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Background

The known world consists of dozens of continents floating in an airy void. These continents range from small islands a few square kilometers in size, to great land masses up to 1,000 square kilometers and more.

In these regions, there is a human society, strongly divided into castes. The proprietors, sorcerers, and merchants all live together in each continent, but rarely intermingle. Mining is a strictly a job for the merchants; the other classes wouldn't touch it. Most of the surface land on each continent belongs to the proprietor's class, so the merchants have limited options for mining.

But the underside of these continents is unclaimed. A detailed in popular imagination, the underside is simply and exposed rocky surface, with all sorts of minerals visible to those who care to look. How can the merchants mine and transport minerals available on the underside of the floating continents?

Restrictions

  • The continents float by an unknown mechanism. Gravity otherwise works as expected; if you fall off you don't come back.
  • The continents are roughly hemi-spherical. A continent 10 km wide would be 5 km deep.
  • The continents all float at the same 'level.' Ships can float at the same level as well to trade between continents, but they can't go down to the underside of the continents.
  • There exists magic, but it is the province of the sorcerer caste, and is not available to the merchants.
  • There are various flying beasts, drakes in particular, that could be of use, but they belong to the proprietor's class, and are similarly not available.
  • Most surface land belongs to the proprietors, so the goal is to start mining from the sides or bottom.
  • There is no chance the sorcerers or proprietors would assist in a business venture with the merchants.
  • Comments are not for extended discussion; this conversation has been moved to chat. – L.Dutch Sep 18 at 18:47
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    Does an overloaded ship float lower, or suddenly fall? – Anton Sherwood Sep 19 at 6:05

10 Answers 10

up vote 33 down vote accepted

Diving Mining bells suspended from ships

Your merchants have access to ships, and probably more so than the other castes. The ships themselves may not be able to go under the floating level, but as the continents themselves show, they should be able to carry quite a load suspended underneath.

A mining operation starts with one ship floating near the edge. It lowers the mining bell, a large cage with enough room for several miners, holding tanks for ore and equipment racks. The mining bell has one side with sliding doors, wheels (aligned vertically) and a ballista loaded with harpoons.

The bell is lowered by a long chain until it's roughly at a level with promising deposits. The crew then fires the ballista repeatedly until at least three harpoons lodge themselves in the vertical rock face. The chains are then reeled into until the bell itself is lodged against the rock. (My extremely basic MS Paint skills make it look like this:)

Mining at Worlds Edge

The sliding doors are opened, proper hooks are secured in the rock and the digging commences. When the easy to reach deposits are gone, hooks are secured lower and the bell rolls down the rock face using its wheels, always anchored to several hooks. Should the fastening fail, the mining bell will still hang from the ship's chain.

More advanced mining

If you want operations to be more advanced, the next logical step would be to construct a base station (actually top station) at a level reachable from the ships, before the curvature of the continent becomes too pronounced. This station would be inside the rock with a large wooden receiving platform where crews and supplies are lowered and ore plus offduty crew sent back up.

From there, vertical elevator rails will be built down along the rock face, because digging in and then down is too expensive and boring. When the overhang becomes too much for the rails to carry loaded carts without tearing free, the digging goes inwards or branches off to the sides.

Alternate scenario

If the floating force is much stronger than gravity, an alternate option is for mining to start with the bells as above, but then the crew anchors a second chain directly to a large block, gets to a safe distance and detonates explosives around the block. Hopefully, the block will swing free and can then be hoisted up to floating level, at which point miners can more safely extract the ores.

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    Always +1 for MS paint! Great ideas. – kingledion Sep 17 at 19:50

Physically hold your miners over the side. Send them down on ropes, or set up scaffolds and other works that anchor into the rockface beside/above them. This would be a complex undertaking, but compared to construction scaffolding, or the elaborate works that were used for mining in the real world, they're not out of scope with what you can do with basic tools and a lot of motivation.

It should go without saying that this will be dangerous work. The slightest mistake and you could be swept from the scaffold to certain doom, or a whole platform could collapse and kill entire work crews. Again, though, mining was (and is!) a dangerous proposition in the real world, and yet it got done. Largely this was through slaves, or whoever was at the bottom of the local labor market - people who had few if any safer alternatives to pursue.

The other problem is how you get the spoils. You'll need to arrange your platforms rather cleverly to make sure that what you're mining doesn't just fall off the continent, and that you can drag it back topside when you're done. On the other hand, you can simply drop your overburden (underburden?) into the abyss after tunneling, something I'm sure real miners would love to be able to do.

