Subjects
- Coal mining - Medical care.1
- Coal mining - New River field.1
- Coal mining - Regulation.1
- Coal mining - Safety.1
- Coal mining - Winding Gulf field.1
- Coal mining - coal and coke sales.1
- Coal mining - coal companies.5
- Coal mining - coal operators associations.2
- Coal mining -- Strikes1
- Coal mining.4
- Depression.1
- Depressions - 19291
- Diaries and journals.3
- Economics1
- Editors - letters and papers.3