- Increasing the building level increases the coal production rate.
- Maximum level is 20, which is 570 an hour.
- Can be demolished to the ground and transferred to another place in the city that contains stone. This is a paid service, transferring will cost 100 gold.
- When enemy destroys a resource extraction site, the new site will appear in any part of the city but the building will begin only if the land type matches the type needed for resource extraction. If the landscape type does not match, terraforming or changing the location will be required.