ATERRA Updates Totora Inferred Mineral Resource and Files NI 43-101 Technical Report
Revised extraction constraints reduced reported tonnage and contained metals, while average copper and gold grades increased.
Sentiment and the balance of points
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Rhea-AI Summary
ATERRA Metals (CSSCF) updated its Totora inferred mineral resource in Chile to 150.1 million tonnes and filed its supporting technical report. Effective October 27, 2026, the estimate grades 0.517% copper equivalent at a 0.20% copper cut-off, containing 1,009 million pounds of copper and 768.7 thousand troy ounces of gold.
Compared with September 24, tonnage fell 6.1%, contained copper fell 5.5% and contained gold fell 3.0%, while average grades increased. Revised conceptual extraction constraints, rather than changes to the underlying block model, drove the reduction. The resource remains entirely inferred, a category with substantial uncertainty. Following a completed $8.355 million financing, ATERRA plans to begin 13,000 metres of drilling in November, including extension and infill work and sampling for metallurgical testing. It also signed a contract for a geophysical survey to identify potential extensions and additional targets.
How this balance works
Rhea-AI gives every point it takes from this document a weight. Minor counts 1, Moderate 3 and Major 9, so one Major point outweighs several Minor ones. The bar adds up the weights on each side, and when neither side holds more than 65% of the total the balance reads Mixed.
It reads the document as published, with the same rules for every company, and it does not look at what the market expected or at how the stock traded, so a point can be objectively good on a day the stock falls.
Rhea-AI Sentiment measures something else, the tone of the wording.
Hollow bars mark forward-looking points. How the balance works
Positive
- Major point$8.355 million financing closed, ahead of the planned Phase II drilling program. 63% of market cap
- Moderate point. Forward-looking: it has not happened yet and may not happen.13,000-metre drill program planned for November to test Frontera and Totora extensions and improve resource confidence.
- Minor point. Forward-looking: it has not happened yet and may not happen.Metallurgical sampling is planned during drilling to support future recovery testing.
- Minor point. Forward-looking: it has not happened yet and may not happen.Magnetotelluric survey contract signed to identify potential deposit extensions and additional exploration targets.
- Minor pointCopper grade increased 0.7% to 0.305% compared with the September 24 estimate.
3 minor points
- Minor pointGold grade increased 3.2% to 0.159 grams per tonne compared with the September 24 estimate.
- Minor pointCopper-equivalent grade increased 1.8% to 0.517% compared with the September 24 estimate.
- Minor pointNI 43-101 technical report filed to support the updated Totora resource estimate.
Negative
- Moderate pointResource tonnage fell 6.1% to 150.1 million tonnes versus September 24, following revised extraction constraints.
- Moderate point. Forward-looking: it has not happened yet and may not happen.Property option agreements require future payments and, in certain cases, exploration commitments; noncompliance could forfeit interests.
- Moderate pointHistorical drilling documentation gaps and limited geological and grade continuity underpin the entirely inferred classification.
- Minor pointContained copper fell 5.5% to 1,009.0 million pounds versus the September 24 estimate.
- Minor pointContained gold fell 3.0% to 768.7 thousand troy ounces versus the September 24 estimate.
- Minor pointNo metallurgical testing has been completed on the resource; historical results from two composites remain unverified by SRK.
AI-generated analysis. How Rhea-AI works. Not financial advice.
