# EDGAR Filing Document

**Accession Number:** 0001001838
**File Stem:** 0001558370-23-002434
**Filing Date:** 2023-3
**Character Count:** 304317
**Document Hash:** 383c64cc4dcf4e9f74c70cdff08c390a
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001558370-23-002434.hdr.sgml**: 20230301

**ACCESSION NUMBER**: 0001558370-23-002434

**CONFORMED SUBMISSION TYPE**: 10-K/A

**PUBLIC DOCUMENT COUNT**: 23

**CONFORMED PERIOD OF REPORT**: 20221231

**FILED AS OF DATE**: 20230301

**DATE AS OF CHANGE**: 20230228

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** SOUTHERN COPPER CORP/
- **CENTRAL INDEX KEY:** 0001001838
- **STANDARD INDUSTRIAL CLASSIFICATION:** METAL MINING [1000]
- **IRS NUMBER:** 133849074
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 10-K/A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-14066
- **FILM NUMBER:** 23688570

**BUSINESS ADDRESS:**
- **STREET 1:** 7310 NORTH 16TH ST.
- **STREET 2:** SUITE 135
- **CITY:** PHOENIX
- **STATE:** AZ
- **ZIP:** 85020
- **BUSINESS PHONE:** 602-264-1375

**MAIL ADDRESS:**
- **STREET 1:** 7310 NORTH 16TH ST.
- **STREET 2:** SUITE 135
- **CITY:** PHOENIX
- **STATE:** AZ
- **ZIP:** 85020

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** SOUTHERN PERU COPPER CORP/
- **DATE OF NAME CHANGE:** 19960726

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** SOUTHERN PERU COPPER HOLDING CO
- **DATE OF NAME CHANGE:** 19951006

?xml version='1.0' encoding='UTF-8'?

------

**UNITED STATES**

**SECURITIES AND EXCHANGE COMMISSION**

**Washington, D.C. 20549**

**FORM 10-K/A**

**Amendment No. 1**

**☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934**

**For the fiscal year ended: December 31, 2022**

**OR**

**☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934**

**For the transition period from&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;to&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;** 

**Commission File Number: 1-14066**

![Graphic](scco-20221231x10ka001.jpg)

**SOUTHERN COPPER CORPORATION**

(Exact name of registrant as specified in its charter)

---

| | | |
|:---|:---|:---|
| **Delaware** |  | **13-3849074** |
| (State or other jurisdiction of <br>incorporation or organization) |  | (I.R.S. Employer <br>Identification No.) |

---

---

| | | |
|:---|:---|:---|
| **7310 North 16th St, Suite 135 Phoenix, AZ** |  | **85020** |
| (Address of principal executive offices) |  | (Zip code) |

---

Registrant's telephone number, including area code: **(602) 264-1375**

Securities registered pursuant to Section 12(b) of the Act:

---

| | | |
|:---|:---|:---|
| **Title of each class:** | **Trading Symbol** | **Name of each exchange on which registered:** |
| Common stock, par value $0.01 per share | SCCO | New York Stock Exchange<br>Lima Stock Exchange |

---

Securities registered pursuant to Section 12(g) of the Act: **None**

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ⌧ No ◻

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes ◻ No ⌧

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ⌧ No ◻

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files).

Yes ⌧ No ◻

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company, or an emerging growth company. See definitions of "large accelerated filer," "accelerated filer," "smaller reporting company" and "emerging growth company" in Rule 12b-2 of the Exchange Act.

Large accelerated filer ⌧ Accelerated filer ◻ Non-accelerated filer ◻ Smaller reporting company ☐ <br> Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ◻

Indicate by check mark whether the registrant has filed a report on and attestation to its management's assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. Yes ⌧ No ◻

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements ☐

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant's executive offi cers during the relevant recovery period pursuant to §240.10D-1(b). ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act). Yes ☐ No ⌧

At February 28, 2023, there were of record 773,101,669 shares of common stock, par value $0.01 per share, outstanding.

The aggregate market value of the shares of common stock (based upon the closing price at June 30, 2022 as reported on the New York Stock Exchange-Composite Transactions) of Southern Copper Corporation held by non-affiliates was approximately $4,274.5 million.

PORTIONS OF THE FOLLOWING DOCUMENTS ARE INCORPORATED BY REFERENCE:

Part III: &nbsp;&nbsp;&nbsp;&nbsp; Proxy statement for 2022 Annual Meeting of Stockholders

------

**Explanatory Note**

Southern Copper Corporation is filing this Amendment No. 1 (this Amendment) to its Annual Report on Form 10-K for the fiscal year ended December 31, 2022, filed with the Securities and Exchange Commission (SEC) on February 28, 2023 (the Original Filing), for the sole purpose of filing the following Exhibits: 96.1, 96.2, 96.6, 96.7, 96.11, 96.12 and 96.13, that exceed the SEC file size limitations for a single submission.

Except as described above, this Amendment does not amend, update or change any other items or disclosures contained in the Original Filing. This Amendment does not reflect or purport to reflect any information or events occurring after the date of the Original Filing nor does it modify or update the disclosures contained in the Original Filing that may be affected by subsequent events. Accordingly, this Amendment should be read in conjunction with the Original Filing and Southern Copper Corporation's other filings made with the SEC subsequent to the filing of the Original Filing.

**Supplemental information**

**Southern Copper Corporation**

**Exhibit Index**

---

| | | |
|:---|:---|:---|
| **Sequential**<br>**Exhibit**<br>**Number** | **Document Description** | **Page**<br>**Number** |
| 3.1 | [(a) Amended and Restated Certificate of Incorporation, filed on October 11, 2005. (Filed as Exhibit 3.1 to the Company's Quarterly Report on Form 10-Q for the third quarter of 2005 and incorporated herein by reference).](http://www.sec.gov/Archives/edgar/data/1001838/000110465905054002/a05-18386_1ex3d1.htm) |  |
|  | [(b) Certificate of Amendment of Amended and Restated Certificate of Incorporation dated May 2, 2006. (Filed as Exhibit 3.1 to Registration Statement on Form S-4, File No. 333-135170, filed on June 20, 2006 and incorporated herein by reference).](http://www.sec.gov/Archives/edgar/data/1001838/000104746906008632/a2171259zex-3_1.htm) |  |
|  | [(c) Certificate of Amendment of Amended and Restated Certificate of Incorporation dated May 28, 2008. (Filed as Exhibit 3.1 to the Company's Quarterly Report on Form 10-Q for the second quarter of 2008 and incorporated herein by reference).](http://www.sec.gov/Archives/edgar/data/1001838/000110465908049238/a08-19021_1ex3d1.htm) |  |
| 3.2 | [By-Laws, as last amended on January 27, 2022. (Filed as Exhibit 3.2 to the Company's Form 8-K filed on January 31, 2022 and incorporated herein by reference).](http://www.sec.gov/Archives/edgar/data/1001838/000110465911011083/a11-2140_1ex3d2.htm) |  |
| 4.1 | [(a) Indenture governing $600 million 7.500% Notes due 2035, by and among Southern Copper Corporation, The Bank of New York and The Bank of New York (Luxembourg) S.A. (Filed as Exhibit 4.2 to the Company's Current Report on Form 8-K filed on August 1, 2005 and incorporated herein by reference).](http://www.sec.gov/Archives/edgar/data/1001838/000110465905035449/a05-13959_1ex4d2.htm) |  |
|  | [(b) Indenture governing $400 million 7.500% Notes due 2035, by and among Southern Copper Corporation, The Bank of New York, and The Bank of New York (Luxembourg) S.A. (Filed as Exhibit 4.2 to the Company's Current Report on Form 8-K filed on August 1, 2005 and incorporated herein by reference).](http://www.sec.gov/Archives/edgar/data/1001838/000110465905035449/a05-13959_1ex4d2.htm) |  |
| 4.2 | [Form of 6.375% Note (included in exhibit 4.1).](http://www.sec.gov/Archives/edgar/data/1001838/000110465905035449/a05-13959_1ex4d1.htm) |  |
| 4.3 | [Form of New 7.500% Note (included in Exhibit 4.2(a)).](http://www.sec.gov/Archives/edgar/data/1001838/000110465905035449/a05-13959_1ex4d2.htm) |  |
| 4.4 | [Form of New 7.500% Note (included in Exhibit 4.2(b))](http://www.sec.gov/Archives/edgar/data/1001838/000110465905035449/a05-13959_1ex4d2.htm) |  |
| 4.5 | [Indenture, dated as of April 16, 2010, between Southern Copper Corporation and Wells Fargo Bank, National Association, as trustee, pursuant to which $1.1 billion of 6.750% Notes due 2040 were issued. (Filed as Exhibit 4.1 to the Company's Current Report on Form 8-K filed on April 19, 2010 and incorporated herein by reference).](http://www.sec.gov/Archives/edgar/data/1001838/000095012310035945/y03351exv4w1.htm) |  |
| 4.6 | [Second Supplemental Indenture, dated as of April 16, 2010, between Southern Copper Corporation and Wells Fargo Bank, National Association, as trustee, pursuant to which the 6.750% Notes due 2040 were issued. (Filed as an Exhibit to the Company's Current Report on Form 8-K filed on April 19, 2010 and incorporated herein by reference).](http://www.sec.gov/Archives/edgar/data/1001838/000095012310035945/y03351exv4w3.htm) |  |
| 4.7 | [Form of 6.750% Notes due 2040. (Filed as an Exhibit to the Company's Current Report on Form 8-K filed on April 19, 2010 and incorporated herein by reference).](http://www.sec.gov/Archives/edgar/data/1001838/000095012310035945/y03351exv4w5.htm) |  |
| 4.8 | [Fourth Supplemental Indenture, dated as of November 8, 2012, between Southern Copper Corporation and Wells Fargo Bank, National Association, as trustee, pursuant to which the 5.250% Notes due 2042 were issued. (Filed as an Exhibit to the Company's Current Report on Form 8-K filed on November 9, 2012 and incorporated herein by reference).](http://www.sec.gov/Archives/edgar/data/1001838/000119312512463440/d435056dex42.htm) |  |
| 4.9 | [Form of 5.250% Notes due 2042. (Filed as an Exhibit to the Company's Current Report on Form 8-K filed on November 9, 2012 and incorporated herein by reference).](http://www.sec.gov/Archives/edgar/data/1001838/000119312512463440/d435056dex42.htm) |  |
| 4.10 | [Fifth Supplemental Indenture dated as of April 23, 2015, between Southern Copper Corporation and Wells Fargo Bank, National Association, as trustee, pursuant to which the 3.875% Notes due 2025 were issued. (Filed as an Exhibit to the Company's Current Report on Form 8-K filed on April 24, 2015 and incorporated herein by reference).](http://www.sec.gov/Archives/edgar/data/1001838/000156761915000589/s000872x1_ex4-1.htm) |  |
| 4.11 | [Sixth Supplemental Indenture, dated as of April 23, 2015, between Southern Copper Corporation and Wells Fargo Bank, National Association, as trustee, pursuant to which the 5.875% Notes due 2045 were issued. (Filed as an Exhibit to the Company's Current Report on Form 8-K filed on April 24, 2015 and incorporated herein by reference).](http://www.sec.gov/Archives/edgar/data/1001838/000156761915000589/s000872x1_ex4-2.htm) |  |
| 4.12 | [Form of 3.875% Notes due 2025. (Filed as Exhibit A to Exhibit 4.1 to the Company's Current Report on Form 8-K filed on April 24, 2015 and incorporated herein by reference).](http://www.sec.gov/Archives/edgar/data/1001838/000156761915000589/s000872x1_ex4-1.htm) |  |
| 4.13 | [Form of 5.875% Notes due 2045. (Filed as Exhibit A to Exhibit 4.2 to the Company's Current Report on Form 8-K filed on April 24, 2015 and incorporated herein by reference).](http://www.sec.gov/Archives/edgar/data/1001838/000156761915000589/s000872x1_ex4-2.htm) |  |

---

4.14 [Description of the Company's securities registered pursuant to Section 12 of the Securities Exchange Act of 1934, as amended (Filed as Exhibit 4.14 to the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2022 and incorporated herein by reference).](https://www.sec.gov/Archives/edgar/data/1001838/000155837023002328/scco-20221231xex4d14.htm)

10.1 [Directors' Stock Award Plan of the Company, as amended through January 28, 2028. (Filed as an exhibit to the Company's Current Report on Form S-8 filed on January 27, 2023 and incorporated herein by reference). The plan expired by its terms on January 28, 2023. A 5-year extension of the plan was approved by the Company's stockholders at the 2022 Annual Meeting of Stockholders .](http://www.sec.gov/Archives/edgar/data/1001838/000110465917020071/a17-2208_1def14a.htm)

10.2 [Agreement and Plan of Merger, dated as of October 21, 2004, by and among Southern Copper Corporation, SCC Merger Sub, Inc., Americas Sales Company, Inc., Americas Mining Corporation and Minera Mexico S.A. de C.V. (Filed as an Exhibit to Current Report on Form 8-K filed on October 22, 2004 and incorporated herein by reference).](http://www.sec.gov/Archives/edgar/data/1001838/000110465904031568/a04-11935_2ex2d1.htm)

10.3 [Tax Agreement entered into by the Company and Americas Mining Corporation, effective as of February 20, 2017. (Filed as Exhibit 10.4 to the Company's Quarterly Report on Form 10-Q for the first quarter of 2017 and incorporated herein by reference).](http://www.sec.gov/Archives/edgar/data/1001838/000110465917030725/a17-8900_1ex10d4.htm)

14.0 [Code of Business Conduct and Ethics adopted by the Board of Directors on May 8, 2003 and amended on July 21, 2022. (Filed as Exhibit 14.1 to the Company's Current Report on Form 8-K filed July 26, 2022 and incorporated herein by reference).](http://www.sec.gov/Archives/edgar/data/1001838/000110465915031138/a15-10087_1ex14.htm)

21.1 [Subsidiaries of the Company (Filed as Exhibit 21.1 to the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2022 and incorporated herein by reference).](https://www.sec.gov/Archives/edgar/data/1001838/000155837023002328/scco-20221231xex21d1.htm)

23.1 [Consent of Registered Public Accounting Firm](https://www.sec.gov/Archives/edgar/data/1001838/000155837023002328/scco-20221231xex23d1.htm) (Galaz, Yamazaki, Ruiz Urquiza, S.C.—Member of Deloitte Touche Tohmatsu, Limited, Mexico City, Mexico) (PCAOB ID 1153) (Filed as Exhibit 23.1 to the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2022 and incorporated herein by reference).

