ok, so this will probably won't seem like much of a guide.... but more of a tip
go to silithus and just circle around the whole place and mine everything you find.... you will mine a collection of mithril and thorium... but you will need to go inside the underground caves to get most of it...
i can mine about 2 stacks of thorium and a stack of mithril in about 30 mins, and i don't know about your servers, but mine (Durotan US) mithril sells for 30g+ a stack, and thorium sells for 50g+ a stack