ATHA Energy Closes Over-Subscribed Bought Deal – Makes Third New Discovery of 2025 Exploration Program at RIB West and Continues to Expand Mineralization at RIB East

18 September 2025

HIGHLIGHTS

  • ATHA closes previously announced CAD $11.5 Million Over-Subscribed Bought Deal (See detail below, “Underwritten Private Placement”);
  • First two drill holes completed at the RIB West Discovery successfully intersected uranium mineralization, including high-grade, over a strike length of ~340 m (Figure 2);
  • Results represent the third new discovery of uranium mineralization – beyond the Lac 50 Deposit Trend – during the 2025 Angilak Exploration Program, within the Angikuni Basin along the 31 km RIB-Nine Iron Trend (Figure 1);
  • RIB East Discovery is currently defined by eight mineralized drill holes, intersecting shallow uranium mineralization (<275 m depth), the five latest holes extend mineralization from 400 m to a strike length of ~750 m (Figure 2). Based on EM Inversion modelling (see below), RIB East now has prospective strike length of more than 5 km, which remains largely untested by drilling;
  • In August 2025, Expert Geophysics Ltd. utilized the MMT survey data acquired in 2024 to complete Advanced Electromagnetic Inversion modelling (“EM Inversion”) across 12 km of the 31 km long RIB-Nine Iron Trend, focused on the RIB East and West Discovery areas. The EM Inversion has proved successful in mapping out multiple stacked conductors, including numerous interpreted north-south and east-west trending cross cutting structures. Drilling at both RIB East and West has demonstrated the EM Inversion is accurately mapping graphitic structural corridors which are associated with uranium mineralization (Figure 2);
  • To date the Company has only explored a small proportion of the 12 km long prospective EM Inversion model at RIB East and West. The Company will be completing additional EM inversion modelling over the remaining 62% of the RIB-Nine Iron Trend where MMT data was acquired in 2024;
  • Through the end of the 2025 Angilak Exploration Program, the Company will be focused on targeting newly derived EM Inversion anomalies, including the newly identified north-south and east-west cross cutting trends;
  • The 2025 Angilak Exploration Program is on-going, to date, only ~55% of expected diamond drillhole results have been announced.

RIB West Discovery:

  • RIB West Discovery is located approximately 1.5 km to the west of the RIB East Discovery and is currently defined by two drill holes, both intersecting uranium mineralization, over a strike length of approximately ~340 m (Figure 2). The mineralization is hosted within graphitic structures accurately mapped by the advanced EM Inversion. Based on the EM Inversion model, the RIB West Discovery has a prospective strike length over 3 km, with an associated EM conductor;
  • RIB_W-DD-001, intersected high-grade uranium mineralization with total composite mineralization of 2.1 m, hosted within a broad graphitic structure. Mineralization was found between 396.25 m and 398.35 m, including 0.5 m of high-grade mineralization with a maximum down-hole-triple gamma probe value of 18,485 counts per second (CPS1) over 0.1 m (Figure 2 & 3);
  • RIB_W-DD-002, drilled ~340 m along strike to the northeast of RIB_W-DD-001, intersected six zones of uranium mineralization within a broad graphitic structure. The hole intersected total composite mineralization of 8.5 m between 204.8 m and 269.5 m, including 2.0 m with an average of 1,586 CPS1 and a max peak of 5,193 CPS1 (Figure 2 & 4).

RIB East Discovery:

  • ATHA has completed eight drill holes at the RIB East Discovery during the 2025 Angilak Exploration Program (See July 21st, 2025, News Release, for results from the first three drill holes). To date, all holes have successfully intersected uranium mineralization;
  • Today’s release comprises five additional drill holes that have extended the strike length of mineralization at the RIB East Discovery from 400 m to ~750 m.
  • Drilling is highlighted by:
  •  
    • RIBE-DD-005, tested 100 m down-dip and 100 m along strike to the north of mineralization intersected in RIBE-DD-003. The hole intersected three zones of mineralization totaling 2.2 m of composite mineralization, including a shallow interval (between 282.9 m and 284.4 m) of high-grade uranium mineralization that had an average down-hole probe value of 3,711 CPS1 and a peak of 12,357 CPS1 over 0.10 m (Figure 2 & 6);
  •  
    • RIBE-DD-007, was drilled in a scissor orientation ~400 m to the southeast of RIBE-DD-003. The hole intersected four zones of mineralization (between 192.5 m and 214.9 m) with a total composite mineralization of 6.0 m, including a high-grade intersection from 207.3 m to 209.7 m, with an average down hole probe value of 4,477 CPS1 and a peak of 19,956 CPS1, over 0.10 m (Figure 2 & 8).

Troy Boisjoli, CEO commented: “The newest discovery along the 31 km long RIB-Nine Iron Trend – at RIB West – is the Company’s third discovery of the 2025 Angilak Exploration Program. This is an unprecedented feat from a greenfield exploration program targeting uranium discovery and speaks to the metal endowment at the Angilak Project area, beyond the Lac 50 Deposit area and ATHA’s top tier technical teams’ ability to plan and execute on its thesis. We continue to see the hallmarks of a generational bull market for uranium and based on ATHA’s continued exploration success over the last two years, the Company is well positioned to accelerate uranium discovery and build value for this cycle.”

Cliff Revering, VP Exploration added: “We are very excited about the results emerging from the RIB regional target area, including another discovery along the RIB West trend and the continued expansion of the mineralized strike length along the RIB East trend. To date, we have drill-tested only a relatively small proportion of the prospective trends within the RIB area, with all completed holes intersecting uranium mineralization associated with graphitic structural corridors. All prospective trends remain open along strike and at depth. We are also very encouraged by the accuracy of the EM inversion model provided by Expert Geophysics in locating graphitic structural corridors associated with uranium mineralization. This model has been highly valuable in guiding our targeting strategy in the RIB area, and in highlighting numerous additional prospective trends that have yet to be drill-tested.”

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