Casgliadau Arlein
Amgueddfa Cymru
Chwilio Uwch
Continuous Mining with the AB Longwall Trepanner (article)
Article reprinted from 'Iron and Coal Trades Review, April 22 1955.' 15 pages in green covers.
Nid yw sylwadau ar gael ar hyn o bryd. Ymddiheuriadau am yr anghyfleustra.