In 1960s the gold price was $36/oz in todays money that equates to $465, however the gold price is actually $1720.
Given that the head grade from MS over its life has averaged at 26.5 g/t it is logical that if the head grade from RoD was half but by today standards still very high of around the 12 g/t mark, in 1960 MS would be economical but RoD would not, but as I have pointed out with the current gold price, it makes your point look like petty sniping.