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    Dropping useless rock off the floating continents might anger any intelligent beings who live below, causing them to retaliate. – M. A. Golding Sep 17 at 13:56
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    @M.A.Golding I wouldn't want to be those beings below. It's a lot easier to drop hundreds of tonnes of rock down onto someone than it is to throw it up at someone. Also, depending on what mechanism is holding your floating continent aloft, dropping useless rock off the bottom might cause it to slowly ascend as its overall mass decreases... – anaximander Sep 17 at 14:25
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    @anaxamander The beings below wouldn't necessarily retaliate by throwing the rocks back up. This is a setting where at least some of the technology possible in our world is possible, including maybe the technology o f 3018 AD, and a lot of magic (floating islands) is also possible. Thus hypothetical below beings might use death rays or destruction spells or something else to retaliate. – M. A. Golding Sep 18 at 17:34

How can the merchants mine and transport minerals available on the underside of the floating continents?

  • Dig tunnels
  • Harvest minerals from within the tunnels

Once the underside has been reached

  • secure miners with ropes
  • send miners to build a network of anchor points on the underside
  • have miners harvest minerals from underside using said network of anchor points and carry them on the upperside using the available tunnels and facilities.

NOTE: secure miners with rope before reaching the underside. Else they will fall down as soon as the passage is open.

If the proprietors are so insensible to the scent of money to not allow digging tunnels from their land, you can reach the borders of the continent and from there secure wooden/metallic frames descending along the side. At any convenient level you can then start digging inwards.

At the very beginning it will look like this:

mountain side hiking trail

As bonus point, you don't have to worry about carrying valueless material up: just throw it down.

  • So I tried to specify in the question that most of the land on the top belongs to the proprietors, and thus the goal is to start from the bottom. I'll try to make this more clear. – kingledion Sep 17 at 12:18
  • @kingledion, edited to cover that, too (I hope) – L.Dutch Sep 17 at 12:28
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    Dropping useless rock off the floating continents might anger any intelligent beings who live below, causing them to retaliate. – M. A. Golding Sep 17 at 13:55
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    @M.A.Golding: Then you still have the high ground... – arc_lupus Sep 17 at 17:44
  • @M.A.Golding: In the world described by the OP, it is not clear whether any such intelligent beings are known or suspected to exist. If there is not clear and unambiguous evidence of them, they would likely be ignored in favor of profit. – Kevin Sep 17 at 22:35

Submarines

Ok so I would say use submarines. If you have ships that float and humans that fall there must be some point at which ships sinks. If you load enough humans on a ship it will go down. Now lets replace humans with sand (no particular reason but it's slightly more humane when you want to go back up...) And get ship to sink slowly. There are to options what will happen then. First one ship stops sinking after it reaches some depth. Second it will just sink indefinitely. while first one is better for us we can live with second one easily. What you now need is some way to power the ships. I think merchants should be pretty good at this but if they have any problems just use some sort of railing system (the boats are almost weightless so that should be easy enough). You will need some sort of platform for your miners and it has to be on top that should be ok se long as railing system support these big mining ships. and you can use light fast ships to create attachments for "rails". You have to balance the weight of the ship as you mine but that seems like part of the fun. If you drop too much contraweight your miners are 2D now if too little they end up in abyss.

  • note that OP stated: "Ships can float at the same level as well to trade between continents, but they can't go down to the underside of the continents" – L.Dutch Sep 17 at 15:11
  • I kind of hope they are not unsinkable if so we can use some sort of revers cranes as weight doesn't matter but but it really sinks this idea... – Teddy Sep 17 at 15:16
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    I suppose a 'submarine' could be suspended below a ship that floats on the plane of the continents. – kingledion Sep 17 at 17:00
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    @kingledion If it is impossible to "sink" a ship, how does anything ever cross the floating plane at all? Wouldn't whatever is suspended just float as well? If not, and you can force it past the barrier then you could force a submarine as well. – Jason_c_o Sep 18 at 6:20
  • @kingledion What if you extended a ballast load up from the deck of your ship to raise the center of gravity? Would that cause the ship to sink as it lined up again with the mysterious buoyancy force? – thepizzaelemental Sep 18 at 18:02

Harnesses.

Mining Harness

Think something similar to rock climbing, but in reverse. You hang tools, netting, and drilling items over the side connected to ropes and cables, and from there use a series of hanging excavation buckets to raise it up to the top, where it can be refined further into useful metals.

Bucket chains

Depending on the type of mining (marble mining for example is in large chunks or slabs usually, whereas the process is different for materials like coal or precious metals or salt, etc.), the lifting process might be a bit different but the mining process itself should be the same.

enter image description here

For really big islands it could be a problem, but for smaller ones...

