The union was founded in November 1863 at a five-day long conference at the People's Hall in Leeds.[1] It was originally known as the National Association of Coal, Lime and Ironstone Miners of Great Britain or Miners' National Association. It campaigned for legislation in the interests of its members, but did not involve itself in trade disputes, and disappointed strikers who hoped it would provide them with financial support. Its most prominent achievement was in getting the Coal Mines Regulation Act 1872 passed; this required payment of miners by weight and restricted working hours for children in the mines.[2]
The Amalgamated Association of Miners was formed by former members of the union in 1869 and for a few years established new unions across the country.[2] However, by 1875 it was in financial trouble and the two negotiated a merger; however, Macdonald ultimately only changed the name to the "Miners' National Union" and advised former members of the Amalgamated Association to join.[3]
In 1898, the Durham Miners and a few remaining minor bodies withdrew from the union; with only the Northumberland Miners still affiliated, the MNU was dissolved.[2]