INJURY TO VEGETATION AND ANIMAL LIFE BY 
SMELTER WASTES. 
INTRODUCTION. 
PROCESS OF EXTRACTING METALS FROM ORES. 
Before considering the injurious effects which wastes from plants 
smelting sulphid copper ores may have on vegetation and animal life, 
a brief account will be given of the process generally used to extract 
the metal from the ores. For this purpose an outline of the process 
followed at Anaconda, Mont., will be given, which, though differing 
in some details from the process used at other plants, is based on the 
same general principles and produces similar waste products. 
The ores when they arrive at the plant are graded as first and second 
class, the former being sent to the bins of the blast furnaces and 
the latter to the concentrator bins. The second-class ores are next 
sampled, crushed, and passed over jigs, by which process a product 
richer in copper, known as the * concentrates,” 1s obtained. 
The reject from the jigs is crushed again and passed over jigs fitted 
with finer screens, ‘ concentrates ” being again obtained. After ex- 
tracting all that can be taken out by the jigs, the ore is again crushed 
and passed over the Wilfley tables, thus giving rise to the “ table con- 
centrates.” The concentrates are sent to a bin at the foot of the 
concentrator. There remain in the water used for concentration some 
fine particles of valuable material, and this is allowed to flow into 
ponds outside the plant, where the fine particles settle out in the form 
of “slimes” and the water is finally drawn off. The slimes are 
briquetted and blast-smelted. The waste products from the con- 
centration are known as “ tailings.” These tailings, consisting princi- 
pally of silica, iron, ete., with small quantities of copper and arsenic, 
in case the latter is present, are discharged on the dump heap. 
The concentrates are dumped into roasting furnaces, where large 
quantities of sulphur and arsenic are driven off, the former as 
sulphur dioxid and trioxid and the latter in volatile form. The 
residue, now known as “ calcine,’ is transferred to reverberatory 
furnaces. This process yields (1) a slag consisting principally of 
silicates of iron and calcium with very small quantities of copper; 
(2) a product richer in copper known as “ matte;” and (3) volatile 
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