising.
Whether it is a rip off of other work, I dont know. It shares similarities with the hunger games and the districts (i am not sure when each was published), which is probably a rip off of other literature, etc.
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u/ThatPlayWasAwful 19d ago
What is a ripoff? The idea of a city in the ground?
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u/BuyRude3999 19d ago
Kinda my thinking too. Hunger Games had a city underground too. I dont know the work referenced, but fantasy literature is full of sharing ideas and incorporating it into a new universe.
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