Got, it - the picture helped.
So the width and channel samples are measured at the advancing face of the drive.
So if we use the averages ORS have pulled out
38x3.7x3(height of the drive??) x2.5SG = 1054.5t @18.8g/t
= 19824.6g /31.2g = 635.4oz in that area of the drive alone.
Not too shabby at all.
