Thanks, Cardiff and Halfasheep, for the wonderful background details. This is my wife's family and I had heard some snippets but you have made it possible for me to put them into a more complete context.
Rena, I had found the record of Jesse's accident, from which I deduce he was alive when he left the pit. Many thanks for directing my attention to the Compensation Register. I have now submitted an enquiry to the West Glam Archives.
I am now waiting for GRO to do their stuff. Hopefully the death certificate will confirm where, and of what, he died and make the sequence of events a little clearer.