hmm, this sounds good, with some changes it will be good.
By sesmic activites the ground shakes, probably in the epicentre will some ore appear to mine or, to the edge or near lava fumaroles.
It will be a good choice for a quick start, in campaign or skirmish.
It will be mined with the cargo truck (scrapes the ground.)
Scouting? Sonar on scouts will be good.
Probably if you want medium yeild, you could set up a mine.