Have something like four or six ships connected by a veeeeery big net/network of flexible bridges. They go around the island with the net very low under the island and then pull it up so that it goes against the cliffs. Have people work on these nets/platforms and when the work is done, just lower it again and go away.

You may still need to have people to climb the cliff with ropes and scaffoldings, but at list you won't have trouble getting the ore back.

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  • did you think about how much force this would aplly to the ships? – Jannis Sep 18 at 12:49
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    The author didn't explain what cause the floating (if there's a weight limit or not), what is the state of their technology nor the materials they have access to. I let to his discretion to determine if my idea is feasible. Maybe with bigger platforms instead of ships, maybe with hundreds of ships, maybe a net made of spider web... He's the one world building ! – Echox Sep 18 at 15:40

Keep in mind that one of the main issues with mining in pre-modern times was getting rid of the water - that's what limited the depth you could reasonably mine into. If you can't drain the water, mines will quickly flood and prevent further mining.

In your scenario, this limit wouldn't exist - you could relatively easily keep drainage tunnels to the sides of the floating islands, allowing you to dig pretty much wherever you want, as long as you started on the sides or the bottom.

So suspend a bunch of miners from a ship and have them mine out an initial tunnel. After that, all you need to do is dig up at a certain angle to keep the water draining. You don't need to remove topsoil, you don't need to bother with getting permits from the top-side land owners etc. As long as you don't endanger the structural stability of the island or its water stores, you pretty much eliminated most of the technical difficulties medieval miners had. And if you do endanger those... sounds like a pretty cool start of a disaster story :)

the question fails to address hydro static equilibrium. the density of the air beneath the continent must be greater than the continent itself, it were to float using buoyancy force... which it doesnt... the problem with ignoring hydro static equilibrium is present in allowing ships to sail from one continent to another (which implies a sharp density gradient). therein are two things implying hydro static equilibrium.

any answer will have to address the immense pressure that would be present beneath the continent. (gravity otherwise works as it should). any miner would need pressure protection and significant 'dive' weights, as each miner would be very buoyant.

In addition to all the practical suggestions about the mechanics of mining, you might like to consider the socioeconomic aspects. How did your landowners get to be landowners? Probably by having a bigger army than their predecessor. If so then as soon as mining becomes profitable some landowner is going to go to the miners and make them an offer they can't refuse.

Nice Question and inspiring answers: i want to thank everyone that has continued the ideas of this special 'climbmining'. But its more or less not practiceable:
Netting the whole island is even more impossible: the longest rope is about 3.4 km long and made by specialists. it weights 320 tons and could only serve for small islands. It's using way too much resources to make such ropes than the whole mining busines would make. so netting the whole island is not makeable without magic ...
You could whyever mine at the outside of the island, but why there? The islands are soo big, that most mines wouldn't even reach completely down.
Even at only 1 squaremile you have half a mile room for mining, that's so much that normal mid-age mines wouldn't come there
if your miners are super agressive or want to have a dig down record they can use ropes inside the mines.
If you want to have miners in your story digging the outside of the island, because there is a special mineral, then they would use climbmining by making nets of ropes and anchoring points. simple and easy, nothing too complicated
I'm sorry for sounding arrogant, but mining outside of the island is in the way i think just ineffective and insecure, than mining inside and watching the height.
You also said the surface is claimed for other classes. so mines arent buildable there? No problem: climb a bit down and then dig in.
I hope it helps

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    Before calling something stupid, maybe you should understand that creating a world is about building something interesting and that, if you have an interesting concept, you can bend any rules you want to make it work. As an example, if I find your idea of a normal mining tunnel incredibly boring, I'd just say that the ore is only on the surface of the islands and that mining farther than a few meters deep is either useless (just rocks), dangerous (the floating stuff is there, removing it will sink the island) or impossible (the core of the island is too hard). And now you need scaffoldings! – Echox Sep 18 at 15:53
  • You shouldn't need a cable that can hang free for multiple kilometres: use a chain and staple it to the rock at short intervals. – Anton Sherwood Sep 19 at 6:15
  • @Echox i'm sorry for calling it stupid, i know normal mining can be boring. but it is normally the most efficent way. That's why rare ores or minerals sholud grow/be on the outer side, that make it profitable to mine the outer side. Maybe the outer side has may little ores with an own magical field similar to magnet force, which are pushing the islang up to float. ... I'm really sorry for saying stupid things like stupid, it's a not appropriate way saying 'Physics should be considert'. Have a nice day – Jannis Sep 19 at 7:45
  • @AntonSherwood If you want to have a net under the whole island, you need since it's normally way too hard to climb in 90°, while gravity is forcing you away from the stone. But it could be a Job for a special magical race or animal to make this net for the miners. Have a nice day – Jannis Sep 19 at 7:48

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