Florida Phosphate Mining History — Florida

Florida is the dominant producer of phosphate rock in the United States, accounting for more than 60 percent of domestic output and approximately 25 percent of global supply, according to the Bureau of Land Management as of September 2025. The industry is geographically concentrated in a region of central Florida known as Bone Valley, spanning parts of Hardee, Hillsborough, Manatee, and Polk counties, where marine sedimentary deposits formed over tens of millions of years. Commercial extraction began in 1883 near Hawthorne in Alachua County and expanded dramatically after pebble phosphate was identified in the Peace River basin in the late 1880s.

Phosphorus is an essential, non-substitutable nutrient in agricultural fertilizers, and Florida's deposits have made the state a linchpin in the international fertilizer supply chain, as documented by the Florida Industrial and Phosphate Research Institute (FIPR) at Florida Polytechnic University in Lakeland. The industry's footprint—mines, beneficiation plants, rail lines, phosphogypsum stacks, and port facilities—developed over more than 140 years and remains entirely confined to the central Florida peninsula. The Florida Department of Environmental Protection (FDEP) reports 28 phosphate mines in Florida covering more than 450,000 acres, of which eleven were active as of its most recent data.

Florida's commercially mined phosphate deposits are products of ancient marine environments in which phosphorus-rich sediments accumulated over geological time. The formation that hosts the dominant pebble phosphate resource—the Bone Valley Formation—lies beneath 15 to 50 feet of overburden, making it one of the most economically accessible phosphate deposits in the world, according to the USGS LCMAP Geonarrative. The name Bone Valley derives from the large number of fossilized bones of prehistoric creatures—including ancestors of the mastodon—found embedded in the phosphate matrix.

The recorded history of Florida phosphate discovery began in 1881, when Captain J. Francis LeBaron of the U.S. Army Corps of Engineers identified phosphate pebbles while surveying the Peace River south of Fort Meade, as documented by the Southwest Florida Water Management District. Commercial extraction in the Peace River basin commenced around 1888, and the FDEP records that hard-rock phosphate mining began even earlier, in 1883, in a belt running from Alachua to Citrus counties in north-central Florida. That northern hard-rock district was largely exhausted by the mid-20th century, leaving the Bone Valley pebble district as the state's economically dominant phosphate region.

The overall phosphate-mining district as defined by the FDEP's Integrated Habitat Network encompasses approximately 1.3 million acres of central Florida land, a geographic footprint that reflects both historical extraction areas and the broader zone of planned or potential future mining.

The discovery of pebble phosphate in the Peace River basin touched off a rapid commercial expansion. By the early 20th century, more than 200 companies were active in central Florida's phosphate fields, as reported by the Thompson Earth Systems Institute at the Florida Museum of Natural History. By the 1980s, Florida's central phosphate district accounted for nearly 30 percent of worldwide phosphate production and approximately 75 percent of U.S. production, according to the USGS EROS Center.

Consolidation over subsequent decades reduced the number of active operators sharply. As of 2023, the USGS Mineral Commodity Summaries 2024 reported that phosphate rock was mined by five companies at nine mines across four states, with total U.S. marketable output estimated at 20 million tons valued at $2 billion. In Florida specifically, the Mosaic Company—headquartered in Tampa and traded on the New York Stock Exchange as MOS—is now the dominant operator, effectively controlling nearly all phosphate production in Bone Valley, as described by the Center for Land Use Interpretation. Canada-based Nutrien operates as the second active company. WUFT reporting from 2023 noted that Mosaic produces approximately 8 million tons of finished phosphate annually in Florida, and that in 2022—a year marked by supply chain disruptions and sanctions on Russian fertilizer exports—Mosaic recorded net income of $3.6 billion while Nutrien recorded $7.7 billion.

The primary extraction method in Florida is open-pit strip mining. Large electric draglines—among the largest earth-moving machines on the planet, according to the Center for Land Use Interpretation's documentation of the Mosaic Four Corners mine—operate around the clock, removing overburden to expose the phosphate matrix. The matrix is then pumped as a slurry through pipelines to a beneficiation plant, where the phosphate pebbles are separated from sand and clay. From the beneficiation plant, the concentrate moves by rail to a chemical processing facility—typically a sulfuric acid plant—where acidulation converts phosphate rock into phosphoric acid, which is in turn processed into fertilizer products such as diammonium phosphate (DAP).

