ORES OF COPPER 
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per cent. of the total and is exceeded by that of seventeen 
other countries. 
The price of copper undergoes great variations, which make 
or mar the fortunes of mining fields. The price of English 
tough copper (994 per cent. of copper; standard copper, 
now generally quoted, has 96 per cent.), was £160 a ton from 
1801-10; the price fell to £55 between 1891-1900; it rose 
to £127 in 1017, but since the War it has again fallen, and 
early in 1927 was below £35. 
The fall in price has been due to the increased output 
especially from America. In 1801-10 Russia was the second 
Producer with 18 per cent. of the total. Australia, towards 
the middle of the last century, was the third producer, but its 
output has fallen by two-thirds. The United States now 
provides sometimes 75 per cent of the world’s output, the 
test coming mainly from Chile, Africa (owing to the growing 
production from Katanga in the Congo basin), Portugal, 
Peru, and Australasia. The world's production in 1890 was 
260,000 tons; the record, 1,415,000 tons, was in 1917 owing 
to the demands of the War, after which there was a serious 
decline; the output has again increased to a little over 
1,400,000 tons in 1925. 
CrassiFicaTioN oF ORES 
Copper deposits may be divided into four chief groups— 
Primary lodes, replacement ores, secondary enrichments, 
and sedimentary ores; the classification is difficult and in- 
definite as the copper minerals, being easily soluble, are liable 
fo" concentration by repeated solution and redeposition. 
Primary and secondary ores often occur in the same mine. 
The value of many mines depends on the secondary enrich- 
ments, the primary ores being of low grade. The copper 
ores may be classified as follows :— 
SECT. A. Primary OrEs— 
L Primary Lodes— 
(2) Pneumatolytic—(1) Svartdal, Norway ; Vogtland, 
Saxony; Rossland; Burra-burra; (2) in vol- 
canic pipe—Braden, Chile. 
(6) Quartz-lodes. Cornwall. 
(c) Pipe-lodes and shoots. Wallaroo; Namaqualand. 
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