Unless the "DING" is really horrendus (more than 1/8") you can continue. You can also turn the blank over with no ill effects and start over which would probably be more pleasing from a cosmetic point of view. Have you put a good chamfer on the edge? If not, this is probably the reason that you chipped it. You should always have at least a 1/16" chamfer (1/8" in the rough grinding stages)through the completion of grinding. Lack of chamfer is the biggest cause of chipping when grinding. Also once you have a curve in the blank, make a curved backing for the tiles so that you have an approximate match to the curve. This will eliminate much heart ache.

Jarvis Krumbein,