The shear depth of the whole block would use far too much copper. Just like Mr O's copper tube theory. The copper usage rate was 50 percent greater than the hole depth! For ever 6cm of copper it used 9cm of copper.
Copper to cut granite on that scale is a non starter.
Keep trying though.
In the case of hardrocks like granite, the expense incurred by the loss of copper during the cutting process (less with bronze and iron) would restricted it to royal monuments, for usage where other tools would not suffice (Arnold 1991).