23.2 [Consent of Qualified Persons for Technical Report Summary of Mineral Reserves and Mineral Resources for the Cuajone Mine (Filed as Exhibit 23.2 to the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2022 and incorporated herein by reference).](https://www.sec.gov/Archives/edgar/data/1001838/000155837023002328/scco-20221231xex23d2.htm)

23.3 [Consent of Qualified Persons for Technical Report Summary of Mineral Reserves and Mineral Resources for the Toquepala Mine (Filed as Exhibit 23.3 to the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2022 and incorporated herein by reference).](https://www.sec.gov/Archives/edgar/data/1001838/000155837023002328/scco-20221231xex23d3.htm)

23.4 [Consent of Qualified Persons for Technical Report Summary of Mineral Reserves and Mineral Resources for the Tia Maria Project (Filed as Exhibit 23.4 to the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2022 and incorporated herein by reference).](https://www.sec.gov/Archives/edgar/data/1001838/000155837023002328/scco-20221231xex23d4.htm)

23.5 [Consent of Qualified Persons for Technical Report Summary of Mineral Resources for the Los Chancas Project (Filed as Exhibit 23.5 to the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2022 and incorporated herein by reference).](https://www.sec.gov/Archives/edgar/data/1001838/000155837023002328/scco-20221231xex23d5.htm)

23.6 [Consent of Qualified Persons for Technical Report Summary of Mineral Resources for the Michiquillay Project (Filed as Exhibit 23.6 to the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2022 and incorporated herein by reference).](https://www.sec.gov/Archives/edgar/data/1001838/000155837023002328/scco-20221231xex23d6.htm)

23.7 [Consent of Qualified Persons for Technical Report Summary of Mineral Reserves and Mineral Resources for Buenavista del Cobre (Filed as Exhibit 23.7 to the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2022 and incorporated herein by reference).](https://www.sec.gov/Archives/edgar/data/1001838/000155837023002328/scco-20221231xex23d7.htm)

23.8 [Consent of Qualified Persons for Technical Report Summary of Mineral Reserves and Mineral Resources for the La Caridad Mine (Filed as Exhibit 23.8 to the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2022 and incorporated herein by reference).](https://www.sec.gov/Archives/edgar/data/1001838/000155837023002328/scco-20221231xex23d8.htm)

23.9 [Consent of Qualified Persons for Technical Report Summary of Mineral Resources for the Pilares Project (Filed as Exhibit 23.9 to the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2022 and incorporated herein by reference).](https://www.sec.gov/Archives/edgar/data/1001838/000155837023002328/scco-20221231xex23d9.htm)

23.10 [Consent of Qualified Persons for Technical Report Summary of Mineral Reserves and Mineral Resources for the El Pilar Project (Filed as Exhibit 23.10 to the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2022 and incorporated herein by reference).](https://www.sec.gov/Archives/edgar/data/1001838/000155837023002328/scco-20221231xex23d10.htm)

23.11 [Consent of Qualified Persons for Technical Report Summary of Mineral Reserves and Mineral Resources for the El Arco Project (Filed as Exhibit 23.11 to the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2022 and incorporated herein by reference).](https://www.sec.gov/Archives/edgar/data/1001838/000155837023002328/scco-20221231xex23d11.htm)

23.12 [Consent of Qualified Persons for Technical Report Summary of Mineral Resources for the Charcas Mine (Filed as Exhibit 23.12 to the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2022 and incorporated herein by reference).](https://www.sec.gov/Archives/edgar/data/1001838/000155837023002328/scco-20221231xex23d12.htm)

---

| | |
|:---|:---|
| 23.13 | [Consent of Qualified Persons for Technical Report Summary of Mineral Resources for the Santa Barbara Mine (Filed as Exhibit 23.13 to the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2022 and incorporated herein by reference).](https://www.sec.gov/Archives/edgar/data/1001838/000155837023002328/scco-20221231xex23d13.htm) |
| 23.14 | [Consent of Qualified Persons for Technical Report Summary of Mineral Resources for the San Martin Mine (Filed as Exhibit 23.14 to the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2022 and incorporated herein by reference).](https://www.sec.gov/Archives/edgar/data/1001838/000155837023002328/scco-20221231xex23d14.htm) |
| 31.1 | [Certification Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 (Filed herewith).](scco-20221231xex31d1.htm) |
| 31.2 | [Certification Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 (Filed herewith).](scco-20221231xex31d2.htm) |
| 32.1 | [Certification Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, 18 U.S.C., section 1350. This document is being furnished in accordance with SEC Release No. 33-8238. (Filed as Exhibit 32.1 to the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2022 and incorporated herein by reference).](https://www.sec.gov/Archives/edgar/data/1001838/000155837023002328/scco-20221231xex32d1.htm) |
| 32.2 | [Certification Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, 18 U.S.C., section 1350. This document is being furnished in accordance with SEC Release No. 33-8238. (Filed as Exhibit 32.2 to the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2022 and incorporated herein by reference).](https://www.sec.gov/Archives/edgar/data/1001838/000155837023002328/scco-20221231xex32d2.htm) |
| 96.1 | [Technical Report Summary of Mineral Reserves and Mineral Resources for the Cuajone Mine (Filed herewith).](scco-20221231xex96d1.pdf) |
| 96.2 | [Technical Report Summary of Mineral Reserves and Mineral Resources for the Toquepala Mine (Filed herewith).](scco-20221231xex96d2.pdf) |
| 96.3 | [Technical Report Summary of Mineral Reserves and Mineral Resources for the Tia Maria Project (Filed as an Exhibit to the Company's Report on Form 10-K/A filed on March 7, 2022 and incorporated herein by reference).](https://www.sec.gov/Archives/edgar/data/1001838/000155837022002995/scco-20211231ex963f7e8e2.pdf) |
| 96.4 | [Technical Report Summary of Mineral Resources for the Los Chancas Project (Filed as an Exhibit to the Company's Report on Form 10-K/A filed on March 7, 2022 and incorporated herein by reference).](https://www.sec.gov/Archives/edgar/data/1001838/000155837022002995/scco-20211231ex964f113db.pdf) |
| 96.5 | [Technical Report Summary of Mineral Resources for the Michiquillay Project (Filed as an Exhibit to the Company's Report on Form 10-K/A filed on March 7, 2022 and incorporated herein by reference).](https://www.sec.gov/Archives/edgar/data/1001838/000155837022002995/scco-20211231ex965e7c6c1.pdf) |
| 96.6 | [Technical Report Summary of Mineral Reserves and Mineral Resources for Buenavista del Cobre (Filed herewith).](scco-20221231xex96d6.pdf) |
| 96.7 | [Technical Report Summary of Mineral Reserves and Mineral Resources for the La Caridad Mine (Filed herewith).](scco-20221231xex96d7.pdf) |
| 96.8 | [Technical Report Summary of Mineral Resources for the Pilares Project (Filed as an Exhibit to the Company's Report on Form 10-K/A filed on March 7, 2022 and incorporated herein by reference).](https://www.sec.gov/Archives/edgar/data/1001838/000155837022002995/scco-20211231ex968d77397.pdf) |
| 96.9 | [Technical Report Summary of Mineral Reserves and Mineral Resources for the El Pilar Project (Filed as an Exhibit to the Company's Report on Form 10-K/A filed on March 7, 2022 and incorporated herein by reference).](https://www.sec.gov/Archives/edgar/data/1001838/000155837022002995/scco-20211231ex9692df9bd.pdf) |
| 96.10 | [Technical Report Summary of Mineral Reserves and Mineral Resources for the El Arco Project (Filed as an Exhibit to the Company's Report on Form 10-K/A filed on March 7, 2022 and incorporated herein by reference).](https://www.sec.gov/Archives/edgar/data/1001838/000155837022002999/scco-20211231ex96109e0df.pdf) |
| 96.11 | [Technical Report Summary of Mineral Resources for the Charcas Mine (Filed herewith).](scco-20221231xex96d11.pdf) |
| 96.12 | [Technical Report Summary of Mineral Resources for the Santa Barbara Mine (Filed herewith).](scco-20221231xex96d12.pdf) |
| 96.13 | [Technical Report Summary of Mineral Resources for the San Martin Mine (Filed herewith).](scco-20221231xex96d13.pdf) |
| 101.INS | XBRL Instance Document (submitted electronically with this report). The instance document does not appear in the Interactive Data File because its XBRL tags are embedded within the Inline XBRL document. |
| 101.SCH | XBRL Taxonomy Extension Schema Document (submitted electronically with this report). |
| 101.CAL | XBRL Taxonomy Calculation Linkbase Document (submitted electronically with this report). |
| 101.DEF | XBRL Taxonomy Extension Definition Linkbase Document (submitted electronically with this report). |
| 101.LAB | XBRL Taxonomy Label Linkbase Document (submitted electronically with this report). |
| 101.PRE | XBRL Taxonomy Presentation Linkbase Document (submitted electronically with this report). |
| 104 | Cover Page Interactive Data File (formatted in Inline XBRL and contained in Exhibit 101) |

---

The exhibit listed as 10.1 is the management contract or compensatory plan or arrangement required to be filed pursuant to Item 15(b) of Form 10-K.

Attached as Exhibit 101 to this report are the following documents formatted in Inline XBRL (Inline Extensible Business Reporting Language): (i) the Consolidated Statements of Earnings for the years ended December 31, 2022, 2021 and 2020; (ii) the Consolidated Statements of Comprehensive Income for the years ended December 31, 2022, 2021 and 2020; (iii) the Consolidated Balance Sheets at December 31, 2022 and 2021; (iv) the Consolidated Statements of Cash Flows for the years ended December 31, 2022, 2021 and 2020; (v) the Consolidated Statements of changes in equity for the years ended December 31, 2022, 2021 and 2020, and (vi) the Notes to Consolidated Financial Statements tagged in detail. Users of this data are advised pursuant to Rule 406T of Regulation S-T that this interactive data file is deemed not filed or part of a registration statement or prospectus for purposes of sections 11 or 12 of the Securities Act of 1933, is deemed not filed for purposes of section 18 of the Securities Exchange Act of 1934, and otherwise is not subject to liability under these sections.

**Signatures**

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this Report on Form 10-K/A Amendment N°1 to be signed on its behalf by the undersigned, thereunto duly authorized.

---

| | |
|:---|:---|
| SOUTHERN COPPER CORPORATION | SOUTHERN COPPER CORPORATION |
| (Registrant) | (Registrant) |
| By: | /s/ OSCAR GONZALEZ ROCHA |
|  | Oscar Gonzalez Rocha |
|  | President and Chief Executive Officer |

---

Date: February 28, 2023

## Exhibit 31.1

#### Exhibit 31.1

#### CERTIFICATION PURSUANT TO
**Section 302 of the Sarbanes-Oxley Act of 2002**

I, Oscar Gonzalez Rocha, certify that:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1. I have reviewed this Amendment No. 1 to the annual report on Form 10-K/A of Southern Copper Corporation; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report.

February 28, 2023

---

| |
|:---|
| <u>/s/ OSCAR GONZALEZ ROCHA</u> |
| Oscar Gonzalez Rocha |
| President and Chief Executive Officer |

---

------

## Exhibit 31.2

#### Exhibit 31.2

#### CERTIFICATION PURSUANT TO
**Section 302 of the Sarbanes-Oxley Act of 2002**

I, Raul Jacob, certify that:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1. I have reviewed this Amendment No. 1 to the annual report on Form 10-K/A of Southern Copper Corporation; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

February 28, 2023

---

| |
|:---|
| /s/ RAUL JACOB |
| Raul Jacob |
| Vice President, Finance, Treasurer and |
| Chief Financial Officer |

---

------

### Attached PDF Documents

**Attachment 1:** `scco-20221231xex96d1.pdf`

# SouthernCopper

and

![img-0.jpeg](img-0.jpeg)

## Cuajone Operations
Peru
Technical Report Summary

![img-1.jpeg](img-1.jpeg)

Report prepared for:
Southern Copper Corporation

Report current as at: December 31, 2022

Report prepared by:
Wood Group USA, Inc.

wood.

# Date and Signature Page

This technical report summary (the Report), entitled “Cuajone Operations, Peru, Technical Report Summary” is current as at December 31, 2022. The Report was prepared by Wood Group USA, Inc. (Wood), acting as a Qualified Person Firm.

Dated: February 06, 2023.

“signed”

Wood Group USA, Inc.  
17325 Park Row, Houston  
Texas, 77084  
USA.

![img-2.jpeg](img-2.jpeg)

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

# CONTENTS

| 1.0 | SUMMARY | 1-1 |
| --- | --- | --- |
| 1.1 | Introduction | 1-1 |
| 1.2 | Terms of Reference | 1-1 |
| 1.3 | Property Setting | 1-1 |
| 1.4 | Mineral Tenure, Surface Rights, Water Rights, Royalties and Agreements | 1-2 |
| 1.5 | Geology and Mineralization | 1-2 |
| 1.6 | History | 1-3 |
| 1.7 | Exploration, Drilling, and Sampling | 1-3 |
| 1.8 | Data Verification | 1-5 |
| 1.9 | Metallurgical Testwork | 1-5 |
| 1.10 | Mineral Resource Estimates | 1-6 |
| 1.10.1 | Estimation Methodology | 1-6 |
| 1.10.2 | Mineral Resource Statement | 1-7 |
| 1.11 | Mineral Reserve Estimates | 1-9 |
| 1.11.1 | Estimation Methodology | 1-9 |
| 1.11.2 | Mineral Reserve Statement | 1-10 |
| 1.12 | Mining Methods | 1-11 |
| 1.13 | Recovery Methods | 1-12 |
| 1.14 | Infrastructure | 1-13 |
| 1.15 | Market Studies | 1-14 |
| 1.16 | Environmental, Permitting and Social Considerations | 1-16 |
| 1.16.1 | Environmental Studies and Monitoring | 1-16 |
| 1.16.2 | Closure and Reclamation Considerations | 1-16 |
| 1.16.3 | Permitting | 1-17 |
| 1.16.4 | Social Considerations, Plans, Negotiations and Agreements | 1-17 |
| 1.17 | Capital Cost Estimates | 1-17 |
| 1.18 | Operating Cost Estimates | 1-19 |
| 1.19 | Economic Analysis | 1-20 |
| 1.19.1 | Forward-Looking Information Caution | 1-20 |
| 1.19.2 | Methodology | 1-21 |
| 1.19.3 | Key Parameters and Assumptions | 1-21 |
| 1.19.4 | Economic Analysis | 1-22 |
| 1.19.5 | Sensitivity Analysis | 1-23 |
| 1.20 | Risks and Opportunities | 1-24 |
| 1.20.1 | Risks | 1-24 |
| 1.20.2 | Opportunities | 1-25 |
| 1.21 | Conclusions | 1-26 |
| 1.22 | Recommendations | 1-26 |
| 2.0 | INTRODUCTION | 2-1 |

Project No.: 252233
6 February 2023

TOC i

wood.

SouthernCopper

GrupoMéxico
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

| 2.1 | Registrant | 2-1 |
| --- | --- | --- |
| 2.2 | Terms of Reference | 2-1 |
| 2.2.1 | Report Purpose | 2-1 |
| 2.2.2 | Terms of Reference | 2-1 |
| 2.3 | Qualified Persons | 2-3 |
| 2.4 | Site Visits and Scope of Personal Inspection | 2-3 |
| 2.5 | Report Date | 2-3 |
| 2.6 | Information Sources | 2-3 |
| 2.7 | Previous Technical Report Summaries | 2-3 |
| 3.0 | PROPERTY DESCRIPTION | 3-1 |
| 3.1 | Property Location | 3-1 |
| 3.2 | Property and Title in Peru | 3-1 |
| 3.2.1 | Regulatory Oversight | 3-1 |
| 3.2.2 | Mineral Tenure | 3-2 |
| 3.2.3 | Surface Rights | 3-3 |
| 3.2.4 | Water Rights | 3-3 |
| 3.2.5 | Environmental Considerations | 3-4 |
| 3.2.6 | Permits | 3-5 |
| 3.2.7 | Royalties | 3-5 |
| 3.2.8 | Other Considerations | 3-5 |
| 3.2.9 | Fraser Institute Survey | 3-6 |
| 3.3 | Ownership | 3-6 |
| 3.4 | Mineral Title | 3-7 |
| 3.5 | Surface Rights | 3-10 |
| 3.6 | Water Rights | 3-10 |
| 3.7 | Royalties | 3-12 |
| 3.8 | Encumbrances | 3-12 |
| 3.9 | Permitting | 3-12 |
| 3.10 | Violations and Fines | 3-12 |
| 3.11 | Significant Factors and Risks That May Affect Access, Title or Work Programs | 3-12 |
| 4.0 | ACCESSIBILITY, CLIMATE, LOCAL RESOURCES, INFRASTRUCTURE AND PHYSIOGRAPHY | 4-1 |
| 4.1 | Physiography | 4-1 |
| 4.2 | Accessibility | 4-1 |
| 4.3 | Climate | 4-2 |
| 4.4 | Infrastructure | 4-2 |
| 5.0 | HISTORY | 5-1 |
| 6.0 | GEOLOGICAL SETTING, MINERALIZATION, AND DEPOSIT | 6-1 |
| 6.1 | Deposit Type and Mineralization | 6-1 |
| 6.2 | Regional Geology | 6-1 |
| 6.3 | Local Geology | 6-4 |
| 6.3.1 | Lithologies and Stratigraphy | 6-4 |

Project No.: 252233
6 February 2023

TOC ii

wood.

