Columbia subject headings:
Coal mines and mining--Safety regulations--United States--Cases.
Mine safety--Law and legislation--United States--Cases.
Mine safety--United States--Cases.
Mine sanitation--Law and legislation--United States--Cases.
Harvard subject headings:
Coal mines and mining--Safety regulations--United States--Cases.
Mine safety--Law and legislation--United States--Cases.
Mine sanitation--Law and legislation--United States--Cases.
Princeton subject headings:
Coal mines and mining--Safety regulations--United States--Cases.
Mine safety--Law and legislation--United States--Cases.
Mine sanitation--Law and legislation--United States--Cases.