The price of coal
Reaching out under Swansea Bay from Blackpill are the workings of a colliery drowned when the sea broke through into the galleries. The owners denied that certain men had lost their lives and refused the families compensation. Years later high tides caused the water level to rise up the old shaft in Clyne Valley, bringing with it several skeletons from the old workings.
Details of the accident are scant and I need to do some more research, but I’m guessing the accident happened around 1870 because in 1943 a local poet called John Beynon wrote the following:
AN OLD LIE OUT
We had no time to pray
who shared poverty and were brave:
a row of faces, hung ballons,
in the darkness as the roof split
lengthwise, squashed under its hammer,
a soft melon to the forged wall
of water we could not see
but had, unwillingly, to obey:
we rolled unconscious, already drowned.
They closed the pit and a mile inland
seventy years later the sea rose up
the crumbled shaft and burst
over the long grass and lay
our bones in homage under a drying sun,
to kindle, not disown:
how we would have laughed to see
the flash of windscreens and curious eyes
as we were spat out, one by one,
the rank earth repelling all their lies
and our voiceless anger gloriously sown.
Mr KRoss 
Interesting story… you say that no compensation was paid – this suggests compensation was sought? If so the date and names of folk involved should be recorded somewhere.