Tectonic Metals Drills 1.40 g/t Au over 30.00 metres, Including 4.58 g/t Au over 4.50 metres, Extending Higher-Grade Corridor to 300 metres Vertical Depth at Chicken Mountain, Flat Gold Project, Alaska

Drilling Also Returns 0.51 g/t Au Over 118.16 Metres of Continuous Mineralization to End of Hole; Step-Out Drilling Expands Southern Mineralized Footprint by 200 Metres to 600 Metres

Assays Pending from 97 Drill Holes Representing 18,000 Metres of 2026 Drilling; Maiden Mineral Resource Estimate Targeted for Q1 2027

VANCOUVER, BC / ACCESS Newswire / September 10, 2026 / Tectonic Metals Inc. ("Tectonic" or the "Company") (TSXV:TECT)(OTCQX:TETOF) today announced the first assay results from its 2026 drill program at Chicken Mountain, the most advanced intrusion target at the Company's flagship 99,840-acre Flat Gold Project ("Flat") in southwest Alaska, U.S. The results from 15 drill holes totalling 2,276 metres ("m") have expanded gold mineralization both at depth and to the south, further substantiating Chicken Mountain as a bulk-tonnage Reduced Intrusion Related Gold System ("RIRGS"), with potential for heap-leach processing.

Chicken Mountain is one of six district-scale intrusion targets currently identified at Flat and is being advanced toward a maiden Mineral Resource Estimate ("MRE") targeted for Q1 2027.

Key Drill Results & Geological Highlights[i]

The 2026 drill program at Flat has completed over 22,000 m year-to-date, with assay results from 15 holes totalling 2,276 m reported in this release. These results extend gold mineralization in two priority areas at Chicken Mountain: Central Corridor 2, one of six higher-grade corridors identified across 3.3 kilometres ("km") of drilled strike; and the southern extension of the near-surface mineralized footprint.

Central Corridor 2 Depth Extension to Over 300 m:

Diamond hole CMD26-036 returned 1.40 grams per tonne gold ("g/t Au") over 30.00 m from 183.00 m, including 4.58 g/t Au over 4.50 m, and a separate deeper interval of 0.51 g/t Au over 118.16 m from 270.00 m to the end of the hole at 388.16 m, including 0.93 g/t Au over 19.50 m and 1.42 g/t Au over 7.50 m.

This area, defined as Central Corridor 2, was first described in Tectonic's January 22, 2026 news release[ii] with CMD25-011, which intersected 0.69 g/t Au over 124.97 m, including 1.46 g/t Au over 26.00 m, across a corridor measuring approximately 200 m strike × 150 m width × 100 m depth.

CMD26-036 now confirms the continuation of this zone down to over 300 m vertical depth. Central Corridor 2 remains open in all directions.

Southern Mineralized Footprint Expanded by 200 m to 600 m in Length: Located 1.2 km south of CMD26-036, RC holes CMR26-141 and CMR26-142 expanded the drilled southern margin of Chicken Mountain by 200 m to the southwest, increasing its interpreted length in the southernmost tested area to approximately 600 m:

CMR26-141: 0.31 g/t Au over 25.91 m from 144.78 m, including 0.81 g/t Au over 4.57 m; hole ended in mineralization at 172.21 m.

CMR26-142 - southwestern step-out: 0.56 g/t Au over 38.10 m from 80.77 m, including 3.06 g/t Au over 4.57 m.

Together, these step-out holes confirm gold mineralization 200 m southwest of previous drilling and materially expand the drilled footprint in the southern portion of Chicken Mountain.

Higher-grade Interval Within Broader Mineralization: RC hole CMR26-128 located in the southern mineralized footprint returned 0.71 g/t Au over 22.86 m from 59.44 m, including 6.79 g/t Au over 1.52 m; hole ended in mineralization at 111.25 m.

Higher-Grade Corridor Characterization:

Currently, there are six higher-grade corridors identified within the broader mineralized envelope across the 3.3 km of drilled strike (see Figure 1). They range from 200 to 300 m in strike and up to 200 m in width, remaining open at depth. These corridors warrant further drilling (see Figure 4) and may have the potential to support future starter-pit opportunities.

Central Corridor 2 and the other higher-grade gold corridors are commonly associated with intense oxidization and/or sericite alteration, with a mineralized quartz and quartz-carbonate vein density of 1-3 veins per metre. These veins and alteration commonly host fine- to medium-grained arsenopyrite, pyrite and stibnite.

Tectonic is integrating oriented-core structural measurements with alteration, vein-density and multi-element geochemical data to refine the controls on higher-grade mineralization.

