United States

Four Corners Mine

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Categories

Overview

Mine TypeOpen Pit
StatusActive
Commodities
  • Phosphate rock
Mining Method
  • Dragline
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Mine Life... Lock
SnapshotFlorida phosphates are included three phosphate production stage mining facilities (South Fort Meade, Four Corners and Wingate) and three exploration properties (DeSoto, Pioneer and South Pasture) in Florida consisting of over 210,000 acres of property in Central Florida.
Related AssetFlorida phosphates Operation

Owners

SourceSource
CompanyInterestOwnership
The Mosaic Company 100 % Indirect
The mining facilities and exploration properties are owned by or have controlling interest granted to Mosaic Fertilizer LLC, South Ft. Meade Land Management or South Ft. Meade Land Partnership, L.P. (“SFMLP”), each a subsidiary of Mosaic.

Contractors

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Deposit type

  • Sedimentary

Summary:

The entirety of Mosaic’s mineral reserves and resources exist within sedimentary deposits. Economic phosphorite exists in a matrix of gravels, sands, silts and clays that are readily extractible. These economic deposits overlay a carbonate platform where phosphorite is absent. The bedrock and economic matrix are overlain by sands, clays and silts that are easily removed. Limitations of extraction arc the case of excavation, the capacity of the matrix to slurry, the grade of the phosphorite, gangue minerals, the depth of the matrix, and the overburden to be removed.

Deposition of phosphorite occurred in the Miocene and Pliocene epochs. The depositional environment was shallow marine with sea levels of 300 ft. (100 m) or less. Cold phosphate rich waters were upwelled and mixed with warm surface waters creating vigorous biologic activity. Biological remains settled on the sea floor in regional anoxic zones. Phosphate subsequently substituted into calcium carbonate in the form of the mineral francolite. Accessory- mineralization does occur, but it is of little economic consequence. The deposit underwent transport and rework through marine winnowing. Post-depositional rework is extensive and site factors such as hydrology and groundwater geochemistry influence grade and gangue mineralization.

Gangue minerals are generally limestone, dolomitic limestone, iron concretions of varying sizes and competent clays that resist disaggregation by washing. Limestone, dolomite and iron concretions exist as distinct particles that are inseparable through conventional sizing. There is limited intracrystalline substitution of metals within francolite. Most of the gangue minerals arc distinct particles.

Mosaic's Florida phosphate mining currently consists of three producing facilities and three exploration properties. The geology across all the sites is a consistent sequence of sub- aerial and marine sediments. The upper most sediments are lacking in phosphates. The marine sediments and carbonate system that follow contains an economic concentration phosphate. The lower carbonate system is devoid of phosphate. At a site level, the geology is unique enough to warrant different ore management practices based on gangue clast size, composition and concentration.

The Four Comers property geology consists of 21 to 41 ft. (6.4 to 12.5 m) of gray to white poorly graded quartz sand with varying abundance of reworked phosphate grains as waste overburden. The first economic zone is 13 to 26 ft. (4.0 to 7.9 m) of tan-gray to gray quartz sands, clays and silts with phosphate nodules and pellets present with phosphate grains and clasts predominate. There is an interbedded waste zone of 0 to 10 ft. (0.0 to 3.0 m) in thickness comprised of beds of blue to green barren sandy clays. Occasionally, there are beds of marine limestone and dolostones or marginally phosphatic sandy beds of dolomitic clasts and grains. The second economic zone is 0 to 15 ft. (0.0 to 4.6 m) of dark gray to dark gray-blue-green clays, silts with quartz sands with phosphate nodules and pellets present with phosphate grains.

Reserves

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Mining Methods

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Comminution

Crushers and Mills

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Processing

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Production

CommodityUnits2021202020192018201720162015
Phosphate rock kt  ....  Subscribe  ....  Subscribe6,5006,9006,4005,3005,700
All production numbers are expressed as concentrate.

Operational metrics

Metrics202120202019201820172016
Ore tonnes mined  ....  Subscribe  ....  Subscribe35,159,800 bcy33,740,400 bcy
Annual production capacity  ....  Subscribe  ....  Subscribe7 Mt of phosphate rock concentrate7 Mt of phosphate rock concentrate7 Mt of phosphate rock concentrate7 Mt of phosphate rock concentrate

Production Costs

Commodity production costs have not been reported.

Heavy Mobile Equipment

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EV - Electric

Personnel

Mine Management

Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required May 1, 2024
....................... Subscription required ....................... Subscription required Subscription required May 1, 2024
....................... Subscription required ....................... Subscription required Subscription required May 1, 2024
....................... Subscription required ....................... Subscription required Subscription required May 1, 2024

Total WorkforceYear
...... Subscription required 2023
...... Subscription required 2022
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Aerial view:

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