Copper, Silver, Gold, Platinum....Follow

Hey, just a thought, I know you can harvest silver and gold, we use silver and gold as our money(obviously). I think I remember harvesting copper somewhere. But this leads me to a questions. How much silver or gold do you get? is it worth more than coinage? less? Could I melt down my coins to make equipment? There's a room at the bank that I can't get into because it's locked. Is that where the equipment is to make the coins? since I can select the door I'd have to assume I can get in there somehow. If I do can I rob the bank? Or can I use the machine to make counterfit coins? Or am I just bored at work and have nothing better to do or think about?