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

| 6.3.2 | Structure | 6-4 |
| --- | --- | --- |
| 6.3.3 | Alteration | 6-4 |
| 6.4 | Property Geology | 6-4 |
| 6.4.1 | Deposit Dimensions | 6-4 |
| 6.4.2 | Lithologies | 6-6 |
| 6.4.3 | Structure | 6-12 |
| 6.4.4 | Alteration | 6-12 |
| 6.4.5 | Mineralization | 6-12 |
| 6.4.5.1 | Supergene Mineralization | 6-12 |
| 6.4.5.2 | Hypogene Mineralization | 6-12 |
| 7.0 | EXPLORATION | 7-1 |
| 7.1 | Exploration | 7-1 |
| 7.1.1 | Grids and Surveys | 7-1 |
| 7.1.2 | Geological Mapping | 7-1 |
| 7.1.3 | Geochemistry | 7-1 |
| 7.1.4 | Geophysics | 7-2 |
| 7.1.5 | Qualified Person's Interpretation of the Exploration Information | 7-2 |
| 7.1.6 | Exploration Potential | 7-2 |
| 7.2 | Drilling | 7-2 |
| 7.2.1 | Overview | 7-2 |
| 7.2.2 | Drill Methods | 7-9 |
| 7.2.3 | Logging | 7-10 |
| 7.2.4 | Recovery | 7-10 |
| 7.2.5 | Collar Surveys | 7-10 |
| 7.2.6 | Downhole Surveys | 7-10 |
| 7.2.7 | Comment on Material Results and Interpretation | 7-11 |
| 7.3 | Hydrogeology | 7-12 |
| 7.3.1 | Sampling Methods and Laboratory Determinations | 7-12 |
| 7.3.2 | Groundwater Models | 7-13 |
| 7.3.3 | Water Balance | 7-13 |
| 7.3.4 | Comment on Results | 7-13 |
| 7.4 | Geotechnical | 7-13 |
| 7.4.1 | Sampling Methods and Laboratory Determinations | 7-14 |
| 7.4.2 | Comment on Results | 7-14 |
| 7.4.3 | Facilities | 7-15 |
| 7.4.3.1 | Heap Leach Geotechnical | 7-15 |
| 7.4.3.2 | Waste Rock Storage Facilities | 7-15 |
| 8.0 | SAMPLE PREPARATION, ANALYSES, AND SECURITY | 8-1 |
| 8.1 | Sampling Methods | 8-1 |
| 8.2 | Sample Security Methods | 8-1 |
| 8.3 | Density Determinations | 8-1 |
| 8.4 | Analytical and Test Laboratories | 8-1 |
| 8.5 | Sample Preparation | 8-3 |

Project No.: 252233
6 February 2023

TOC iii

wood.

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

| 8.6 | Analysis | 8-3 |
| --- | --- | --- |
| 8.7 | Quality Assurance and Quality Control | 8-3 |
| 8.8 | Database | 8-5 |
| 8.9 | Qualified Person's Opinion on Sample Preparation, Security, and Analytical Procedures | 8-5 |
| 9.0 | DATA VERIFICATION | 9-1 |
| 9.1 | Data Verification by Qualified Person | 9-1 |
| 9.1.1 | Site Visit | 9-1 |
| 9.1.2 | Database Audit | 9-1 |
| 9.1.3 | Peer Review | 9-2 |
| 9.2 | Qualified Person's Opinion on Data Adequacy | 9-2 |
| 10.0 | MINERAL PROCESSING AND METALLURGICAL TESTING | 10-1 |
| 10.1 | Test Laboratories | 10-1 |
| 10.2 | Metallurgical Testwork | 10-1 |
| 10.3 | Oxide Recovery Estimates | 10-1 |
| 10.3.1 | Copper Recovery Equation | 10-1 |
| 10.3.2 | Fines Adjustment | 10-5 |
| 10.3.3 | Carbonate Adjustment | 10-6 |
| 10.4 | Sulfide Recovery Estimates | 10-6 |
| 10.4.1 | Throughput Models | 10-6 |
| 10.4.2 | Copper Recovery Model | 10-8 |
| 10.4.3 | Molybdenum Recovery Model | 10-9 |
| 10.5 | Metallurgical Variability | 10-10 |
| 10.6 | Deleterious Elements | 10-12 |
| 10.7 | Qualified Person's Opinion on Data Adequacy | 10-13 |
| 11.0 | MINERAL RESOURCE ESTIMATES | 11-1 |
| 11.1 | Introduction | 11-1 |
| 11.2 | Exploratory Data Analysis | 11-1 |
| 11.2.1 | Anomalous Cu (total) | 11-1 |
| 11.2.2 | Acid and Cyanide Soluble Cu | 11-2 |
| 11.2.3 | Lithology Grouping | 11-2 |
| 11.3 | Geological Models | 11-3 |
| 11.4 | Density Assignment | 11-4 |
| 11.5 | Grade Capping/Outlier Restrictions | 11-4 |
| 11.6 | Composites | 11-7 |
| 11.7 | Variography | 11-8 |
| 11.8 | Estimation/interpolation Methods | 11-8 |
| 11.9 | Validation | 11-9 |
| 11.10 | Confidence Classification of Mineral Resource Estimate | 11-9 |
| 11.10.1 | Mineral Resource Confidence Classification | 11-9 |
| 11.10.2 | Uncertainties Considered During Confidence Classification | 11-10 |
| 11.11 | Reasonable Prospects of Economic Extraction | 11-10 |
| 11.11.1 | Input Assumptions | 11-10 |

Project No.: 252233
6 February 2023

TOC iv

wood.

SouthernCopper

GrupoMéxico
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

| 11.11.2 | Commodity Prices and Market | 11-10 |
| --- | --- | --- |
| 11.11.3 | Cut-off | 11-10 |
| 11.12 | Mineral Resource Estimate | 11-12 |
| 11.12.1 | Mineral Resource Statement | 11-12 |
| 11.12.2 | Uncertainties (Factors) That May Affect the Mineral Resource Estimate | 11-13 |
| 11.12.3 | QP Statement | 11-14 |
| 12.0 | MINERAL RESERVE ESTIMATES | 12-1 |
| 12.1 | Introduction | 12-1 |
| 12.2 | Development of Mining Case | 12-1 |
| 12.2.1 | Pit Optimization | 12-1 |
| 12.2.2 | Block Model | 12-1 |
| 12.2.3 | Adjustment Factors to Mineral Reserves | 12-4 |
| 12.2.4 | Topography | 12-4 |
| 12.2.5 | Slope Angles | 12-4 |
| 12.2.6 | Metallurgical Recoveries | 12-5 |
| 12.2.7 | Mining Costs | 12-5 |
| 12.2.8 | Processing Costs | 12-6 |
| 12.2.9 | Selling Costs for Concentration Process | 12-6 |
| 12.2.10 | Selling Costs for Leaching Process | 12-7 |
| 12.2.11 | Royalties | 12-7 |
| 12.2.12 | Commodity Prices and Market | 12-7 |
| 12.2.13 | Cut-offs | 12-7 |
| 12.2.14 | Pit Design | 12-8 |
| 12.2.15 | Ore Versus Waste Determinations | 12-9 |
| 12.3 | Mineral Reserve Estimate | 12-11 |
| 12.3.1 | Mineral Reserve Statement | 12-11 |
| 12.3.2 | Uncertainties (Factors) That May Affect the Mineral Reserve Estimate | 12-12 |
| 13.0 | MINING METHODS | 13-1 |
| 13.1 | Introduction | 13-1 |
| 13.2 | Geotechnical Considerations | 13-1 |
| 13.3 | Hydrogeological Considerations | 13-1 |
| 13.4 | Operations | 13-1 |
| 13.4.1 | Pit Phases | 13-1 |
| 13.4.2 | Throughput | 13-1 |
| 13.4.3 | Operations | 13-4 |
| 13.4.4 | Production Plan | 13-5 |
| 13.5 | Equipment | 13-17 |
| 13.6 | Personnel | 13-20 |
| 14.0 | PROCESSING AND RECOVERY METHODS | 14-1 |
| 14.1 | Process Method Selection | 14-1 |
| 14.2 | Flowsheets | 14-1 |
| 14.3 | Oxide Heap Leaching Facilities | 14-1 |
| 14.3.1 | Overview | 14-1 |

Project No.: 252233
6 February 2023

TOC v

wood.

SouthernCopper

GrupoMéxico
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

| 14.3.2 | Crushing | 14-4 |
| --- | --- | --- |
| 14.3.3 | Agglomeration and Heap Leach Loading | 14-5 |
| 14.3.4 | Leaching | 14-5 |
| 14.3.5 | Solution Management | 14-5 |
| 14.3.6 | Equipment Sizing | 14-6 |
| 14.3.7 | Power and Consumables | 14-6 |
| 14.3.8 | Personnel | 14-7 |
| 14.4 | Sulfide Process Plant | 14-7 |
| 14.4.1 | Overview | 14-7 |
| 14.4.2 | Primary Crushing | 14-7 |
| 14.4.3 | Secondary and Tertiary Crushing | 14-7 |
| 14.4.4 | Grinding | 14-8 |
| 14.4.5 | Rougher Flotation | 14-8 |
| 14.4.6 | Cleaner-Scavenger Flotation | 14-8 |
| 14.4.7 | Molybdenum Plant | 14-9 |
| 14.4.8 | Filtration and Drying Plant | 14-10 |
| 14.4.9 | Tailings Thickening | 14-10 |
| 14.4.10 | Tailings Transport and Disposal | 14-10 |
| 14.4.11 | Equipment Sizing | 14-10 |
| 14.4.12 | Power and Consumables | 14-11 |
| 14.4.13 | Personnel | 14-12 |
| 14.5 | Ilo Smelter | 14-12 |
| 14.5.1 | Overview | 14-12 |
| 14.5.2 | Flowsheet | 14-12 |
| 14.5.3 | Concentrate Smelting | 14-14 |
| 14.5.4 | Matte Conversion | 14-14 |
| 14.5.5 | Anode Refining and Casting | 14-15 |
| 14.5.6 | Acid Plants | 14-15 |
| 14.5.7 | Oxygen Plant and Ancillary Systems | 14-16 |
| 14.5.8 | Equipment Sizing | 14-16 |
| 14.5.9 | Power and Consumables | 14-16 |
| 14.5.9.1 | Power | 14-16 |
| 14.5.9.2 | Water | 14-17 |
| 14.5.9.3 | Consumables | 14-18 |
| 14.5.10 | Personnel | 14-18 |
| 14.6 | Ilo Refinery | 14-18 |
| 14.6.1 | Overview | 14-18 |
| 14.6.2 | Flowsheet | 14-18 |
| 14.6.3 | Electrolytic Plant | 14-20 |
| 14.6.4 | Precious Metals Plant | 14-21 |
| 14.6.5 | Equipment Sizing | 14-21 |
| 14.6.6 | Power and Consumables | 14-21 |
| 14.6.6.1 | Power | 14-21 |

Project No.: 252233
6 February 2023

TOC vi

wood.

Southern Copper

Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

|  | 14.6.6.2 Water | 14-23 |
| --- | --- | --- |
|  | 14.6.6.3 Consumables | 14-23 |
|  | 14.6.7 Personnel | 14-23 |
| 15.0 | INFRASTRUCTURE | 15-1 |
| 15.1 | Introduction | 15-1 |
| 15.2 | Roads and Logistics | 15-2 |
| 15.2.1 | Road | 15-2 |
| 15.2.2 | Rail | 15-2 |
| 15.2.3 | Port | 15-8 |
| 15.3 | Stockpiles | 15-8 |
| 15.4 | Waste Rock Storage Facilities | 15-9 |
| 15.5 | Tailings Storage Facilities | 15-9 |
| 15.6 | Water Management Structures | 15-10 |
| 15.7 | Built Infrastructure | 15-11 |
| 15.8 | Camps and Accommodation | 15-11 |
| 15.9 | Power and Electrical | 15-11 |
| 15.10 | Water Supply | 15-12 |
| 16.0 | MARKET STUDIES | 16-1 |
| 16.1 | Markets | 16-1 |
| 16.1.1 | Copper | 16-1 |
| 16.1.2 | Molybdenum | 16-1 |
| 16.1.3 | Gold and Silver | 16-1 |
| 16.2 | Market Strategy | 16-2 |
| 16.3 | Product Marketability, Cuajone Operations | 16-2 |
| 16.4 | Product Marketability, Ilo Smelter | 16-2 |
| 16.5 | Commodity Pricing | 16-2 |
| 16.6 | Contracts | 16-4 |
| 17.0 | ENVIRONMENTAL STUDIES, PERMITTING, AND PLANS, NEGOTIATIONS, OR AGREEMENTS WITH LOCAL INDIVIDUALS OR GROUPS | 17-1 |
| 17.1 | Introduction | 17-1 |
| 17.2 | Baseline and Supporting Studies | 17-1 |
| 17.3 | Environmental Considerations/Monitoring Programs | 17-2 |
| 17.4 | Closure and Reclamation Considerations | 17-2 |
| 17.5 | Permitting | 17-3 |
| 17.6 | Social Considerations, Plans, Negotiations and Agreements | 17-8 |
| 17.7 | Qualified Person's Opinion on Adequacy of Current Plans to Address Issues | 17-9 |
| 18.0 | CAPITAL AND OPERATING COSTS | 18-1 |
| 18.1 | Introduction | 18-1 |
| 18.2 | Capital Cost Estimates | 18-1 |
| 18.2.1 | Basis of Estimate | 18-1 |
| 18.2.2 | Capital Cost Estimate Summary | 18-4 |
| 18.3 | Operating Cost Estimates | 18-4 |

Project No.: 252233
6 February 2023

TOC vii

wood.

SouthernCopper

GrupoMéxico
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations

Peru

| 18.3.1 | Basis of Estimate | 18-4 |
| --- | --- | --- |
| 18.3.2 | Mining Costs | 18-5 |
| 18.3.3 | Process Costs | 18-6 |
| 18.3.4 | General and Administrative Costs | 18-8 |
| 18.3.5 | Operating Cost Estimate Summary | 18-8 |
| 19.0 | ECONOMIC ANALYSIS | 19-1 |
| 19.1 | Forward-looking Information Caution | 19-1 |
| 19.2 | Methodology | 19-1 |
| 19.3 | Input Parameters | 19-2 |
| 19.3.1 | Mineral Reserves and Mine Life | 19-2 |
| 19.3.2 | Metallurgical Recoveries | 19-2 |
| 19.3.3 | Smelting and Refining Terms | 19-2 |
| 19.3.3.1 | Copper Concentrate | 19-2 |
| 19.3.3.2 | Molybdenum Concentrate | 19-3 |
| 19.3.3.3 | Copper Cathodes | 19-4 |
| 19.3.3.4 | Ilo Smelter and Refinery | 19-4 |
| 19.3.4 | Commodity Price and Exchange Rate Assumptions | 19-5 |
| 19.3.5 | Capital Costs | 19-6 |
| 19.3.6 | Operating Costs | 19-6 |
| 19.3.7 | Royalties | 19-6 |
| 19.3.8 | Working Capital | 19-6 |
| 19.3.9 | Closure and Reclamation Costs | 19-6 |
| 19.3.10 | Financing | 19-6 |
| 19.3.11 | Inflation | 19-6 |
| 19.3.12 | Taxation Considerations | 19-7 |
| 19.4 | Results of Economic Analysis | 19-8 |
| 19.5 | Sensitivity Analysis | 19-27 |
| 20.0 | ADJACENT PROPERTIES | 20-1 |
| 21.0 | OTHER RELEVANT DATA AND INFORMATION | 21-1 |
| 22.0 | INTERPRETATION AND CONCLUSIONS | 22-1 |
| 22.1 | Introduction | 22-1 |
| 22.2 | Mineral Tenure, Surface Rights, Water Rights, Royalties and Agreements | 22-1 |
| 22.3 | Geology and Mineralization | 22-1 |
| 22.4 | Exploration, Drilling, and Sampling | 22-2 |
| 22.5 | Data Verification | 22-2 |
| 22.6 | Metallurgical Testwork | 22-3 |
| 22.7 | Mineral Resource Estimates | 22-3 |
| 22.8 | Mineral Reserve Estimates | 22-4 |
| 22.9 | Mining Methods | 22-4 |
| 22.10 | Recovery Methods | 22-4 |
| 22.11 | Infrastructure | 22-5 |
| 22.12 | Market Studies | 22-5 |

Project No.: 252233

6 February 2023

TOC viii

wood.

