Columbia subject headings:
Coal mines and mining--Scotland--History--19th century.
Coal mines and mining--Scotland--History--20th century.
Harvard subject headings:
Coal miners--Labor unions--Scotland--History.
Coal miners--Scotland--History.
Coal miners--Scotland--Social conditions.
Coal mines and mining--Scotland--History.
Coal trade--Scotland--History.
Princeton subject headings:
Coal mines and mining--Scotland--History--19th century.
Coal mines and mining--Scotland--History--20th century.