Well fix it of course.
This is what I am starting with. Someone had tried to fix it before by super gluing it and using bees wax to try and hide the cracks...well lets just say that didn't work out too well.

After scraping off the old wax and chipping out the loose slate that was still there, I used some JB Weld to attach the pieces together. I clamped it and let it dry over night. The next day I filled the rest or the cracks with some jell super glue.

After the super glue dried, I cut 2 channels in the slate across the crack with a 4" diamond blade in a tile cutter.

Next some aluminum was cut and shaped to fit in the channels.

Mix up a good amount of JB Weld, smear it in the channels and push the aluminum in. Make sure you scrape off the majority of the squeezed out JB Weld before it dries.

more to come...
This is what I am starting with. Someone had tried to fix it before by super gluing it and using bees wax to try and hide the cracks...well lets just say that didn't work out too well.

After scraping off the old wax and chipping out the loose slate that was still there, I used some JB Weld to attach the pieces together. I clamped it and let it dry over night. The next day I filled the rest or the cracks with some jell super glue.

After the super glue dried, I cut 2 channels in the slate across the crack with a 4" diamond blade in a tile cutter.

Next some aluminum was cut and shaped to fit in the channels.

Mix up a good amount of JB Weld, smear it in the channels and push the aluminum in. Make sure you scrape off the majority of the squeezed out JB Weld before it dries.

more to come...