List of collieries in the Rhondda Valleys
List entries. Colliery states the name the colliery or level was known as when it first opened; many sites were enlarged, and some levels were developed into collieries. If a site was expanded from a level to a colliery, or significant additional shafts were added, the column Formerly draws attention to the original site name.. The Date opened records the first attempt to open a level or pit ...