SouthernCopper

GrupoMéxico
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

| 22.13 | Environmental, Permitting and Social Considerations | 22-7 |
| --- | --- | --- |
| 22.14 | Capital Cost Estimates | 22-8 |
| 22.15 | Operating Cost Estimates | 22-8 |
| 22.16 | Economic Analysis | 22-8 |
| 22.17 | Risks and Opportunities | 22-9 |
| 22.17.1 | Risks | 22-9 |
| 22.17.2 | Opportunities | 22-10 |
| 22.18 | Conclusions | 22-11 |
| 23.0 | RECOMMENDATIONS | 23-1 |
| 23.1 | Introduction | 23-1 |
| 23.2 | Internal Controls | 23-1 |
| 23.3 | Database | 23-1 |
| 23.4 | Mineral Resources | 23-1 |
| 23.5 | Mine Plan | 23-2 |
| 23.6 | Tailings Storage Facility | 23-2 |
| 23.7 | Tailings and Waste Management | 23-2 |
| 23.8 | Permitting | 23-2 |
| 24.0 | REFERENCES | 24-1 |
| 24.1 | Bibliography | 24-1 |
| 24.2 | Abbreviations and Symbols | 24-4 |
| 24.3 | Glossary of Terms | 24-5 |
| 25.0 | RELIANCE ON INFORMATION PROVIDED BY THE REGISTRANT | 25-1 |
| 25.1 | Introduction | 25-1 |
| 25.2 | Macroeconomic Trends | 25-1 |
| 25.3 | Marketing Information | 25-1 |
| 25.4 | Legal Matters | 25-1 |
| 25.5 | Environmental Matters | 25-2 |
| 25.6 | Stakeholder Accommodations | 25-2 |
| 25.7 | Governmental Factors | 25-2 |

# TABLES

| Table 1-1: | Indicated Mineral Resource Statement | 1-8 |
| --- | --- | --- |
| Table 1-2: | Inferred Mineral Resource Statement | 1-8 |
| Table 1-3: | Probable Mineral Reserve Statement | 1-10 |
| Table 1-4: | Sustaining Capital Cost Estimate | 1-19 |
| Table 1-5: | LOM Operating Cost Estimate | 1-20 |
| Table 1-6: | Summary of Economic Results | 1-23 |
| Table 1-7: | After-Tax NPV Sensitivity to Discount Rates (base case is highlighted) | 1-24 |
| Table 2-1: | Scope of Personal Inspection by Wood | 2-4 |
| Table 3-1: | Acumulación Cuajone Vertex Locations | 3-9 |
| Table 3-2: | Water Rights | 3-11 |

Project No.: 252233
6 February 2023

TOC ix

wood.

SouthernCopper

GrupoMéxico
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

| Table 5-1: | Exploration and Development History | 5-1 |
| --- | --- | --- |
| Table 6-1: | Sedimentary and Volcanic Lithology Table | 6-5 |
| Table 6-2: | Intrusive Lithology Table and Mineralization Description | 6-5 |
| Table 6-3: | Breccia Type Table | 6-6 |
| Table 6-4: | Alteration Assemblages | 6-16 |
| Table 7-1: | Project Drill Summary Table | 7-5 |
| Table 7-2: | Drilling Supporting Mineral Resource Estimation | 7-6 |
| Table 8-1: | Summary of Preparation and Analysis Laboratories | 8-2 |
| Table 10-1: | Copper Recovery by Phase | 10-5 |
| Table 10-2: | Molybdenum Recoveries, Test vs. Plant Actual | 10-10 |
| Table 10-3: | Copper Concentrate Average Grades, 2020-2022 | 10-12 |
| Table 10-4: | Copper Concentrate Average Mineralogical Composition, 2020-2022 | 10-12 |
| Table 10-5: | Molybdenum Concentrate Average Grades, 2020-2022 | 10-13 |
| Table 10-6: | Molybdenum Concentrate Average Mineralogical Composition, 2020-2022 | 10-13 |
| Table 11-1: | Specific Gravity by Work Index Assigned | 11-6 |
| Table 11-2: | Input Parameters, Mineral Resource | 11-11 |
| Table 11-3: | Indicated Mineral Resource Statement | 11-12 |
| Table 11-4: | Inferred Mineral Resource Statement | 11-12 |
| Table 12-1: | Input Parameters Mineral Reserve Pit Shell | 12-2 |
| Table 12-2: | Overall Slope Angle by Geotechnical Zones | 12-5 |
| Table 12-3: | Probable Mineral Reserve Statement | 12-11 |
| Table 13-1: | Pit Slope Design Criteria by Geotechnical Zones | 13-2 |
| Table 13-2: | Pit Design Criteria Summary | 13-3 |
| Table 13-3: | LOM Material Movement Plan (Sulfide Material) | 13-9 |
| Table 13-4: | LOM Material Movement Plan (Sulfide and Oxide Material) | 13-12 |
| Table 13-5: | LOM Material Movement Plan (Waste and LOM Total) | 13-15 |
| Table 13-6: | LOM Peak Equipment Requirements | 13-20 |
| Table 14-1: | Key Equipment, Leach Facility | 14-6 |
| Table 14-2: | Key Equipment, Sulfide Concentrator | 14-11 |
| Table 14-3: | Average Chemical Composition of Anodes Produced | 14-15 |
| Table 14-4: | Ilo Smelter, Major Mechanical Equipment and Operational Parameters | 14-17 |
| Table 14-5: | Average Cathode Chemical Composition | 14-21 |
| Table 14-6: | Ilo Refinery Major Mechanical Equipment and Design Parameters | 14-22 |
| Table 15-1: | Waste Rock Storage Facilities | 15-9 |
| Table 17-1: | Cuajone Operations Permits | 17-4 |
| Table 17-2: | Ilo Smelter/Refinery Permits | 17-7 |
| Table 18-1: | Sustaining Capital Cost Estimate | 18-4 |
| Table 18-2: | Cuajone Concentrator Operating Costs | 18-7 |
| Table 18-3: | Cuajone Leaching and SX/EW Operating Costs | 18-7 |
| Table 18-4: | Ilo Smelter Operating Costs | 18-8 |
| Table 18-5: | Ilo Refinery Operating Costs | 18-8 |
| Table 18-6: | Cuajone LOM Operating Cost Estimate | 18-9 |
| Table 19-1: | Summary of Economic Results | 19-8 |

Project No.: 252233
6 February 2023

TOC x

wood.

SouthernCopper

GrupoMéxico
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

Table 19-2: Cash Flow Forecast on an Annual Basis (2023-2031)...19-9
Table 19-3: Cash Flow Forecast on an Annual Basis (2032-2041)...19-12
Table 19-4: Cash Flow Forecast on an Annual Basis (2042-2051)...19-15
Table 19-5: Cash Flow Forecast on an Annual Basis (2052-2061)...19-18
Table 19-6: Cash Flow Forecast on an Annual Basis (2062-2071)...19-21
Table 19-7: Cash Flow Forecast on an Annual Basis (2072-2079)...19-24
Table 19-8: After-Tax NPV Sensitivity to Discount Rates (base case is highlighted)...19-28

# FIGURES

Figure 1-1: After-Tax NPV Sensitivity (10% discount rate)...1-23
Figure 2-1: Project Location Plan...2-2
Figure 3-1: Ownership Organogram...3-7
Figure 3-2: Mineral Tenure Location Plan...3-8
Figure 6-1: Regional Geology Map...6-2
Figure 6-2: Regional and Project Geology...6-3
Figure 6-3: Stratigraphic Column...6-7
Figure 6-4: Geology Map...6-8
Figure 6-5: Lithology Cross-section (R-R')...6-9
Figure 6-6: Lithology Cross-section (32-32')...6-10
Figure 6-7: Alteration Map...6-13
Figure 6-8: Alteration Section (R-R')...6-14
Figure 6-9: Alteration Section (32-32')...6-15
Figure 6-10: Mineralization Map...6-16
Figure 6-11: Cross-section Showing Mineralization (R-R')...6-17
Figure 6-12: Cross-section Showing Mineralization (32-32')...6-18
Figure 7-1: Self Potential and Resistivity Summary Map (% sulfide)...7-3
Figure 7-2: Induced Polarization: Chargeability...7-4
Figure 7-3: Property Drill Collar Location Plan...7-7
Figure 7-4: Drill Collar Location Plan for Drilling Supporting Mineral Resource Estimates...7-8
Figure 10-1: Cu and Mo Recovery - Basaltic Andesite...10-2
Figure 10-2: Cu and Mo Recovery - Breccia...10-2
Figure 10-3: Cu and Mo Recovery - Intrusive Andesite...10-3
Figure 10-4: Cu and Mo Recovery - Porphyritic Latite...10-3
Figure 10-5: Cu and Mo Recovery - Porphyritic Rhyolite...10-4
Figure 10-6: Copper Grade Variability Tests...10-11
Figure 10-7: Molybdenum Grade Variability Tests...10-11
Figure 11-1: Work Index Geometallurgical Domains...11-5
Figure 12-1: Nested Pit Shells from Pit Optimization (Plan View)...12-3
Figure 12-2: Nested Pit Shells from Pit Optimization (Section View)...12-3
Figure 12-3: Final Pit Design (Plan View)...12-9
Figure 13-1: Geotechnical Zones Projected to Final Pit Design Surface...13-2

Project No.: 252233
6 February 2023

TOC xi

wood.

SouthernCopper

GrupoMéxico
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

Figure 13-2: LOM Pit Phases ... 13-3
Figure 13-3: LOM Pit Phases (Section View) ... 13-4
Figure 13-4: Mine Operation Flow Diagram ... 13-5
Figure 13-5: LOM Material Movement by Destinations ... 13-7
Figure 13-6: LOM Feed to Sulfide Crusher ... 13-7
Figure 13-7: LOM Feed to Oxide Crusher ... 13-8
Figure 13-8: LOM Layout Plan ... 13-17
Figure 13-9: LOM Drilling Equipment Requirements ... 13-18
Figure 13-10: LOM Loading Equipment Requirements ... 13-18
Figure 13-11: LOM Haulage Equipment Requirements ... 13-19
Figure 14-1: Simplified Process Flowsheet, Leach Plant ... 14-2
Figure 14-2: Simplified Process Flowsheet, Sulfide Concentrator ... 14-3
Figure 14-3: Summary Flowsheet Ilo Smelter ... 14-13
Figure 14-4: Summary Flowsheet Ilo Refinery ... 14-19
Figure 15-1: Final Design Configuration Open Pit and WRSF Layout Plan ... 15-3
Figure 15-2: Plant Infrastructure ... 15-4
Figure 15-3: Overland Conveyor, Crusher and Stockpile Infrastructure ... 15-5
Figure 15-4: Overland Conveyor, Railway and Stockpile Infrastructure ... 15-6
Figure 15-5: Accommodations Infrastructure ... 15-7
Figure 19-1: After-Tax NPV Sensitivity (10% discount rate) ... 19-27

Project No.: 252233
6 February 2023

TOC xii

wood.

**Southern Copper**  
![Southern Copper logo]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

## **1.0 SUMMARY**

### **1.1 Introduction**

This technical report summary (the Report) was prepared for Southern Copper Corporation (Southern Copper) by qualified persons employed by Wood Group USA, Inc. (Wood, acting as the QP Firm) on the Cuajone Operations (the Project), located in the District of Torata, Province of Mariscal Nieto within the Moquegua Region, Peru.

### **1.2 Terms of Reference**

The Report was prepared to be attached as an exhibit to support mineral property disclosure, including mineral resource estimates, for the Cuajone Operations in Southern Copper’s Form 10-K for the year ending December 31, 2022.

Mineral resources and mineral reserves are reported for the Cuajone deposit.

Unless otherwise indicated, all financial values are reported in United States (US) currency (US$) including all operating costs, capital costs, cash flows, taxes, revenues, expenses, and overhead distributions. Unless otherwise indicated, the metric system is used in this report for mineral resources and mineral reserves and associated financials. Mineral resources and mineral reserves are reported using the definitions in Regulation S-K 1300 (S-K 1300), under Item 1300. The Report uses US English.

### **1.3 Property Setting**

The Cuajone Operations are located in the Torata District, Mariscal Nieto Region, of Moquegua, approximately 878 km from the city of Lima and 27 km from the city of Moquegua.

The Cuajone mine is accessible by paved road from Lima or Tacna by the Pan-American Highway. The Quebrada Honda tailings storage facility (TSF) is about 120 km via local roads, south of the Cuajone Operations. Access within the Project area is via developed roads that are routinely maintained.

Tacna, Moquegua, and Ilo have regularly scheduled air services from Lima.

Climate conditions vary with altitude, from moderately temperate at lower elevations to intensely cold at high elevations. Mining operations are conducted year-round. Exploration activities are conducted year-round.

Project No.: 252233  
6 February 2023

Summary  
Page 1-1

**wood.**

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

## 1.4 Mineral Tenure, Surface Rights, Water Rights, Royalties and Agreements

The Cuajone Operations and the Ilo smelter/refinery are owned and operated by Southern Peru Copper Corporation, Sucursal del Perú.

The Project consists of a single mining concession, “Acumulación Cuajone”, registration code 010000512L, which was granted on 16 July 2021, and covers an area of 15,024.5 ha. There are two approved beneficiation concessions: Concentradora de Botiflaca, which allows for 90,000 t/d processing capacity; and Cuajone solvent extraction (SX) leach plant, permitted for 3,100 t/d. The beneficiation concessions have been amended on a number of occasions.

Southern Copper holds a “right of free use” on the uncultivated lands in the Cuajone mining concession and Quebrada Honda tailings TSF areas. There are granted easements covering the TSF and related facilities, the TSF pipelines, and water pipelines from the Suches lagoon to the Cuajone Operations. These easements will be maintained as current as long as the mine operates and Southern Copper pays the government annual fees.

Southern Copper has both groundwater and surface water usage licenses, for a total extraction rate of 1,950 L/s.

A mining royalty is payable to the Government of Peru, based on operating income margins with graduated rates ranging from 1-12% of operating profits with a minimum royalty payment of 1% NSR on mine production. There is also a mining tax payable, based on operating income, with rates that range from 2-8.4%.

## 1.5 Geology and Mineralization

The Cuajone deposit is considered to be an example of a porphyry copper-molybdenum deposit.

The basal regional geology consists of Precambrian metamorphic rocks that are cut by Paleozoic granite, and are unconformably overlain by Upper Triassic to Jurassic marine volcanic and sedimentary lithologies. Overlying these units are late Cretaceous to early Tertiary rhyolites, andesites and agglomerates of the Toquepala Group. These lithologies are intruded by the composite, polyphase Cretaceous to Paleogene Coastal (Andean) Batholith.

Mineralization and alteration at the Cuajone deposit is directly related to a multi-stage latite porphyry that intrudes basaltic andesites and the overlying 370 m of rhyolite porphyries of the Toquepala Group. The Cuajone porphyry deposit exhibits a zoned alteration pattern that includes potassic, propylitic, sericitic and intermediate argillic hydrothermal alteration styles.

Project No.: 252233  
6 February 2023

Summary  
Page 1-2

**wood.**

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

Hypogene mineralization represents >98% of the remaining mineralization within the Cuajone open pit. The mineralogy is typically simple and consists of pyrite, chalcopyrite, and bornite, with sparse sphalerite, galena, and enargite.

## 1.6 History

Southern Copper has had an interest in the Project area since 1954. Predecessor companies included Cerro de Pasco Corporation, Newmont and Asarco. Work conducted by Southern Copper and its predecessor companies included geology and photogeology studies, tunneling, churn drill, core and reverse circulation (RC) drill campaigns, metallurgical testwork, and engineering studies. The Cuajone mine commenced operations in 1976.

## 1.7 Exploration, Drilling, and Sampling

Drilling totals 1,600 core, churn and reverse circulation (RC) drill holes (446,593 m). Drilling that supports mineral resource estimation consists of 870 core, churn and RC drill holes (301,037 m).

