Phrases such as "Enemy structures cannot be mined." do not make a lot of sense in English - since it may be unclear what exactly you're trying to do to the structure when you "mine" it. That is, maybe you cannot mine a structure simply because it makes no sense to try hitting a building with a mining pick, rather than the intended meaning which is that you cannot "deconstruct + pick up" enemy buildings.
Moreover, mining resources is fundamentally different in terms of game mechanics from "mining" entities, because:
- "Mining" entities is something only a player can do (as opposed to drills which mine resources).
- You can only "mine" an entity once as opposed to resources which can be mined repeatedly.
- Mining a resource is irreversible (i.e. you cannot take a lump of coal and place it back into a coal deposit to increase its count).
- And so on...
Other alternative may include "dismantled" or even the "deconstructed" which is used for bots.