The comments about gold mining costs being higher as a price support floor is invalid.  First the only reason it's higher is because the higher market price led miners to invest in low margin mines.  With lower prices unprofitable mines will close and mining cost price will drop.  Secondly the argument is similar to stating bitcoin is hugely overpriced because the electricity costs to mine a single bitcoin are magnitudes lower then the current price.  Market prices are just bets by market participants with production costs being one of many different factors.