| District | Metric quintals | |||||
|---|---|---|---|---|---|---|
| 1897 | 1898 | 1899 | 1900 | 1901 | 1902 | |
| Oruro | 14,256 | 17,215 | 44,256 | 82,269 | 100,206 | 96,981 |
| Chorolque | 8,680 | 10,960 | 20,615 | 40,146 | 68,998 | 56,201 |
| Potosi | 8,361 | 9,153 | 19,826 | 29,979 | 39,175 | 13,365 |
| La Paz | 6,198 | 6,632 | 8,097 | 9,948 | 10,780 | 9,536 |
| Total | 37,495 | 43,960 | 92,794 | 162,342 | 219,159 | 176,083 |
This shows that the production rose from 37,495 metric quintals, in 1897, to 176,083 in 1902. The value as expressed in bolivianos mounted from 2,986,000 to 8,783,000, or from $1,255,000 to $3,689,000. Since then the output has grown continuously. The Potosi district has increased its production steadily, but the greatest development is in the Oruro zone. The tin is exported mainly to Liverpool, though a variable quantity goes to Hamburg. It is subject to a small export duty, the rate being 1.60 bolivianos for each 46 kilograms of bar tin and 1 boliviano for the mineral in the spongy form known as barilla, or black tin. For the bar this is about 70 cents per 100 pounds, and 43 cents for the barilla. The latter is the form preferred for export. In a recent year the exports through the port of Antofagasta were: barillas, 29,583,000 pounds, and bars, 4,686,000 pounds.
In every sense the tin-mining industry may be said to be one of the future, notwithstanding that it has been worked for years chiefly with a view to securing the pure tin and without much regard to the silver associated with the deposits. In the Oruro region some oxidized ores from near the outcrops are operated for tin, but the bulk of the mineral comes from the sulphide zone. From 2 to 4 per cent of tin has been obtained by concentration and lixiviation tailings. In Potosi there are also silver amalgamation tailings. The past development of the industry was due to the building of the railroad from Antofagasta to Oruro. This provided means of transportation which made it profitable to work the tin deposits within the limited zone where lower freights could be assured. The company granted a special tariff for the transport of machinery, fuel, and ores. By the llama or other pack animals it cost about $1.25 per ton for each mile of transportation to the concentration mills. The freight to Europe for each metric ton of 2,204 pounds averaged 35 bolivianos, or $14.90, the proportion charged by the railroad from Oruro to Antofagasta being about 4.89 bolivianos per metric quintal of 220 pounds. Other transport and shipping charges were about 3 bolivianos for each quintal.
Of the world’s total tin output, say 100,000 tons, the Bolivian production under present conditions may be placed at from 9,000 to 10,000 tons, or more than equal that of Cornwall and Australia combined. Since the United States consumes 43 per cent of the entire production of tin, the importance of the development of the deposits in Bolivia and of the transportation facilities should be appreciated.
The richest silver-producing districts of Bolivia are in the western part and along the metalliferous zones of the central plateau which form the base of the great plain. Toward the north, south, and east the ore deposits crown the summits of the Andine sierras sloping to the west. The region is divided into three sections which differ fundamentally in their geological composition. The Department of Potosi is the most abundant in silver ores. In it are situated the deposits of Huanchaca, Aullogas, Colquechaca, Porco, Guadalupe, Chorolque, Portugalete, and Lipez.
The famous, though not fabulous, silver field of Bolivia was the Potosi. It is said that there may be people in the world who never have heard of Bolivia, but there can be no one to whom the name Potosi is unknown. “Were I to pay thee, Sancho,” said Don Quixote to his squire, when the servitor was bargaining to inflict lashes on himself in order to disenchant the knight’s Dulcinea, “in proportion to the magnitude of the service, the treasure of Venice and the mines of Potosi would be too small a recompense.”
The discovery was made by an Indian herder, named Gualca, who was pasturing his drove of llamas when he came upon what seemed to be a white metal cord. It was silver. The cerro, or conical hill, of Potosi at the apex is 4,780 metres, 15,675 feet, above sea-level. The configuration is volcanic. The veins run from north to south, with an average inclination of 75 degrees crossing to the east. The igneous rock which composes the interior mass of the cerro is impregnated in all directions with metallic substances,—lead, tin, copper, and iron. It is distinguished principally by the abundance of silver in the state of chlorides and sulphides. The great system of lagoons or canals was finished in 1621, and cost $2,500,000, or what would be equivalent to-day to $12,000,000. Originally there were thirty-two of these canals.
A chain of authorities from Humboldt to Soetbeer have estimated the silver production of the Potosi district through different periods. From 1545 to 1800 these mines rendered to Spain $163,000,000, which was the tribute that the Crown exacted of one-fifth of the production. This would fix the taxed output at more than $800,000,000, but historians are agreed that this was far from the actual amount. In 1611 the Spanish authorities tabulated 160,000 inhabitants in this district. In 1905 the population was 12,000. This measures the decadence of the industry.
The carved stone head which marks the entrance to the old mint, the one established by the Spaniards in 1585 and kept in operation for more than two centuries, now grins on the few Indians who gather around the fountain under it with their droves of llamas. The grinning head seems to mock their present meagre burdens with the memories of the silver caravans of the past. But it does not follow that those days have gone forever. The Potosi mines await the railway to replace the llama, and they want also modern methods to restore the riches that defy the old processes of mining.
The most productive silver mine in South America is the Pulacayo. It is located in the Province of Porco in the Huanchaca district, and is operated by the Huanchaca Company. The height is 15,153 feet, and the entrance is through a tunnel, or socavon, known as the San Leon. The claim is made that this mine as a silver producer is the second in the world, the first being the Broken Hill of Australia. From 1873 to 1901 the production was 4,520 tons of silver, and the value of the output was estimated at $116,000,000. Formerly the ore was smelted at Huanchaca, Asiento, and Ubina, but now much of it is carried down to Playa Blanca, near Antofagasta. The company employs 3,200 laborers.