Hi, its me the proud owner of the slab. I barely even dug up that much clay to get it as well which is even more crazy. My original goal was just to replace the top layer with dirt instead of clay so it wouldn't look as ugly where I'm building, and about half way through I randomly picked up this clay slab. In total the amount of blue clay I got from digging was about 2000, and I don't know if each clay that drops from mining has a chance to drop the slab, or if the block will give no clay and just the slab. Either way pretty cool find, and I'll definitely be storing it somewhere secure, since I'll probably never get another one ever again .