A few more songs relating to the Disaster from youtube:
A range of people expressing their feelings and emotions through song.

On the hill in Aberfan by Kelvin Evans

Aberfan Coal tip tragedy by Thom Parrott

Aberfan by Dave Collins

Aberfan - Tears of the Valley by Johnny

Remembering Aberfan by Amy Goddard

Aberfan Disaster by Paul Hughes

Black Blanket by Chris Beck

A Tribute to the Aberfan Disaster: 50 years on

Aberfan by Dave Ackles

Aberfan: Do you remember by Mac Oldman

Close the coalhouse door by Alex Glasgow

ABERFAN by Emma Maybery (Video Quality poor)

Palaces of Gold by Leon Rosselson

And a fitting hymn:
Abide With Me