A Mine is a tile improvement that can be built by Workers immediately upon the discovery of Mining. A mine adds 2 to its tile. Mines may be created on all hills, and on flatland tiles that have resources which are unlocked by mines.
- Gems , Gold , and Silver are always revealed, but are enabled with Mining. Settling a city on these resources will not unlock them until Mining is discovered.
- Copper requires Bronze Working.
- Iron requires Iron Working.
- Coal requires Steam Power.
- Uranium is revealed with Physics and enabled with Fission.
- Aluminum requires Industrialism.
When a Mine is worked, and it is not already on a resource tile, there is a small chance every turn that it will discover a new resource. A civ must have the tech unlocking a resource to gain it via a discovery.