Updated Inferred Mineral Resource of 150.1 Mt Grading
Toronto, Ontario--(Newsfile Corp. - November 10, 2026) - ATERRA Metals Inc. (CSE: ATC) (OTCQB: CSSCF) ("ATERRA" or the "Company") announces an updated Inferred Mineral Resource estimate for its Totora Copper-Gold Project (the "Totora Project" or the "Project") in Region III, Chile (see Table 1). The updated estimate revises and supersedes the estimate announced on September 24, 2026, reflecting refinements by SRK Consulting (Chile) SpA ("SRK") to the conceptual constraints used to establish reasonable prospects for eventual economic extraction ("RPEEE") during preparation of the supporting technical report. The Company also announces the filing of that report in accordance with National Instrument 43-101 - Standards of Disclosure for Mineral Projects ("NI 43-101"). The updated estimate has an effective date of October 27, 2026
Highlights
Updated Inferred Mineral Resource: 150.1 million tonnes ("Mt") grading
0.305% copper ("Cu") and 0.159 grams per tonne ("g/t") gold ("Au"), or0.517% copper equivalent ("CuEq"), at a base-case cut-off grade of0.20% Cu.Contained Metals: 1,009 million pounds ("Mlb") of copper and 768.7 thousand troy ounces ("koz") of gold, equivalent to 1,710.5 Mlb CuEq.
Established Mining District: The Project is located in Chile's Dos Amigos Mining District with nearby highway and high-voltage power infrastructure
Updated Inferred Mineral Resource
The Mineral Resource comprises the Frontera, Clinton and Totora-Algarrobilla deposits as summarized in Table 1. The differences from the September 24, 2026 estimate and the basis for the revision are described in the reconciliation below and summarized in Table 2.
Table 1 - Updated Inferred Mineral Resource (
| Deposit | Tonnes | Cu | Au | CuEq | Cu | Au | CuEq |
| (Mt) | (%) | (g/t) | (%) | (Mlb) | (koz) | (Mlb) | |
| Frontera | 79.9 | 0.337 | 0.191 | 0.591 | 593.2 | 491.9 | 1,040.3 |
| Totora-Algarrobilla | 54.3 | 0.280 | 0.095 | 0.406 | 335.9 | 165.4 | 486.2 |
| Clinton | 15.8 | 0.232 | 0.221 | 0.525 | 80.8 | 112.3 | 183.2 |
| Total | 150.1 | 0.305 | 0.159 | 0.517 | 1,009.0 | 768.7 | 1,710.5 |
See the notes to Tables 1 below Table 3 for the resource assumptions, CuEq calculation and qualifications. Mineral Resources are not Mineral Reserves and do not have demonstrated economic viability. Figures are rounded and totals may not sum exactly.
"Filing our NI 43-101 technical report is an important step for the Totora Project," said Carl Hansen, CEO of ATERRA Metals. "The updated Inferred Mineral Resource totals 150.1 million tonnes grading
"Our next step is Phase II. With the successful closing of our
Reconciliation with the September 24 estimate
SRK confirmed that the underlying block model used for the September 24 estimate was unchanged. The resource revision reflects changes solely to the conceptual extraction models used to assess RPEEE. The updated estimate includes mineralization within conceptual open-pit shells and underground shapes. As compared to the initial resource estimate, at the
Table 2 - Reconciliation of Updated Inferred Mineral Resource
| Measure | Sept. 24, 2026 | Updated Estimate | Change |
| Frontera Deposit Tonnes (Mt) | 81.5 | 79.9 | - |
| Totora-Algarrobilla Deposit Tonnes (Mt) | 62.3 | 54.3 | - |
| Clinton Deposit Tonnes (Mt) | 16.0 | 15.8 | - |
| Totora Project - Total Tonnes (Mt) | 159.8 | 150.1 | − |
| Cu (%) | 0.303 | 0.305 | + |
| Au (g/t) | 0.154 | 0.159 | + |
| CuEq (%) | 0.508 | 0.517 | + |
| Contained Cu (Mlb) | 1,067.3 | 1,009.0 | − |
| Contained Au (koz) | 792.9 | 768.7 | − |
| Contained CuEq (Mlb) | 1,790.8 | 1,710.5 | − |
The updated conceptual open-pit shells use a copper price of US
The conceptual extraction scenarios are used to establish RPEEE for resource reporting purposes. They do not constitute a development plan or demonstrate economic viability. Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability. The resource estimate remains classified entirely as Inferred.
