Cyfyngwch eich canlyniadau yn ôl:
- Pob un
- Coal -- Research -- Wales., 2 canlyniadau
- Wages -- Coal miners -- Wales, South., 1 canlyniadau
- Coal miners -- Diseases -- Wales, South., 1 canlyniadau
- Coal -- Law and legislation -- Great Britain., 1 canlyniadau
- Coal mines and mining -- Employees -- Wales, South., 1 canlyniadau
- Labor disputes -- Wales, South., 1 canlyniadau
