Phosphate mining in the United States

In 2015, 27.6 million metric tons of marketable phosphate rock, or phosphorite, was mined in the United States, making the US the world's third-largest producer, after China and Morocco.

As of 2016, remaining reserves of phosphate rock in the United States totaled 1.1 billion metric tons.

Parts of the Phosphoria Formation of the western United States carry economic grades of phosphorus.

The Phosphoria has been mined in a wide area stretching north-south from southwest Montana, through western Wyoming and southeast Idaho, and into northeast Utah.

[10][11] Phosphate rock was formerly mined in Beaverhead, Granite, Powell, and Silver Bow counties in southwest Montana.

Small amounts of phosphate were mined from igneous apatite deposits in Virginia, New Jersey, and New York.

[12] Most phosphate mining is of sedimentary phosphorite, a phosphorus-rich deposit formed under shallow marine conditions.

[13] The Florida Hard Rock district mines phosphate from the Alachua Formation of Pliocene age.

[13] The North Carolina phosphate deposit occurs in the Pungo River Formation of Miocene age.

The highest-grade deposits were found where weathering or shallow groundwater had preferentially dissolved away the calcium carbonate.

Although not presently mined, phosphate deposits occur in the Brazer limestone of Mississippian age in Utah.

Access to river transport and proximity to the port of Charleston encouraged exports, and by 1885 South Carolina was producing half the world's phosphate.

The United States was the world's largest producer of phosphate rock from at least 1900, up until 2006, when US production was exceeded by that of China.

[17] These tailings piles and related ponds and dams can be sources of toxic chemicals, and are vulnerable to breach.

For example, the 2021 Piney Point phosphate plant dam breach is predicted to have significant negative impacts on Tampa Bay.

In 2015, fluorosilicic acid equivalent to 114,000 tons of fluorite (fluorspar) was produced as a byproduct of phosphate rock processing.

[21] Some parts of the Phosphoria Formation, which is mined for phosphate in the western US, contain potentially economic concentrations of vanadium.

In 2008, Rocky Mountain Resources announced that they had defined 6.7 million tons of ore containing 0.88 percent V2O5, at its Paris Hills prospect.