Thanks, no he doesn't mine anything sorry, but he is investigating the disapearence of Dr. Freeman. There should be some really strange stuff going on since the theme for the competition in Nine Times were gonna have Nine versions of your dude.
Oh. Hmm. Is he underground, then? If not, I don't think he needs a lightbulb on his helmet, unless it's going to be dark where he is. There should be a decent explanation for everything on and about your character. Also, depending on the setting altering the palette would change, slightly. Mostly for atmospheric effect. Just a thing to consider.
The tile looks nice, by the way, but those marks--I'm thinking they're craters/imperfections in the rock surface--don't really look like craters at all. Somewhat ill-defined, they don't seem to be affected by the light-source much. However I'm probably not going to make an edit. Why?
Good question. Probably a mix of laziness and inexperience, but I'll try.