Historically, geological data were recorded on paper log forms; however, since 2017, logging data have been entered directly into GVMapper. Logging currently uses pre-set geological codes. Logging consists of collection of structural and geological data, and recovery statistics. Core recoveries were reported by Southern Copper to be generally good.

The collar survey method for the earlier campaigns is not known and there is no original hard copy data to verify the collar locations in the database. Southern Copper has, whenever possible, picked up historical collar locations with modern equipment. Such surveys have largely confirmed the drill hole collar locations. Collar surveys for the 2015-2020 drilling were performed by mine surveyors using Trimble R12 GPS instruments.

The majority of the drill holes were vertical. The database does not record why certain drill holes and not others, were down-hole surveyed. Downhole surveys were not systematically performed during the pre-2011 drill campaigns, with exception of some drill holes completed during the 2000 drill campaign. Where surveys were performed, instrumentation included Sperry Sun single- and multi-shot, Eastman, CBC Welany, Christensen, and WhipStock GmbH single-shot, Flexit, Peewee, and Devishot instruments, and Precision Tools gyroscopes. Where recorded, surveys could be on 3, 5 or 50 m intervals.

Core and RC drill holes were sampled on 3 m intervals. Blasthole samples are sampled by cutting four channels on opposite sides of the cuttings pile. Samples are scraped from the walls of the channels and placed in a bag.

Project No.: 252233  
6 February 2023

Summary  
Page 1-3

**wood.**

**Southern Copper**  
![Southern Copper logo]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

The database contains 24,174 density determinations performed by Southern Copper personnel using the water immersion method.

Laboratories used for analysis have primarily been internal company laboratories, either at the Toquepala mine site or at the Ilo smelter (neither were accredited). Independent laboratories included Certimin, ALS Global, Bureau Veritas, SGS Perú, and Inspectorate. Where known, accreditations held included ISO 14001, ISO 9001, and ISO 17025.

Sample preparation methods varied over time. Depending on the program this included: drying; initial crushing to 90% passing 6 mm, secondary crushing to 90% passing 2 mm (10 mesh), and pulverizing to 95% passing 105 μm.

Analytical methods, where known, included atomic absorption (copper and molybdenum) and inductively coupled plasma (multi-element suite). Sequential copper analyses were also conducted, as were carbonate and chlorine assays.

Quality control programs for pre-2017 drill campaigns are not recorded. Southern Copper selected 160 samples (80 one-half core samples; 80 pulp samples) from 69 holes drilled in 1980, 1994, 2000, 2006, and 2011-2015 and sent them to Certimin for check-assaying. Accuracy was judged by Wood to be generally acceptable.

Quality control programs for exploration core holes and bast holes were implemented in 2017 with insertion of certified reference materials (standards), coarse blanks, fine blanks, twin samples, coarse duplicates, and pulp duplicates. The use of check samples was also adopted. Precision for copper and molybdenum is considered to be acceptable. The standards showed analytical bias are within acceptable limits.

Bureau Veritas was sent a total of 268 pulp samples, from drill campaigns in 1982, 2009, 2011, 2012, 2017, and 2018, to evaluate the quality of the internal Ilo laboratory facility. Biases of the Ilo data relative to Bureau Veritas were acceptable for copper (-1.6%) and questionable for molybdenum (-6.3%).

Southern Copper personnel collected 40 samples per month during the months of December 2020 to March 2021 to send to Certimin to evaluate the quality of the primary Ilo laboratory. Results indicate acceptable correspondence between the two laboratories.

Selected blasthole pulps from late 2020 and early 2021 that were analyzed at the internal Ilo laboratory were submitted to the Inspectorate laboratory in Lima (Inspectorate) for check assay. The results of the blasthole check assays are good.

Project No.: 252233  
6 February 2023

Summary  
Page 1-4

**wood.**

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

Selected drill hole sample pulps and archived core intervals from resource drill programs from the late 1990s to 2021, which were analyzed at the Cuajone mine laboratory until 2016 and at the Ilo laboratory from 2016 to 2020, were submitted to Inspectorate for check assay. Reproducibility of the samples from before 2016 is poorer than expected, suggesting potential issues with sampling, sample preparation, assaying or database integrity for the samples analyzed at the Cuajone mine laboratory before the implementation of QA/QC programs and use of the Ilo laboratory.

## 1.8 Data Verification

Wood's data verification included site visits, comparisons of the dataset and its available original sources including collar, survey, density, assay certificates and reports, a limited check assay program, and reconciliation and other operational data. Wood's QP is of the opinion that the data verification programs for Project data adequately support the geological interpretations, the analytical and database quality, and therefore support the use of the data in mineral resource estimation.

## 1.9 Metallurgical Testwork

Mining operations commenced in 1976, and the original samples supporting metallurgical testwork and process designs are long since mined out. Two different laboratories were used to perform metallurgical testwork. The Southern Copper-operated Cuajone concentrator was used from 2007-2012, and is not independent. Inmet Chapi in Arequipa (Inmet) was used in 2008 and is an independent laboratory. Leach Inc., a metallurgical consultancy, was retained to provide advice to the Southern Copper metallurgical team.

Testwork consisted of Bond ball mill work index, and flotation tests.

The LOM head grade and copper recovery for the oxide facilities are expected at 0.52% (including the ore from the existing oxide stockpile) and 48.2% respectively.

Within the sulfide plant (including the ore from the existing sulfide stockpile):

- The LOM expected copper recovery is estimated at 84.4%.
- The LOM expected molybdenum recovery is estimated at 62.5%.

Copper and molybdenum recovery from sulfide ore stockpiled (70.8 Mt with 0.28% copper grade and 0.012% molybdenum grade), assumed to be treated in the last years of the LOM, was reduced by 10% as a provision to account for potential metallurgical degradation.

Project No.: 252233
6 February 2023

Summary
Page 1-5

wood.

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

The forecast LOM copper concentrate grade is 25.34%, and the LOM molybdenum concentrate grade forecast is 54.05%.

A significant number of samples were selected by rock type/alteration for comminution and flotation testing. Tests were performed on samples that are considered to be representative of the different orebodies/zones and the mineralogy and alteration styles.

The copper and molybdenum concentrates produced at the Cuajone Operations are considered clean concentrates as they do not contain significant amounts of deleterious elements.

Wood's qualified person for metallurgy consider the metallurgical data adequate for the purposes of estimating mineral resources, mineral reserves and the economic analysis in this Report.

## **1.10 Mineral Resource Estimates**

### **1.10.1 Estimation Methodology**

Mineral resources were prepared by third-party consultants, Hexagon and reviewed, adjusted and endorsed by Wood's QP with relevant experience in resource estimation for porphyry copper deposits in accordance with the standards and definitions under S-K 1300.

A partial model indicator kriging approach was used to estimate copper and molybdenum grades. Exploratory data analysis consisted of review of histogram and probability plots.

The lithological model consists of four groups, there are eight alteration domains, and eight geometallurgical domains. Geometallurgical zones were assigned based on the percentages of lithology, alteration, and mineralization types in each block.

Lithology, alteration and mineralization domains were combined to produce geometallurgical domains for estimation of work index and the geometallurgical domains were also used for bulk density assignment. The mean value of bulk density determinations was assigned to each geometallurgical domain for tonnage estimation.

No capping or outlier restrictions were used during mineral resource estimation.

More than 90% of the intervals of the exploratory holes have a length of 3 m. Data were composited to 3 m.

Variography was completed in MineSight software on total copper (CuT), solubility index for soluble copper (ROX), solubility index for cyanide-soluble copper (RSUL), soluble copper (CuS)

Project No.: 252233  
6 February 2023

Summary  
Page 1-6

**wood.**

SouthernCopper

GrupoMéxico
MINERÍA

Southern Copper Corporation

Technical Report Summary on Cuajone Operations

Peru

(CUSAC), cyanide soluble copper (CuCN) (CUSCN), molybdenum, silver, iron, and soluble Fe (FESAC).

Copper, CUSAC, CUSCN, molybdenum, iron, arsenic, antimony, bismuth, lead, zinc, potassium, magnesium, sodium, calcium, Al2O3, chlorite, CO3, manganese, FESAC, sulfur, selenium, SiO2, and silver were estimated with ordinary kriging (OK). Blocks that were not estimated were assigned a mean grade according to their corresponding estimation domain. Indicators of total copper grade anomalies were estimated using OK. To complement the global statistical reviews, estimates were constructed using polygonal and inverse distance to the second power (ID2) methods.

Wood completed visual inspection of copper and molybdenum models and geostatistical validation of global bias (comparison of OK and nearest neighbor (NN) models), local trends in grade profiles (swath plots using ID2 and NN estimates and declustered composites) and change of support for each estimation domain. Reconciliation was also used as a validation tool.

Mineral resource classification was based on the distance from the block center to the closest estimation composite. The final classification was:

- Indicated: 60 m average distance (two-hole); 30 m extrapolation around single drill holes
- Inferred: maximum 300 m average distance (two-hole) and were restricted to 120 m average distance to the three closest composites to avoid classifying blocks with assigned grades as inferred mineral resources.

No measured mineral resources were classified.

Wood constrained the mineral resource estimates within conceptual pit shells using a Lerchs-Grossmann algorithm. Commodity prices used in resource estimation were based on Southern Copper's interpretations of market analysis from analyst and bank forecasts. The estimated timeframe used for the price forecasts is the 48-year LOM assumption that supports the mineral reserve estimates. The cut-off grade used for mineral resource estimation for sulfide material was 0.112% Cu. Oxide material to be sent to the leach pad was reported at a cut-off of 0.149% Cu. Wood considers those blocks within the constraining resource pit shell and above the cut-off applied to have reasonable prospects for economic extraction.

### 1.10.2 Mineral Resource Statement

Mineral resources are reported using the mineral resource definitions set out in S-K 1300 and are reported exclusive of those mineral resources converted to mineral reserves. The reference

Project No.: 252233

6 February 2023

Summary

Page 1-7

wood.

**Southern Copper**  
 **Grupo México**  
 MINERÍA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

point for the mineral resource estimate is in situ. The mineral resource estimate is current as at 31 December, 2022.

The indicated mineral resource estimates for the Cuajone Operations are provided in Table 1-1. The inferred mineral resource estimates are included in Table 1-2. Wood is the QP Firm responsible for the estimate.

**Table 1-1: Indicated Mineral Resource Statement**

| Process Type | Tonnage (Mt) | Cu (%) | Mo (%) | Contained Cu (Mlb) | Contained Mo (Mlb) |
| --- | --- | --- | --- | --- | --- |
| Sulfide | 331.6 | 0.46 | 0.017 | 3,381.5 | 121.7 |
| Oxide | 0.2 | 0.62 | - | 3.2 | - |
| Total | 331.8 | 0.46 | - | 3,384.7 | 121.7 |

**Table 1-2: Inferred Mineral Resource Statement**

| Process Type | Tonnage (Mt) | Cu (%) | Mo (%) | Contained Cu (Mlb) | Contained Mo (Mlb) |
| --- | --- | --- | --- | --- | --- |
| Sulfide | 850.9 | 0.31 | 0.011 | 5,901.7 | 201.8 |
| Oxide | 0.3 | 0.51 | - | 3.4 | - |
| Total | 851.2 | 0.31 | - | 5,905.1 | 201.8 |

Note: (1) Mineral resources are reported in place and are current as at December 31, 2022. Mineral resources are reported exclusive of mineral reserves. Wood is the QP Firm responsible for the estimate.

(2) Mineral resources are constrained within an optimized pit shell based on copper and molybdenum only. Mineral resources are reported within a conceptual pit shell that use the following input parameters: metal prices of US$3.80/lb Cu and US$11.50/lb Mo; average metallurgical recovery assumptions of 84.8% for copper and 62.9% for molybdenum from a process plant and 42.4% copper recovery from a heap leach; based mining cost of US$1.76/t, mill process operating costs of US$7.05/t processed, leach costs of US$5.26/t processed; copper concentrate payable price of US$3.36/lb Cu, molybdenum concentrate payable price of US$9.72/lb Mo, and leach copper payable price of US$3.77/lb Cu.

(3) No estimates for molybdenum are reported for leachable material as this element cannot currently be recovered using the leach process envisaged.

(4) Numbers in the table have been rounded. Totals may not sum due to rounding.

Areas of uncertainty that may materially impact the mineral resource estimates include: changes to long-term metal price and exchange rate assumptions; changes in local interpretations of mineralization geometry such as presence of unrecognized mineralization off-shoots; faults, dikes and other structures; and continuity of mineralized zones; changes to geological and grade shape, and geological and grade continuity assumptions; changes to metallurgical recovery

Project No.: 252233  
 6 February 2023

Summary  
 Page 1-8

**wood.**

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

assumptions; changes to the input assumptions used to derive the conceptual open pit shell that is used to constrain the estimates; changes to the cut-off values applied to the estimates; variations in geotechnical (including seismicity), hydrogeological and mining assumptions; and changes to environmental, permitting and social license assumptions.

Wood's qualified person is of the opinion that all issues relating to all relevant technical and economic factors likely to influence the prospect of economic extraction can be resolved with further work.

## **1.11 Mineral Reserve Estimates**

### **1.11.1 Estimation Methodology**

Indicated mineral resources were converted to mineral reserves. Inferred mineral resources were set to waste.

Mineral reserves were constrained within an optimized pit shell that included consideration of appropriate pit revenue factors, reconciliation data, current topography, geotechnical pit slope recommendations, metallurgical recoveries, operating costs (mining, processing, general and administrative (G&A), smelting, refining and processing costs, SX/EW and selling costs), royalties, metal prices, and net smelter return (NSR) cut-offs.

To define the ultimate reserve pit for a concentration process it was considered a variable NSR cut-off value ranging from US$10.31/t to US$11.39/t. To define destination of the material it was based on a NSR cut-off ranging from US$7.791/t to US$8.079/t.

For heap leach it was considered a variable NSR cut-off value ranging from US$11.40/t to US$11.74/t. To define the destination of the material it was based on a NSR cut-off of US$9.061/t.

Currently there are two crushers at the Cuajone operation, a main crusher for sulfide material at the entrance to the pit, and another crusher for oxide material adjacent to the Torata West waste rock storage facility (WRSF). By year 2042, because of mine development, a new crusher for sulfide will be used. Since the oxide crusher is close to the WRSF, no differential cost between sending the material to the leach pad or to the WRSF was applied.

The mine plan considers a strategy of elevated cut-off being applied for the early years with the purpose of increasing short term cash flows, the following approach of cut-off grade for Cu was used to define the material that goes directly to mill:

Project No.: 252233  
6 February 2023

Summary  
Page 1-9

**wood.**

**Southern Copper**  
 **Grupo México**  
 MINERÍA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

- Year 2023 to 2025: ≥ 0.25 % Cu

Material below the specific COG in years 2023 to 2026 is sent to a stockpile if it is above ≈0.15% of Cu.

### 1.11.2 Mineral Reserve Statement

Mineral reserves are reported using the mineral reserve standards and definitions set out in S-K 1300. The selected point of reference for the mineral reserve estimate is point of delivery to the process plant. Mineral reserves are summarized in Table 1-3. The concentration and leach type ore currently stockpiled at the site is reported as concentration and leach ore from stockpile. Wood is the QP Firm responsible for the mineral reserve estimates. Qualified persons with relevant experience in reserve estimation for open pit mining operations involving porphyry deposits prepared or supervised the preparation of the mineral reserve estimates.

**Table 1-3: Probable Mineral Reserve Statement**

| Process Type | Tonnes (Mt) | Copper Grade (%) | Molybdenum Grade (%) | Contained Copper (Mlb) | Contained Molybdenum (Mlb) |
| --- | --- | --- | --- | --- | --- |
| Concentration | 1,307.0 | 0.48 | 0.017 | 13,956.7 | 497.5 |
| Concentration from stockpile | 29.1 | 0.41 | 0.017 | 260.0 | 10.8 |
| Leach | 0.4 | 0.68 | - | 5.6 | - |
| Leach from stockpile | 21.1 | 0.51 | - | 238.9 | - |
| Total | 1,357.6 | 0.48 | - | 14,461.2 | 508.3 |

Note: (1) Mineral reserves are current as of December 31, 2022. Wood is the QP Firm responsible for the estimate.

