Russell Lake

Highlights:

• The 73,314 ha Russell Lake Project is strategically located on a prolific uranium corridor in the central part of the Eastern Athabasca Basin of northern Saskatchewan
• Highway 914 and a high-voltage power line cross the western claims, with a fully permitted 40-person camp on-site just 5 km from Denison’s Phoenix deposit
• Historically the property has seen 95,000+ metres of drilling in 220+ holes, providing a strong dataset to guide high-priority targets with near-term discovery potential
• Previous work outlined multiple high-priority targets, including historical high-grade intercepts and 35 km of untested conductors in favourable basement rocks
• Skyharbour completed an inaugural drilling campaign which consisted of 9,595m in nineteen holes over three phases back in 2023
• A total of 5,152 metres of drilling in ten holes was drilled earlier in 2024 with an additional 4,500 metres of drilling completed in late 2024
• High-grade, sandstone-hosted mineralization of 2.99% U₃O₈ was intersected over 0.5 metres in hole RSL24-02 at the new Fork Zone within an interval of 0.721% U₃O₈ over 2.5 metres from 338.1 to 340.6 metres downhole just above the unconformity
• Skyharbour carried out additional phases of drilling in 2025 and is planning for a substantial drill campaign in 2026
• In November 2025, Skyharbour announced a transformative Strategic Agreement  with Denison Mines at the Russell Lake Uranium Project; this new partnership brings Denison in as a strategic and funding partner to advance Russell alongside Skyharbour
• The property transaction totals up to CAD $61.5 million in combined consideration from Denison ($21.5M in cash and shares, and $40M in exploration expenditures), with Denison acquiring between 20% to 70% ownership interests across various claims at Russell over seven years
• The project has been reorganized into four distinct properties — Russell Lake (RL), Getty East, Wheeler North, and Wheeler River Inliers with Skyharbour owning an initial JV interest of 80%, 70%, 51% and 30%, respectively, in the properties (Denison can earn up to 70% at the Getty East and Wheeler North properties)
• Skyharbour will remain operator of the majority of the project consisting of the RL and Getty East properties, continuing to drive exploration while both geological teams will work collaboratively to advance the various property areas

Overview of Russell Lake Project:

The Russell Lake Project is a 73,314-hectare advanced-stage uranium property strategically located between Cameco’s Key Lake and McArthur River operations, adjoining Denison Mines’ Wheeler River Project to the west and Skyharbour’s Moore Project to the east. Highway 914 and a high-voltage powerline run directly through the property, which also hosts a fully permitted 30+ person exploration camp just 5 km from Denison’s Phoenix deposit. With Russell Lake and Moore combined, Skyharbour now possesses interest in nearly 109,019 hectares of highly prospective claims in one of the most active uranium districts in the world.

Russell Lake has seen extensive historical exploration, though much of it predates the major modern discoveries in the region. Historically the property has seen 95,000+ metres of drilling in 220+ holes, providing a strong dataset to guide high-priority targets with near-term discovery potential. Previous work outlined multiple high-priority targets, including historical high-grade intercepts and 35 km of untested conductors in favourable basement rocks.

Skyharbour completed an inaugural drilling campaign which consisted of 9,595m in nineteen holes over three phases back in 2023. The drilling confirmed uranium mineralization over a one-kilometre strike at the Grayling Zone, highlighted by 5.9 m of 0.151% U₃O₈, including 1.0 m of 0.366% U₃O₈.

A total of 5,152 metres of drilling in ten holes was drilled earlier in 2024 with an additional 4,500 metres of drilling completed in late 2024. The 2024 winter drill program led to a new discovery at the Fork Zone, where hole RSL24-02 intersected 2.5 m of 0.721% U₃O₈, including 0.5 m of 2.99% U₃O₈ just above the unconformity—the best intercept historically at the project.

Skyharbour carried out additional phases of drilling in 2025 and is planning for a substantial drill campaign in 2026.

