Asteroids vs Planetary Mines

[johndallman]

Originally Posted by Varyon

It seems to me that, unless there are materials that can only be found planetside (like various flavors of unobtanium), a colonized planet would be unlikely to contain any mines (because who wants to punch holes in a perfectly-good planet?).

Possibly no metal mines, but sand and gravel are naturally created and partly sorted by weathering processes. They are used in such vast quantities for construction that bringing them down from orbit is unlikely to be worth the cost.