Onyx Gold Drills New High-Grade Structure at Argus Main: 4.9 g/t Gold over 15.0 Meters Within 1.3 g/t Gold over 77.2 Meters; 2.9 g/t Gold over 12.5 Meters Within 1.2 g/t Gold over 99.5 Meters Northeast-Trending Structures Analogous to Argus North Drive Higher Grades
Onyx Gold Corp. 405 - 375 Water Street, Vancouver, BC, V6B 5C6 TSXV: ONYX OTCQX: ONXGF
March 31st, 2026 NR# 08-2026
Onyx Gold Drills New High-Grade Structure at Argus Main: 4.9 g/t Gold over 15.0 Meters Within 1.3 g/t Gold over 77.2 Meters; 2.9 g/t Gold over 12.5 Meters Within 1.2 g/t Gold over 99.5 Meters
Northeast-Trending Structures Analogous to Argus North Drive Higher Grades and Expand Scale Potential at Argus Main
Vancouver, BC – March 31st, 2026 – Onyx Gold Corp. (“Onyx” or the "Company") (TSX-V: ONYX, OTCQX: ONXGF) is pleased to report new drill results from the Company’s fully-funded 75,000-meter drill program (the “Program”) at its 100%-owned Munro-Croesus Project (“Munro- Croesus” or the “Project”), located 75 km east of Timmins, Ontario (Figure 4).
Today’s results are from 12 drill holes, including five (5) drill holes on the Argus Main Zone, and seven (7) regional reconnaissance drill holes targeting new ‘Argus-style’ mineralization up to 900 meters (“m”) to the southwest of Argus North along previously undrilled sections of the prospective Pipestone Fault.
The drill highlights include drill holes MC26-267 and MC26-270, which have identified a new highgrade, northeast-trending structure along the eastern margin of the Argus Main Zone, exhibiting characteristics directly analogous to the Argus North discovery located approximately 600 m to the northwest. This structural linkage is significant, as it confirms that higher-grade mineralization at Argus Main is similarly controlled and materially enhances the zone’s expansion and grade profile potential.
Highlights from Argus Main
- Drill holes MC26-267 and MC26-270, collared 50 m apart on the same cross-section, targeted a northeast-trending fault in the eastern section of the Argus Main Zone, exceeded expectations with the intersection of two encouraging zones of gold mineralization: an Upper Zone and a Lower Zone, 100 m to 200 m below surface, respectively (Figures 1, 2 and 3). Highlights are included below.
- Drill hole MC26-267:
- 60.0 m grading 0.6 g/t Au (Upper Zone), including
- 20.6 m grading 1.1 g/t Au, AND
- 99.5 m grading 1.2 g/t Au (Lower Zone), including
- 16.5 m grading 2.2 g/t Au, including
- 3.0 m grading 6.4 g/t Au AND
- 12.5 m grading 2.9 g/t Au, including
- 3.0 m grading 7.5 g/t Au
- 16.5 m grading 2.2 g/t Au, including
- 60.0 m grading 0.6 g/t Au (Upper Zone), including
- Drill hole MC26-270 (collared 50 m in front and above MC26-267):
- 32.0 m grading 0.7 g/t Au (Upper Zone), including
- 6.0 m grading 2.1 g/t Au, AND
- 77.2 m grading 1.3 g/t Au (Lower Zone), including
- 15.0 m grading 4.9 g/t Au, including
- 5.0 m grading 9.5 g/t Au, including
- 2.0 m grading 14.9 g/t Au
- 5.0 m grading 9.5 g/t Au, including
- 15.0 m grading 4.9 g/t Au, including
- 32.0 m grading 0.7 g/t Au (Upper Zone), including
- The results, which expand Argus Main to the east and to depth, represent the strongest grade x width intersections to date at Argus Main, highlighting excellent potential for further expansion.
- These new high-grade intervals are interpreted to be part of the same mineralizing system observed at surface, where channel and grab samples returned 5.2 to 14.7 g/t Au over a 35 x 30 m area. This surface zone is located approximately 70 m to the east-northeast and 300 m vertically above the Lower Zone in drill hole MC26-267, highlighting the potential for vertically continuous high-grade mineralization.
Highlights from Argus Regional Reconnaissance Drilling
- Seven (7) Argus regional reconnaissance drill holes were completed up to 900 m southwest of Argus North to investigate for Argus-style mineralization, and to test known quartz-feldspar felsic intrusions within sericite-altered metasedimentary rocks – analogous to the setting of Mayfair Gold Corp.’s Fenn-Gib deposit located 7 km along trend.
