I didn't get a picture but will post when I do.

Older Brunswick Heritage 8 foot table, 3 piece slate 1 inch thick. We assembled the base, put the slate onto the base. Scraped all the joints and surface clean with razor blades. The slates have metal dowel pins to locate everything and we slid them together for an initial fit. One of the ends wasn't sliding in and my friend who owns the table got it to go, but we didn't notice that it forced the dowel up towards the playing surface. The weight was enough to crack the slate which we didn't notice until he got a nasty cut running his hand over it. I gave it a poke and at least 2x3 inch chunk of slate popped off down to the dowel pin. The piece still fits tightly where it came off.

My plan of attack is to use JB Weld, or a quicker 15 min epoxy to glue that back getting it as flush as possible. I have beeswax that we where planning to fill the joints with that shouldn't be a problem. I've read that bondo is a alternative also for larger repairs. My only worry is if that piece doesn't stay long term. If it lets go and pokes up through the felt it'll be a nightmare! Would I be better off just removing it and replacing with bondo? Sand that flat and move on? Any guidance would be appreciated.