- Full assay results from Hole AG-CG-PH2-002 confirm two distinct, high-grade copper-silver-gold skarn zones totaling 68.43 metres of combined mineralized interval, averaging 1.2% CuEq¹ (at 80% assumed metallurgical recovery)
- Upper zone (previously reported): 30.23 metres grading 1.5% CuEq from 146.70 metres, including 3.55 metres at 9.4% CuEq and a 1.20-metre interval at 15.8% CuEq
- Newly reported lower zone: 38.20 metres grading 1.0% CuEq from 243.80 metres, including 1.70 metres at 4.5% CuEq and 11.50 metres at 2.0% CuEq, extending high-grade mineralization to 282 metres downhole and roughly 67 metres below the base of the upper zone
- AG-CG-PH2-002 has also pinpointed, for the first time on this section, the base of the prospective limestone-skarn package that hosts the high-grade mineralization, defining the contact with underlying fresh, unmineralized granodiorite at 364.00 metres and sharpening geological targeting across the broader Cerro Grande corridor
VANCOUVER, BC — September 23, 2026 — Algo Grande Copper Corp. (“Algo Grande” or the “Company”) (TSX-V: ALGR | OTC: ALGRF | FRA: KM00) reports full assay results from Hole AG-CG-PH2-002 at the Cerro Grande skarn discovery, part of the Company’s Adelita Project in Sonora, Mexico. AG-CG-PH2-002 was designed to test the vertical extension and along-strike continuity of the Cerro Grande skarn system, and full assay results confirm that this objective has been achieved: high-grade copper-silver-gold mineralization is now demonstrated from 146.70 metres to 282.00 metres downhole, divided into two zones. The hole has returned a second zone of 38.20 metres grading 1.0% CuEq from 243.80 metres, approximately 67 metres below the base of the 30.23-metre zone grading 1.5% CuEq previously reported from 146.70 metres, confirming a multi-horizon skarn system at Cerro Grande.
The two zones together total 68.43 metres of combined mineralized interval, averaging 1.2% CuEq at 80% assumed metallurgical recovery. Downhole survey data confirm a gradual, systematic drift in azimuth over the interval between the two zones, which the Company considers a contributing factor to the lower grades returned between them (see below). Sampling of the hole was discontinued at 364.00 metres, where the hole passed into fresh, unmineralized granodiorite; the hole was previously reported to have reached a final depth of 661.80 metres (see news release dated September 11, 2026).
João Rocha, EurGeol, Vice President of Exploration of Algo Grande Copper, commented: “AG-CG-PH2-002 was designed to test the vertical extent and continuity of the Cerro Grande skarn system, and it has delivered exactly that: confirmed high-grade mineralization from 146.70 metres to 282 metres downhole, with a second, discrete high-grade horizon 67 metres below the base of the zone we reported from the first assays. This confirms that Cerro Grande is not a single lens but a multi-horizon skarn system with real vertical continuity. With 68.43 metres of combined high-grade mineralization now confirmed across two zones, and the system still open along strike, up-dip and at depth, we believe we are only beginning to define the scale of this discovery.”
¹ CuEq% is calculated as Cu% + (Au g/t × 0.9816) + (Ag g/t × 0.0140), using metal prices of US$5.20/lb Cu, US$3,500/oz Au and US$50/oz Ag, and is reported here at an assumed 80% metallurgical recovery of copper, gold and silver, consistent with the sensitivity basis disclosed in the Company’s prior news release dated September 11, 2026; metallurgical recoveries have not yet been established for the Adelita Project, and readers are cautioned that CuEq figures are for illustrative purposes only and may not accurately reflect potential future recoveries. Reported intervals are drill-indicated (downhole) lengths; true widths have not yet been determined.
² The lower zone also returned locally anomalous zinc, up to 0.48% Zn within the 11.50-metre high-grade interval. No metallurgical testwork has been completed for the Adelita Project, and it has not yet been determined whether this zinc endowment is recoverable, or whether it would represent a byproduct credit or a penalty element within a copper-gold-silver concentrate. Zinc has not been included in the CuEq figures reported herein.
Figure 1 - Cross-section (looking north) through AG-CG-PH2-002 showing the upper and lower mineralized zones in the context of the broader Phase II drilling program, including AG-CG-PH2-003 through AG-CG-PH2-006.
Figure 2 - Plan view of the Cerro Grande drill target corridor showing AG-CG-PH2-002 and the broader Phase II drilling program, including AG-CG-PH2-003 through AG-CG-PH2-006, and the interpreted copper skarn horizon along the granodiorite-limestone contact.
