Hmm. Seems that's a planetary 700% bonus in total. That should be equal to a single Precursor Mine.
No.
Here, the planet gets 12 factories from 5 tiles. One Precursor Mine gives you 8 factories on 1 tile. An 8:1 ratio is way better than a 12:5 ratio. The Precursors were POWERFUL. No amount of 'rare elements' can match their technology.
Shouldn't the Dread Lords have their Class 45 planet, Amalda, covered in Precursor Mines and Precursor Libraries? It would make them too over-powerful, but it would be realistic since they are, after all, the Precursors.