Phosphate - Occurrence and Mining

Occurrence and Mining

Phosphates are the naturally occurring form of the element phosphorus, found in many phosphate minerals. In mineralogy and geology, phosphate refers to a rock or ore containing phosphate ions. Inorganic phosphates are mined to obtain phosphorus for use in agriculture and industry.

The largest phosphorite or rock phosphate deposits in North America lie in the Bone Valley region of central Florida, United States, the Soda Springs region of Idaho, and the coast of North Carolina. Smaller deposits are located in Montana, Tennessee, Georgia and South Carolina near Charleston along Ashley Phosphate road. The small island nation of Nauru and its neighbor Banaba Island, which used to have massive phosphate deposits of the best quality, have been mined excessively. Rock phosphate can also be found in Egypt, Israel, Morocco, Navassa Island, Tunisia, Togo and Jordan, countries that have large phosphate mining industries.

Phosphorite mines are primarily found in:

• North America: United States of America, especially North Carolina, with lesser deposits in Florida, Idaho and Tennessee.
• Africa: Egypt, Morocco, mainly near Khouribga and Youssoufia; Senegal, Togo, Tunisia and Western Sahara, at the town of Bu Craa.
• Middle East: Israel, Saudi Arabia, Jordan, and Iraq, at the town of Akashat, near the Jordanian border.
• Oceania: Australia, Makatea, Nauru, and Banaba Island.

In 2007, at the current rate of consumption, the supply of phosphorus was estimated to run out in 345 years. However, some scientists now believe that a "peak phosphorus" will occur in 30 years and that at "current rates, reserves will be depleted in the next 50 to 100 years." Reserves refer to the amount assumed recoverable at current market prices, and, in 2012, the USGS estimated 71 billion tons of world reserves, while 0.19 billion tons were mined globally in 2011. Phosphorus comprises 0.1% by mass of the average rock (while, for perspective, its typical concentration in vegetation is 0.03% to 0.2%), and consequently there are quadrillions of tons of phosphorus in Earth's 3 * 1019 ton crust, albeit at predominantly lower concentration than the deposits counted as reserves from being inventoried and cheaper to extract.

Some phosphate rock deposits are notable for their inclusion of significant quantities of radioactive uranium isotopes. This syndrome is noteworthy because radioactivity can be released into surface waters in the process of application of the resultant phosphate fertilizer (e.g. in many tobacco farming operations in the southeast USA).