Table 3 - Updated Inferred Mineral Resource by Conceptual RPEEE Constraint (
| Conceptual constraint | Tonnes | Cu | Au | CuEq | Cu | Au | CuEq |
| (Mt) | (%) | (g/t) | (%) | (Mlb) | (koz) | (Mlb) | |
| Open-pit shells | 124.3 | 0.31 | 0.16 | 0.52 | 849.5 | 638.6 | 1,432.2 |
| Underground shapes | 25.8 | 0.28 | 0.16 | 0.49 | 159.5 | 130.1 | 278.2 |
| Total | 150.1 | 0.31 | 0.16 | 0.52 | 1,009.0 | 768.7 | 1,710.5 |
Notes to Tables 1 and 3
- The independent Qualified Person for the Mineral Resource is Joled Nur, RM CMC, Registration No. 181, of SRK. The estimate has an effective date of October 27, 2026 and was prepared in accordance with the CIM Definition Standards for Mineral Resources and Mineral Reserves incorporated by reference in NI 43-101.
- The resource estimate is classified entirely in the Inferred category. Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability. Inferred Mineral Resources are subject to a high degree of uncertainty, and there is no assurance that any part of an Inferred Mineral Resource will be converted to an Indicated or Measured Mineral Resource or to a Mineral Reserve.
- Tonnes are metric tonnes; pounds are imperial pounds and gold ounces are troy ounces. Figures are rounded and totals may not sum exactly. Contained metals are reported before metallurgical recovery.
- The
0.20% Cu reporting cut-off applies to mineralization within both the conceptual open-pit shells and underground shapes. - RPEEE conceptual open-pit shells were generated using Whittle software with US
$6.00 /lb copper and US$3,650 /oz gold; a 45° pit slope;85% recoveries for copper and gold and75% copper recovery for oxide leach material; mining costs of US$1.20 /t plus US$0.23 /t-km transport; processing costs of US$11.30 /t processed; G&A of US$0.30 /lb sold; selling costs of US$0.418 /lb copper and US$5 /oz gold; and a10% discount rate. The conceptual underground shapes were developed using bulk-caving assumptions, the0.30% CuEq shape-generation criterion, and underground mining cost of US$8.50 /t. - No metallurgical testing has been completed on the Mineral Resources. Actual recoveries established through future metallurgical test work may differ from the assumed recoveries.
- Bulk density was estimated by deposit and mineralization type: 2.62 t/m³ (Frontera oxide), 2.67 t/m³ (Frontera secondary sulphide) and 2.73 t/m³ (Frontera primary sulphide); 2.45 t/m³ (Totora and Algarrobilla oxide) and 2.67 t/m³ (Totora and Algarrobilla sulphide); and a global average of 2.65 t/m³ at Clinton, where no site-specific density determinations were available.
- The CuEq calculation uses
85% recovery for copper and gold and prices of US$4.00 /lb copper and US$3,650 /oz gold. The recoveries are assumptions and may differ from those determined by future testing. Molybdenum and silver are excluded. CuEq (%) = Cu (%) + [Au (g/t) × (3,650 ÷ 31.1035) × 0.85] ÷ [22.0462 × 4.00 × 0.85].
Cut-off Grade Sensitivity
The following sensitivity cases, summarized in Table 4, show how tonnes, grades and contained metal vary with the Cu reporting cut-off within the combined conceptual open-pit and underground envelopes.
