Quoted from "Geggo"
I'm pretty sure the mining head covers 62x62 area and the frame of the quarry covers the 64x64 area.
My bad, forgot completely about the frames.
@above : It IS intended that you are able to aquire steel from dungeons. The namefix is just an aesthetical nerf (aka making the name flint and STEEL mean what it is).
To go to the nether you don't need diamonds nor flint and steel, just lava buckets, water and some flammable blocks (wood).
oh.....I realized I was mistaken now.
And I tried that way many times but not work.