Does successful prospecting ALWAYS Mean you can build a mine

[Shask]

Quite excited as I've had my first ever prospecting success. I walked inside a cave and immediately got 28% Iron, however that number fell everywhere I went in the cave. My logic is that it's detected it in another cave. I've tried using multiple prospects to try and geometrically pinpoint the node, e.g. if I go from east to west and it goes from 28% to 20%, it is surely in the east. However I can't find any other caves in the general area. Any advice?

Are there are underground areas in the game that exist without an entrance? Assuming it's not at the edge of the world, is it therefore always possible to find a mineral and mine it if you have success?

Btw, the first cave had lots of runestones scattered throughout it. Why would this be done?

[Ciorba]

It's pretty likely that if you go west, at some point the cave will start going down or up a lot, then after a while east, until it goes around and past the entrance you found and keeps going in that direction. So it looks like you can't go east from where you are, but you probably can. Just remember that the cave system is freaking huge, you might have to walk for an hour or more to end up east.

The runestones are used to mark paths. Could be the path to the mine or to the nearest waterspot or someone's cave cheese, who knows.

[Potjeh]

The mine is most likely in another cave system. It's entrance could be quite far from where you prospected, and most likely is since you got just 28%.

[Shask]

Thanks for the tips.

I found a cave about 7 minimaps away......
.....it's about 4 squares past the edge of the world and can't be accessed.

FML