COMMON MINERALS AND VALUABLE ORES. 



IV.— COPPER AND LEAD ORES. 



THEO. F. BKOOKINS, B. S. 



THE first metal that was employed 

 by man is copper. It is prob- 

 able that prehistoric man made 

 use of the metal in its native 

 condition only, as no knowledge of 

 metallurgy would be essential in pre- 

 paring it for use from that condition. 

 Copper implements have been found 

 in the lake dwellings of Switzerland, 

 and bronze, an alloy of copper and tin, 

 is mentioned in the writings of Ho- 

 meric times. 



Cuprum, the origin of our English 

 word copper, is derived from cyprium, 

 which refers to the occurrence of the 

 metal in especial abundance on the 

 island of Cyprus, the main source of 

 the metal during the epochs of early 

 alchemy. In the Hebrew scriptures 

 copper is termed Nehosheth (from 

 nahash, meaning to glisten) which is 

 translated by XatCkos in the Septuagint 

 and by Aes in the Vulgate. Later Aes 

 cyprium was the special designation, 

 which was finally shortened to cyprium, 

 as indicated above. Thus we see that 

 our present term represents in no sense 

 the characteristic of the metal at first 

 so noticeable. 



Native copper scarcely needs a de- 

 scription. Its occurrence in the free 

 state provides an interesting subject of 

 conjecture. Briefly stated, the ques- 

 tion of origin is whether the copper 

 was set free by the decomposition 

 of silicates or was in the form of a 

 sulphide in the rock. The chief re- 

 gion of occurrence of native copper is 

 the Lake Superior district. Here are 

 found occasionally large masses of 

 copper, which, strange as it seems, are 

 practically valueless if too heavy to 

 transport, since they cannot be divided 

 without great dif^culty. Of the world's 

 total output of copper in 1897, 399-250 

 long *tons, a single mine of the Lake 



♦The common short Ion is 2.000 pounds;' tbe'Ionp 

 ton contains 2.240 pounrs; the metrir ton fqual? 2.204 

 pounds. It will be noted that statistics of the produc- 

 tion of different metals frequently employ different 

 tons as units. 



Superior region, the famous Calumet 

 and Hecla, produced 40,350 long tons. 



Montana is now the first copper pro- 

 ducing state in the United States. The 

 state contains the largest mining camp in 

 the world, located in the town of Butte. 

 In 1897 the mines of Montana produced 

 102,800 long tons of copper. The ore 

 chalcocite, sometimes called copper 

 glance, has a metallic luster, often tar- 

 nished green or blue. It is commonly 

 lead-gray and rather soft. Its streak 

 is a blackish lead-gray. Chalcopyrite, 

 a sulphide of copper and iron com- 

 bined, has already been mentioned un- 

 der "Iron Minerals"(November issue of 

 Birds AND All Nature.) When copper 

 is much in predominance the color 

 of the ore is golden yellow. The streak 

 is dark green. The mineral is harder 

 than chalcocite, but less hard than 

 pyrite, being easily scratched with a 

 knife. Both chalcocite and chalco- 

 pyrite frequently occur in silver-bear- 

 ing rocks. 



A method of extracting copper from 

 its ores, equal!}- useful with regard to 

 any of the ores, is known as the Eng- 

 lish process. The details of this are 

 too elaborate and technical for consid- 

 eration here. In brief, the process con- 

 sists of six distinct parts — roasting the 

 mixed ores, fusion of the roasted ores 

 to produce coarse metal, roasting the 

 coarse metal, fusion of the wasted 

 coarse metal to produce what is known 

 as white metal, roasting of the white 

 metal to produce blister copper, i. e., 

 copper filled with cavities, and finally 

 the refining and toughening of the 

 blister copper until marketable copper 

 is yielded. The English method of 

 copper smelting is classed among the 

 so-called "dry" processes, in contra- 

 distinction from "wet" processes, or 

 methods involving the use of solutions. 



It may be of interest to know the 

 importance of copper in that curious 

 problem of ancient alchemy, the trans- 



