Convert how many Metric tonnes ( t ) of gold are in 1 ounce (troy) ( oz t ). One (oz t) ounce (troy) of gold mass equals zero point zero zero zero zero three one Metric tonnes (t) in mass of gold. This gold calculator can be used to change a conversion factor from 1 ounce (troy) oz t equals = 0.000031 Metric tonnes t exactly. Convert gold measuring units.