Overview
Stage | Production |
Mine Type | Open Pit |
Commodities |
|
Mining Method |
|
Processing |
- Wash plant
- Wet Screening
- Flotation
|
Mine Life | 2030 |
Source:
p. 1-3
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 South Fort Meade property geology consists of 5 to 50 ft. (1.5 to 15.2 m) of gray to white poorly graded quartz sand with varying abundance of reworked phosphate grains. The economic zone is 0 to 50 ft. (0.0 to 15.2 m) thick, ranging in grade from 30 to 40% P2O5sand comprised gray to gray-blue clayey sands with lincation of red, brown, and white. Phosphate nodules and pellets arc the dominant constituent to gray to gray-blue quartz sands, clays, and phosphate grains and some nodules. The basal units are gray to gray-blue barren clays to phosphatic limestone nibble to beds of phosphatic limestone.
Summary:
South Fort Meade is a phosphates production stage mining facility. Phosphate is extracted using surface mining techniques. Mining is utilizing electric walking draglines to remove overburden and mine the phosphate ore (matrix). The matrix is hydraulicaly transported to the benefication plants via a series of centrifugal pumping systems.
Draglines utilize a one-pass. modified simple side-cast method for overburden removal and mining of matrix. Overburden will be spoiled on top of the ground, in an adjacent mined out cut or pumped, depending on overburden matrix thickness and available area. Geological considerations such as overburden matrix thickness, spoil stacking characteristics and dragline reach arc considered in cut design to ensure spoiled overburden does not encroach on uncovered matrix.
Regardless of the cut type and spoil placement, matrix is mined in a consistent manner. An earthen well is formed with earthmoving equipment outside of the dragline cut but within the dragline dumping radius. After the dragline uncovers an advance of approximately 50 ft. (16 m). matrix is mined and placed in the well where it is slurried with 10.000 US gpm of water at high pressure (250 to 3(X) psi). Once all matrix is mined, the dragline walks back and repeats the process. While the dragline generally advances in one direction the tub follows an arc within the cut as the dragline is dumping matrix to a fixed location. Once the dragline advances past the reach of the well, crews and equipment will move the well 300 ft (91 m) parallel to the cut in the direction of advance such that the new location is within the dragline's reach. Depending on geology and rate of mining, this lakes place every 3 to 5 days.
Mined phosphate matrix is slurried and pumped to the beneficiation plant via a series centrifugal pumping systems. Upon dumping into the well, matrix is slurried by the addition of high-pressure water (250 to 300 psi) at around 10,000 US gpm. Water is delivered via a centrifugal pumping system in a 24 inch (61 cm) outside diameter steel pipeline. Matrix pumping systems are engineered to move 1.800 to 2.200 tons per hour in 20 to 22 inch (51 to 56 cm) outside diameter steel pipelines at a velocity of 15 to 17 fij'sec at the pit (13,000 to 15.000 US gpin). Centrifugal pumps ranging from 1.750 to 2.000 hp arc spaced to match static head and friction resulting from flow and slurry' characteristics. Slurry properties considered in design are concentration, solids density, shape and size distribution. Solid size distribution ranges from six inches to microns. The pumping systems arc controlled by an operator with feedback on slurry flow, density, electrical pump demand and pipeline pressures.
General mill tailings (GMT), already slurried from the Dotation process, arc pumped back into previously mined cuts for reclamation purposes via a series centrifugal pumping system in 20 to 24 inch (51 to 61 cm) outside diameter steel pipe. The same parameters used in matrix pumping design are applied to the tailings pumping system. Solid particles range from 16 mesh (1mm) to 150 mesh (0.1mm). The water is recovered and re-introduced to the recirculating water system for use by the plant or matrix pumping systems.
Flow Sheet:
Crusher / Mill Type | Model | Size | Power | Quantity |
Sizer
|
|
|
|
6
|
Processing
- Wash plant
- Wet Screening
- Flotation
Flow Sheet:
Summary:
The Mosaic processes the ore(matrix) at beneficiation plant. The ore goes through washing, screening, sizing and flotation processes designed to separate the phosphate rock from sands, clays and other foreign materials.
Beneficiation Plant Operations:
Washer
* Removes oversize material.
* Produces “pebble” phosphate.
* Removes clay by scrubbing and rinsing.
* Feeds all undersized phosphate and sand to the sizer.
* Same-sized sand and phosphate is pumped to the flotation plant for separation.
Flotation Plant
* Produces fine-sized “Concentrate” phosphate.
* Uses special additives (mostly biodegradable oils from the pulp and paper industry) to coat the phosphate.
* Phosphate separates from the sand, floats to the top and is skimmed off.
* Pumps sand back to the field for reclamation.
The debris is mineralization rejected due to the high MgO content. The minimum size for the rejected debris is 5/16 inch, % ........

Recoveries & Grades:
Commodity | Parameter | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 |
Phosphate rock
|
Head Grade, %
| ......  | ......  | ......  | ......  | 28.9 | 29.1 | 28.8 |
Production:
Commodity | Units | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 |
Phosphate rock
|
kt
| ...... ^ | ......  | ......  | ......  | 4,200 | 4,400 | 4,200 |
All production numbers are expressed as concentrate.
^ Guidance / Forecast.
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Operational Metrics:
Metrics | 2020 | 2019 | 2018 | 2017 | 2016 |
Annual production capacity
| ......  | 5 Mt of phosphate rock concentrate | 5.5 Mt of phosphate rock concentrate | 5.5 Mt of phosphate rock concentrate | 5.5 Mt of phosphate rock concentrate |
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Reserves at December 31, 2021:
Category | Tonnage | Commodity | Grade |
Proven
|
5 Mt
|
P2O5
|
27.4 %
|
Probable
|
21 Mt
|
P2O5
|
26.7 %
|
Proven & Probable
|
26 Mt
|
P2O5
|
26.9 %
|
Heavy Mobile Equipment as of December 31, 2021:
HME Type | Size | Quantity |
Dragline
|
55 cu. yd
|
.......................
|
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Aerial view:
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