1823.] Account of the Process of smelting Copper. 113 



Article V. 



An Account of the Process of smelting Copper as conducted at the 

 Hafod Copper Works, near Swansea. By John Henry Vivian, 

 Esq. FRS. MGS. 



[Having lately been consulted by Messrs. Vivian and Sons, 

 proprietors of the Hafod Copper Works, as to the means by 

 which the inconvenience arising from the smoke of the copper 

 works might be remedied, the following account, forming a part 

 of Messrs. Vivian's statement, appeared to me to possess much 

 general interest : I, therefore, requested, and readily obtained, 

 permission to publish it. — Edit.'] 



The copper ores smelted in the works in South Wales are for 

 the most part raised in the mines of Cornwall and Devon. They 

 consist chiefly of yellow copper ore or copper pyrites, and the 

 grey sulphuret of copper. The yellow ore is a compound of 

 sulphur, iron, and copper, in nearly equal proportions. The 

 grey ore, at least what is known in Cornwall under that deno- 

 mination, is almost a pure sulphuret of copper containing about 

 80 per cent, of metal. Yellow ore, which is by far the most 

 abundant, is usually accompanied by iron pyrites, or sulphuret 

 of iron. The earthy minerals that occur with these metallic 

 substances are chiefly siliceous, although in some mines the 

 veins are of an argillaceous or clayey nature, while in others they 

 contain fluor spar, or fluate of lime. Thus the component parts 

 of the Cornish copper ores, as prepared for smelting, may be 

 said to be sulphur, copper, iron, and from 60 to 70 per cent, of 

 earthy matter. To these may be added, as accidental, tin and 

 arsenic; for although these substances are not chemically 

 combined with the copper, still as the ores of tin and copper fre- 

 quently occur in the same vein, it is impossible to effect their 

 complete separation by mechanical means. The quantity, how- 

 ever, compared with the substances above enumerated, is incon- 

 siderable ; for as the miner is not paid for the tin when contained 

 in copper ores, it is of course his interest to separate it as clean 

 as possible. The arsenic is derived from the arsenical pyrites 

 which usually accompanies tin ores. The average produce in 

 copper may be stated at 8} r per cent. 



The ores are conveyed from Cornwall to Wales to be smelted 

 on account of the supply of fuel, as not only carrying the smaller 

 quantity to the greater, the ore to the coal, but because the ves- 

 sels load back coal for the use of the engines of the mines. The 

 principal smelting works are situated on the, navigable rivers of 



New Series, vol. v. i 



