really hard to quantify how much is left there mate - but your...

really hard to quantify how much is left there mate - but your wizardry demonstrates the scale - its massive.
the highlighted 300m x 250m area, assume ave width 0.8m and grade of 15g/t, SG 2.8, recovery 95% = 77koz recovered - plenty of areas like that there - maybe ten of those to be conservative, so potentially 700-800koz worth of gold bars.
all areas may not be accessible, or they have incomplete or inaccurate records. but def could be systematic about it.
step one getting the current plan working, this should be the step 2 IMO