- Two drill holes intersected anomalous gold values with MC25-234 returning 5.8 m grading 1.0 g/t Au and MC26-262 returning a broad interval of 40.5 m grading 0.2 g/t Au, indicating the presence of a new mineralized system in this previously untested area (Figure 1).
- The intersection of gold mineralization several hundred meters from any prior drilling provides strong validation of the Company’s regional exploration strategy and highlights the potential for additional discoveries along the Pipestone Fault. In 2026, the Company plans to continue systematic step-outs along the Pipestone Fault both west and east of the Argus zones, with the objective of discovering additional gold mineralization along the underexplored Pipestone Fault corridor.
Highlights on Drill Progress
- The Company continues to execute on its fully funded 75,000-m Phase I/II/III Drill Program at Munro-Croesus with 129 drill holes totalling >47,500 m (63%) with assays now announced for 77 holes.
- The Company has noted strong lateral and vertical continuity of gold mineralization within a variety of host lithologies over a total strike length of 1,400 m, to a vertical depth of more than 500 m and with an apparent periodicity to the zones of 400 m along strike within the host mafic variolitic volcanic unit. Results suggest the Argus Zones (Argus Main, Argus North and Argus
West) remain open along strike, down-dip, and down-plunge, with mineralization also projecting to the near-surface in multiple locations.
- Gold zones in all reported results for the Argus Zones are associated with strong silica and albite alteration with sulfides including pyrite. Visible gold has been observed in several of the reported intervals.
- There are two primary styles of gold mineralization along the Argus Zones, both of which extend to the near-surface in places and are being actively drilled by Onyx:
1) Steeply plunging high-grade gold zones associated with northeast-trending faults;
2) Disseminated zones of low to moderate gold grades which surround and flank the highgrade intervals.
- Fully funded with approximately $24 million in cash, Onyx is executing an aggressive, multirig drill program with three rigs currently turning and plans to maintain at least this pace through year-end.
“These results are a major step forward for Argus Main, where we are now intersecting our best combination of width and grade to date, including nearly 100 meters grading over 1 g/t gold with strong higher-grade intervals,” stated Brock Colterjohn, CEO. “Importantly, the identification of northeast-trending structures, directly analogous to Argus North, meaningfully increases our confidence in the potential to discover additional higher-grade zones that could materially enhance both the size and grade profile of Argus Main.”
“Our initial regional reconnaissance drilling, completed up to 900 meters to the west of Argus North, has intersected encouraging gold mineralization within the same favourable geological setting as the Argus zones, providing strong proof of concept for the broader opportunity along the 8 kilometers of the Pipestone Fault that is under the Company’s control.”
“With this growing confidence, our 2026 strategy is focused on three key priorities: rapidly expanding the Argus zones through systematic step-outs, executing bold regional step-outs along the Pipestone Fault to unlock new discoveries, and advancing multiple high-grade and bulktonnage targets within 6 kilometers of the Argus zones. With three rigs currently turning and a fully funded program, we believe we are just beginning to unlock the broader potential of the Munro-Croesus property.”
The Geological Setting of the Argus Zones
The Argus Zones are located on the western half of the Munro-Croesus Project, approximately 3 km northwest of the historic Croesus Gold Mine and immediately north of the regional Pipestone Fault, a major structural corridor host to many of the significant gold deposits in the Timmins camp (Figure 1). Following a multi-year consolidation effort, Onyx now controls over 8 km of strike extent of the Pipestone Fault, most of which remains undrilled or has not seen any modern exploration. Gold mineralization is hosted within volcanic rocks of the Kidd-Munro assemblage across all Argus Zones.
The Argus North Zone is situated 150 m north of the Pipestone Fault and is distinguished by both broad zones (50 m to over 100 m) of +1 g/t Au mineralization containing wide zones of highergrade mineralization (+5 g/t Au). The higher-grade sub-intervals are associated with zones of strong albitization and silicification, pyritic stringers, and localized porphyritic intrusions within mafic variolitic basalt and volcanic breccias cut by dominant moderate to steeply dipping, northeast-trending faults and associated fractures. This combination of host lithology, alteration and structural preparation is interpreted to be a key control on gold deposition. The discovery hole, MC24-163, was reported last year, and returned 69.6 m grading 3.4 g/t Au, including 34.5 m grading 5.4 g/t Au and 9.5 m grading 13.9 g/t Au (see Company news release dated April 10, 2025).
