In Dwarf Fortress, your dwarves aren’t mindless peons who’ll do everything you say. Sometimes they’ll stop doing something for their own safety and preservation. One of these things is mining. If a Dwarf comes into contact with warm or damp stone, they’ll stop digging, and you’ll receive an Alert. Here’s what those notifications mean and how to navigate them.
Digging Designation cancelled: Damp Stone located
If you see this notification, it's because the stone you’ve just mined is adjacent to or below a water source. Water will make all materials around it damp in a one-tile area. This will mean you can prevent flooding or otherwise damaging your fortress. However, this can also be annoying if you dig below a pond, river, stream, brook, or another water source. In this case, you can ignore it and keep going.
Digging Designation cancelled: Warm Stone located
Warm Stone is created when magma is on the other side of the wall. Like water, magma will make warm stone on all materials around it in a one-tile area. You’ll need to avoid the warm stone to prevent lava flow into your fortress. Warm Stone will also happen below magma, in the unlikely occasion you’re below it.
Notes on navigating Damp and Warm stone
Bear in mind, Magma and Water will not make stone damp or warm above their position, so you won’t know if you’re right on top of water or magma. You can mine into a piece that’s been cancelled by simply re-designating that area for mining. You can also disable the notifications for these warnings in the options. This is useful for mining out large areas under rivers and other water features. However, it's best to leave the warnings on, just for safety’s sake!
For info on Dwarf Fortress, check out How to make the perfect dwarf bedroom in Dwarf Fortress on Pro Game Guides.