Mining Nitrate, Chile


This photograph of sodium nitrate mining in Chile in the first part of the 20th century is from the Frank and Frances Carpenter Collection at the Library of Congress. Frank G. Carpenter (1855–1924) was an American writer of books on travel and world geography, whose works helped to popularize cultural anthropology and geography in the United States in the early years of the 20th century. Consisting of photographs taken and gathered by Carpenter and his daughter Frances (1890–1972) to illustrate his writings, the collection includes an estimated 16,800 photographs and 7,000 glass and film negatives. Nitrate of soda, better known as sodium nitrate (NaNO3), is a salt used as fertilizer and as a raw material in the manufacture of gunpowder. Chile began to export sodium nitrate to Europe in the 1820s. According to Carpenter’s Geographical Reader: South America (1899), the sodium nitrate found in the desert was so valuable that cities grew up “on this barren coast, inhabited by the people who dug out nitrate of soda and prepared it for sale.”The mining process, as described by Carpenter, was as follows: “In getting out the nitrate rock a hole about a foot wide is bored down through the sand, salt rock, and nitrate to the soft earth underneath. A small boy is now let down into the hole. He scoops a pocket out of the earth just under the stratum of nitrate, and fills it with powder, inserting a fuse which extends up over the top. The boy is then pulled out and the fuse lighted. There is a loud explosion. A cloud of yellow smoke and dust goes up into the air, and the earth for a wide distance about is broken into pieces. The nitrate rock is now dug out with picks and crowbars.”

Last updated: May 11, 2015