Avery Island Salt Mine, Louisiana

Cargill operates an underground salt mine inside the Avery Island salt dome, one of five heavily developed domes in a row near New Iberia, Louisiana. Its first salt mines date back to 1862, making it possibly the first salt dome mined for salt in the USA. Cargill extracting around 2.5 million tons per year, mostly for use as road salt, which is shipped by barge to the northeast.