Just a quick caveat:
Some folk can get quite heated about "mineral collectors"* going underground and collecting samples for display.
I think you will find this is why in certain areas mine explorers are "discouraged" from venturing underground.
Personally I think it is far better to spend one's time fossicking over the tailings pile - you can find what you are looking for on the surface, with out damaging in situ examples underground.
*"mineral collectors" have in the past damaged some beautiful specimins and/or removed/damaged valuable in situ artefacts.
(Just playing devils advocate here, I'm not saying "Don't do it" - just be aware of the repucussions of your actions, some places have been sealed off to mine explorers, because the "mineral collectors" got there first - plus there is also the legal aspect of removing samples without the landownder/title holder's permission.)
Better to regret something you have done - than to regret something you have not done.