The Argus Main Zone lies ~100 m south of Argus North and represents a separate, broad eastwest trending, 900 m x 200 m near-surface bulk-tonnage gold target. The best surface expression of the Argus Main Zone is stripped of overburden and consists of 10 grab and channel samples grading between 5.2 g/t Au and 14.7 g/t Au, within a 35 x 30 m area. Gold mineralization is associated with mafic variolitic volcanic flows that are strongly albite- and silica-altered and cut by east-northeast-trending pyritic veinlets within a broader halo of carbonate alteration and local development of specular hematite. Highlights from past drilling include 63.3 m grading 1.0 g/t Au, including 17.4 m grading 2.2 g/t Au in MC24-166 (see Company news release dated June 17, 2024), 62.8 m grading 0.8 g/t Au within 136.0 m grading 0.5 g/t Au in MC22-110 (see Company news release issued dated May 9, 2022), 59.7 m grading 1.0 g/t Au, including 18.4 m grading 2.0 g/t Au in MC25-255 (see Company news release issued dated February 18, 2026) and 27.6 m grading 1.0 g/t Au in MC23-140, and Figures 1, 2, and 3).
The Argus West Zone is located ~250 m west of Argus North, along the recently delineated ‘Argus Fault’, a key northeast-trending, moderately-to-steeply NW-dipping structure that appears to play an important role as a locus for gold mineralization. Drill hole MC25-213 returned 21.2 m grading 2.1 g/t Au (with local visible gold) starting at 9.8 m downhole within strongly albite-altered mafic variolitic volcanics with a moderate crackle brecciation, and fine-grained disseminated to fracture-controlled pyrite in the structural hanging wall to the Argus Fault (see Company news release dated December 3, 2025). Drill hole MC25-199, located a further 180 m to the southwest, intersected 14.0 m grading 1.0 g/t Au hosted by fine-grained metasedimentary rocks of the Porcupine Group, in the structural footwall to the Argus Fault.
Discussion of Argus Main Drill Results
Results reported today include those from 12 drill holes, including five (5) drill holes from Argus Main. The results are very positive, with the first indications of a more robust gold system at depth with broader widths of higher grades than intersected in past drilling.
Two (2) drill holes, MC26-267 and MC26-270, collared 50 m apart on the same cross-section, targeted a northeast-trending fault in the eastern section of the Argus Main Zone, and intersected two encouraging zones of gold mineralization: an Upper Zone located 100 m below surface; and a Lower Zone located 200 m below surface (Figures 1, 2 and 3). These higher-grade intersections are interpreted to be continuous with the best high-grade mineralization at surface (10 grab and channel samples grading between 5.2 g/t Au and 14.7 g/t Au within a 35 x 30 m area) located approximately 70 m to the east-northeast and approximately 300 m vertically above the Lower Zone in drill hole MC26-267.
Highlights from Argus Main include:
- 60.0 m grading 0.6 g/t Au (Upper Zone), in drill hole MC26-267, including
- 20.6 m grading 1.1 g/t Au, AND
- 99.5 m grading 1.2 g/t Au (Lower Zone), including
- 16.5 m grading 2.2 g/t Au, including
- 3.0 m grading 6.4 g/t Au,
- 1.0 m grading 10.1 g/t Au, AND
- 3.0 m grading 6.4 g/t Au,
- 12.5 m grading 2.9 g/t Au, including
- 3.0 m grading 7.5 g/t Au
- 16.5 m grading 2.2 g/t Au, including
- 32.0 m grading 0.7 g/t Au (Upper Zone), in drill hole MC26-270, collared 50 m in front and above MC26-267, including
- 6.0 m grading 2.1 g/t Au, AND
- 77.2 m grading 1.3 g/t Au (Lower Zone), including
- 15.0 m grading 4.9 g/t Au, including
- 5.0 m grading 9.5 g/t Au, including
- 2.0 m grading 14.9 g/t Au
- 5.0 m grading 9.5 g/t Au, including
- 15.0 m grading 4.9 g/t Au, including
One drill hole, MC26-265, was collared 100 m southwest of the collar of drill hole MC26-267 and drilled to the northwest to assess the Pipestone Fault and associated hanging wall and footwall sequences. Highlights include:
- 2.6 m grading 2.6 g/t Au, in drill hole MC26-265, AND
- 22.0 m grading 0.4 g/t Au, including
- 2.9 m grading 1.2 g/t au
Two additional drill holes, MC25-223 and MC25-225, were also completed 200 m west of the Argus Main core area, testing an area of low drill density with elevated gold in grab samples. Highlights include:
- 36.4 m grading 0.7 g/t Au, in drill hole MC25-223, including
- 7.9 m grading 2.4 g/t Au, including
- 1.1m grading 9.4 g/t Au
- 7.9 m grading 2.4 g/t Au, including
- 20.2 m grading 0.6 g/t Au, in drill hole MC25-225, AND
- 8.1 m grading 1.0 g/t Au, AND
- 13.0 m grading 0.4 g/t Au
Additional drill holes have been planned on the same cross-section and adjacent cross-sections to follow up on the encouraging results in drill holes MC26-267 and MC26-270.
