Assuming we're on Earth (or something geologically and biologically comparable). Humans are at best in the middle ages, and there's no "magic" or advanced science.

Now the difference is, there is also a "Dwarf" species (presumably just some "Humans" that split off from the main branch a few thousand years ago). They don't like living on the surface, for whatever reason (could be as simple as "religion", for example). So they live underground, but presumably have shafts to the surface at regular distances (for fresh air, commerce with Humans, ...) Dwarves have a similar technological level to Humans, but are more advanced in dwarven skills like mining and forging...

So the question is: since Dwarves need to mine to "open up space" to allow their population to expand (and to gain resources, obviously), how do they get rid of all that stone? They would have so much of the stuff that it's basically a waste product. They have many options; they could drop it into "sinkholes" (if they happen to find one), or drag it to the surface and just dump it there, or use it to do commerce with the Humans, or build fortifications and infrastructure on the surface...

Which of those options would they favor best (and why), from a traditional fantasy dwarvish point-of-view? It should ideally take into consideration Dwarve's "values", and their strong technical and logistics abilities.

For example, Dwarves are traditionally "xenophobic"; they might deal with a few select Human traders that come to them, but they would probably not drive around in carts, selling their ware directly in the Human markets. OTOH, they probably would accept (large) orders from the local Human nobility, as refusing could make their life more difficult.

  • $\begingroup$ Comments are not for extended discussion; this conversation has been moved to chat. $\endgroup$
    – user
    Commented Nov 8, 2017 at 8:19

13 Answers 13


There are several obvious options, and I think three of them follow a roughly chronological progression.

  1. Dumping: The earliest option available. Rubbish heaps are the obvious choice for what to do with waste stone. In the absence of local buyers interested in the stuff, it's unlikely to go anywhere, so will just end up littering the lands around a Dwarf mine. This I would hold to be the most likely option, as every Dwarf mine is going to engage in dumping. Those smart Dwarf kings who catch enough Men pilfering their waste heaps will come up with a novel solution...

  2. Trade: Dwarves need to eat, and since they are descended from Humans, can't eat stone. Farming in the mines is next to impossible, as is hunting. If all the Dwarves like to live and work in the mine, then they'll increasingly need to trade for food. Trading stone --- whether gravel, rough hewn or dressed and perhaps artistically carved --- for food is a no brainer. Dwarves will also control the monopoly on coal, ores, precious gems and precious metals. Those commodities too can be traded for needful things. This could lead to Dwarves breaking into new underground opportunities...

  3. Banking: Not all stones are granite. Why just trade lumps of stone for lumps of meat? When you control the source of wealth, you can literally control the fate, direction and policy of every nation around you! The smart Dwarf kings now will enter the financial realms. Given that your Human realms are living in Medieval Times, on the very cusp of the Renaissance, money will become a key driver of national policy again. Armies need to be raised, equipped and paid. Provender needs to be bought. And who better to provide the financing and perhaps even the arms you will need, o noble king of Men! Did not the Dwarves cut the stones for your fortresses and castles and cities? They will certainly stand ready to forge weapons, forward ready cash! (And if they're at all savvy, they'll be doing it for both sides of the conflict --- after all, wasn't it Underking Andvari who quipped war is good for business, very good indeed; and business is booming lads!

  4. Sinkholes: Basically, dumping the extra stone into a huge, insatiable pit. Such places do exist, but not everywhere. Best known places are Siberia and Florida. There are others. I certainly wouldn't want to be a Dwarf living in a mine anywhere near a sinkhole as the geological instability of the neighborhood might lead to the collapse of the mine itself. This option is fine if you have a handy sinkhole nearby. Ultimately they'd just be wasting a resource that could be put to better use.

