COLLECTIONS IN ECONOMIC GEOLOGY AND METALLURGY. 101 



(C) Black copper, obtained with the Hecoiid matte, coutaius W lo 0,1 per cent, cop- 

 per. (:U27G.) 



(71 Blister 'topper, obtained l)y siiioltiiij; second matte in a reverlxiratory fnruace. 

 (312HU.) 



(8) Slag, obtained in smelting blister csopper. (:U'277.) 



Final jjyodiictii. 



' (I) Ingot, from refining blister copper. (:}12rfl.) 



(2) Refined copper, cast in a long bar for rod rolling. (31282.) 



(3) Refined copper, cast in a plate for sheet rolling, weighs 220 ponuds. (3129fi.) 



THE STE. GENEVIEVE COPPER WORKS. 



These works are located at Ste. Geuevieve, Ste. Genevieve Couuty, 

 Missouri, and treat the ores of the Cornwall Mine, about 12 miles from 

 the works. The ore from the upper levels of the mine was mostly oxi- 

 dized, containing a great deal of malachite and oxides of iron, but as 

 these ores have been gradually worked out more and more of the utial- 

 tered sulphide ores froin the lower levels have been used, necessitating 

 some changes iu the operation. The sulphide ores are roasted in large 

 heaps containing about 100 tons each. This is a slow and tedious oper- 

 ation, requiring sometimes 9 mouths for its completion, and frequently 

 considerable amounts of sulphur remain iu the roasted ores. 



The ores are iirst smelted in channel cupola furnaces for the produc- 

 tion of matte. A charge in this furnace consists of: 



Pounds. 



Raw ore, more or less oxidized 125 



Roasted sulphide ore 12.'> 



Limestone 105 



Iron ore 30 



Coke 85 to 125 



The limestone comes from a quarry near the furnace ; the iron ore is a 

 limonite altered from pyrite, and contains some unaltered pyrite. Basic 

 slags from the roaster and retiuer are used instead of iron ore when 

 they can be had. 



The matte from the cupola smelting is subjected to a roasting fusiou 

 in a re verberatory furnace, called the roaster; 7,000 to 10,000 pounds 

 of matte are charged into the furnace and melted, when the slag is 

 skimmed oft. The slag is allowed to accumulate again until it covers 

 the bath, when it is again skimmed, and this is repeated until all the 

 blastfurnace slag entangled in the matte has been removed. From 

 three to six of these slags are skimmed oft", and are called limestone 

 slags. The bath is then cooled oft a little, and subjected to an oxidiz- 

 ing action to remove sulphur and iron, and when this has been carried 

 far enough, the metal, now caHed pig copper, but really black copper, 

 is tapped from the furnace. The matte yields about 40 per cent, of pig 

 copper in the roaster. 



