United States

Paris Hills Project

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Mine TypeUnderground
StatusInactive / Suspended
  • Phosphate rock
Mining Method
  • Room-and-pillar
  • Continuous
Mine Life19 years (as of Jan 1, 2013)
ShapshotParis Hills is a high-grade phosphate mine project. Itafos Inc. decided to wind down Paris Hills following completion of the Conda Technical Report, which defined Husky 1/North Dry Ridge (“H1/NDR”) as the Company’s path forward for mine life extension at Conda and decided to wind down Mantaro as part of its cost savings initiatives. As at December 31, 2022, the Company has completed the wind down process of Paris Hills.


Itafos Inc. 100 % Indirect
Paris Hills is controlled solely by Itafos through its 100% subsidiary Paris Hills Agricom, Inc. (PHA).



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Deposit type

  • Sedimentary


Phosphate and vanadium-rich mineralized beds within the Paris Hills Phosphate Project (the Property) are hosted in the Meade Peak Member of the Permian Phosphoria Formation. The Phosphoria Formation is folded into the Paris Syncline, a north-plunging asymmetrical syncline with a gently dipping to horizontal eastern limb and a steeply dipping to overturned western limb. The mineralized beds dip north-northwest between 7 degrees (°) and 22° along the northplunging horizontal limb of the syncline. The horizontal limb contains the principal resource target with additional mineralization contained in the steeply dipping, upturned limb of the syncline.

The target phosphate mineralization is contained in two zones (beds) within the Meade Peak Member, the Upper Phosphate Zone (UPZ) and Lower Phosphate Zone (LPZ), which range in depth from outcrop to more than 1,000 meters (m) deep. Vanadium is contained in a zone located immediately below the UPZ. Mineralization in the upturned limb has a strike length of over 3 km on the Property.

At PHA ( Paris Hills Agricom), three stratiform-bedded zones within the Meade Peak Member of the Phosphoria Formation are of potential economic interest. These are, from top to bottom:

- Upper Phosphate Zone (UPZ) occurs approximately 3 m below the contact with the Rex Chert Member. Based on historical evaluation of outcrops, trenches, underground workings and drill penetrations, this bed averages about 4.6 m thick and averages between 21 percent (%) and 25% phosphorus pentoxide (P2O5). The UPZ is regionally called the “D” bed and consists of interbedded pelletal and argillitic material with a relatively sharp lower contact grading upward to higher grade coarse pelletal and pisolitic phosphorite and mudstones (Hale 1967).

- Vanadium Zone (VZ) occurs as three beds, lies immediately below the UPZ, and is designated the “D1” bed. Based on historical reports, it averages between 3.4 and 3.8 m thick with an average vanadium pentoxide (V2O5) grade of 0.74% to 0.92%. The VZ includes three lithologic types with different vanadium grades.

- Lower Phosphate Zone (LPZ) occurs about 1.5 m above the Meade Peak Member’s contact with the underlying Wells Formation and approximately 50 m below the VZ. Regionally called the “A” bed, it is a high-grade pelletal phosphorite overlying a basal mudstone and phosphoric fish- scale marker bed (Hale 1967). This bed ranges from 1.1 to 2.9 m thick and averages an overall grade of about 25.0% P2O5. Resource grades were subject to a cutoff of greater than or equal to 24%, resulting in much higher average grade.

In addition to the three beds described above, there are significant intervals located between the VZ and the LPZ, ranging from 3 to 15 m thick, and averaging from 10% to 15% P2O5.

The mineralized beds described above occur in both the upturned limb and the horizontal limb of the Paris Syncline. Grades and thicknesses in both the upturned limb and the horizontal limb of the anticline are similar, although improvement in grade is noted in areas where the phosphorite has been weathered and/or alteration. This is largely due to driving off contaminants such as calcium carbonate in the weathering process, thereby concentrating the grade. That process may be by chemical or mechanical means and may occur due to areal and sub-areal exposure and faulting.

