Minerals inside Factorismo factories

[Avacado]

I was inspired by the imgur album posted to reddit: http://imgur.com/a/IpTgu

Notice the 4th picture is a factory filled with coal. I was thinking a mod would be a good way to avoid having to manually create that in creative mode. I'm not sure what the best pricing scheme is for factories full of mineable resources. Perhaps they could be free or perhaps there could be levels of them (each level having more minerals or being larger or both) with scaling costs.