(2) Mineral reserves are constrained within an engineered pit based on copper and molybdenum revenues only. The following parameters were used in estimation: assumed open-pit mining methods; assumed concentration and leaching processes; copper price of US$3.30/lb, molybdenum price of US$10.00/lb; variable NSR cut-off values of US$7.791-US$8.079/t-processed for concentration material, and a NSR cut-off value of US$9.061/t-processed for leaching material; mining recovery of 100%; variable metallurgical recoveries (average LOM recoveries of 84.4% for copper by concentration, 62.5 % for molybdenum by concentration, and 48.2% for copper by leaching, including concentration and leach ore existing in stockpiles); average copper recoveries of 97.4% for smelting and 99.9% for refining; variable mining costs that range from US$2.337-US$3.417/t-mined; average process costs of US$7.971/t-processed for concentration material, and US$9.061/t for leaching material; average smelting and refining cost of US$0.382/lb Cu; selling costs of US$0.0024/lb Cu for concentration process, US$1.679/lb Mo for concentration process, and US$0.009/lb Cu for leaching process; and 1% NSR royalty applied to the for Cu and Mo.

(3) Numbers in the table have been rounded. Totals may not sum due to rounding.

Project No.: 252233  
 6 February 2023

Summary  
 Page 1-10

**wood.**

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

Areas of uncertainty that may materially impact the mineral reserve estimates include: changes to long-term metal price and exchange rate assumptions; changes to metallurgical recovery assumptions; changes to the input assumptions used to derive the mineable shapes applicable to the open pit mining methods used to constrain the estimates; changes to the forecast dilution and mining recovery assumptions; changes to the NSR cut-off values applied to the estimates; variations in geotechnical (including seismicity), hydrogeological and mining method assumptions; and changes to environmental, permitting and social license assumptions.

## 1.12 Mining Methods

The Cuajone Operations use conventional truck-and-shovel open pit mining methods.

Geotechnical zones used for pit designs were based on guidance provided by a third-party consultant. Overall slope angles were estimated based on the 2022 optimized reserves pit design developed by Southern Copper.

Water that accumulates in the base of the pit is pumped out of the pit and used for dust suppression.

Nine pit phases remain in the LOM plan, starting with phase 6 and ending with phase 10C. Three pit phases will be operational at any one time, to ensure that production rates can be met. A maximum mining capacity per phase of 110 Mt/a is assumed, with a maximum vertical advance rate of 10 benches per year. The mine plan assumed a maximum mining capacity of 158 Mt of annual movement and a nominal processing rate of 90 kt/d of sulfide ore at the concentration facility.

The mill crusher is located at elevation 3295 masl in the northern zone of the pit. Material is supplied either directly by haul trucks or is fed from a short-term sulfide stockpile near the crusher. From the crusher, the crushed material is transported using a 7 km long conveyor belt to the concentrator plant. The mill crusher throughput is a nominal 90 kt/d.

Material destined for the heap leach can be sent either directly to a short-term stockpile, or to the leach crusher that is located at elevation 3,480 masl, 5.9 km southwest of the pit. Crushed leachable material is rehandled by loaders and trucks and deposited on a heap leach pad approximately 1.0 km northeast of the leach crusher.

Equipment is conventional, and consists of drill, load, haul and support equipment.

Project No.: 252233  
6 February 2023

Summary  
Page 1-11

**wood.**

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

## 1.13 Recovery Methods

The process designs were based on existing technologies and proven equipment, and the plants constructed using those designs have a 45-year operating history.

The Cuajone heap leach facility was designed to treat oxide ores and produce a copper-rich pregnant leach solution (PLS) that is sent to the Toquepala Operations for solvent extraction/electrowinning (SX/EW) recovery. Oxide ore is treated in a conventional leaching facility consisting of two stages of crushing, agglomeration and permanent leaching pads.

The Cuajone concentrator treats sulfide material to produce copper and molybdenum concentrates. The majority of the copper concentrate is sent to the Ilo smelter and refinery to produce copper cathodes as the final product. The molybdenum concentrate is sold to third parties. The Cuajone concentrator commenced operations on November 25, 1976 and was initially designed to process 40,823 t/d. Following upgrades and plant modifications, the current plant capacity is 90,000 t/d.

The Ilo smelter processes the copper concentrates from the Cuajone and Toquepala concentrators and produces copper anodes for the Ilo refinery. In 2007 a new smelter was commissioned at Ilo, with a nominal capacity of 1,200,000 t/a of copper concentrate. The smelter consists of one single Isasmelt smelting unit associated with two rotary holding furnaces, four Peirce Smith converters, two anode furnaces associated with twin anode casting wheels, two acid plants, two oxygen plants, and auxiliary services plants.

The Ilo refinery is located in the Pampa de Caliche at 9 km north of the city of Ilo. The plant was acquired by Southern Copper in 1994 and modernized to produce 246,000 t/a of copper cathodes. It was subsequently expanded to the current annual capacity of 294,763 t/a of copper cathodes. The Ilo refinery has the capacity to produce 125,000 kg Ag, 840 kg Au, and 50,000 kg Se annually. Although the Ilo refinery has produced these elements historically as by-products, their revenues and process costs are excluded from the mine plan and cash flow analysis since silver, gold, and selenium are not included in the mineral resource or mineral reserve estimates.

Power is sourced from the National Interconnected Electric System (SEIN).

Fresh water for the mine and process facilities is obtained from both ground and surface sources. All sources discharge into the Vina Blanca lagoon from where the fresh water is supplied to the process facilities.

The primary consumables in the various process plants include:

- Heap leach plant: sulfuric acid

Project No.: 252233  
6 February 2023

Summary  
Page 1-12

**wood.**

**Southern Copper**  
![Southern Copper logo]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

- Concentrator: flotation reagents such as: collector, frother, flocculant, sodium hydrosulfide (NaSH), diesel and lime; steel grinding media.

Power is sourced for process needs from the Peruvian grid.

## 1.14 Infrastructure

All required infrastructure to support the Cuajone Operations is in place. Additional tailings storage will be required to support the LOM plan after approximately the end of 2036.

On-site infrastructure that supports the Cuajone Operations include: an open pit; four WRSFs; two oxide stockpiles; one sulfide stockpile; four leach pads; process facilities; warehouses, workshops, and offices; 138 kV and 220 kV power transmission lines; electrical substation and power distribution system; water handling facilities; permanent camp for operations; and a railway and rail yard.

Off-site infrastructure includes: access road; 138 kV and 220 kV power transmission lines; electrical substations and power distribution systems; railway; Quebrada Honda TSF; water supply system; SX/EW plant located at Toquepala; smelter, refinery and sulfuric acid plants at Ilo; port facilities in Ilo including dock and storage areas, rail yard, and wagon repair shop; port facilities in Tablones, where hydrocarbons and sulfuric acid are unloaded and sent to the mine site; and the Simón railway yard, which has assembly and dispatch areas, as well as workshops and offices.

Railways extend from Ilo to Toquepala, and a spur railway runs from the Toquepala Operations to the Cuajone Operations. Supplies such as sulfuric acid, equipment, fuel, and mining supplies are transported to the operations using the rail network. Concentrates are railed from the mine site to the Ilo smelter/refinery, and cathodes produced at the refinery are railed to the Port of Ilo. The Port of Ilo is a private port, operated by Southern Copper. It has two berths and can take vessels to 40,000 tonnes deadweight. The port is the export point for copper cathodes, copper concentrate, sulfuric acid and molybdenum; and the import location for general containerized and loose cargo to support operations.

The TSF operates as a cross-valley impoundment and is confined by two dams constructed of cyclone tailings sand. The remaining capacity of the existing TSF will support operations until approximately the end of 2036.

No waters are discharged from the operations as no mining effluents are generated at the mine site. At Quebrada Honda, Southern Copper is authorized to dispose of decanted water from the

Project No.: 252233  
6 February 2023

Summary  
Page 1-13

**wood.**

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

tailings. Water from the TSF is used in the process plant, following treatment in a neutralization facility.

Collectively, the Toquepala and Cuajone Operations, together with the Ilo smelter/refinery complex, have five accommodations areas, which provide a permanent accommodation capacity of 4,756 persons.

The energy supply for the Toquepala Operations comes from SEIN, primarily from natural gas-fired thermal power plants located in the Chilca-Lima district of Peru, and from the Antunez de Mayolo and Cerro del Aguila hydroelectric power plants. Power is transmitted to the Southern Copper facilities in transmission networks of 500, 220 and 138 kV, using two Southern Copper-owned transmission lines of 138 kV (225 km long) and 220 kV (240 km long). The Ilo facilities are supported by 564 MW of power supplied by SEIN, and 564 MW of gas reserve power from the southern Peru gas pipeline.

## 1.15 Market Studies

Copper futures are exchange-traded contracts on all of the world's major commodity exchanges. Copper is the world's third most widely used metal after iron and aluminum and is primarily consumed in industries such as construction and industrial machinery manufacturing. The Cuajone Operations produce copper concentrates and copper cathodes.

Molybdenum is mainly used as an alloying agent in stainless steel, and also in the manufacture of aircraft parts and industrial motors. Molybdenum futures are available for trading in The London Metal Exchange (LME). Prices are generally determined by principal-to-principal negotiations between producers, trading houses, and end users. The Cuajone Operations produce molybdenum concentrates.

Southern Copper employs a corporate strategy that is in line with the company's marketing experience, and experience with obtaining long-term contracts with strategic business partners in the Asian and European markets, as well as annual contracts with other active market participants.

Normally over 60% of the molybdenum concentrate is sold to Chile, with the remainder sold into the Northern Europe, Asia and the US markets. Cathode copper is sold onto the Asian, European, Brazilian and/or North American markets.

Southern Copper provided Wood with Southern Copper's internal price forecast and a presentation on their market outlook in the form of a slide deck. The commodity price forecast covered the period 2022-2026 and provided a long-term forecast for 2026 onward. Forecasts

Project No.: 252233  
6 February 2023

Summary  
Page 1-14

**wood.**

**Southern Copper**
**Grupo México**
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

were based on Southern Copper's interpretations of market analysis from Wood Mackenzie, CRU and 23 analysts and banks on copper price, and six analysts and banks on molybdenum price.

Wood reviewed the Southern Copper long-term forecast price for copper of US$3.30/lb, and concluded that the copper price selected by Southern Copper is reasonable as it is consistent with Wood's assessment of industry consensus on long-term copper price used for reserve estimation and cash flows in the mining industry.

It is industry-accepted practice to use higher long-term metal prices for the mineral resource estimates than the pricing used for mineral reserves. The long-term copper price forecast of US$3.30/lb for mineral reserves and cash-flows was increased by 15% to provide the mineral resource estimate copper price of US$3.80/lb.

Wood reviewed the Southern Copper long term forecast price for molybdenum of US$10.00/lb, and concluded that the molybdenum price selected by Southern Copper is reasonable compared to what others have recently been using for mineral reserves and cash flows in the mining industry. The Southern Copper molybdenum price forecast of US$10.00/lb was increased by 15% to US$11.50/lb to provide the input to the mineral resource constraining pit shell and NSR cut-off applied to the mineral resource.

Mineral reserves and mineral resources were constrained by pit shells that used inputs from copper and molybdenum only, with no other metal revenue contribution to the NSR value determinations. The economic analysis also excluded any revenue from by-products generated by the Ilo smelter and refinery.

The long-term metal price forecasts used were fixed over the life of mine of 48 years and are:

- Mineral resources:
  - Copper: US$3.80/lb
  - Molybdenum: US$11.50/lb
- Mineral reserves and cashflows:
  - Copper: US$3.30/lb
  - Molybdenum: US$10.00/lb.

The exchange rate used was US$1.00 = PENS/3.81. This exchange rate was provided by Southern Copper.

Cuajone Operations concentrates are sent to the Ilo Smelter and Refinery for processing to produce refined cathodes. When the production from the Cuajone and Toquepala Operations

Project No.: 252233
6 February 2023

Summary
Page 1-15

wood.

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

exceeds the smelter’s capacity, a portion is sold to third parties. In recent years, these third-party sales of Cuajone and Toquepala Operations concentrates have represented about 20-25% of the annual production. Approximately 95% of the production of refined cathodes is sold under annual contracts with industrial customers (mainly copper rod producers), with whom Southern Copper has had a commercial relationship for many years, and about 5% is sold on the spot market.

The largest in-place contracts other than for product sales cover items such as bulk commodities, operational and technical services, mining and process equipment, and administrative support services. Contracts are negotiated and renewed as needed.

## **1.16 Environmental, Permitting and Social Considerations**

### **1.16.1 Environmental Studies and Monitoring**

Baseline studies were completed prior to mine start-up, and included assessments of air quality, noise, water and sediment quality, flora and fauna surveys, and the human environment. Baseline and supporting studies were completed in support of Project permitting, together with development of management plans to address major impacts. These included environmental impact assessments, environmental management plans, evaluation of flood controls on the Torata River, archaeological surveys, and closure planning.

As per permit requirements, Southern Copper has a number of monitoring programs in place, and monitors surface water and air quality in accordance with commitments made in the Environmental Management and Adjustment Plan, Environmental Impact Study, Closure Plans and updates to those plans and studies.

### **1.16.2 Closure and Reclamation Considerations**

The Mine Closure Plan for the Cuajone Operations was approved in 2009, and modifications were approved in 2012 and 2019. Closure costs are included in the mine site financial model as cash costs on an annual basis. The current closure plan and cost estimates were prepared in 2019 and closure costs were escalated to Q3 2022 for this assessment. For this assessment, the Quebrada Honda TSF closure costs and the Ilo Smelter and Refinery closure costs were allocated to the Cuajone and Toquepala Operations proportionally to nominal mill production throughputs of each and the total LOM concentrate fed by each mine, respectively. A provision was included to account for the closure cost of the filtered tailings plant.

Project No.: 252233  
6 February 2023

Summary  
Page 1-16

**wood.**

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERIA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

The closure cost used in the economic analysis is US$317.0 million, inclusive of the Peruvian general sales tax.

### **1.16.3 Permitting**

The Cuajone Operations and the Ilo Smelter and Refinery have all of the required permits to operate. The operations maintain a permit register, which includes a record of the legal permits obtained, the approval authority, permit validity period and expiration dates, permit status (current, canceled or replaced) and whether or not the permit requires renewal. The operations also have a control and monitoring system to ensure that the requirements of each permit are monitored to comply with the relevant regulatory conditions imposed.

### **1.16.4 Social Considerations, Plans, Negotiations and Agreements**

Southern Copper has community programs in place as part of its Social Management Plan. However, the Social Management Plan is not currently formally incorporated into the base EIA or subsequent amendments.

Southern Copper has communication channels and tools in place, based on the company's community development model, which allow the company to identify potential conflicts early, to work with the community to find appropriate solutions to address their concerns, and generate positive social license conditions for the continued operation of Southern Copper's mining projects.

Wood's qualified person is of the opinion that the current plans to address any issues related to environmental compliance, permitting, and local individuals or groups are adequate to support mineral resources and mineral reserves.

### **1.17 Capital Cost Estimates**

Capital cost estimates are at a pre-feasibility level of accuracy range of $\pm 25\%$ and a contingency not exceeding 15%. All capital costs were expressed in Q3 2022 US dollars.

In general, the Cuajone Operations have the necessary facilities to carry out the current operations. Sustaining capital costs were estimated by area and allocated over time to support the proposed mine production schedule at current production throughputs.

Mine equipment requirements were estimated by operating area (drilling, loading, hauling, support, etc.) based on the proposed LOM plan and equipment replacement ratios provided by

Project No.: 252233  
6 February 2023

Summary  
Page 1-17

**wood.**

**Southern Copper**  
![Southern Copper logo]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

Southern Copper. Mine equipment maintenance costs were also accounted for in the capital cost estimate.

Leach pad expansion costs were estimated based on a unit cost of US$3.00/t of oxide ore.

