New gold is a very small fraction of the gold supply, so I'm not giving much power to those who mine the most (currently). A major new discovery could change things, but it would have to be huge. Mining (or, more probably, refining) becoming easier could change things more than a big discovery, by making many uneconomic deposits suddenly economically viable to work.
Most fundamentally, I'm gambling that the chemical composition of the earth's crust isn't going to change much. That part of the gamble I feel pretty confident about.
Mining yields 2% of existing supply every year, and gold isn’t used up (it is reused and recycled), that isn’t insignificant. We also have no idea how much China and Russia are actually mining, there is suspicion that they have a lot more than they say they do. Gold is not all that rare, it is abundant in the earth’s crust, those reserves are just largely inaccessible with today’s tech. See http://www.westcoastplacer.com/how-much-gold-is-left-on-eart....
Most fundamentally, I'm gambling that the chemical composition of the earth's crust isn't going to change much. That part of the gamble I feel pretty confident about.