1881 Capt. J. Francis LeBaron discovers phosphate pebbles in the Peace River.
1889 Arcadia Phosphate Co. in DeSoto County mines the first commercial phosphate in Florida, beating Polk County producers by a year.
1889 John Jones and W.R. McKee create the Peace River Phosphate Co. Many other companies soon follow.
1890 Polk County's phosphate boom begins in earnest, resulting in a proliferation of mines and company-owned towns.
1891 Phosphate prices fall. Small companies begin failing.
1892 Land pebble production becomes concentrated in Polk County; river pebble production falters further south.
1893 River pebble production peaks; Great Panic strikes, sending nation into depression.
1895 Great Freeze strikes Florida, further depressing phosphate sales
1900 Mulberry forms; railroad-type steam shovels arrive
1902 Mechanized excavation begins using steam shovels and dredges
1908 Production of pebble phosphate from the Peace River ends. In the almost 20 years river pebble was mined, total production equaled 1.2 million tons.
1919 Violent phosphate strike takes place over wages and union recognition. Several residents and workers are killed during the six-month strike.
1920 First full-sized dragline employed by Swift and Co. for strip mining.
1926 Phosphate mines switch to draglines exclusively.
1927 Flotation - in which oil is used to separate phosphate from other materials - is developed, allowing companies to extract more phosphate.
1940s Phosphoric acid is introduced.
1950s Phosphate company-owned towns slowly phase out.
1960s Phosphate experiences its biggest boom, prompting many oil companies to invest in the industry.
1975 Land reclamation becomes mandatory in Florida.
1978 Florida Institute for Phosphate Research established in Bartow.
1980s Consolidation of phosphate companies begins.
1990s Mining operations start moving south.
2000s As mining in Polk County begins to gradually sunset, the industry expands its outlook southward to unmined reserves in Hardee, Manatee, and DeSoto Counties.