The costs associated with the raise of the existing Quebrada Honda TSF account for the works required to expand the TSF to its maximum design storage capacity until approximately the end of 2036. Costs were distributed between the Cuajone and Toquepala Operations proportionally to nominal mill feed throughputs of each.

Additional tailings storage capacity is required once the Quebrada Honda TSF reaches capacity. Wood assumed that a co-stack (dry-stack) facility which would store waste and tailings would be constructed on site. Land acquisition costs as provision for waste and tailings management space were also included in the estimate. Sustaining costs at US$0.6 million each year and US$12.4 million every three years were included for relocating conveyors for continued operation, equipment replacement, associated with the conveyor systems, and additional cost related to changing/updating filtering equipment.

A filtered tailings pilot plant with a production capacity between 8 and 10 kt/d is currently under construction near the Quebrada Honda TSF area. The remaining cost estimated by Southern Copper to complete the construction of this facility was included, distributed between the Cuajone and Toquepala Operations proportionally to nominal mill feed throughputs of each.

Cost allocations were made for sulfide crusher relocation, which assumed that a new crusher would be installed.

The remaining cost estimated by Southern Copper to complete the construction of a new additional screening and transferring system currently under construction in the Cuajone concentrator was also accounted for.

Process facilities sustaining and maintenance, and other general sustaining and maintenance costs were accounted for based on the following unit costs derived from a five-year (2023-2027) sustaining and maintenance cost schedule developed by Southern Copper.

The sustaining capital cost estimate totals US$4,105.2 million (Table 1-4), exclusive of the Peruvian general sales tax.

Project No.: 252233  
6 February 2023

Summary  
Page 1-18

**wood.**

**Southern Copper**  
 **Grupo México**  
 MINERÍA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

**Table 1-4: Sustaining Capital Cost Estimate**

| Area | Sustaining Capital Cost (US$M) |
| --- | --- |
| Mining equipment | 1,775.4 |
| Leach pad expansion | 64.5 |
| Existing tailings storage facility (Quebrada Honda) raise | 103.3 |
| Filtered tailings plant, inc. land acquisition and pilot plant | 697.6 |
| Primary crusher relocation | 71.9 |
| Additional screening system (for HPGR) in concentrator | 52.6 |
| Process facilities sustaining and maintenance | 1,125.5 |
| Other general sustaining and maintenance | 214.4 |
| Total | 4,105.2 |

Note: Numbers have been rounded. Totals may not sum due to rounding.

## 1.18 Operating Cost Estimates

Operating cost estimates are at a pre-feasibility level of confidence, having an accuracy range of $\pm 25\%$ and a contingency not exceeding 15%.

Operating costs were based on actual costs and data from Southern Copper’s operating mines in Peru, Wood’s experience and the proposed mine and process plans.

Mine operating costs are forecast to average US$2.00/t mined over the LOM. The mine cost increases gradually starting at US$1.76/t mined in year 1 (2023) to a cost of US$2.42/t mined in Year 45 (2067), due to the increase in ex-pit hauling distance (waste dump facilities) and the deepening of the pit. A cost of US$1.37/t reclaimed was applied to account for reclamation costs from the oxide and sulfide stockpiles, which include ore loading, hauling, and feeding to the leach pad or concentrator.

Process operating costs were based on a combination of actual costs averages over the period 2018-2022, adjusted to account for the LOM based on expected variations of key commodities costs such as energy, consumables and services; and a projection of the leaching and SX/EW costs provided by Southern Copper based on the leach and cathodes production schedule and operational parameters and main consumable costs based on data from their operations.

Operating costs were allocated to the planned dry-stack facility that will be required once the Quebrada Honda TSF reaches capacity in approximately the end of 2036. A cost of US$1.83/t was estimated, which includes tailings filtering/drying, tailings conveying and placement of tailings on a dry-stack facility. The operating cost of the filtered tailings pilot plant was also included and distributed between the Cuajone and Toquepala Operations proportionally to nominal mill feed throughputs of each.

Project No.: 252233  
 6 February 2023

Summary  
 Page 1-19

**wood.**

**Southern Copper**  
 **Grupo México**  
 MINERÍA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

General and administrative costs are included in the corresponding mining and processing costs.

Table 1-5 is a summary of the operating cost estimates, exclusive of value-added taxes.

As Southern Copper assumes, in its cashflow planning, that the Tia Maria Project will source the required sulfuric acid for that operation from the Ilo smelter and refinery at the cost of production, which represents approximately 720,000 t/a, or about 60% of the total acid production from the Ilo smelter, over approximately 20 years. This sulfuric acid production cost was removed from the Ilo smelter operating costs.

**Table 1-5: LOM Operating Cost Estimate**

| Description | Total (US$M) | Unit Cost |  |
| --- | --- | --- | --- |
| Mining* | 7,912.3 | US$/t mined* | 2.03 |
| Process | 13,725.6 | US$/t processed** | 10.11 |
| Total | 21,637.9 |  |  |

Note: Numbers have been rounded. Totals may not sum due to rounding.

* Including ore rehandling

** Including sulfides and oxides

## 1.19 Economic Analysis

### 1.19.1 Forward-Looking Information Caution

Certain information and statements contained in this section are forward-looking in nature and are subject to known and unknown risks, uncertainties, and other factors, many of which cannot be controlled or predicted and may cause actual results to differ materially from those presented here. Forward-looking statements include, but are not limited to, statements with respect to the economic and study parameters of the Cuajone Operations; mineral reserves; the proposed mine plan and mining strategy; ability of mine designs to withstand seismic events; dilution and extraction recoveries; processing method and rates and production rates; projected metallurgical recovery rates; infrastructure requirements; capital, operating and sustaining cost estimates; concentrates and cathodes marketability and commercial terms; the projected LOM and other expected attributes of the Project; the net present value (NPV); future metal prices and currency exchange rates; government regulations and permitting timelines; estimates of reclamation obligations; requirements for additional capital; environmental and social risks; and general business and economic conditions.

Project No.: 252233  
 6 February 2023

Summary  
 Page 1-20

**wood.**

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

### 1.19.2 Methodology

The financial analysis was performed using a discounted cash flow (DCF) method. Net annual cash flows were estimated projecting yearly cash inflows (or revenues) and subtracting projected yearly cash outflows (such as capital and operating costs, royalties, and taxes).

The financial model that supports the mineral reserve declaration was a standalone model that calculated annual cash flows based on: scheduled ore production; assumed processing recoveries; metal sale prices; projected operating and capital costs; and estimated taxes.

The financial analysis was based on an after-tax discount rate of 10%. Cash flows were assumed to occur at the end of each year and were be discounted to the beginning of 2023 (Year 1 of the economic analysis).

Costs projected within the cash flows are based on constant Q3 2022 US dollars.

Revenue was calculated from the recoverable metal and the long-term forecasts of metal prices and exchange rates. Recoverable metal and products include those recovered at the Ilo smelter and refinery from the copper concentrate feed from the mine operation.

### 1.19.3 Key Parameters and Assumptions

The cashflow assumes, based on Southern Copper’s forecast, that on average, in those years when the total annual copper concentrate production from Cuajone and Toquepala Operations is equal or less than the Ilo Smelter nominal capacity (1.2 Mt/a of Cu concentrate), all the copper concentrate from the Cuajone and Toquepala Operations will be treated at the Ilo smelter; in those years when the total annual copper concentrate production from Cuajone and Toquepala Operations exceeds the Ilo smelter nominal capacity up to 10%, 90% of the copper concentrate from the Cuajone and Toquepala Operations will be treated at the Ilo smelter, with the remaining 10% sent to third parties; and in those years when the total annual copper concentrate production from Cuajone and Toquepala Operations exceeds the Ilo smelter nominal capacity in more than 10%, the copper concentrate from the Cuajone and Toquepala Operations will be treated at the Ilo smelter at nominal capacity, with surplus concentrate production sent to third parties.

Typically, about only about 4.5% of the copper anodes produced are sold to third parties; the remainder is sent to the Ilo refinery for cathode production.

Project No.: 252233  
6 February 2023

Summary  
Page 1-21

**wood.**

**Southern Copper**  
![Southern Copper logo]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

Copper and molybdenum concentrate transport costs were based on average costs incurred from 2020 to August 2022. Copper concentrate transport losses were based on benchmark. Concentrate moisture contents were based on average values from 2021 to August 2022. Commercial terms were applied to the portion of the copper concentrate that is assumed to be sold to third parties and to molybdenum concentrate and copper cathode sales.

Approximately 88% of the sulfuric acid produced is sold within South America, with 60% of that acid production figure going to Chile, and 40% to Peru. The remaining 12% is used in the Cuajone and Toquepala Operations. Southern Copper assumes, in its cashflow planning, that the Tia Maria Project will source the required sulfuric acid for that operation from the Ilo smelter and refinery at the cost of production, which represents approximately 720,000 t/a, or about 60% of the total acid production from the Ilo smelter. All other revenue from acid sales apart from that from the Tia Maria project have been excluded from the financial model.

Special mining taxes and the modified mining royalty are included in the economic analysis.

Closure costs were allocated in the relevant cashflow years based on the progressive, final and post closure schedule. It was assumed that closure cost accruals are not required, and closure obligations will be satisfied by either escrow with other Southern Copper assets as collateral, a bond or a bank letter of credit. The salvage value was assumed to be zero.

The taxation modeled within the financial analysis is based on the taxation scheme that was provided and validated by Southern Copper.

#### **1.19.4 Economic Analysis**

The Cuajone Operations are anticipated to generate a pre-tax NPV of US$2,674.7 million at a 10% discount rate and an after-tax NPV of US$1,644.2 million at a 10% discount rate.

As the mine is operating, and initial capital is already sunk, considerations of IRR and payback are not relevant.

Cashflow summary results are provided in Table 1-6.

Project No.: 252233  
6 February 2023

Summary  
Page 1-22

**wood.**

**Southern Copper**  
 **Grupo México**  
 MINERÍA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

**Table 1-6: Summary of Economic Results**

| Description | Unit | Value |
| --- | --- | --- |
| Remaining mine life | years | 48 |
| Copper payable | Mlb | 11,759.1 |
| Molybdenum payable | Mlb | 317.7 |
| After-Tax Valuation Indicators |  |  |
| Undiscounted cash flow | US$M | 9,180.2 |
| NPV @ 10.0% | US$M | 1,644.2 |
| Sustaining capital | US$M | 4,105.2 |
| Closure cost (inc. IGV) | US$M | 317.0 |
| Mining operating cost | US$M | 7,912.3 |
| Process operating cost | US$M | 13,725.6 |

Note: Numbers have been rounded. IGV = value-added tax (Impuesto General a las Ventas).

### 1.19.5 Sensitivity Analysis

A sensitivity analysis was performed to identify potential impacts on the after-tax NPV of variations in metal prices, grades, sustaining capital costs and operating costs. The results of this analysis are presented in Figure 1-1. For the purpose of the sensitivity to metal grades, it was assumed that the capacity of the processing facilities are not a constraint.

**Figure 1-1: After-Tax NPV Sensitivity (10% discount rate)**

![img-0.jpeg](img-0.jpeg)

(Source: Wood, 2022)

Project No.: 252233  
 6 February 2023

Summary  
 Page 1-23

**wood.**

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

The Cuajone Operations are most sensitive to fluctuations in copper price and grade. It is less sensitive to changes in operating costs and capital costs. The operations are least sensitive to variations in molybdenum price and grade.

Table 1-7 presents the after-tax NPV at a range of discount rates from 8-12% with the base case highlighted.

Table 1-7: After-Tax NPV Sensitivity to Discount Rates (base case is highlighted)

| Discount Rate | After-Tax NPV (US$M) |
| --- | --- |
| NPV @ 8% | 2,050.5 |
| NPV @ 9% | 1,826.2 |
| NPV @ 10% | 1,644.2 |
| NPV @ 11% | 1,494.3 |
| NPV @ 12% | 1,369.2 |

## 1.20 Risks and Opportunities

### 1.20.1 Risks

Risks to the Cuajone Operations include:

- The mineral reserve estimates are sensitive to metal prices. Lower metal prices than forecast in the LOM plan may require revisions to the mine plan, with impacts to the mineral reserve estimates and the economic analysis that supports the mineral reserve estimates.
- Geotechnical and hydrological assumptions used in mine planning are based on historical performance, and to date historical performance has been a reasonable predictor of current conditions. Any changes to the geotechnical, including seismicity, and hydrological assumptions could affect mine planning, affect capital cost estimates if any major rehabilitation is required due to a geotechnical (seismic) or hydrological event, affect operating costs due to mitigation measures that may need to be imposed, and impact the economic analysis that supports the mineral reserve estimates.
- An increase in the clay content of the deposit could have an effect on the process flow, resulting in treatment capacity reduction and increases in operating costs when pumping tailings material to the TSF.

Project No.: 252233
6 February 2023

Summary
Page 1-24

wood.

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

- The Quebrada Honda TSF does not have sufficient storage capacity for the LOM. The mine plan assumes that a new facility location can be obtained, designs can be completed and approved by the relevant regulatory authorities, and the new facility can be constructed and commissioned prior to approximately the end of 2036. If the new TSF is not available by the time envisaged, this could affect the mineral reserves, capital and operating cost estimates, and the economic analysis.
- Wood has assumed that the new TSF will be a co-stack (dry-stack) facility and has estimated capital and operating costs for such a facility. If the final TSF option uses a different disposal method, this could affect the mineral reserves, capital and operating cost estimates, and the economic analysis.
- The new Global Industry Standard on Tailings Management (GISTM) provides a set of industry Standard to guide design and management of TSF's. Members and non-members of International Council on Mining and Metals (ICMM) are required to be in compliance with the GISTM over the next several years. The TSF design needs to be revisited and be revised as needed to be in full compliance with the recently-published global tailings standard (GISTM, 2020). This may result in changes to the design criteria. Such changes may result in increases to the capital cost estimates, and changes to the operating cost estimates, which could affect the mineral reserve estimates.
- Labor cost increases or productivity decreases, particularly due to the impact of Covid-19, could also impact the estimated mineral reserves, operating cost estimates and the economic analysis.
- Commodity price increases for key consumables such diesel, electricity, tires and chemicals would negatively impact the stated mineral reserves because of the effect on the forecast operating costs.
- Assumed permitting and project development timelines may be longer than anticipated for the new TSF.
- Political risk from challenges to mining licenses and/or Southern Copper's right to operate.

### 1.20.2 Opportunities

Opportunities include:

- Conversion of some or all of the indicated mineral resources currently reported exclusive of mineral reserves to mineral reserves, with appropriate supporting studies.

Project No.: 252233
6 February 2023

Summary
Page 1-25

wood.

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

- Upgrade of some or all of the inferred mineral resources to higher-confidence categories, such that such better-confidence material could be used in mineral reserve estimation and potentially reduce the mining costs through reduced waste rock to be mined.
- Considering an elevated cut-off strategy over a longer period of the mine life and revision of the life of mine plan could result in a better economic outcome.
- Higher metal prices than forecast could present upside sales opportunities and potentially an increase in predicted Project economics.

## 1.21 Conclusions

Under the assumptions in this Report, the operations evaluated show a positive NPV over the remaining LOM and support the mineral reserves. The mine plan is considered achievable under the set of assumptions and parameters used.

## 1.22 Recommendations

The recommendations cover the discipline areas of data storage, mineral resource estimates, tailings storage and permitting. The total recommended budget estimate to complete the programs is US$1.5-US$2.2 million.

Recommendations include:

- Internal controls:
  - Establish a controlled documents database to store copies of internal protocols, key milestone sign-offs, management plans, and registers
- Database:
  - Implement a document storage system for all supporting documentation
  - Complete a verification program on recovery, logging, and density data and ensure that only verified data are included in the Project database
- Mineral resources:
  - Complete a capping study and implement a grade capping/outlier restriction process in the next mineral resource update
- Mine plan:
  - Review the mine plan to assess opportunities for optimizing the mine sequencing and expansion of the elevated cut-off strategy over a longer period of the mine life

Project No.: 252233
6 February 2023

Summary
Page 1-26

wood.

