I think the machinery requires a cut of at least 1 meter in width. A lot of our veins are only 1/4 to 1/2 meter wide so if the cut is centered on the mineralization, the high grade ore gets mixed with low grade rock beside it and its value per tonne is diluted. What GM appears to be doing is cutting the 1 meter path thru the waste rock to one side of the vein first and then removing the valuable ore second and feeding it into the mill without dilution. This way the metal grade fed to the mills is 2 or 3 times higher.