Russell Lake Strategic Agreement with Denison Mines:

In 2025, Skyharbour entered into a major strategic partnership with Denison Mines, whereby Denison acquired Rio Tinto’s previous interest and joined Skyharbour as an active funding and operating partner at Russell Lake. The transaction, valued at up to C$61.5 million in combined consideration, establishes Denison as a key strategic shareholder and joint venture partner, with earn-in rights of 20% to 70% across the newly restructured Russell Lake property package. Skyharbour remains the operator across the majority of the project area, including the Russell Lake (RL) and Getty East claims, while Denison will lead exploration at Wheeler North and the Wheeler Inlier claims.

The partnership brings significant technical and financial strength to accelerate discovery efforts at Russell Lake, leveraging Denison’s expertise and proximity to Wheeler River. It also provides Skyharbour with substantial near-term funding and long-term exposure to one of the most prospective uranium corridors in the Athabasca Basin.

After the upfront payment, Denison will acquire an initial 20% in the RL claims, 49% interest in Wheeler North,  30% in Getty East, and 70% in the Wheeler River Inlier claims.

Russell Lake (RL) includes 53,192 hectares over 16 claims and remains Skyharbour’s core land package within the broader property area. These claims host multiple high-priority targets including Christie Lake, NE Russell, Blue Steel, Taylor Bay, South Russell, and Kowalchuk Lake. Skyharbour will continue as operator and majority 80% owner. Denison must fund its 20% pro-rata share of expenditures, up to a maximum of C$10 million, to maintain its initial interest.

Wheeler North consists of 16,409 hectares across eight claims adjacent to Denison’s Wheeler River Project and covering targets such as the Grayling and Fork Zones as well as the Sphinx and Fox Lake Trail (“FLT”) target areas. Skyharbour retains 51% at closing, with Denison holding 49% and the option to earn up to 70%. Denison will be operator at Wheeler North.

Getty East is a 3,105-hectare claim block hosting the Little Man Lake prospect and bordering Cameco’s Key Lake operations. Skyharbour holds 70% at closing and remains the operator, while Denison holds 30% and may earn up to 70% through staged exploration spending.

Wheeler River Inliers cover 608 hectares within Denison’s Wheeler River project, hosting the West Russell and C-Block target areas. Denison will own 70% upon closing and will be the operator.

Transaction Terms and Earn-In Options:

The consideration includes an immediate cash payment of $2 million upon execution of the agreement and deferred consideration totaling $16 million, payable on or before December 31, 2025. This deferred amount will be paid in two $8 million tranches, each in cash or Denison shares at Denison’s election. Closing is expected on or before December 21, 2025.

Skyharbour will continue to operate the McGowan Lake exploration camp, with Denison paying an administrative fee. All claims remain subject to existing underlying royalties.

Denison has the ability to increase its ownership in Wheeler North and Getty East through additional staged exploration spending.

At Wheeler North, Denison may increase its ownership from 49% to 70% in two phases. To reach 60%, Denison must complete $10 million in exploration within 48 months (including $2.5 million within the first 24 months) and make a $1.5 million cash payment to Skyharbour. To increase from 60% to 70%, Denison must complete an additional $15 million in exploration and make a further $2 million payment within seven years of closing.

At Getty East, Denison can increase its ownership from 30% to 70% through similar staged commitments. To reach 49%, Denison must incur $5 million in exploration expenditures within 48 months (with $1.5 million required in the first 24 months). To reach 70%, Denison must complete an additional $10 million in exploration within seven years, at which point Denison may elect to become the operator.

Previous Drilling by SYH:

2025 Diamond Drilling at Russell Lake:

Skyharbour carried out its 2025 drilling program at the Russell Lake Project to follow up on notable recent exploration success and to test new targets developed by the geological team. The focus for the drilling was on the Fork and Sphinx targets within the broader Grayling target area, as well as the M-Zone Extension (“MZE”) target and the Fox Lake Trail target.