100% Drill Success Rate Continues at Chicken Mountain:

All 206 holes drilled to date at Chicken Mountain have intersected gold mineralization, demonstrating the widespread distribution of gold across the system.

Of these holes, 127 (over 60%) ended in mineralization, providing numerous opportunities for follow-up drilling below current hole depths.

Chicken Mountain Growth Potential Still Remains Largely Untested:

Gold-in-soil anomaly, based on historical data, extends 4.0 km in length and up to 1.0 km in width.

Mapped monzonitic gold intrusive host rock complex measures approximately 4.5 km x 3.0 km, with a larger geophysical intrusive footprint of 6.5 km x 6.0 km.

More than 90% of the mapped intrusion complex remains untested by drilling.

The currently defined mineralized area (3.3 km strike x up to 700 m width x 300 m depth) remains open in all directions.

Near-Term Catalysts:

Substantial Assay Pipeline: Assays are pending for 97 additional drill holes currently in the laboratory queue, representing nearly 18,000 m of the 2026 drill program. The majority of these holes are targeting resource delineation and infill drilling in support of the maiden MRE.

Drilling Continues: Five drill rigs remain active at Flat and are expected to operate through the end of the field season in late October, supporting a steady flow of assay results through year-end.

Regional Surface Exploration: Results from the regional soil-sampling program are pending and will help refine and prioritize exploration targets beyond the current drilled footprint.

Heap Leach Column Testwork: Results are pending from column-leach tests evaluating multiple crush sizes, including material crushed to two inches.

Completion of the maiden MRE is targeted for Q1 2027.

Maps and Multimedia

Chicken Mountain Drill Plan Maps and Images

Chicken Mountain Drill Plan Video

Tony Reda, Co-Founder, President & CEO, commented:

"Drilling at Chicken Mountain continues to answer the questions that matter at this stage: does the mineralization continue at depth, does the footprint keep growing and can higher grades recur within the broader system? These first 2026 results provide encouraging evidence on all three fronts.

"Every one of the 206 holes reported to date at Chicken Mountain has intersected gold, and over 60% have ended in mineralization. We are combining disciplined resource-delineation drilling with structural interpretation, geochemistry, environmental baseline work and geotechnical studies to evaluate Chicken Mountain's potential as a large-scale, open-pit, heap-leach gold opportunity while substantial exploration upside remains across Flat and its other intrusion targets."

Figure 1: Simplified regional geology map of the Flat Gold Project and map of the Chicken Mountain intrusion drilling area, highlighting the six identified higher-grade corridors.

Chicken Mountain: In Pursuit of a Heap-Leachable Bulk-Tonnage Mining Opportunity

Chicken Mountain is interpreted as a RIRGS, hosted by a monzonitic intrusive complex. Gold mineralization occurs in sericite-altered and variably oxidized monzonite containing sheeted, millimetre- to centimetre-scale quartz to quartz-carbonate veinlets. Drilling has outlined a mineralized footprint extending 3.3 km along strike, up to 700 m wide and to 300 m vertical depth (see Figure 2). Mineralization remains open in all directions.

Tectonic is using oriented-core structural measurements, alteration and vein-density observations, and multi-element geochemistry to refine the geological model, define the controls on higher-grade mineralization and prioritize follow-up drilling. This integrated work is intended to improve confidence in the geometry and grade distribution of the broader mineralized envelope and its internal higher-grade corridors.

The 15 holes reported in this release represent 2,276 m of step-out and early-stage resource-delineation drilling at Chicken Mountain. Assays remain pending from 97 additional drill holes representing nearly 18,000 m of 2026 drilling. Results from regional soil sampling are also pending and will be used to refine targets beyond the current drilled footprint. Environmental baseline, geochemical and geotechnical programs are advancing in parallel as the Company works toward its maiden MRE targeted for Q1 2027.

Figure 2: Chicken Mountain plan view and long section showing the mineralized drill results, 3.3 km drilled strike extent and gold-in-soil anomalism.

Figure 3: Chicken Mountain drill plan highlighting three of the six interpreted higher-grade corridors.

Figure 4: Cross section L1-L1′, looking north, showing CMD26-036 and mineralization across a 500 m-wide section.

Table 1 - 2026 Chicken Mountain Diamond Drill Hole Assay Results

Note: All reported intercepts are reported as downhole lengths, as insufficient data exists to determine true widths. Select composites utilizing 0.10, 0.30 or 0.50 g/t Au cut-offs, with a maximum 3.2 m continuous (two sample) below the cut-off inclusion.

Table 2 - 2026 Chicken Mountain RC Hole Assay Results