Source:
p. 44
The Property is controlled solely by Itafos through its 100% subsidiaries, Itafos Conda LLC (Itafos Conda) and Paris Hills Agricom, Inc. (PHA). Itafos’ subsidiaries control surface and mineral rights on the Property through leases from private landowners and on public lands from the State of Idaho and U.S. Federal government.
Summary:
Property lies within the Rocky Mountain Physiographic Province in southeastern Idaho, United States of America. The geologic units within the study area are generally marine sedimentary deposits that range from Pennsylvania to recent in age.
The local and project geology of the deposits of the Itafos Conda projects are generally similar in that they are structurally dominated by a series of northwest / southeast trending anticlines and synclines with thrust and normal faults disrupting the strata.
The Meade Peak Member of the Phosphoria Formation contains the phosphate ore within the Conda Projects and is overlain by the Rex Chert member and underlain by the Park City Formation. The Quaternary Alluvium is not very extensive and where present, is only about 5 ft to 20 ft thick.
The Meade Peak Member is broken into five mining zones throughout the Conda Projects where the Upper Phosphate and Lower Phosphate Zones are the primary phosphate mineralized zones. The significant mineralized zones encountered on the property are shown below:
- Upper Overburden Zone (Hanging Wall mud).
- Upper Phosphate Zone - Low/medium to high grade phosphate zone. Interbedded phosphorite, mudstone, siltstone, limestone, and shale.
- Center Interburden Zone – Shale and mudstone.
- Lower Phosphate Zone – Low to high grade phosphate zone. Interbedded phosphorite, mudstone, siltstone, limestone, and shale.
- Lower Underburden Zone (Footwall mud) – Reddish brown siltstone with black fossiliferous siltstone and some phosphorite.
The phosphate mineralization is sedimentary in nature, occurring in a conformable sequence of alternating phosphatic and weakly- to non-phosphatic shale, mudstone, carbonate, and chert beds within the Meade Peak Member of the Permian Phosphoria Formation. The Phosphoria Formation occurs within the Western Phosphate Field that occupies in excess of 135,000 square miles, spanning Eastern Idaho, Southern Montana, Western Wyoming, and northern half of Utah (Sheldon 1989).
The phosphate mineralization encountered in the Meade Peak Member is stratigraphic in nature and the deposit type is considered a typical example of a marine sedimentary phosphate deposit. The phosphate mineralization occurred during the primary depositional processes and there are no known secondary phases of phosphate mineralization or enrichment identified in the deposits.
The beds of the Meade Peak Member were deposited within a marine sedimentary basin within the Phosphoria Sea that marked the western margin of the North American craton approximately 250 Ma. During the period that the Meade Peak Member was being deposited, access to the open ocean was intermittently restricted by barrier islands during cyclical periods of eustatic sea level change resulting from periods of glaciation and deglaciation (Sheldon, 1984). This cyclical process resulted in the alternating beds of phosphatic shale and mudstone with layers of non-phosphatic shale, carbonate, and chert beds.
The phosphate mineralization within the Meade Peak Member consists of apatite pellets, oolites, and sand grains, some of which are further cemented together into clusters of pellets and grains in an apatite cement; the apatite within the Meade Peak is entirely in the form of carbonate fluorapatite (Altschuler et. al. 1958). Individual beds of the Meade Peak Member are laterally continuous over significant distances, with some beds commonly found distributed over tens of thousands of square miles within the Western Phosphate Field (Sheldon 1989); however, the thickness and geometry of the beds has been locally impacted on a deposit scale by both primary depositional variability as well as post-depositional structural modification due to both regional and deposit scale faulting and folding.
Summary:
A combined RVM and LCM mine production schedule was prepared to provide 548 Kt dry of P2O5 annually to the CPP. The mine production schedule includes the existing temporary LCM stockpile and the RVM/LCM combined stockpile located at the WV Tipple.
Rasmussen Valley Mine
During operations, direct placement of overburden as pit backfill (concurrent reclamation) reduces the volume of material requiring re-handle post mining. Direct placement of overburden is not always possible as the volume of overburden and available volumes of open pit space are not always fully synchronized. As such the RVM will create overfill piles that will be placed on backfill during mining.
Lanes Creek Mine
The LCM is designed as a three-phase mine from south to north with no opportunity for concurrent reclamation. Therefore, three piles external to the pit are designed to temporarily store overburden during mining. The northern pile is designed for non-Selenium Overburden, the eastern pile is designed for Growth Media (GM), and the southern pile is designed for Selenium Overburden. The southern Selenium Overburden pile is built on top of the historic external pile.
Flow Sheet:
Crusher / Mill Type | Model | Size | Power | Quantity |
Impact crusher
|
|
|
|
1
|
Ball mill
|
|
11.5' x 21.5'
|
1260 kW
|
2
|
Rod mill
|
.......................
|
9' x 12'
|
373 kW
|
1
|
Summary:
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.
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.
Under these conditions used in grinding, the production of finer than 325-mesh material (44 µm) is limited to between 5.5% and 9.8%, contributing to a small fraction of the overall tailings (-325 mesh or -44 µm) of 32.11% produced.
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.
Processing
- Wash plant
- Dewatering
- Vacuum filtration
Flow Sheet:
Summary:
No ore processing occurs at any of the mineral projects. However, phosphate ores to be mined and delivered must be suitable for consumption by the CPP. Suitable for consumption means that delivered phosphate ores may be blended, if needed, and washed to meet certain quality characteristics required of the chemical plant feed. This Item includes information on the recovery methods use at the CPP Wash Plant that is used to process RVM and LCM ores to meet the requirements of the CPP. This Item also includes information on CPP Wash Plant upgrades that are likely to be needed to process mined tonnages delivered from the H1 and NDR mineral resources. The above is achieved by feeding the material to the Wash Plant at -8 inch, and subject it to horizontal scrubbing, sizing, crushing and grinding, classification, and dewatering unit operations.
Wash Plant
The Wash Plant comprises physical unit operations to separate the phosphate minerals from aluminum silicates, clays, quartz ........

Production:
Commodity | Units | 2020 | 2019 |
Phosphorus
|
t
| ......  | ......  |
All production numbers are expressed as oxide.
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Operational Metrics:
Metrics | 2020 | 2019 |
Annual processing rate
| ......  | |
Annual mining capacity
| ......  | 2.2 M tons of ore |
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Reserves at December 31, 2020:
Category | Tonnage | Commodity | Grade | Contained Metal |
Proven & Probable
|
13.1 Mt
|
P2O5
|
26.6 %
|
3.5 Mt
|
Measured & Indicated
|
50.3 Mt
|
P2O5
|
25.5 %
|
12.5 Mt
|
Inferred
|
0.7 Mt
|
P2O5
|
25 %
|
0.2 Mt
|
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