Cerro Grande Mining Corporation

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 / ACCESS Newswire / September 23, 2026 / Algo Grande Copper Corp. ("Algo Grande" or the "Company") (TSXV:ALGR)(OTCID: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.

AG_CG_PH2_002 (Hole 2) copper zone continues to expand: a newly logged interval has grown Hole 2's copper-bearing footprint to 68.77 metres of visually observed mineralization across a 154-metre span, more than double what was reported previously, reinforcing the scale of the discovery beneath Cerro Grande. AG_CG_PH2_003 (Hole 3) delivers an extensive copper zone at Cerro Grande: copper mineralization was logged across a combined 74 metres of the hole, including a standout 32-metre section in its lower zone.

at Cerro Grande: Hole AG_CG_PH2_003 ("Hole 3") has commenced drilling at the Cerro Grande skarn target, collared approximately 100 metres along strike from the Phase I discovery hole, AG_GC_002 ( see news release here ), and planned to a total depth of 450 metres. Hole 3 objectives: confirm and expand the five known skarn horizons at Cerro Grande while testing for additional mineralized horizons in previously untested limestone.