One of the prominent mines known for producing specimens in the West Cumbrian Iron Field (formerly Cumberland) was focused on extracting hematite, the primary ore mineral. Most mines in this ore field were active from the mid-19th to the early 20th centuries, although some, like the Florence-Beckermet-Ullcoats complex and Halle Moor Mine in the southern portion of the district, continued operations into the latter half of the 20th century.

1864-1865 Thomas Massicks & Co. 1866 Gibson, Cook & Co. 1867-1874 Mowbray Mining Co. 1875-1894 Mowbray Iron Co. Ltd 1896-1902 Charles Cammell & Co. Ltd 1903 Cammell Laird & Co. 1904-1908 Cammell Laird & Co. Ltd 1909-1913 Workington Iron & St