Page:Popular Science Monthly Volume 83.djvu/223

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into smaller pieces with a heavy hammer. This is the process of nitrate mining. No operation could be simpler.

If the miner works by the day, he is known as a barretero literally a "crowbar man." If he is paid according to the amount of caliche mined, as the most energetic prefer to do, he is a particular, or private worker. The former earns about 6 pesos to 7 pesos a day, while the latter, under favorable conditions, often makes 9 pesos to 12 pesos a day. A group of particulares, working early and late, quickly dispels any idea that no people of that part of the world will work hard.

Carts or trains of small dumping cars carry the caliche to the maquina, as the refining plant is called. Here it is first crushed into pieces no larger than a man's fist. From the crushers it goes up inclined planes to the boiling tanks, or cachuchos as they are still known, though earthen pots have been replaced by great iron affairs 33 feet long, 9 feet wide and 8 feet deep, capable of holding 70 tons. The newest maquinas have twenty to thirty of these tanks. When the charge of caliche is in, water is added, steam is turned into a coil of pipes which runs around inside the tanks, and the boiling process begins to dissolve out the soluble nitrates from the insoluble and worthless earthy substances. Thus the industry, which in one respect owes its existence to absence of water, must have water in order to operate, for nowhere are there large amounts of caliche rich enough to ship without refining, and the process of leaching is the only economical method of refining.

Much Australian and English coal, costing 35 pesos to 50 pesos or more per ton, is used to generate the steam. About half a million tons of coal have been imported for this purpose in recent years; but the