If I may just give my two cents on this topic, I personally like the idea of magic being utilized. We have a Geomancer class who can control earth and stone, why not have some form of resource growing like @Heilari is doing in the map game? It can be balanced so that there would be serious risks tied to it too. Just picture the following:
You set out to found your own little civilization in the wilderness. At first, you only use wooden and stone tools, and only really ever dig for stone. Then, upon finding metals deep in your mines, you advance to iron then steel tools, uncovering more and more ores. As you dig deeper and find different metals and such, you start to notice how you aren’t mining up as much iron or steel anymore. Thankfully, you find and establish another mine on the other side of the town.
This is where the situation could split, taking either the Minecraft style of keep pushing mines further and further out either bringing the supplies back or moving homes to match the mines, or the more magical style.
Amazingly, during her studies of the earth and it’s bounties, your wizard Tilda Iron-Leg found a peculiar magic flowing through every bit of metal and gem we dug up! She noted how, once stimulated, this magic rapidly expanded, causing the accompanying metal to expand and grow as well!
This could start off simple, as just a boon that allows for double the ores to be dug up, or it could just go ahead as a method to provide infinite resources to a late game civilization. However, these resources could have several terrible consequences on the world…
From the Journal of Fraum Stormbrow
Curse that geomancer Iron-Leg, curse her very name! She did something to the silver today, said she was trying to make it grow faster, and changed something about the metal. Aye, it grows faster, that’s true, but now the metal is ALIVE, and eating our people! It keeps growing and growing, and none of our adamantine arms seem to harm the beast!"
There could be tons of different risks for this, from your town becoming a beacon to dragons, to once weak goblin armies being able to buy enough cheap adamantine and mythril to supply their whole horde.
I know this post is rather long winded, but what are your guy’s thoughts?