A significant and contested byproduct of that acidulation process is phosphogypsum, a slightly radioactive calcium sulfate material produced in large quantities for every ton of phosphoric acid manufactured. Florida currently holds an estimated one billion tons of phosphogypsum stored in above-ground stacks, according to the Thompson Earth Systems Institute at the Florida Museum of Natural History. U.S. Environmental Protection Agency regulations restrict the use of phosphogypsum outside of stacks due to low-level radioactivity, primarily from radium-226. These stacks also impound large volumes of acidic process water. The Port of Tampa serves as the primary export gateway for Florida's finished phosphate products; the USGS EROS Center has reported that 93 percent of Tampa Bay's exports by volume are phosphates.

The FDEP reports that phosphate mining disturbs between 3,000 and 6,000 acres of Florida land annually, and that approximately 25 to 30 percent of those disturbed lands are wetlands or other surface waters.

Florida's statutory framework for phosphate mine reclamation is rooted in a 1975 law requiring restoration of all lands mined after July 1 of that year. Chapter 378 of the Florida Statutes codifies these obligations, and Manatee County government documentation confirms that operators must obtain county approval for Master Mining Plans before disturbing land. The University of Florida IFAS Extension has reported that in excess of 190,000 acres in Florida are subject to mandatory reclamation requirements under this framework. As of FDEP data, ten mines have been 100 percent reclaimed and released from reclamation obligations.

Before 1975, no reclamation was required. The FDEP's Nonmandatory Land Reclamation Program identifies 149,130 acres across 748 parcels as pre-1975 mined lands and reimburses landowners for approved reclamation costs. The program exists because these lands—stripped of topsoil and left without restoration obligations—represent a legacy liability spread across hundreds of private parcels in central Florida.

The Florida Industrial and Phosphate Research Institute (FIPR) at Florida Polytechnic University in Lakeland serves as the state's principal applied research body for the industry, studying reclamation methods, phosphogypsum management, and the economic dimensions of the phosphate supply chain.

In April 2021, a reservoir dam at the former Piney Point phosphate processing facility in Manatee County began to fail. Governor Ron DeSantis declared a state of emergency, and approximately 215 million gallons of polluted process water were discharged into Tampa Bay, as reported by WUSF. The Center for Biological Diversity reported the discharge fueled a red tide that killed more than 1,600 tons of marine life. The Piney Point site had been abandoned when Mulberry Corporation declared bankruptcy in 2001, placing remediation costs on the state, as documented by FIPR. A separate incident at Mosaic's New Wales plant in Mulberry in 2016 involved a sinkhole that discharged more than 200 million gallons of process water into the Floridan Aquifer, according to the Center for Biological Diversity; the organization noted four major sinkholes at that facility.

In 2023, the Florida Legislature passed HB 1191, which Governor DeSantis signed, directing the Florida Department of Transportation to study whether phosphogypsum could serve as a road base material, as reported by WMNF 88.5 FM. In February 2025, the Center for Biological Diversity filed a federal lawsuit challenging EPA authorization of a Mosaic test road in Polk County constructed with phosphogypsum, citing radon exposure risks for workers, as covered by WUSF. As of January 2026, Florida Phoenix reported that Mosaic had sought Florida legislative protection from lawsuits filed under the Florida Water Quality Assurance Act related to radioactive contamination of residential properties on former mine lands, and that legislative efforts to provide that protection in both 2024 and 2025 had failed to pass.

Florida's phosphate industry intersects with several other state-level systems. The Peace River watershed—the geographic center of Bone Valley—is also a critical freshwater corridor for southwest Florida municipalities and a habitat for listed species including the Florida manatee, linking phosphate regulation directly to water management and wildlife conservation policy. The Floridan Aquifer, the primary drinking water source for millions of Floridians, has been directly affected by process water intrusion from sinkhole events at processing facilities, as documented in connection with the 2016 New Wales incident.

The Port of Tampa's role as the state's phosphate export hub—handling 93 percent of Tampa Bay's export volume by weight, per the USGS EROS Center—ties the industry to Florida's maritime economy and port infrastructure priorities. Phosphogypsum stack regulation intersects simultaneously with federal EPA authority, the state's environmental permitting framework, and ongoing debates over radioactive waste management. The industry's historical labor base—including African American and immigrant workers in early-20th-century mining camps—is a documented chapter of Florida labor and social history. Geographically, the depletion of shallower Polk County reserves is driving proposed southward expansion into Hardee and Manatee counties, placing phosphate permitting decisions in direct tension with agricultural land use, Everglades watershed protection, and the state's growth management framework.