Morfa Copper Works, Landore [Glandwr] was originally worked by Williams Foster and Company 1835-1880. In 1880 they were acquired briefly by H. R. Merton and Company but were in the same year obtained by Williams Foster and Company who ran them from 1890-1893. From 1893 until 1924 the works were operated by Williams Foster and company and Pascoe Grenfell and Sons Limited.
Middle Bank or Plas Canol Copper works, Lower Swansea Valley originally worked lead under the firm of Chauncey Townsend and Company 1755-1764. Copper working was introduced when the firm of John Rotton and Company took over the works fo the period 1765-1769. At the time of the writing of George Nancarrow's memoranda book (1872-1892) the firms operating the copper works were Pascoe Grenfell and Sons (1828-1890) and Pascoe Grenfell and Sons Limited (1890-1893). From 1893 until 1924 the works were operated by Williams Foster and Company and Pascoe Grenfell and Company Limited.
The records were deposited by Mr or Ms Kirkham.