Table 4 - Totora Cu-Au Project Cut-off Grade Sensitivity
| Cu cut-off | Tonnes | Cu | Au | CuEq | Cu | Au | CuEq |
| (Mt) | (%) | (g/t) | (%) | (Mlb) | (koz) | (Mlb) | |
| 0.15 | 250.0 | 0.252 | 0.135 | 0.432 | 1,391.2 | 1,088.1 | 2,384.1 |
| 0.18 | 185.6 | 0.283 | 0.149 | 0.482 | 1,157.7 | 890.8 | 1,970.5 |
| 0.20 | 150.1 | 0.305 | 0.159 | 0.517 | 1,009.0 | 768.7 | 1,710.5 |
| 0.25 | 96.7 | 0.351 | 0.180 | 0.591 | 748.2 | 559.7 | 1,258.9 |
| 0.30 | 69.5 | 0.381 | 0.197 | 0.644 | 584.5 | 441.4 | 987.2 |
Notes: See the notes to Table 3 and the Technical Disclosure section of this news release. Only the
Estimation Methods and Principal Risks
SRK estimated Mineral Resources separately for Frontera, Clinton and Totora-Algarrobilla. SRK used ordinary kriging for grade estimation and simple kriging or inverse distance in units with limited samples or continuity. SRK estimated bulk density by inverse distance at Frontera and Totora-Algarrobilla and assigned a fixed density at Clinton. SRK applied domain-specific grade caps before compositing and used a 10 × 10 × 10 metre parent block model with subcells.
SRK classified the Mineral Resource entirely as Inferred, reflecting the limited geological and grade continuity and gaps in historical drilling and QA/QC documentation for the historical drilling.
Factors That May Materially Affect the Mineral Resource: The Inferred Resource is subject to factors that could materially affect potential development of the Project. The Company holds its interests in the properties comprising the Totora Project under option agreements that require future payments and, in certain cases, exploration commitments to maintain or increase its interests. Failure to satisfy an applicable option requirement could result in the Company losing some or all of its interest in the applicable property.
Historical metallurgical testing was limited to two composite samples and SRK has not verified those results. The recovery assumptions for the Mineral Resource are subject to confirmation through future test work. The estimate is also sensitive to metal prices, operating costs and other assumptions used to establish RPEEE. Water and infrastructure availability, permitting, environmental requirements, surface and mineral tenure, community matters and changes in Chilean laws and regulations may affect future development.
Technical Disclosure
Qualified Persons: Joled Nur, Registered Member of the Comisión Calificadora de Competencias en Recursos y Reservas Mineras (RM CMC), Registration No 181, of SRK is the independent qualified person for the Inferred Mineral Resource, as defined by NI 43-101. The Inferred Mineral Resource has an effective date of October 27, 2026 and the technical report has an effective date of November 6, 2026. Mr. Nur has reviewed and approved the scientific and technical information in this news release relating to the Inferred Resource.
Sophia Bascuñán, Registered Member of the Comisión Calificadora de Competencias en Recursos y Reservas Mineras (RM CMC), Registration No 518, of SRK is the independent qualified person responsible for the geological modelling and verification of the data underlying the Inferred Resource, including the quality-assurance and quality-control ("QA/QC") information. Ms. Bascuñán reviewed ATERRA's Phase I QA/QC procedures and the available QA/QC documentation for historical drilling and considers the data adequate for the purpose of estimating Mineral Resources.
Francisco Bravo, a resident of Santiago, Chile and the Company's Chief Geologist, is a qualified person as defined by NI 43-101 and has reviewed and approved the remaining scientific and technical information in this news release. Mr. Bravo is not independent of the Company within the meaning of NI 43-101. Mr. Bravo is a 'Competent Person' registered with the Comisión Calificadora de Competencias en Recursos y Reservas Mineras, Registro N° 51' and is registered with the Colegio de Geólogos de Chile (No. 725).
Data Verification and QA/QC: Sophia Bascuñán carried out the verification of the available data. She reviewed all the available background, databases, quality control results and the available certificates of the historical data and the data produced by ATERRA. On September 21, 2026 and from October 5 to 8, 2026, Sophia Bascuñán and Francisco Bravo visited the Project, verifying more than
ATERRA completed both diamond and reverse-circulation ("RC") drilling on the Totora Project. RC holes were drilled using a 5½-inch-diameter bit. Rock cuttings were lifted to surface by compressed air and collected from the cyclone, or a hydraulic cyclone for wet samples, into the splitter by the drilling contractor under the supervision of Company geologists. Samples were split twice to produce a laboratory sample, a twin sample and a coarse reject. Each sample was weighed, bagged and tagged using a pre-prepared sampling list. Chip boxes were generated during sample extraction. Sealed sample bags were stored securely before dispatch to the laboratory, with certified reference materials inserted for QA/QC monitoring. Preliminary chip logging was completed in the field; RC chip trays were then sent to IMG facilities in Vallenar for detailed logging and secure storage.