2024 Fall Diamond Drilling Program:

Skyharbour completed approx. 4,500 metres of drilling at Russell to follow up on notable previous exploration and findings and to test new targets developed by the geological team. The drilling program focused on the road-accessible Fork target within the broader Grayling target area as well as the M-Zone Extension (“MZE”) target. 

2024 Winter Diamond Drilling Program:

A total of 5,152 metres of drilling in ten holes was drilled in two phases during the winter of 2024 at the Russell Lake Project. The first phase of drilling consisted of a total of 3,094 metres in six holes, while the second phase of drilling consisted of 2,058 metres of drilling in four holes. 

For more details, see our News Release - July 9, 2024

2024 Phase One Winter Drilling at Russell:

The first phase of drilling focused on drill testing the newly identified Fork Target area related to and south-southwest of the Grayling Zone. One hole during Phase One was drilled to test an East Grayling target, approximately 3 km to the southeast of the Fork Target area.

During Phase One, the best intercept of uranium mineralization historically on the property was discovered in hole RSL24-02, which returned a 2.5 metre wide intercept of 0.721% U₃O₈ at a relatively shallow depth of 338.1 metres, including 2.99% U₃O₈ over 0.5 metres at 339.6 metres just above the unconformity in the sandstone. This high-grade intercept is a new discovery at the recently identified Fork Target which has very limited historical exploration due to a lack of reliable geophysical data and drill targets resulting from nearby powerline interference. The mineralization is open in most directions including along strike, and will be a focus of upcoming drilling. The Fork Target area is approx. 1 km southwest of the central Grayling Target area and approx. 4 km southeast of Denison Mines’ Phoenix Deposit. It is a newly identified high-priority target hosting interpreted ENE and NNE-trending structures, with limited historical drilling as powerline interference affected the historical geophysical data, thereby hindering detection of EM conductors and selection of drill targets. Assays are pending for the second phase of the winter drill program at Russell.

2024 Phase Two Winter Drilling at Russell:

During the second phase of drilling at Russell Lake, three holes totaling 1,649 metres (holes RSL24-07 to -09) were drilled at the regional MZE target area, approximately 10 km northeast of the Fork target. Holes RSL24-07 and -08 were drilled to completion, while hole RSL24-09 was abandoned approximately 70 metres above the unconformity due to faulted ground conditions. The final hole of the second phase of the 2024 winter/spring drilling program, RSL24-10, was drilled at the Fork target area but missed the primary target due to excessive deviation during drilling. The MZE target lies on trend from Denison’s Wheeler River Project M-Zone, where historical drilling intersected significant uranium mineralization. 

For more details, see our News Release - October 24, 2024

2023 Diamond Drilling Program:

A total of 9,595 metres of drilling in nineteen holes was drilled in three phases during 2023. The first phase of drilling consisted of a total of 3,662 metres in eight completed holes at the Grayling Zone, while an additional four holes totaling 2,730 metres were drilled in the Fox Lake Trail Zone during the second phase. The third phase of drilling was comprised of 3,203 metres in seven holes on additional targets at the Grayling Zone.

For more details, see our News Release - January 10, 2024

2023 Phase One – Grayling Zone Drilling:

The first phase of Skyharbour’s inaugural drill program at Russell consisted of a total of 3,662 metres in eight holes at the Grayling Zone. The majority of the holes drilled at the Grayling Zone during this phase that successfully reached their intended targets intersected uranium mineralization and the Grayling Zone will be a primary target area at the project moving forward.

2023 Phase Two – Fox Lake Trail Zone Drilling:

The second phase of drilling was focused in the Fox Lake Trail area at the north end of the project. Four holes were completed for a total of 2,730 metres. The exploratory holes in this area targeted previously drilled fertile conductors and other previously untested but prospective EM and resistivity features.

2023 Phase Three – Grayling Zone Drilling:

The third phase and final phase of drilling took place within the Grayling Zone, with seven holes completed for a total of 3,203 metres. This phase of drilling was designed to follow up on previously identified mineralization and to better define the controls and geometry of the Grayling Thrust Block, which is the controlling structure hosting the Grayling mineralized zone.