I would think the expenses you would need to get started would far outweigh any chance of striking it rich. The places gold can be found have been taken over by corrupt games who bully their neighbors to leave or end up missing. I'm talking about foreign countries of course, not in the United States.
There is a show on the Discovery Channel called Gold Rush that follows people who mine for a living. I think they're located in Alaska and Canada. Also, like JThomp42 said, most of these people have inherited the business from their parents/grandparents or are friends of the family. I don't think it would be an easy task to start up a new operation.