Highlights

Hole PNDH-06 intersected 44 metres grading 1.23% CuEq within 236 metres of 0.57% CuEq

Hole PND-02 intersected 43.6 metres grading 1% CuEq within 208 metres of 0.56% CuEq

Hole PNR-30 intersected 18 metres grading 1.26% CuEq within 161 metres of 0.54% CuEq

Hole PNDH-03 intersected 62 metres grading 0.66% CuEq within 268 metres of 0.49% CuEq

Hole PNDH-04 intersected 52 metres grading 0.61% CuEq within 266 metres of 0.48% CuEq

Hole PNR-03 intersected 52 metres grading 1.26% CuEq within 68 metres of 1.15% CuEq

Hole PNR-28 intersected 32 metres grading 1.95% CuEq within 102 metres of 0.93% CuEq

Vancouver, British Columbia – (September 23, 2026) – TheNewswire - Sendero Resources Corp. (TSXV: SEND) (FSE:9O40) (the “Company” or “Sendero”) is pleased to report a review and the recalculation of Metal Equivalents on historical drilling on the Peñas Negras copper-gold project in La Rioja province, Argentina.  The Company has rebuilt the database from historical drill programs conducted by notable prior owners and operators evaluating 77 holes and 6,433 assay samples. Applying one consistent CuEq methodology across the entire historical database provides a broader, project-wide view of the project.  

"For the first time, we have a consistent, project-wide depiction of the historical drilling at Peñas Negras, reinforcing why we're so excited about this project," said Jeremy Gillis, Interim CEO of Sendero. "Mineralization begins near surface and extends to more than 350 metres downhole, highlighted by 24 metres of 1.53% CuEq in PNDH-06. This work brings the full value of decades of prior exploration into focus, and we look forward to what is to come from our fully funded drill program."

 

Hole		From (m)	To (m)	Length (m)	CuEq %	Au g/t	Ag g/t	Cu ppm	Mo ppm	Zn ppm	Pb ppm
PNDH-06		31.9	268	236.1	0.57	0.27	5.87	770	33.4	2036	806
	including	33.8	78	44.2	1.23	0.4	23.55	927	40.1	5829	3567
	including	54	78	24	1.53	0.4	28.32	1535	38.3	10679	3813
PNDH-03		84	352	268	0.49	0.29	0.74	1372	45.6	152	33
	including	92	154	62	0.66	0.37	1.12	1834	70.2	284	55
PNDH-04		96	362	266	0.48	0.22	2.22	1299	39	1308	467
	including	122	174	52	0.61	0.3	1.73	1905	42.8	775	308
PND-02		38.6	247	208.4	0.56	0.38	1.54	757	23.3	699	195
	including	47.4	91	43.6	1	0.75	0.47	1405	34.2	461	79
PNR-28		56	158	102	0.93	0.78	1.84	104	2.6	737	283
	including	100	132	32	1.95	1.69	3.48	157	2.4	489	189
	including	130	132	2	23.15	20.58	31.2	118	3	582	262
PNR-30		59	220	161	0.54	0.33	2.02	961	24.2	925	263
	including	110	128	18	1.26	0.66	10.91	1236	27.9	5232	1618
PNR-33		82	270	188	0.46	0.27	0.8	1217	38.7	155	39
	including	118	150	32	0.61	0.33	0.88	2003	51.1	73	28
PNR-23		44	240	196	0.44	0.23	2.3	872	26.7	1135	270
	including	200	214	14	1.11	0.75	6.26	824	18.3	2237	556
PNR-03		32	100	68	1.15	0.85	2.94	1170	51.2	339	353
	including	34	86	52	1.26	0.95	2.9	1213	55.9	327	418
PNDH-05		234	428	194	0.4	0.19	1.99	899	40.6	971	247
	including	384	400	16	0.67	0.28	7.54	1113	20.5	2988	683
PNR-22		34	156	122	0.51	0.35	0.98	803	32	469	90
	including	48	92	44	0.66	0.45	1.07	1122	43.2	543	93
PNR-36		8	156	148	0.36	0.2	2.39	394	9.3	1496	325
	including	108	110	2	2.3	0.33	50.4	6027	26	10000	3052
PNR-39		2	102	100	0.49	0.35	2.69	319	9.1	553	150
	including	2	16	14	0.92	0.67	8.13	131	4.9	30	432
PNR-29		58	208	150	0.27	0.17	0.42	511	13.2	443	57
	including	98	100	2	0.8	0.57	2	937	19	1075	365
PNDH-01		84	278	194	0.2	0.08	0.53	897	17.7	172	18
PNDH-08		2	84	82	0.42	0.27	2.56	365	11.9	758	254
PNR-61		260	354	94	0.35	0.24	0.64	313	12.6	1000	100
PNR-21		24	108	84	0.32	0.18	2.34	307	13	1131	346
	including	44	56	12	0.73	0.36	7.82	722	8.8	3102	1073
PND-01		149.4	195.6	46.2	0.5	0.4	0.48	298	18.3	187	76
PNDH-02		0	76	76	0.29	0.19	0.36	553	26.2	192	34

