Astra Defines a Large-Drill Ready High Sulphidation Gold Target at Don Mario in Chile

Astra’s CEO, Brian Miller commented:

“Astra has a unique portfolio of exploration properties in Argentina and Chile and recently has taken the opportunity to advance Don Mario to the drill stage. The combination of outcropping gold mineralization with a large alteration zone and overlapping geophysical and geochemical targets makes for a compelling large-scale HSE target in the Maricunga Belt – a belt known to produce several world-class gold mines. We intend to proceed and drill the project in the coming months with a 2,000 – 3,000 metre fully-funded program and are pleased to add this discovery opportunity to our large flagship La Manchuria drilling program.”

Astra’s Exploration Director, Diego Guido commented:

“The different exploration tools used at Don Mario have significantly improved our understanding of this large high sulphidation target, vectoring toward the prospective portions of the system. The distribution of the gold-silver surface anomalies into silicified diatreme breccias, together with the deeper resistive anomaly identified by the CS-NSAMT survey, suggests that the system may preserve both shallow disseminated mineralization and deeper feeder structures.”

Don Mario Exploration Results

The Company has received the results of a low-cost exploration program completed at the Don Mario Project (See NR 2026-05-30 Astra Provides Exploration Update and Receives Independent Analyst Coverage from ATB Cormark Capital Markets), located within the eastern Maricunga gold belt of northern Chile. The program included geological mapping of the property, a combined geochemical and spectral mineralogy survey and three Controlled and Natural Source Audiofrequency Magnetotelluric (CS-NSAMT) survey lines.

The results outline a 2 kilometre by 1 kilometre gold and silver geochemical target concentrated in the southwestern portion of a larger 2 kilometre by 2 kilometre lithocap within the 4,480 hectare property. Don Mario is located within the Maricunga gold belt, which is one of the most prolific gold districts in the world containing several large HSE and porphyry deposits.

Eight shallow RC holes were completed by previous operators and returned 20 metres and 32 metres of 0.41 g/t gold and 0.38 g/t gold respectively, in two separate holes. These holes were completed to the east of the current focus of exploration, and did not test Astra’s currently high-priority drill targets. Drill results by previous operators are historical in nature and have not been verified by Astra.

Geology of Don Mario project

Astra’s geological mapping of the Don Mario project (Figure 1) shows a strong overlapping 2 kilometre by 1.8 kilometre area of intense hydrothermal alteration identified from satellite imagery and the Cerro Bayo Volcanic Complex. The Complex includes a dacitic to rhyodacitic dome forming the Cerro Bayo hill in the northeast portion of the alteration anomaly, surrounded by phreatomagmatic tuffs exposed mainly to the west (Figure 1).

The Cerro Bayo Volcanic Complex is interpreted to continue westward beneath shallow modern cover, based on several subcrops and small outcrops identified along creeks in this area. Portions of the target geology are pervasively silicified and locally form vuggy silica and hydrothermal breccias cemented by quartz-alunite and jarosite. Previous exploration by other operators at the Project identified locally elevated gold values within some of these hydrothermal breccias.

Alteration and Geochemistry of Don Mario

A total of 261 grid samples were collected and analyzed for alteration assemblages. The results show a strong correlation with the alteration patterns interpreted from satellite imagery and confirm the presence of a quartz-alunite-pyrophyllite alteration assemblage (Figure 2). Alteration assemblage interpretation defined 3 zones: the shallow lithocap with K-rich alunite (Zone 1), the deeper lithocap with Na-rich alunite (Zone 2) and the higher temperature feeder zones with pyrophyllite (Zone 3).

The same grid was sampled for lag geochemistry. The results define a 2 kilometre by 1 kilometre, NW-elongated gold-silver anomaly, concentrated predominantly west and southwest of the main lithocap (Figure 3). The strongest gold anomalies range up to 0.2 g/t gold and display a predominantly E-W orientation. Silver anomalies are more extensive and range up to 2.0 g/t silver.

In addition to the grid sampling, nine rock-chip samples were collected from surface outcrops within the survey area. These samples returned gold and silver anomalies, with maximum values of 1.35 g/t gold and 1.14 g/t silver. The highest gold value was obtained from a hydrothermal breccia located south of Cerro Bayo hill (photo in Figure 2).

Geophysics of Don Mario

To further evaluate the lithocap alteration and associated geochemical anomalies, Astra completed a three-line CS-NSAMT survey along NE-SW-oriented profiles crossing the NW-oriented target area (green lines, Figure 2).

