How much Knowledge is needed to mine Platinum?

Do not need to smelt it, just mine the ore. I want a low level miner with as much strength as possible and want to make best use of my Exp

None... Only skill, and finding a location that has it (hint: there is some around the dragon's lair in dragonhead mines). There are some other spots around the world as well but in general they are going to be in more difficult places to get to.