F1 Four Corners Mine

MYAKKA RIVER· Manatee, Florida· Built 1989· Earth· 55 ft tall
Significant Hazard Tailings Private

Key Takeaway

F1 Four Corners Mine is classified as significant hazard in Florida. It was completed in 1989 and is 37 years old. Its primary use is tailings. Significant hazard means failure could cause economic or environmental damage. Learn more.

Physical Details

Dam Height 55 ft (taller than 89.6% in FL)
Dam Length14,160 ft
Dam TypeEarth
Max Storage17.5K acre-ft
Normal Storage16.1K acre-ft
Surface Area322 acres
Drainage Area1 sq mi
Max Discharge80 cfs
Year Completed1989 (37 years old)
NID IDFL11049

Safety Information

Significant Hazard

No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities.

Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?

Emergency Action Plan: Yes
Last Inspection: January 23, 2006
State Regulated: Yes
Regulatory Agency: FDEP

Ownership

THE MOSAIC COMPANY

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of F1 Four Corners Mine?

F1 Four Corners Mine is classified as Significant Hazard. No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates F1 Four Corners Mine?

F1 Four Corners Mine is owned by THE MOSAIC COMPANY (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was F1 Four Corners Mine built?

F1 Four Corners Mine was completed in 1989, making it 37 years old. Many U.S. dams were built between the 1930s and 1970s during a period of major infrastructure investment.

What is the primary purpose of F1 Four Corners Mine?

F1 Four Corners Mine serves the following purposes: Tailings. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is F1 Four Corners Mine?

F1 Four Corners Mine has a dam height of 55 ft. Dam height is measured from the natural streambed at the downstream toe to the top of the dam, and may differ from the visible height.

When was F1 Four Corners Mine last inspected?

F1 Four Corners Mine was last inspected on January 23, 2006. Inspection dates indicate when a formal review occurred, not the results of that inspection.

Data from the National Inventory of Dams (NID) maintained by the US Army Corps of Engineers. Dam conditions may have changed since the last update. This site is not affiliated with USACE. Do not use for emergency planning — contact your local dam safety program.