A Mining Station is a special type of station that can either be built by the state or by its citizens. They can be built around Asteroids, Gas Giants and Barren worlds. They do NOT take up station slots, unlike the other types.
Each mining station in a system gives +500 IO to all the colonies in that system. Each mining station in a system without any colonies gives +250 IO to the nearest system with a colony.  This bonus IO does stack with multiple mining stations.  Mining stations can be built with construction ships, but it is also possible to let your civilians build them by using mining Stimulus.
Requires Mega-Strip Mining Tech to construct (either by empire, or spontaneously by citizens)