Discussion of Argus Regional Reconnaissance Drill Results
Seven (7) regional reconnaissance drill holes were completed up to 900 m southwest of Argus North to investigate the host mafic variolitic volcanic sequence for Argus-style mineralization and test known quartz-feldspar felsic intrusions within sericite-altered fine-grained sedimentary rocks adjacent to the Pipestone Fault – a similar geological setting to Mayfair Gold’s Fenn-Gib deposit located 7 km along trend. Two (2) drill holes intersected anomalous gold values with MC25-234 returning 5.8 m grading 1.0 g/t Au, and MC26-262 returning a broad interval of low-grade mineralization assaying 40.5 m grading 0.2 g/t Au (Figure 1).
Details for drill hole assays reported in this news release are shown in Figures 1/2/3 and in Table 1.
Update of Argus Zone Results
The Argus Zones continue to show excellent lateral and vertical continuity of gold mineralization within a variety of host lithologies over a total strike length of 1,400 m and a vertical depth of more than 500 m. The Argus Zones remain open along strike, down-dip, and down-plunge, and the opportunity to expand the zones through ongoing drilling is considered excellent. There is also an apparent periodicity to the zones of 400 m along strike within the host mafic variolitic volcanic unit.
The Company continues to execute the approved 75,000-m Phase I/II/III Drill Program at Munro- Croesus with 129 drill holes totalling >47,500 m (63%) with assays now announced for 77
holes.
Acquisition of the Hewitt West Property
The Company announces that it has entered into an agreement to acquire a property consisting of four unpatented mining claims totalling 64 hectares of mineral rights from an arm’s length party located in the Matheson area, east of Timmins, Ontario. The property is contiguous with the Company’s 100%-owned Hewitt Property located 2 km to the west of the Company’s Munro- Croesus Property (Figure 4). Under the terms of the agreement, the Company will issue 70,000 of its common shares to the vendor, subject to regulatory approval and grant a 2% NSR royalty on the Property to the vendor.
The acquisition of these claims expands the Hewitt Property to cover an undrilled portion of the Pipestone Fault, providing additional exposure to this important structure known to host multiple gold deposits, and the Company’s Argus zones.
The Munro-Croesus Project
The Munro-Croesus Project is located along Highway 101 in the heart of the Abitibi greenstone belt, Canada's premier gold mining jurisdiction (Figure 3). This large, 100% owned land package includes the past-producing Croesus Gold Mine, which yielded some of the highest-grade gold ever mined in Ontario. Extensive land consolidation since 2020 has unified the patchwork of patented and unpatented mining claims surrounding the Croesus Gold Mine into one coherent package and enhanced the project's exploration potential.
The Project covers 109 km2 of highly prospective geology within the influence of major goldbearing structural breaks. Bulk-tonnage gold deposits located in the immediate region include the Fenn-Gib gold project being developed by Mayfair Gold Corp., and the Tower Gold Project being developed by STLLR Gold Inc.
