re: chart of zinc not wanting to be a smartie ..................
assuming this is dollar value at the time indicated on chart ............... if you applied the rule of 72 then this line might look pretty flattened and 4000+ now would probably be less than 1700 in the 70's ....i haven't got the patience and it's all a bit of a furphy anyway ..... those on zinc are taking a risk ........ those not on zinc are taking a risk!
that's life!