  • 6
    $\begingroup$ Another option (probably between 'Dumping' and 'Trade') - Crafting: as there's a lot of available stone but wood is scarce, it makes sense to create furniture, tools, structures and art from stone. It's logical and fitting thematically that most dwarven structures and crafted objects will be made from stone or a combination of stone and metal. $\endgroup$
    – G0BLiN
    Commented Nov 5, 2017 at 16:45
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    $\begingroup$ Apparently, it's "bad practice" to accept answers early, as was commented by @Gryphon. So I'll uncheck your answer as accepted for now, because of that. Sorry. $\endgroup$ Commented Nov 5, 2017 at 18:43
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    $\begingroup$ Spencer: yes #4 is a variant of #1, though different in that the waste stone irretrievably disappears. With the slag heap, the rocks are still there if they want to do something later. Why not building? Because per the OP the Dwarves live under ground. Whatever kinds of dwellings they make, they're carved out of the stone of the mountain. No need for "building" as such. $\endgroup$
    – elemtilas
    Commented Nov 5, 2017 at 19:38
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    $\begingroup$ What you remove to get to the ore is spoils (or overburden). What's left over when you concentrate the ore is tailings. What's left over from reducing an ore to metal in a furnace is slag. $\endgroup$
    – Nick T
    Commented Nov 5, 2017 at 20:43
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    $\begingroup$ @PCSgtL Lava in the real world doesn't work like in Minecraft. Even if you had an open volcanic chamber, you'd just add the material on top. Even if the rock you add happened to be more dense than the magma, it'd just sink and raise the magma level anyway. Melting doesn't help you with your problem, and there's nowhere for the stuff to be "swept away". Unless you count "exploding all over the countryside" - in which case just skip the middleman and dump the rock all over the surface yourself :P $\endgroup$
    – Luaan
    Commented Nov 7, 2017 at 9:52

Since you mentioned trade with humans in the middle ages; that adds a likely answer. They build roads with it that link human trade routes to their centers of trade. And if the roads are finely enough graded, then stone wheels, axles and carts would also be a possibility. A horse pack might be able to carry a lot more castle bricks in a single trip after purchasing such a commodity.

Siege engine loads is another definite possibility. Think of a piece of stone carved in the shape of a golfball, at twenty or thirty times the radius. It will travel much further than typical loads. A longer range catapult would justify buying dwarf crafted ammunition.

Other interesting trade goods crafted from igneous rock are possibilities. metal crucibles and tongs for blacksmiths, oven liners, and even cremation chambers. The Plague did demand burning quite a few bodies after all.

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    $\begingroup$ Its hard to attack a castle when my archers keep getting stoned! $\endgroup$
    – steverino
    Commented Nov 5, 2017 at 15:41
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    $\begingroup$ +1 for the roads, better roads equals easier trade, also remember you can make rails for mining carts out of stone. I image dwarves to be a lot like the romans with high quality roads everywhere. $\endgroup$
    – John
    Commented Nov 5, 2017 at 18:59
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    $\begingroup$ Build roads and collect tolls on those roads. Enjoy dwarven taxation, everybody! $\endgroup$
    – Liquid
    Commented Nov 6, 2017 at 10:38

Some great answers here! I imagine they'd do all of these things, to one degree or another. Recall that dwarves are not all of a piece, just like humans.

Removing the stone is something they're very used to -- after all, the ore needs to be refined on the surface, due to the unwisdom of running gigantic furnaces underground. They'll likely have a smooth infrastructure for carting waste-rock away.

A lot depends on each dwarf community's attitude toward the upper world. Is it a ghastly, hated agoraphobic nightmare world? If so, they'll be unconcerned about runoff, ugly piles of gravel, and so on until someone complains.

But maybe they like their garden areas aboveground as well. Any rock or gravel they don't sell could be used to pave roads, make a huge wall around their upper territories, and so on.

At the end of the day, though, there will be just too much rock to dispose of artistically. There will end up being a midden of some kind. Whether it be beautiful alpine valleys getting filled in, renting someone else's useless canyons, or slowly building a new mountain a few miles away, there will be a huge pile of detritus somewhere.

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    $\begingroup$ ther'a no reason to not run the furnace underground, just make sure the flue is tight and opens aboveground. the in-draft of the furnace would bring fresh air down too. $\endgroup$
    – Jasen
    Commented Nov 6, 2017 at 6:24
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    $\begingroup$ Running huge furnaces underground might actually be necessary, for the reason @Jasen suggests - if you can generate heat low down in your underground city, and use that to create a strong rising current of air, it will draw stale air up out of the lower tunnels and out through the air shafts above, while pulling fresh air in from the outermost air shafts. This is why termite mounds are oriented north/south so that the sun hits the flat face and warms them up: so that the rising warm air creates circulation so that they don't suffocate when deep underground. $\endgroup$ Commented Nov 6, 2017 at 13:30
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    $\begingroup$ Good call with the road paving, both gravel and slabs. Start by putting it on all the roads around the mountain, and then start a publicity campaign to get people complaining about how bad the non-dwarf roads are. Then you get one king in on ground floor pricing as the first fully paved kingdom, and all of the other kingdoms around will feel that they need to do it too. $\endgroup$
    – AndyD273
    Commented Nov 6, 2017 at 13:47

There are several things you need to straighten out even before fixing the "excess building material" problem.