Table 1 – Significant Assay Results for Argus Main and Argus Regional Drill Holes Reported in this Release
| Target | From | To | Length | Au | |
|---|---|---|---|---|---|
| Drill Hole | (m) | (m) | (m) | (g/t) | |
| Argus Main – | |||||
| Eastern Section | |||||
| MC26-265 | 124.4 | 127.0 | 2.6 | 2.6 | |
| And 138.4 141.0 2.6 1.2 | |||||
| And | 204.5 | 226.5 | 22.0 | 0.4 | |
| Including 210.9 213.8 2.9 1.2 | |||||
| And | 282.0 | 285.2 | 3.2 | 0.4 | |
| And 315.0 320.5 5.5 0.7 | |||||
| Including | 318.0 | 319.5 | 1.5 | 1.8 | |
| MC26-267 | 161.0 | 221.0 | 60.0 | 0.6 | |
| Including | 177.0 | 218.0 | 41.0 | 0.8 | |
| Including | 177.9 | 198.5 | 20.6 | 1.1 | |
| And Including | 207.5 | 208.3 | 0.8 | 1.3 | |
| And Including 211.5 212.5 1.0 1.1 | |||||
| And Including | 216.0 | 218.0 | 2.0 | 1.8 | |
| And 268.5 269.5 1.0 7.6 | |||||
| And | 321.4 | 325.2 | 3.8 | 7.1 | |
| Including 321.4 322.4 1.0 16.4 | |||||
| And | 344.0 | 443.5 | 99.5 | 1.2 | |
| Including | 363.0 | 379.5 | 16.5 | 2.2 | |
| Including | 376.5 | 379.5 | 3.0 | 6.4 | |
| Including | 376.5 | 377.5 | 1.0 | 10.1 | |
| And Including | 393.5 | 406.0 | 12.5 | 2.9 | |
| Including | 393.5 | 396.5 | 3.0 | 7.5 | |
| And Including | 416.5 | 418.5 | 2.0 | 4.7 | |
| And Including 430.0 431.7 1.7 3.3 | |||||
| And | 462.0 | 480.0 | 18.0 | 0.5 | |
| Including 469.5 471.5 2.0 3.9 |
| Target | From | To | Length | Au | |
|---|---|---|---|---|---|
| Drill Hole | (m) | (m) | (m) | (g/t) | |
| Argus Main – | |||||
| Eastern Section | |||||
| MC26-270 | 104.0 | 132.0 | 28.0 | 0.3 | |
| Including 105.5 116.0 10.5 0.6 | |||||
| And | 150.0 | 182.0 | 32.0 | 0.7 | |
| Including | 172.0 | 178.0 | 6.0 | 2.1 | |
| And | 251.0 | 252.5 | 1.5 | 8.0 | |
| And 260.0 263.5 3.5 2.3 | |||||
| And | 278.8 | 356.0 | 77.2 | 1.3 | |
| Including | 295.0 | 346.0 | 51.0 | 1.9 | |
| Including | 303.0 | 318.0 | 15.0 | 4.9 | |
| Including | 305.0 | 310.0 | 5.0 | 9.5 | |
| Including | 306.0 | 308.0 | 2.0 | 14.9 | |
| Target | From | To | Length | Au | |
| Drill Hole | (m) | (m) | (m) | (g/t) | |
| Argus Main – | |||||
| Western Section | |||||
| MC25-223 | 4.0 | 40.4 | 36.4 | 0.7 | |
| Including | 4.9 | 7.7 | 2.8 | 1.4 | |
| And Including | 25.0 | 32.9 | 7.9 | 2.4 | |
| Including | 28.0 | 32.9 | 4.9 | 3.5 | |
| Including | 31.8 | 32.9 | 1.1 | 9.4 | |
| And | 79.0 | 82.0 | 3.0 | 1.0 | |
| MC25-225 | 7.3 | 27.5 | 20.2 | 0.6 | |
| Including | 7.3 | 10.7 | 3.4 | 1.3 | |
| Including 9.5 10.7 1.2 3.0 | |||||
| And Including | 22.0 | 24.4 | 2.4 | 1.7 | |
| Including 23.7 24.4 0.7 4.4 | |||||
| And | 207.0 | 215.1 | 8.1 | 1.0 | |
| Including 214.3 215.1 0.8 4.9 | |||||
| And | 226.0 | 239.0 | 13.0 | 0.4 |
Including 238.0 239.0 1.0 4.3
| Target | From | To | Length | Au |
| Drill Hole | (m) | (m) | (m) | (g/t) |
| Argus West | ||||
| MC25-228 No Significant Assays | ||||
| MC25-230B | No Significant Assays | |||
| MC25-234 52.5 58.3 5.8 1.0 | ||||
| MC25-260 | No Significant Assays | |||
| Target | From | To | Length | Au |
| Drill Hole | (m) | (m) | (m) | (g/t) |
| Argus West Pipestone | ||||
| MC25-224 No Significant Assays | ||||
| MC25-226 | No Significant Assays | |||
| MC26-262 198.5 239.0 40.5 0.2 |
*Intersections are reported as drilled width; true width is 60-90% of drilled width
Figure 1 – Plan Map Highlighting Argus Zone Drill Holes Reported in this Release
Figure 2 – Cross-Section Highlighting Argus Main Drill Holes Reported in this Release – Looking Northeast – 100m
Figure 3 – Longitudinal Section Highlighting Argus Main Drill Holes Reported in this Release – Looking North