Mineralization in the upturned limb has a strike length of over 3.2 km and extends from the surface to a depth exceeding 1,000 m, depending on the location of outcrops along the northtrending strike. Depths of the horizontal limb range from surface along the north side of Bloomington Canyon to estimated depths of 915 to 1,035 m at Paris Canyon.



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Mining Methods


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Crushers and Mills

Milling equipment has not been reported.


Impact Crusher
The 8 x 1.375-inch coarse size fraction (203,200x34,925 µm), considered of medium hardness (about 9.0 kwh/t), is submitted to crushing in an impact crusher to liberate, at the coarser size fraction possible, the impure phosphate fluor or hydroxy-apatite from coarse dolomite and other impurities, such as aluminum silicates, clays, quartz, and iron bearing minerals.

This unit operation is carried out in an open circuit, receiving about 20% of the total plant feed (70 tph), and sending the crushed product to join the 1.375 x 0.25-inch size fraction (34,925 x 6,350 µm). Then, this material is pumped to feed the rod mill for further size reduction and liberation of impure fluor or hydroxy-apatite of contaminants. From the characterization studies, it is clear that liberation of the impure fluor or hydroxy-apatite of contaminants requires to be ground to -0.375 inch (-9,525 µm).

Rod Mill Grinding and Sizing
The final size reduction unit operation is conducted in an Allis Chalmers 9 ft x12-ft Rod Mill using 4-inch diameter rods. These 4-inch diameter rods are used to avoid excessive grinding, since the Bond Work Index is about 9.7 kwh/ton (considered soft in the rock hardness range). The rod mill is loaded to an occupied volume of 30% to 35% and operated at 64.8% Cs (16.56 rpm).

Then, the ground product is sized in a trommel attached to the rod mill. This trommel consists of two concentric screens of 0.375 inch (9,525 µm), and 1-inch openings (25,400 µm); thus, producing a +1 inch (+25,400 µm), 1 x 0.375 inch (25,400 x 9,525 µm), and -0.375-inch size fractions (-9,525 µm). A minimum amount of +1-inch material (+25,400 µm) is produced, and it is rejected. The 1x0.375-inch size fraction (25,400 x 9,525 µm) returns to the rod mill as circulating load to be reground, and the -0.375-inch size fraction (-9,525 µm) joins the -0.25-inch material (-6,350 µm) to be submitted to classification.

Ball Mil Grinding
The Washer Plant concentrate is reclaimed by a belt conveyor from the stockpile using dozers, or front-end loaders, to feed a belt conveyor hopper. This belt conveyor feeds the chute of the North Ball Mill while a second one feeds the South Ball Mill. The product is ground in two FFE ball mills 11.5 ft x 21.5-ft running in parallel. These ball mills are fed with 0.375-inch x 325-mesh beneficiated phosphate concentrate (9,525x44 µm) to be ground to 98% -35-mesh size fraction (-420 µm) to allow an acceptable recovery in the PAP.



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CommodityUnitsAvg. AnnualLOM
Phosphate rock Mt 117
All production numbers are expressed as ore.

Operational metrics

Annual production capacity 000
Annual mining rate
* According to 2019 study.

Production Costs

Commodity production costs have not been reported.

Operating Costs

Total operating costs ($/t milled) USD 69.5 *  USD
* According to 2013 study.

Project Costs

MetricsUnitsLOM Total
Initial CapEx $M USD  ......  Subscribe
Sustaining CapEx $M USD  ......  Subscribe
Total CapEx $M USD  ......  Subscribe
Pre-tax NPV @ 8% $M USD  ......  Subscribe
After-tax NPV @ 8% $M USD  ......  Subscribe
Pre-tax IRR, %  ......  Subscribe
After-tax IRR, %  ......  Subscribe
Pre-tax payback period, years  ......  Subscribe
After-tax payback period, years  ......  Subscribe

Heavy Mobile Equipment


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Mine Management

Source Source
Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Jul 1, 2019
....................... Subscription required ....................... Subscription required Subscription required Jul 1, 2019
....................... Subscription required ....................... Subscription required Subscription required Sep 24, 2021

Aerial view:


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