Vertical Extension and Continuity Confirmed: A Second, Deeper Mineralized Zone in AG-CG-PH2-002
AG-CG-PH2-002 was designed to test the vertical extension and along-strike continuity of the Cerro Grande skarn system beyond the footprint established by historic and Phase I drilling. Full assay results confirm that this objective has been achieved: high-grade copper-silver-gold mineralization is now present in two discrete zones, from 146.70 metres to 282.00 metres downhole.
Full assay results for AG-CG-PH2-002, including the interval below 179 metres for which assays were previously reported as pending, confirm a second, discrete high-grade copper-silver-gold skarn zone from 243.80 to 282.00 metres downhole, approximately 67 metres below the base of the upper zone reported previously (146.70–176.93 metres). The lower zone graded 1.0% CuEq over 38.20 metres, including a narrower, higher-grade interval of 1.70 metres grading 4.5% CuEq from 244.30 metres and a higher-grade core of 11.50 metres grading 2.0% CuEq from 268.00 metres. As with the upper zone, the lower zone carries locally anomalous zinc, up to 0.48% Zn within the 11.50-metre high-grade interval, which the Company interprets as a further indication of a sphalerite component within the skarn assemblage.
Because AG-CG-PH2-002 was oriented to test continuity along strike of the skarn system rather than directly down-dip, the Company attributes the lack of continuous intervals between 176.93 and 243.80 metres, at least in part, to a documented deviation of the drillhole trace away from the higher-grade skarn horizon over that interval, rather than to a true break in mineralization. Downhole survey data record a gradual, systematic drift in azimuth over this portion of the hole, from approximately 112.9° near the collar to approximately 115.6–117.7° across the survey stations bracketing this interval (162 to 252 metres). Notwithstanding the deviation, mineralization was intersected at several points within this interval, including 0.85 metres grading 2.7% CuEq from 223.20 metres (1.57% Cu, 98 g/t Ag, 0.46 g/t Au and 1.90% Zn) and 2.10 metres grading 0.7% CuEq from 195.00 metres (0.45% Cu, 20 g/t Ag, 0.16 g/t Au and 1.58% Zn), together with 1.10 metres grading 0.2% CuEq from 192.90 metres (0.14% Cu, 5 g/t Ag, 0.02 g/t Au and 1.08% Zn) and 1.00 metre grading 0.3% CuEq from 202.00 metres (0.16% Cu, 10 g/t Ag, 0.05 g/t Au and 0.46% Zn). The Company therefore interprets the interval as reflecting the position of the drillhole trace relative to the higher-grade skarn horizon rather than an absence of mineralization.
AG-CG-PH2-002 has also, for the first time on this section of Cerro Grande, pinpointed the base of the prospective limestone-skarn package, with the hole passing into fresh, unmineralized granodiorite at 364.00 metres downhole. This revises the preliminary interpretation disclosed in the Company’s news release dated September 11, 2026, which placed the base of the limestone-skarn package at approximately 312 metres on the basis of preliminary core logging then available; completed logging, downhole survey data and the full assay results for the hole now place the contact at 364.00 metres, extending the interpreted thickness of the prospective host package by approximately 52 metres (361.66 metres of core, from 2.34 to 364.00 metres downhole, submitted for analysis). The Company considers this a material, positive result, sharpening the geological architecture of the host package and improving targeting for follow-up drilling along strike and down-dip across the broader Cerro Grande corridor.
AG-CG-PH2-002 was collared at 738,897 m E and 2,961,802 m N (UTM WGS84 Zone 12N, located by handheld GPS) at an elevation of 582 metres, and was drilled at a magnetic azimuth of 112.9° and a dip of -80° to a final depth of 661.80 metres.
AG-CG-PH2-001: Multi-Phase Intrusive Complex and Porphyry-Style Alteration
AG-CG-PH2-001, the first hole of the Phase II program at Cerro Grande, logged a multi-phase quartz monzonite intrusive complex, in at least four discrete pulses cutting the granodiorite host, together with more than 250 metres of pervasive to strong porphyry-style potassic-silicic alteration, which the Company interprets as consistent with a long-lived magmatic-hydrothermal system. Assay results confirm a coincident molybdenum geochemical anomaly averaging 32.6 ppm Mo (peak 110 ppm) over 15.58 metres from 387.42 to 403.00 metres downhole.
QUALITY ASSURANCE / QUALITY CONTROL
All drill core samples referenced in this news release were prepared and analyzed at ALS Laboratories, an independent, internationally accredited laboratory, located in Hermosillo, Mexico and Vancouver, Canada. Sample preparation was completed using ALS preparation methods CRU-31 (crushing), SPL-31 (splitting), and PUL-31 (pulverizing), resulting in a nominal pulp with at least 85% passing a 75-micron sieve.
