What I find quite interesting is the Cardassian side of this equation. Why did they build two seemingly identical stations? Terok Nor was supposedly optimized for controlling and strip-mining Bajor. Was Empok Nor supposed to augment Terok Nor at Bajor, but was abandoned in mid-tow for some reason? Or was it destined for another conquered planet very similar to Bajor?
The conquest is beside the point. It was designed as an ore-processing station. I would assume there's a standardized Nor-class station design used for similar mining operations throughout Cardassian space -- just as Starfleet has had multiple starbases using the Regula I design or the Earth Spacedock design. For a real-world parallel, I'm sure there are a lot of identically designed offshore oil platforms or air traffic control towers scattered about. Or, if you drive along the Pennsylvania Turnpike, you'll find different, nearly-identical travel plazas at various points along its length. Terok Nor served functions analogous to all of those, just combined into one.