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.

Mineralization.
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 ave ........

The December 2012 Feasibility Study (FS) is based on underground room-and-pillar mining with partial pillar extraction in the Lower Phosphate Zone (LPZ). This mining method was selected because the LPZ is a tabular, strata- bound deposit, suitable for mining by heavyduty type coal mining equipment in the LPZ ore bed with bed thickness averaging about 1.6 meters (m).

The underground mine will use the room-and- pillar mining method with partial pillar extraction. Pillars will be sized for 25-m centers to a depth of 850 m and 29-m centers beyond 850 m deep to a maximum depth of 1,100 m. The mine will feature drum-type continuous miners, shuttle cars, roof-bolting machines, feeder-breakers, and mobile roof supports (MRS) for production equipment. At full production, a total of six continuous miners will be employed in three supersections on development and retreat pillar splits. Three of the continuous miners will function as single sections when pillaring.

The annual production is targeted at a nominal 1.0-million tonnes per annum (Mtpa) design mining rate. Underground ore haulage is by 1.2- m-width belt conveyors. Electrical power for the underground mine is provided by a 12,470- volt (V) distribution system, with appropriate step-down transformers located throughout the mine workings for the mobile and stationary electrically powered equipment. Mine drainage water (MDW) will be pumped to the surface and treated prior to reuse or injection via wells. ........

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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