A copper smelting process used in South Wales that originates from the early eighteenth century and was used through to the end of the nineteenth century. It used a furnace in which roasting, fusing, and refining were carried out. The process was superseded by bigger furnaces.

http://www.copper.org/education/history/60centuries/industrial_age/thewelsh.htmlOfficial website of the Copper Development Association Inc., Education pages.