User blog comment:Unownshipper/Metallurgists Wanted: Rapture's Natural Resources/@comment-3967731-20140810040802/@comment-75.36.142.53-20140810061251

Its an old (judged extinct) volcano, so there would be some time for concentration of minerals via underground water action (which causes useful minerals to form near the surface where the lower temperature has them precipitate out of solution).

How large the deposits might be (to be useful or even findable) might be  an issue.

Extracting minerals from the volcanic hot water vents might be more efficent