Chapter III.
COPPER AND TIN.
Copper and tin rank next to gold and silver among the mineral riches of the Republic. The tin mines of the department of Oruro and the copper mines of the department of La Paz are among the richest in the world. The enormous quantity and superior quality of these metals are alone sufficient to give to Bolivia high importance among the mineral-producing regions of America.
COPPER.
Although it is said that the famous mountain of Potosi produced from 1545 to 1864 silver to the amount of 600,000,000 pounds sterling, or $2,919,900,000 (United States money), the mountains adjacent to Corocoro, near the Desaguadero River, are as abundant in copper as Potosi was in silver at the time of its discovery in 1545, while, unlike Potosi, their wealth is yet to be extracted. The annual production is about 4,000 tons, of which about 3,000 tons are exported and 1,000 tons are consumed in the country.
There are three grades of ore: (1) Native copper, called charqui, containing from 80 to 98 per cent of the metal. The present production, amounting to about 1,000 tons per year, is used in working the silver ores of the country. (2) Oxide of copper containing about 40 per cent of the metal. As this grade must be reduced by smelting it is but little used, owing to the cost of fuel. (3) A copper-bearing sandstone yielding granulated copper known as barilla. The metal is extracted by first smelting
