New Tires From Tire Rack, and I just noticed damage!

FedEx shiped the tires, yet I was not here when they arrived. My wife left them in the garage, and when I came back to the island of Oahu I put them in my Hooptie (old Nissan) and drove to the Hobby SHop and had them mount and balance them. When I cam home, put them on the car I realized there was a gouge in the tread on the edge of the contact patch. Its not losing air, and its not the sidewall, after a few days of sitting, but it looks like someone noticed the damage then tried to cut down the block to avoid any visual issues. But, I have a pic on photobucket I will post later.
Just curious as to how much damage a tire can take before it really is not driveable. Due to being out here in Hawaii, shipping isnt cheap, but neither are my BFG KD's.
I will post the pic later, but your comments and ideas would be appreciated.