Multi-element analyses were completed using the ME-ICP61a method, a four-acid digestion (hydrochloric, nitric, perchloric, and hydrofluoric acids) followed by ICP-AES analysis, appropriate for the higher base-metal grades encountered in these intervals. Gold was analyzed using the Au-AA23 method, consisting of a fire assay fusion with an atomic absorption spectroscopy (AAS) finish. Samples returning silver results above the upper detection limit of the ME-ICP61a method were re-assayed using the Ag-OG62 over-limit method.
ALS Laboratories employs internal quality control procedures including the routine insertion of certified reference materials, blanks, and duplicates at regular intervals. The Company implemented an independent quality assurance and quality control program through the systematic insertion of blind certified reference materials and blank samples into the sample stream. Results from QA/QC samples were reviewed on receipt and found to be within acceptable limits.
Qualified Person
The scientific and technical information disclosed in this news release has been reviewed and approved by João Rocha, EurGeol, Vice President of Exploration of Algo Grande Copper Corp., a Qualified Person as defined by National Instrument 43-101.
João Rocha, the Qualified Person, has verified the data disclosed in this news release, including the sampling, analytical and test data underlying the results reported herein. Verification included review of drill collar locations, downhole survey data, sampling and chain-of-custody procedures, and analytical results, together with the QA/QC program described above. There were no limitations on the verification process.
Consulting Agreement
The Company has engaged German Mining Networks GmbH (“GMN”) for investor relations and shareholder communications services, including investor and shareholder scheduling, communications and assistance with roadshows. GMN is expected to provide the Company with the opportunity to broaden its national and international reach by way of introductions to investors in Continental Europe. Peter Krah, Managing Partner of GMN, will be the principal contact responsible for the provision of such services. The engagement is for a term of three (3) months (unless terminated earlier), commencing on or about September 22, 2026, and the Company will pay a flat monthly fee of $6,800. GMN is an arm's length party to the Company and has no interest, directly or indirectly, in the Company or its securities, nor any right or present intent to acquire such an interest. GMN's principal place of business is Postfach: 10 01 26, 98561 Schmalkalden, Germany.
About Algo Grande Copper Corp.
Algo Grande Copper Corp. is a mineral exploration company advancing the Adelita Project, a district-scale, multi-system copper-silver-gold opportunity positioned in the prolific Arizona-Sonora copper belt. The 5,895-hectare Adelita Project is anchored by the high-grade Cerro Grande Cu-Au-Ag skarn discovery, which exhibits strong geophysical continuity along a defined corridor extending over 6 kilometres. Reprocessing of legacy geophysical data and field mapping indicate that a potential porphyry system may occur at depth, suggesting a classic skarn-porphyry mineralization model similar to major deposits found throughout northwestern Mexico.
ON BEHALF OF ALGO GRANDE COPPER CORP.
Enrico Gay
Chief Executive Officer
For more information, please contact:
E-mail: info@algo-grande.com
Website: www.algo-grande.com
+1 (778) 907-2547
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Cautionary Statement on Forward-Looking Information
This news release contains statements and information that, to the extent that they are not historical fact, constitute “forward-looking information” within the meaning of applicable securities legislation. Forward-looking information is based on the reasonable assumptions, estimates, analysis and opinions of management made in light of its experience and its perception of trends, current conditions and expected developments, as well as other factors that management believes to be relevant and reasonable in the circumstances at the date that such statements are made, but which may prove to be incorrect. Forward-looking information involves known and unknown risks, uncertainties and other factors that may cause the actual results, performance or achievements of Algo Grande to differ materially from any future results, performance or achievements expressed or implied by the forward-looking information, including, but not limited to, statements relating to the interpretation of drilling, alteration, lithological and assay results, the receipt and interpretation of outstanding assay results, the continuity and extension of mineralization along strike and at depth, the interpretation of alteration and intrusive character as indicative of a porphyry-style mineralizing system, the Company's exploration plans including the ongoing Phase II drilling program, and those listed in filings made by Algo Grande with the Canadian securities regulatory authorities (which may be viewed at www.sedarplus.ca). Accordingly, readers should not place undue reliance on any such forward-looking information. Further, any forward-looking statement speaks only as of the date on which such statement is made. New factors emerge from time to time, and it is not possible for Algo Grande's management to predict all of such factors and to assess in advance the impact of each such factor on Algo Grande's business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements. Algo Grande does not undertake any obligation to update any forward-looking information to reflect information, events, results, circumstances or otherwise after the date hereof or to reflect the occurrence of unanticipated events, except as required by law including securities laws.