Both the Phoenix and Gryphon deposits are classified as Athabasca Basin unconformity-associated uranium deposits. Phoenix straddles the unconformity contact between the Athabasca Sandstone and underlying basement, while Gryphon is entirely hosted in the basement rocks.

Uranium mineralization at the Phoenix deposit occurs at the unconformity between Athabasca sandstones and basement rocks, with the most intense mineralization adjacent to the WS fault. A minor amount is basement fracture hosted mineralization extending below the north part of Zone A.

Mineralization and alteration have been traced over a strike length of approximately one kilometre. Since discovery hole WR-249 was drilled in 2008, 253 drill holes have reached the target depth, delineating two distinct zones (A and B) of high-grade uranium mineralization.

Mineralization is in the form of the oxide uraninite/pitchblende (UO2).

Average trace metal concentrations for Phoenix assay samples greater than 0.2% U3O8 are as follows: 576 ppm Ni, 194 ppm Co, 319 ppm As, 2,092 ppm Zn, 18 ppm Ag, 7,176 ppm Cu, and 9,143 ppm Pb. Average concentrations of Ni, Co and As are at the low end of the range found in other uranium deposits in the Athabasca basin.

Mineralization at Gryphon occurs 720 m below surface and is centred approximately 220 m below the sub-Athabasca unconformity. It is within 80 m of the unconformity at its highest point and 370 m below the unconformity at its deepest point. The deposit consists of a set of parallel, stacked, elongate lenses that are broadly conformable with the basement geology and associated with a significant fault zone (G Fault) that separates a thin unit of quartzite (quartz-pegmatite) from an overlying graphitic pelite (upper graphite). The lenses dip moderately to the southeast and plunge moderately to the northeast. The deposit is approximately 450 m long in the plunge direction and 80 m wide across the plunge. Thickness is variable and is a function of the number of stacked lenses present, generally varying between 2 m and 20 m. To date, the majority of mineralization is hosted within two lenses associated with the upper and lower graphite units. Two predominant types of mineralization have been noted:
- Irregular Fracture Fill - Weak, dark black, low grade mineralization occurring as blebs and foliation-parallel fracture fill associated with breccias and centimetre-scale dravite veinlets in the Upper Graphite.
- Semi Massive - Black, high grade mineralization associated with hematite and secondary uranium minerals occurring as lenses and pods parallel to foliation. "Worm rock" textures are also observed.

Mineralization at Gryphon is dominated by uraninite/pitchblende, with very minor coffinite and trace carnotite, uranophane, and brannerite. Gangue mineralogy is dominated by alteration clays (illite, kaolinite, chlorite), dravite and hematite with minor relict quartz, biotite, graphite, zircon, and ilmenite. Only trace concentrations of pyrs are noted comprising galena, chalcopyrite, and pyrite.

Average trace metal concentrations for Gryphon assay samples greater than 0.2% U3O8 are as follows: 107 ppm Ni, 62 ppm Co, 30 ppm As, 18 ppm Zn, 14 ppm Ag, 301 ppm Cu, and 3,525 ppm Pb. These concentrations are lower than those recorded for the Phoenix deposit.

Jet bore system (JBS) mining was selected for the high grade Phoenix Zones A and B1, similar to the mining method utilized at the Cigar Lake mine. This mining method requires freeze wall protection in a tent configuration.

The JBS mining method requires an access drill drift within basement (waste) rock below the mineralization. A pilot hole is drilled up into the deposit equipped with a rotating high pressure water jet capable of cutting the surrounding mineralization. A slurry of water and loose broken rock flows by gravity out of the cavity created, down into a receiving car next to the jet bore machine. At the Cigar Lake mine, the JBS method has successfully excavated cavities in the range of 4 to 7 m in diameter. Mined out cavities will be filled with concrete that withstands the force of the water jet when an adjacent cavity is mined. The JBS method allows for mine operators to carry out their work in a protective environment to ensure exposure to high grade mineralization is minimized for all personnel.

Conventional longhole open stoping with backfill is planned for the Gryphon deposit. No freeze wall protection is needed due to the location of the deposit well below the unconformity in basement.
rock.

This PEA study is based on the assumption that the Wheeler River project mill feed will be trucked to an existing uranium mill in northern Saskatchewan for processing under a custom milling agreement. There are currently three such facilities in northern Saskatchewan.

The closest existing uranium mill is the Key Lake operation, owned by Wheeler River joint venture partners Cameco (83%) and AREVA (17%). At present, the Key Lake mill is fully utilized for processing of McArthur River ores and is assumed to be not available for processing Wheeler River deposits.

The furthest existing mill from Wheeler River is at the Rabbit Lake operation, owned by Wheeler River joint venture partner Cameco (100%). It has capacity to process low grade feed such as Gryphon, but is nearing the end of its existing tailings storage capacity. It is uncertain if new capacity will be made available for future potential feed sources.

The third facility, the McClean Lake site’s JEB mill, is owned by AREVA 70%, 22.5% Denison, and 7.5% OURD Canada. Upon completion of upgrades in progress during 2015/2016, the JEB mill will have available capacity in both processing and tailings storage, making it the preferred facility.

The JEB mill process chemistry is typical of acid leach uranium milling, with design details tailored to high grade Saskatchewan ores.

The grinding circuit for coarse dry muck has a SAG mill and a ball mill in closed circuit with cyclones. The slurry receiving circuit is used for container unloading. The two parallel agitated tank leaching circuits use sulphuric acid from an on-site acid plant, and hydrogen peroxide as the oxidizing agent. An on-site oxygen plant is also installed as an alternate oxidant. A six-stage counter-current decantation (CCD) circuit washes the leach discharge slurry, to minimize soluble losses to tailings. The CCD thickener overflow is clarified and then sent to the solvent extraction (SX) step. The dissolved uranium is purified by extraction into the organic phase using tertiary amine and then concentrated in the ammonium sulfate stripping solution. Anhydrous ammonia is added to precipitate the uranium, which is washed and calcined to yield a high purity U3O8 product. Ancillary circuits include an ammonium sulfate by-product crystallization plant, tailings neutralization, and effluent treatment. Tailings are placed in the tailings management facility (TMF) that was originally the JEB open pit mine, adjacent to the mill.