Copper Equivalent (CuEq) values shown in the tables for drill intercepts are calculated on the basis of US$4.50/lb for Cu, US$3,375/oz for Au, US$60/oz for Ag, US$25/lb for Mo, US$1440/t for Pb and US$2940/t for Zn, with 100% recoveries assumed for all metals (since it is unclear what metals will be the principal products, assuming different recoveries is premature at this stage). The formula is: CuEq = Cu % + (Au grade in g/t x (Au recovery / Cu recovery) x [Au price ÷ 31] / [Cu price x 2200 x 1%]) + (Ag grade in g/t x (Ag recovery / Cu recovery) x [Ag price ÷ 31] / [Cu price x 2200 x 1%]) + (Mo grade in % x (Mo recovery / Cu recovery) x [Mo price] / [Cu price]) + (Pb grade (%) × (Pb recovery / Cu recovery) × [Pb price ÷ (Cu price × 2200)]) + (Zn grade (%) × (Zn recovery / Cu recovery) × [Zn price ÷ (Cu price × 2200)]).The 100% recovery assumption is for illustrative purposes only and actual future recoveries may differ. Reported intervals are drill-indicated (downhole) lengths and insufficient data are currently available to state the true thickness of the mineralized intervals.

 

Disclosures

Historically on the Peñas Negras project, Metal Equivalents were reported in AuEq, but this exercise is calculated for CuEq as copper is more widely dispersed and is less variable in the project area. Metal Equivalent Grades are calculated from multi-element geochemical analyses of drill core, based on the combination of the primary metal grade with the relative price and metallurgical recovery of secondary metals in a polymetallic geological occurrence. Metal Equivalents (MEqs) simplify reporting of metal grades and are useful for comparison of drill intercepts within a specific project to guide exploration, or for comparison of grades in separate analogous deposits.

Given the considerable increase in commodity prices since 2021 when Sendero Resources Corp acquired the project, recalculation of the MEq is considered important to assign a more realistic value to drill intercepts. Metal Equivalent calculations are used with caution and are generally not acceptable for public disclosure in mineral resource estimates.

Qualified Person

Steven McMullan, P. Geo., a consultant to the Company and member of the Board supervised the preparation of and reviewed and approved the scientific and technical information pertaining to Peñas Negras Project contained in this news release. Mr. McMullan is a qualified person as defined by National Instrument 43-101 Standards of Disclosure for Mineral Projects.

 

About Sendero Resources Corp.

The Company is focused on copper-gold exploration at its 100% owned Peñas Negras Project in the Vicuña Belt in Argentina. The Peñas Negras Project has similar geological characteristics to other deposits in the Vicuña Belt and multiple porphyry and high-sulfidation epithermal targets have been identified on the project. The Company’s target area is located approximately 12 km north-northeast of the Josemaria resource area, while the centre of the Peñas Negras concession area is situated approximately 18 km southeast of Caserones mine operated by Lundin Mining, approximately 24 km northeast of NGEx Minerals’ Lunahuasi project, and about 32 km north-northeast of BHP-Lundin Mining’s Filo del Sol development stage project. The Company also has an option to earn a 100% interest on eight additional granted mining concessions covering 91.7 km2. The total project area comprises 211.77 km2.

Further Information

For further information, please contact:

Sendero Resources Corp.
Jeremy Gillis, Interim Chief Executive Officer
Email: info@senderoresources.com

+1 (236) 232-0988         

Follow Sendero Resources (@SenderoRes) on X, (Sendero Resources) on LinkedIn, and (@sendero_resources) on Instagram.

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