Things like, font end loaders, bull dozers, etc.
Could have there own specialized vehicle cap, and only work when assigned to mining designations and only within that mining designation. Idea in my mind is mainly working with Stackers to move the material they dump more efficiently. Or any other mining designations that have both mining and dumping in the same zone. None of these would need to use a ore sorting plant even is the mixed ore sorting is enabled, but they also are unable to deposit the material they carry/move in storages.
Also those cranes on rails you often see at ports, in that vein at least, with a tool on the bottom to pick up material and either dump at another location in its path, or spread it out in a line for bulldozers to then spread more easily.
Just more options to move material around in a smaller area basically, that importantly does not use the main vehicle cap, and limited to one mining zone as their working area.
