Summary:
The Arrow Deposit is considered to be an example of a basement-hosted, vein-type uranium deposit.
Mineralization occurs at the following seven locations on the property and is exclusively hosted in basement lithologies below the unconformity within the Athabasca Group.
• Arrow Deposit
• South Arrow Discovery
• Harpoon occurrence
• Bow occurrence
• Cannon occurrence
• Camp East occurrence
• Area A occurrence
Arrow Deposit
The Arrow Deposit is thought to be hosted in quartz-feldspar-garnet-biotite (± graphite) gneisses that are predominantly silicified. They consist of garnet porphyroblast pseudomorphs, which are now almost exclusively altered to chlorite, hematite, illite, or sudoite. Other minor mineral phases present include plagioclase, potassium feldspar, biotite, muscovite, and amphibole, in varying concentrations. Additionally, the Arrow Deposit is also marked by the presence of intermediate orthogneisses consisting of quartz monzodioritic to quartz dioritic gneiss with tonalitic, granodioritic, and granitic gneiss. The main foliation present in the Arrow Deposit area trends towards the northeast and has vertical to sub-vertical dips. Hydrothermal alteration that occurs in the vicinity of the Arrow Deposit is extensive and several distinct styles have been observed:
• Quartz–sericite–sudoite–illite alteration
- A pervasive alteration assemblage that nearly completely replaces the host rock, although pre-alteration textures are often preserved.
• Hematite alteration
- Pervasive and brick red in colour.
• Dravite
- Occurs in centimetre- to decimetre-wide breccia vein bodies beginning tens of metres from HG uranium mineralization and increasing in size and frequency
closer to mineralization.
• Drusy quartz
- Centimetre sized veins that occur ubiquitously in the vicinity of the deposit. Where proximal to HG mineralization, these veins are often pink coloured.
Mineralization at the Arrow Deposit occurs within six graphitic shears, referred to as the A0, A1, A2, A3, A4, and A5 shear zones. Each shear zone is oriented parallel to foliation which strikes at approximately 050° to 060° and dips vertically to subvertically. The mineralization within the shear zones is also oriented parallel and subparallel to the regional foliation. Of the recognized main parallel structural shear zones (A0, A1, A2, A3, A4, and A5), the A2 and A3 shears host higher grade, thicker, and more continuous mineralization than the other shear zones. A continuous zone of higher grade mineralization in the A2 shear is known as the higher grade A2 High Grade Zone (A2-HG).
Two key types of uranium mineralization occur at the Arrow Deposit: open space fillings and chemical replacement style uranium mineralization.
Open space fillings include massive uraninite bodies interpreted to be uranium veins, and breccia bodies where the matrix nearly exclusively comprises massive uraninite. Uranium veins and breccias typically range in thickness from less than 0.1 m to greater than 1.0 m, and display sharp contacts with the surrounding wall rocks. Clasts present in uranium breccias at the Arrow Deposit are fragments of the immediate wall rocks, and they often contain additional disseminated uraninite mineralization. Uranium breccias occur in both clast-supported and matrix-supported forms, with the latter typically hosting higher uranium grades. Both styles of open space filling mineralization are characterized by high uranium grades.
Chemical replacement types of mineralization at the Arrow Deposit include disseminated, worm-rock, and near-complete to complete replacement styles. Disseminated mineralization is typically associated with strong to intense hydrothermal alteration where uraninite occurs as fine to medium grained anhedral crystals, and as crystal agglomerates spread throughout the host inconcentrations of typically less than 5% by modal composition. Worm-rock style mineralization is named for the texture it causes in rocks, which is the result of redox reactions between uranium-bearing fluids and the host wall rocks. Typically, these redox fronts are less than 10 cm thick.
Near-complete to complete uraninite replacement of the host rock has also been observed at the Arrow Deposit. These zones range in thickness from less than 0.1 m to greater than 1.0 m. Uranium mineralization on the property dominantly occurs as uraninite. Other common uranium minerals include coffinite and secondary yellow-coloured minerals, currently interpreted to be autunite, carnotite, and/or uranophane.
Harpoon Occurrence
The Harpoon occurrence is located 4.7 km northeast of the Arrow Deposit, and it has been traced over a strike length of 350 m. Harpoon mineralization expresses parallel foliation, striking towards the northeast at approximately 035° to 045°, and dipping towards the southeast at approximately 60° to 70°. Uranium mineralization occurs as semi-massive to massive uraninite veining and as worm-rock styles, chemical solution fronts, replacement bodies, and as fracture coatings.
Bow Occurrence
The Bow occurrence is located 3.7 km northeast of the Arrow Deposit. Anomalous uranium values occur at or just below the unconformity in fractured, slickensided, and sometimes brecciated sandstone and basement quartz feldspar-biotite (± graphite) gneisses. A strongly silicified unit was also noted in several drill holes.
Cannon Occurrence
The Cannon occurrence is located 1.3 km northeast of the Arrow Deposit. Strong hydrothermal alteration, which typically includes illite-sudoite-hematite mineral assemblages, was commonly intersected in the basement rock in the area of the Cannon occurrence. The alteration zones remain open in all directions, and at the unconformity.
Camp East Occurrence
The Camp East occurrence is located approximately 2.3 km south-southwest of the Arrow Deposit. Two distinctive alteration styles are generally present in the Camp East occurrence area including the following.
• Near-complete to complete silica replacement, with accessory clay and hematite.
• Moderate to intense white clay and dravite alteration where near-complete to complete clay replacement is observed over core lengths of up to 12 m.
Area A Occurrence
Area A is situated approximately 3.5 km southwest of the Arrow Deposit. Mineralization occurs within a 29 m wide shear zone marked by faults, fractures, a variety of veins, and breccias.
South Arrow Discovery
The South Arrow Discovery is located 400 m south-southwest of the Arrow Deposit. The South Arrow Discovery consists of two parallel mineralized shear zones, with an overall strike of 290 m and is observed to occur within an 80 m wide area that extends from 110 m from surface to a depth of 550 m. The shear hosting the South Arrow Discovery mineralization strikes to the northeast at approximately 045°, and dips towards the southeast between 70° and 83°. The mineralization at the South Arrow Discovery remains open in most directions and will require follow-up drilling. Uraniummineralization at the South Arrow Discovery is exclusively basement-hosted, and lithologies observed in the area include porphyroblastic quartz-feldspar-garnetbiotite (± graphite) gneiss and intermediate orthogneisses. The mineralization consists of en-echelon uranium veins that occur within or proximal to chloritic and graphitic shears, with associated clay alteration. Uraninite mineralization occurs as semi-massive veining, worm-rock styles, chemical solution fronts, replacement bodies, and fracture coatings.