I assume by 50% you meant a 50% increase of the ~~average 2% per year increase in the overall gold supply?
Yes, sorry if that wasn't clear. Not a 50% increase in total existing supply, but a 50% increase in production over the previous year. Growing the existing world supply in absolute terms is severely limited by refinery capacity. Total official unmined reserves are currently estimated as being about the same size as all previously mined gold. Additionally, a big chunk of the world gold stock is sitting in above ground national reserves which could be used to float any sudden change in demand if need be.
Interestingly, about 20% of all the gold that has every been mined has been destroyed to date, irretrievably lost in various fashions e.g. highly diluted in industrial processes such that recovery is not economical.