  • Humans are omnivorous and that means plants and livestock (which needs feeding and thus more plants); plants aren't happy in (semi) darkness.
  • Humans need water to live.
  • Industries, even primitive, need huge quantities of water.
  • What kind of "caves" you plan to have your "dwarfs" to live in?
    • "Carsic" caves would be best suited as they provide large natural dwellings and water; in some cases you also get large underground "dolines" or "foibes" partially illuminated that may host vegetation. These don't, usually, provide valuable minerals.
    • Mines: these are mainly man (or dwarf) manufactured and need to dispose of resulting boulders. These are more suitable to "miners", since they are built where valuable minerals are found.
  • In general You wouldn't use a natural opening (sinkhole or whatever) to put wastes; you would use it directly.
  • You would build your underground cities near or on some largish underground river.
  • If You build into Karst area (essentially limestone) you would use much of the material to make lime and it might be possible to get rid of excess simply having the river wash it away.
  • If You build into a mine then you'll need to solve all above problems; in particular finding a suitable underground river might be a bit more problematic but, once found and if fast enough, it might help you disposing of any finely ground wastes you may have.

Although the Dwarves like to be underground not all underground locations are created equal. They might well choose to dig in mountainous areas as these present a number of advantages.

They might find some useful metal ores which they could process themselves or trade. Some mountainous areas also have a great deal of depth between the surface and the water table. This would give them plenty of delving scope and minimise flood risk.

Much deeper vertical shafts could be sunk down to the water table to act as wells in some areas. Horizontal shafts or adits could also be dug from the lower portion of a valley into the mountain tunnel complex. If such adits were dug angled very slightly upward into the mountain, cart loads of spoil could easily be wheeled to the entrance of the adit and dumped (there would be plenty of chippings, loose material and broken blocks.

If they were skilled they could dam a mountain river below the adit entrance using spoil from the mine and then raft the blocks from the adit entrance across the lake produced perhaps dozens or maybe even hundreds of miles away. Any further spoil could be dumped below the dam and periodically “flushed” away downstream by opening the sluice gates. This wouldn’t be popular with the people living downstream but would act as an incentive for them to move upstream and resettle on the edge of the new lake.


Dwarfs, being naturally industrious, would like to make a good use of the stone. Good big blocks of stone will be used first to fortify and protect the entrances and air ventilations. Gravel would be used after a first layer of stone to make thick walls. Big cities will become impressive mountain castles with a network of fortifications. Huge amount of debris will slowly employed to modify the mountain in their advantage. Also, some traps could be prepared in the middle of the mountain where they could throw a ton of stones to their enemies with a single lever.

Leaving protection stone surplus will go into roads and bridges that will be needed in their mountainous lands. Roads would be important as they need wood and other types of goods. Carts would be another improvement that would allow to move weight easier.

They will also create aqueducts even if part of them go underground. Water could be critical to grow some mushrooms. Also, subterranean rivers could help to dispose of sand. With a system of dams and canals they could save water for the moment they need and even use it at a source of power in water mills.

At some point they may need to simply dump stones at the side of the hill. But they won't do it carelessly. Stone dumps would be planned to some purpose like stopping torrents during storms. In fact, living in mountains with a horrible weather may be another thing that makes them prefer underground life. Some cities may even made patterns that form runes when seen from the distance.


Mine something valuable: marble, rock salt, slate, coal, gold, copper, tin, silver, iron, ...

Because, that would make it worthwhile to truck it up to the surface (and then sell it, of course, perhaps after working it further); dwarves are stereotypical smiths (iron-workers with forges) too.

Maybe look into the technologies they used for medieval mines: pit ponies, children, pumps, etc.

Beware this paragraph is speculative because I don't know about mining: you may be mining in the mountains (I guess mountains are a good place to mine, because rock and ore comes up out of the earth to meet you, rather then you having to go digging down into the earth). Anyway if your mine-shafts are half-way up a mountain, if you're lucky they could be more horizontal rather than vertical, and how to getting rid of the spoil might be obvious: you just tip it downhill, forming waste heaps.


So while this may be considered a lazy answer, I can't help but think of a solution presented by a folk tale early in my childhood: The dwarves should make lots of Stone Soup.

enter image description here

Of course, this isn't really a great answer because the entire point of the story, spoiler alert, is that the stone provides nothing, and the soup is instead made up of everything that comes together around it. It's a wonderful morality tale, and in Ann McGovern's version also a story of delightful trickery, but I'm afraid it's probably not the answer you're looking for.