Diamond holes were drilled using HQ core. The drilling contractor extracted the core from the core tube and placed it in core boxes with depth markers. ATERRA geologists completed preliminary logging at site and marked the core at two-metre intervals, including a cut line to guide sawing. Core was cut longitudinally using a diamond saw; one half was bagged, tagged and sealed for laboratory dispatch, and the other half was returned to the core box. Core boxes were stacked on pallets, wrapped and shipped to secure storage in Vallenar. Detailed geological logging followed.
RC and diamond-drill samples were transported to the AGS Cotecna laboratory in Coquimbo for mechanical preparation and chemical analysis. Preparation followed method P70-2EN: drying at 105°C, crushing to
Historical drilling data used in the Inferred Resource were derived from sources that the Company and SRK consider reliable. The Company has not independently verified every item of historical information; however, Ms. Bascuñán reviewed the available QA/QC documentation and considers the data adequate for the purpose of estimating Mineral Resources.
Copper Equivalent: Copper-equivalent grades are reported for comparative purposes and were calculated as follows:
CuEq (%) = Cu (%) + [Au (g/t) × (Au price (US$/oz) ÷ 31.1035) ×
The calculation uses metal prices of US
Technical Report
The technical report, "NI 43-101 Independent Technical Report Mineral Resource Estimate for Totora Cu-Au Project, Atacama Region, Chile," has a report date and effective date of November 6, 2026. The Mineral Resource estimate has an effective date of October 27, 2026. The technical report has been filed on SEDAR+ at www.sedarplus.ca and is available at www.aterrametals.com.
The technical report contains the complete assumptions, parameters and methods underlying the updated estimate. This news release is a summary only.
About ATERRA Metals Inc.
ATERRA Metals Inc. is a mineral exploration company advancing copper-gold projects in Chile. The Company's flagship Totora Copper-Gold Project is located in the Dos Amigos Mining District of Region III, Chile, approximately 60 kilometres south of Vallenar. The Project comprises the Taruca, Clinton, Frontera and Sevilla properties and hosts the Frontera, Totora, Algarrobilla and Clinton copper-gold porphyry systems, together with earlier-stage exploration targets. The Company holds its interests in the Project under option agreements and has no Mineral Reserves on any of its properties.
On behalf of ATERRA Metals Inc.
Carl Hansen, CEO
Phone: 416-953-0258
Email: info@aterrametals.com
Cautionary Note Regarding Forward-Looking Information
This news release contains "forward-looking information" within the meaning of applicable Canadian securities legislation. Forward-looking information is generally identifiable by words such as "anticipates", "believes", "expects", "intends", "plans", "potential", "may", "will", "could", "should" and similar expressions, or by statements that certain events or conditions "will" or "may" occur.
Forward-looking information in this release includes statements regarding the timing, scope and objectives of the Company's planned Phase II exploration program, including the expected commencement in November 2026 of a 13,000-metre drill program. It includes the Company's plans to test potential extensions of the Frontera deposit, including its higher-grade copper-gold core, and to test extensions of the Totora mineralized system. It also includes plans to conduct infill drilling to improve confidence in the Inferred Mineral Resource and to collect samples for preliminary metallurgical testing. Forward-looking information also includes the planned magnetotelluric survey, the Company's objective of completing it in November 2026 and the potential for the survey to help identify extensions of known deposits and define additional targets for follow-up. Other forward-looking information includes statements regarding the potential size, continuity and expansion of the mineralized systems at the Totora Project, the potential for additional discoveries, the potential to expand the Mineral Resource or upgrade portions of it to a higher-confidence category, and the potential recoverability of copper and gold.
