Anyone who's been around the block in this business knows them, but I find it helpful to have them succinctly stated in a mnemonic. Don't even think of investing in a company unless they're all answered in detail. Before putting money into a company, find our exactly who's running it, and what they've been doing with their lives. If you're looking at a serious investment, consider hiring a private investigator. If the people are no good, forget the rest of it.
Bad people are capable of magically transforming lemonade back into a lemon.
There are lots of little public companies left over from the last movie that are trying to make a go of some property with a narrow vein underground deposit. They're living in the past, for lots of reasons I've covered here. Leave those deals to the Treasure of Sierra Madre crowd, guys that will spend the rest of their lives sitting around reminiscing about how they'd all be millionaires if only the mule hadn't died. You want something that can get the attention of a major, not just a hobby for some weekend rock hounds. Phinancing - Mining is a capital intensive business.