The CS-NSAMT results identify a shallow high-resistivity anomaly approximately 200 to 400 metre thick, occurring between approximately 4,600 and 5,000 metres elevation and extending for at least 600 metres across the three sections. A second, deeper resistive anomaly extends to approximately 4,000 metres elevation, or approximately 1,000 metres below surface, and is concentrated toward the southwest on sections L2 and L3 (Figure 4).

These resistive anomalies are the exact targets for vuggy silica at the core of a high sulphidation system.

Don Mario Targeting Summary

The combination of geological mapping, alteration mineralogy, geochemistry and geophysics supports the interpretation of a large HSE system with multiple exploration targets. These include:

• A shallow, disseminated gold and silver mineralization target associated with a large (1 by 1 kilometre) flat lying lithocap with favorable alteration (Zone 1).

• Deeper HSE-porphyry transition target located NW of the area (Zone 2).

• Potentially higher-grade feeder-zone targets (Zones 3), associated with faults and deep resistivity anomalies (L2 line in Figure 4) to the south of the area.

The results provide compelling targets for follow-up exploration, including drill testing of the most prospective portions of the Don Mario HSE system. Astra intends to undertake a drill program of approximately 2,500 metres, currently planned to commence in Q1 2027.

Sampling procedure

At each sampling location, two samples were collected: one for LAG analysis and another for Terraspec analysis. A maximum offset of 10 metres from the theoretical sampling point was established, depending on field conditions.

At each sampling site, the surface soil layer was removed over an area of approximately 1 m², using a brush to eliminate coarse fragments. The material was collected with a plastic scoop, without exceeding a depth of 5 centimetres.

LAG sampling consisted of the collection of surface material with a particle size ranging from 2 milimetres to 4.75 milimetres, using a sieve system (No. 4 mesh over No. 10 mesh). The material was manually sieved in the field, collecting approximately 1 to 1.5 kilograms per sample. Samples were stored in 25 × 35 centimetre bags, properly labeled and identified.

Samples were sent to ALS Labs in Copiapó and analyzed with the following routine: PREP-31B, AuME-ST43.

Additionally, at each sampling location, a sample was collected for Terraspec analysis by manually selecting fragments from the material retained on the upper sieve (approximately 2 to 5 centimetres in size), with an approximate weight of 100 grams. These samples were stored in 10 × 10 centimetre properly labeled Ziploc bags and sent to a consultant company to analyze.

From the designed grid, only samples between localities 250 and 255 could not be surveyed due to operational difficulties associated with terrain conditions.

To ensure analytical quality control (QA/QC), a systematic protocol was implemented that included the insertion of 14 QAQC samples, including duplicate samples, standards, and blanks.

Qualified Person

The technical data and information as disclosed in this news release has been reviewed and approved by Darcy Marud, who is an Independent Director of Astra. Mr. Marud is a Practicing Member of the Association of Professional Geoscientists of Ontario and is a qualified person as defined under the terms of National Instrument 43-101 – Standards of Disclosure for Mineral Projects.

About the Company

Astra Exploration Inc. is a precious metals exploration company based out of Vancouver, BC that is actively building a portfolio of high-quality projects in some of the most important mining jurisdictions in Latin America. 

The 80% owned La Manchuria gold-silver project in Santa Cruz, Argentina, over which Astra has an option to acquire 90% interest from Patagonia Gold Corp, is a high-grade gold and silver low sulphidation epithermal (LSE) deposit located in the prolific Deseado Massif which hosts multiple world-class LSE precious metals deposits including Cerro Vanguardia and Cerro Negro, Santa Cruz, Argentina.

The 100% owned Pampa Paciencia gold and silver project in northern Chile is located in the Paleocene mineral province in proximity to such major operating mines as Spence and Sierra Gorda.  The project shares several important geological similarities to other Paleocene LSE gold-silver deposits including Faride and El Peñón.  

The 100% owned Don Mario (renamed from Cerro Bayo) project in northern Chile is located in the Maricunga belt approximately 20 kilometres from the Refugio Mine. The project hosts a high sulphidation epithermal (HSE) +/- porphyry gold system with similarities to the Salares Norte deposit to the north in the same belt. The Maricunga belt is one of the most endowed regions in the world for gold and copper deposits.

For further information please contact:

Brian Miller
Chief Executive Officer
Tel. 604.428.0939
Email: brian.miller@astra-exploration.com

Katrina Damouni
Corporate Development
Tel. 604.428.0939
Email: katrina.damouni@astra-exploration.com