Still, maybe there's something in here for you to use in your underground society anyway, since I'm sure they have a fun equivalent of the story.

More information on the folk tale here.

  • $\begingroup$ Welcome to Worldbuilding! Is there any way to cook the stone so that it actually becomes edible, or is that something that's handwaved away? $\endgroup$ Commented Nov 7, 2017 at 16:38
  • $\begingroup$ Thank you! No, at the end of the story the stone is discarded from the soup. (Or perhaps left at the bottom of the pot, I can't quite remember.) $\endgroup$
    – Lukas
    Commented Nov 16, 2017 at 16:47

What about building projects? See Machu Picchu as an example, a settlement and farming complex high in the mountains built from the bedrock up using stone largely quarried onsite. Similar artificial framing terraces could be built in the mountains and valleys around the mines reducing dwarven dependency on food imports.

There could also be water harvesting, redirection, and retention systems like dams, dikes, and aqueducts, that can keep water away from mining areas and also utilise it for powered bellows and trip hammers and other tools for metal working and possibly even pumps for clearing water from and pushing clean air into deep workings.

This would primarily make use of cut stone rather than spoil but, especially dams, could also potentially create areas where the miners could dump spoil in large quantities. This would both reinforce built walls and disguise the built nature of some spaces. Spoil dumped downstream of water release sites would eventually be "entrained" by the stream and carried downslope in an fair facsimile of the natural erosion process.

  • $\begingroup$ Well, as I haven't specified why the dwarves prefer to live underground, it might be that very few might want to be farmers on the surface. But it would be easy enough for the dwarves to hire humans as farmers, if needed. So still a good idea. $\endgroup$ Commented Nov 6, 2017 at 18:28

Others have mentioned trading or dumping the stone, but what if they used it to..


Entrances to Dwarven strongholds need defending too! Watchtowers, fortresses, subterranean harbours great stone gates and the like would be a good use for a whole lot of that stone. Not to mention first alert outposts and the like. With stereotypical Dwarven aptitudes for building they'd find good uses for large amounts of stone.

The first (fantasy) examples that come to mind are:

Dwarfs of the Warhammer Old World:

Warhammer Dwarf Hold

Dwarf Harbour of Barak Varr

and Ironforge, the Dwarf capital in the Warcraft universe:


I'm sure that with a bit of thought, they could come up with plenty of uses for the excess stone!


On the assumption the dwarves are a similar technological level as the humans, this implies the mining is carried out by hand.

I would suggest looking at the Roman era as a good guide of tunnel designs and the time it took to create them. By the medieval period, a lot of the construction methods were lost to humans. This could explain the Dwarf advantage in tunnelling.

The Romans used the materials for building in the local area. Either forts or other civil buildings. It was simply to expensive to move over large distances. As we are talking mining by hand, the detritus would be relatively small and could easily be absorbed into other building projects.


They should do what the dwarves in Discworld do and eat it


Dwarf Bread is a rock solid bread containing gravel and other rocky substances

Various forms of dwarf bread can be used as weapons, e.g. battle muffins and drop scones. Fine specimens of dwarf bread can be found in the Dwarf Bread Museum, Whirligig Alley, Ankh-Morpork, open to the public whenever volunteers have time (Feet of Clay). Dwarfs away from home often miss dwarf bread very much, and complain that mass-produced breads by Mr. Ironcrust hardly meet the standards, but dwarfs are too busy working to go and see the exhibits in the museum, much less to volunteer there.

Proper dwarf bread has to be not just baked, but forged (with gravel, of course) and dropped in rivers and dried out, and sat on and left, and looked at every day and then put away again. For preference, its use as a cat's litter box is also recommended. Dwarfs generally devour it with their eyes, because even dwarfs have trouble with devouring it any other way.

It may seem silly to eat stone, but given that your dwarves will need an endless supply of fuel for light or complicated systems, I don't think it's farfetched. Some novel form of stomach acid, or unprecedented evolutionary advantage or symbiosis could explain it, though an air of mystery always helps


Its not like dwarves would start with a solid mountain and extract a little at a time... Instead dwarves would be attracted to natural cave formations which they could then enhance.

While there may be a lot of rubble, I think you would find it a lot less than what you are assuming.

Also, unless its valuable stone like marble, I don't see it being a profitable endeavor for dwarves to quarry stone for the purpose of selling to humans. This would only really make sense if dwarves were near the poverty level and/or intellectually deficient.

Mining for ores for industry is far more likely.


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