Mineshaft

The Mineshaft is a building that allows Townsfolk to generate ore without destroying the terrain.

Requirements

 * It requires 2 torches, 3 wood and 1 iron to create.
 * It must be placed on a flat 2x2 square of ore.
 * It can be placed both above ground and below ground on any level.

Usage
When placed, the Mineshaft will automatically generate ore depending on the blocks it sits upon - a Mineshaft above 4 iron tiles will generate iron, at a rate of approximately 1 iron every 16 minutes.

It seems the amount of ore generated is limitless, and this is therefore a much more environmentally-friendly (and renewable!) way to build stockpiles of ore such as iron and coal. Note: it's not possible to mine silver and gold using mineshafts making them a very limited resource.

While the mineshaft operates automatically, it requires townies to manually retrieve the ingots of metal or lumps of coal from the mineshaft and drop in on the side. This means that if your townies are especially busy with other tasks, it may seem as though the mineshaft is not operating.