The Inferred Mineral Resource and the forward-looking information in this release are based on assumptions that the Company and the Qualified Persons, as applicable, consider reasonable as of the date of this release. Assumptions underlying the estimate include geological and grade continuity between drill holes and the conceptual extraction, cost and recovery assumptions described in this release and the supporting technical report. The conceptual open-pit shells use a copper price of US
Forward-looking information is subject to known and unknown risks, uncertainties and other factors that may cause actual results to differ materially from those expressed or implied. These include the uncertainty inherent in Mineral Resource estimates, particularly Inferred Mineral Resources, and the possibility that further drilling may fail to confirm the geological interpretations, grades, tonnages or continuity reflected in the estimate. Additional drilling may fail to extend known mineralization, identify new mineralization, expand the Mineral Resource or provide sufficient information to support upgrading any portion of the Inferred Mineral Resource. Drilling, surveying and metallurgical testing may be delayed, modified or curtailed due to equipment or contractor availability, weather, access, permitting, increased costs or funding constraints. The magnetotelluric survey may yield inconclusive results or fail to identify extensions or targets that warrant follow-up. Mineralization identified outside the current Mineral Resource may ultimately fail to satisfy the criteria for inclusion in a Mineral Resource.
Other risks include metallurgical test results differing materially from the recoveries assumed in the estimate, lower copper or gold prices, higher mining, processing or other costs, and the Company's ability to fund its activities or satisfy payment and other obligations under its property option agreements. The Project is also subject to risks relating to title and tenure, water availability, permitting and environmental approvals, community relations, infrastructure, and changes in Chilean laws, regulations, taxation or royalty regimes.
Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability. Inferred Mineral Resources are subject to a high degree of uncertainty as to their existence and their economic and legal feasibility. There can be no assurance that any portion of an Inferred Mineral Resource will be upgraded to a higher-confidence Mineral Resource category or ultimately converted to a Mineral Reserve. Exploration results and indications of mineralization outside the current Mineral Resource do not constitute a Mineral Resource, and further exploration may fail to define additional Mineral Resources.
Although the Company has attempted to identify important factors that could cause actual results to differ materially from those expressed or implied by forward-looking information, other factors may cause results to differ from those anticipated, estimated or intended. Readers should not place undue reliance on forward-looking information. The forward-looking information in this release speaks as of the date of this release, and the Company undertakes no obligation to update or revise it except as required by applicable securities laws.
Neither the Canadian Securities Exchange nor its Market Regulator (as that term is defined in the policies of the Canadian Securities Exchange) accepts responsibility for the adequacy or accuracy of this release.

To view the source version of this press release, please visit https://www.newsfilecorp.com/release/323276
FAQ
AI-generated questions and answers. How Rhea-AI works. Not financial advice.
What is ATERRA Metals' updated Totora mineral resource?
Totora's updated inferred resource is 150.1 million tonnes grading 0.517% copper equivalent at a 0.20% copper cut-off. Effective October 27, 2026, it contains 1,009.0 million pounds of copper and 768.7 thousand troy ounces of gold across Frontera, Totora-Algarrobilla and Clinton.
What metal prices and recoveries underpin ATERRA's Totora estimate?
The conceptual open-pit shells use US$6.00 per pound copper and US$3,650 per ounce gold, while the copper-equivalent calculation uses US$4.00 per pound copper and US$3,650 per ounce gold. The latter assumes 85% recovery for both metals. These recoveries remain assumptions subject to future testing.
Are ATERRA's alternative Totora cut-off cases additional mineral resources?
No; only the 0.20% copper cut-off base case is reported as a mineral resource. The 0.15%, 0.18%, 0.25% and 0.30% copper cut-off cases are sensitivity comparisons and must not be interpreted as mineral resources.