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

- Quebrada Honda TSF:
  - Revisit and revise TSF designs to be in full compliance with the recently-published global tailings standard
- Future tailings and waste management:
  - Review the most appropriate storage mechanisms and alternatives for these materials for the LOM after approximately the end of 2036 and devise the most appropriate designs given storage requirements and site conditions
- Permitting
  - Determine what surface rights will need to be obtained in support of the preferred tailings and waste rock storage plan and the path needed to secure these rights and conclude the necessary agreements with current surface rights holders
  - Determine the permitting path, and numbers and types of permits and authorizations required to construct and operate the selected tailings and waste rock storage facility
  - Confirm if any additional baseline studies will be required in support of permit applications for the preferred tailings and waste rock storage facility.

Project No.: 252233
6 February 2023

Summary
Page 1-27

wood.

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

## 2.0 INTRODUCTION

### 2.1 Registrant

This technical report summary (the Report) was prepared for Southern Copper Corporation (Southern Copper) by Wood Group USA, Inc. (Wood, acting as the QP Firm) on the Cuajone Operations (the Project), located in the District of Torata, Province of Mariscal Nieto within the Moquegua Region, Peru (Figure 2-1).

The Cuajone Operations contain the Cuajone deposit.

### 2.2 Terms of Reference

#### 2.2.1 Report Purpose

The Report was prepared to be attached as an exhibit to support mineral property disclosure, including mineral resource and mineral reserve estimates, for the Cuajone Operations in Southern Copper’s Form 10-K for the year ending December 31, 2022.

#### 2.2.2 Terms of Reference

Unless otherwise indicated, all financial values are reported in United States (US) currency (US$) including all operating costs, capital costs, cash flows, taxes, revenues, expenses, and overhead distributions.

Unless otherwise indicated, the metric system is used in this Report.

Mineral resources and mineral reserves are reported using the definitions in Regulation S-K 1300 (S-K 1300), under Item 1300.

The Report uses US English.

Project No.: 252233  
6 February 2023

Introduction  
Page 2-1

**wood.**

Southern Copper

Grupo México

MINERÍA

Southern Copper Corporation

Technical Report Summary on Cuajone Operations

Peru

Figure 2-1: Project Location Plan

![img-0.jpeg](img-0.jpeg)

(Source: Wood, 2022). Note: Red lines are roads, crossed lines are railways, and project infrastructure locations are shown in pink.

Project No.: 252233

6 February 2023

Introduction

Page 2-2

wood.

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

## **2.3 Qualified Persons**

Wood is using the allowance for a third-party firm consisting of mining experts to date and sign the Report.

Wood had appropriate individual Qualified Persons (QPs) prepare the content that is summarized in this Report.

A portion of the information was provided by Southern Copper as the registrant as set forth in Chapter 25. Wood QPs have relied on the registrant for the information specified in Chapter 25.

## **2.4 Site Visits and Scope of Personal Inspection**

Wood QPs and technical staff visited the Project site. The scope of inspection by each discipline area is summarized in Table 2-1.

## **2.5 Report Date**

Information in the Report is current as at December 31, 2022.

## **2.6 Information Sources**

The reports and documents listed in Chapter 24 and Chapter 25 of this Report were used to support Report preparation.

## **2.7 Previous Technical Report Summaries**

This Report updates a previously filed technical report summary on the Project:

- Cuajone Operations, Peru, Technical Report Summary, current as at December 31, 2021, prepared by Wood Group USA, Inc.

Project No.: 252233  
6 February 2023

Introduction  
Page 2-3

**wood.**

**Southern Copper**  
 ![Grupo México logo]() **Grupo México**  
 MINERIA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

**Table 2-1: Scope of Personal Inspection by Wood**

| Discipline Area | Site Visit Date | Scope of Personal Inspection |
| --- | --- | --- |
| Geology/mineral resources | 23-25 September, 2021 | Presentation on the geology of the area by Southern Copper geologists Review of QA/QC procedures with Southern Copper personnel Visit to the core shed; inspection of reject and pulp storage area Pit inspection, observed blast hole sampling Inspected the on-site mine laboratory and observed sample preparation and analysis of blast hole samples. |
| Infrastructure | 25-26 September, 2021 | Inspected selected surface infrastructure, including workshops, pit, accesses, railway, belt surface conveyor (overland), water tanks, fuel storage Inspected infrastructure used for supply of fresh water, including canals, pipelines, dams, and storage ponds Visited the accommodations complex at Villa Cuajone and Villa Botiflaca; sighted hospital, schools, administrative offices, water tanks, sewage treatment plants Visited Cuajone concentrator, inspected warehouses, workshops, fuel tanks, water, rail, tailings management and reclaim water storage. |
|  | 1 October, 2021 | Visited Quebrada Honda TSF. Also visited the refinery facilities, Tablones port terminal, Simón railway yard, foundry, offices and camps, dock, warehouses and workshops in the Puerto area. |
| Mining engineering | 6-7 December, 2021 | Inspected the open pit; visited the primary sulfide crusher; viewed waste rock storage facilities and potential sites for additional waste rock storage; visited the mine site offices and discussed mine operations with Southern Copper staff and reviewed proposed LOM plans. |
|  | 19-21 September, 2022 | Discussions with Southern Copper staff on aspects of mining Visited and inspected the open pit, primary crusher, stockpiles and Cuajone concentrator Visited the Viña Blanca water reservoir. |
| Processing | 6-8 December, 2021 | Inspected the Cuajone concentrator and the heap leach facilities. |

Project No.: 252233  
 6 February 2023

Introduction  
 Page 2-4

**wood.**

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

## **3.0 PROPERTY DESCRIPTION**

### **3.1 Property Location**

The Cuajone Operations are located in the Torata District, Mariscal Nieto Region, of Moquegua, approximately 878 km from the city of Lima and 27 km from the city of Moquegua.

The Project centroid is at about 17° 3.130'S latitude; 70° 44.499'W longitude.

The open pit is centered at approximately 17° 2.601'S latitude; 70° 42.481'W longitude.

The smelter and refinery are located at about 17° 29.924'S latitude; 71° 21.608'W longitude and 17° 34.728'S latitude; 71° 21.188'W longitude respectively.

The tailings storage facility (TSF) at Quebrada Honda is located at approximately 17° 27.724'S latitude; 70° 47.810'W longitude.

### **3.2 Property and Title in Peru**

Wood has not independently verified the following information which is in the public domain and have sourced the data from Elias (2019), Ernst and Young (2017), and KPMG (2016) as well as from official Peruvian Government websites.

#### **3.2.1 Regulatory Oversight**

The right to explore, extract, process and/or produce minerals in Peru is primarily regulated by mining laws and regulations enacted by Peruvian Congress and the executive branch of government, under the 1992 Mining Law. The law regulates nine different mining activities: reconnaissance; prospecting; exploration; exploitation (mining); general labor; beneficiation; commercialization; mineral transport; and mineral storage outside a mining facility.

The Ministry of Energy and Mines (MINEM) is the authority that regulates mining activities. MINEM also grants mining concessions to local or foreign individuals or legal entities, through a specialized body called The Institute of Geology, Mining and Metallurgy (INGEMMET).

Other relevant regulatory authorities include the Ministry of Environment (MINAM), the National Environmental Certification Authority (SENACE), the Supervisory Agency for Investment in Energy and Mining (OSINERGMIN), the Ministry for Agriculture, and the Ministry for Culture. The Environmental Evaluation and Oversight Agency (OEFA) monitors environmental compliance.

Project No.: 252233  
6 February 2023

Property Description  
Page 3-1

**wood.**

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

### 3.2.2 Mineral Tenure

Mining concessions can be granted separately for metallic and non-metallic minerals. Concessions can range in size from a minimum of 100 ha to a maximum of 1,000 ha.

A granted mining concession will remain valid providing the concession owner:

- Pays annual concession taxes or validity fees (derecho de vigencia), currently US$3/ha, by June each year. Failure to pay the applicable license fees for two consecutive years will result in the cancellation of the mining concession.
- Meets minimum expenditure commitments or production levels. The minima are divided into two classes:
  - Achieve "Minimum Annual Production" by the first semester of Year 11 counted from the year after the concession was granted, or pay a penalty for non-production on a sliding scale, as defined by Legislative Decree N° 1320 which became effective on 1 January, 2019. "Minimum Annual Production" is defined as one tax unit (UIT) per hectare per year, which is which is S/4,400 in 2021 (about US$1,220)
  - Alternatively, no penalty is payable if a "Minimum Annual Investment" is made of at least 10 times the amount of the penalty.

The penalty structure sets out that if a concession holder cannot reach the minimum annual production on the first semester of the 11th year from the year in which the concessions were granted, the concession holder will be required to pay a penalty equivalent to 2% of the applicable minimum production per year per hectare until the 15th year. If the concession holder cannot reach the minimum annual production on the first semester of the 16th year from the year in which the concessions were granted, the concession holder will be required to pay a penalty equivalent to 5% of the applicable minimum production per year per hectare until the 20th year. If the holder cannot reach the minimum annual production on the first semester of the 20th year from the year in which the concessions were granted, the holder will be required to pay a penalty equivalent to 10% of the applicable minimum production per year per hectare until the 30th year. Finally, if the holder cannot reach the minimum annual production during this period, the mining concessions will be automatically expired.

Title-holders of mining concessions that were granted before December 2008 were obliged to pay the penalty from 2019 if the title-holder did not reach either the Minimum Annual Production or make the Minimum Annual Investment in 2018.

Mining concessions will lapse automatically if any of the following events take place:

Project No.: 252233
6 February 2023

Property Description
Page 3-2

wood.

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

- The annual fee (derecho de vigencia) is not paid for two consecutive years.
- The applicable penalty is not paid for two consecutive years.
- The Minimum Annual Production Target or Minimum Annual Investment is not met within 30 years following the year after the concession was granted.

Beneficiation concessions follow the same rules as for mining concessions. A fee must be paid that reflects the nominal capacity of the processing plant or level of production. Failure to pay such processing fees or fines for two consecutive years would result in the loss of the beneficiation concession.

### 3.2.3 Surface Rights

Mining companies must negotiate agreements with surface landholders or establish easements. Where surface rights are held by communities, such easements must be approved by a qualified majority of at least two thirds of registered community members. In the case of surface lands owned by communities included in the indigenous community database maintained by the Ministry of Culture, it is necessary to go through a prior consultation process before administrative acts, such as the granting of environmental permits, are finalized. For the purchase of surface lands owned by the government, an acquisition process with the Peruvian state must be followed through the Superintendence of National Properties.

Expropriation procedures have been considered for cases in which landowners are reluctant to allow mining companies to have access to a mineral deposit and the government has determined that the project is in the national interest. Once a decision has been made by the Government, the administrative decision can only be judicially appealed by the original landowner as to the amount of compensation to be paid.

### 3.2.4 Water Rights

Water rights are governed by Law 29338, the Law on Water Resources, and are administered by the National Water Authority (ANA) which is part of the Ministry of Agriculture. There are three types of water rights:

- *License*: this right is granted in order to use the water for a specific purpose in a specific place. The license is valid until the activity for which it was granted terminates, for example, a beneficiary concession.
- *Permission*: this temporary right is granted during periods of surplus water availability

Project No.: 252233
6 February 2023

Property Description
Page 3-3

wood.

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

- Authorization: this right is granted for a specified quantity of water and for a specific purpose. The grant period is two years, which may be extended for an additional year, for example for drilling.

In order to maintain valid water rights valid, the grantee must:

- Make all required payments including water tariffs
- Abide by the conditions of the water right in that water is only used for the purpose granted.

Water rights cannot be transferred or mortgaged. However, in the case of the change of the title holder of a mining concession or the owner of the surface land who is also the beneficiary of a water right, the new title holder or owner can obtain the corresponding water right.

### 3.2.5 Environmental Considerations

MINAM is the environmental authority, although the administrative authority is the Directorate of Environmental Affairs (DGAAM) of MINEM. The environmental regulations for mineral exploration activities were defined by Supreme Decree No. 020-2008-EM of 2008. New regulations for exploration were defined in 2017 by Supreme Decree No. 042-2017-EM.

An Environmental Technical Report (Ficha Técnica Ambiental or FTA) is a study prepared for approval of exploration activities with non-significative environmental impacts and less than 20 drilling platforms. The environmental authority has 10 working days to make observations.

An Environmental Impact Declaration (Declaración de Impacto Ambiental or DIA) must be presented for Category I exploration activities which have a maximum of 40 drilling platforms or disturbance of surface areas of up to 10 ha. The environmental authority has 45 working days to make observations.

A semi-detailed Environmental Impact Study (Estudio de Impacto Ambiental Semi-Detallado or EIAsd) is required for Category II exploration programs which have between 40-700 drilling platforms or a surface disturbance of more than 10 ha. The environmental authority has 96 working days to make observations. The total process including preparation of the study by a registered environmental consulting company can take 6-8 months.

A full detailed Environmental Impact Study (Estudio de Impacto Ambiental Detallado or EIAd) must be presented for mine construction. The preparation and authorization of such a study can take as long as two years.

Project No.: 252233
6 February 2023

Property Description
Page 3-4

wood.

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

### 3.2.6 Permits

In order to start mineral exploration activities, a company is required to comply with the following requirements and obtain a resolution of approval from MINEM, as defined by Supreme Decree No. 020-2012-EM of 6 June 2012:

- • Resolution of approval of the Environmental Impact Declaration
- • Work program
- • A statement from the concession holder indicating that it is owner of the surface land, or if not, that it has authorization from the owners of the surface land to perform exploration activities
- • Water License, Permission or Authorization to use water
- • Mining concession titles
- • A certificate of non-existence of archeological remains (CIRA) whereby the Ministry of Culture certifies that there are no monuments or remains within a project area. However, even with a CIRA, exploration companies can only undertake earth movement under the direct supervision of an onsite archeologist.

### 3.2.7 Royalties

In 2011, the Peruvian Congress approved an amendment to the mining royalty charge. The mining royalty charge is based on operating income margins with graduated rates ranging from 1-12% of operating profits; the minimum royalty charge is equivalent to 1% of net sales. If the operating income margin is 10% or less, the royalty charge is 1% and for each 5% increment in the operating income margin, the royalty charge rate increases by 0.75%, to a maximum of 12%.

At the same time the Peruvian Congress enacted a Special Mining Tax that is also based on operating income. Rates range from 2-8.4%. If the operating income margin is 10% or less, the Special Mining Tax is 2%, and for each 5% increment in the operating income margin, the special mining rate increases by 0.4%, to a maximum of 8.4%.

### 3.2.8 Other Considerations

Producing mining companies must submit, and receive approval for, an environmental impact study that includes a social relations plan, certification that there are no archaeological remains in the area, and a draft mine closure plan. Closure plans must be accompanied by payment of a monetary guarantee.

Project No.: 252233  
6 February 2023

Property Description  
Page 3-5

**wood.**

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

In April 2012, Peru's Government approved the Consulta Previa Law (prior consultation) and its regulations approved by Supreme Decree N° 001-2012-MC. This requires prior consultation with any indigenous communities as determined by the Ministry of Culture, before any infrastructure or projects, in particular mining and energy projects, are developed in their areas.

Mining companies also have to separately obtain water rights from the National Water Authority and surface lands rights from individual landowners.

### **3.2.9 Fraser Institute Survey**

Wood used the Investment Attractiveness Index from the 2021 Fraser Institute Annual Survey of Mining Companies report (the Fraser Institute survey) as a credible source for the assessment of the overall political risk facing an exploration or mining project in Peru. The Fraser Institute annual survey is an attempt to assess how mineral endowments and public policy factors such as taxation and regulatory uncertainty affect exploration investment.

Wood used the Fraser Institute survey because it is globally regarded as an independent report-card style assessment to governments on how attractive their policies are from the point of view of an exploration manager or mining company senior management, and forms a proxy for the assessment by the mining industry of the political risk in Peru.

In 2021, the rankings were from the most attractive (1) to the least attractive (84) jurisdiction, of the 84 jurisdictions included in the survey. Peru ranked 42 out of 84 jurisdictions in the attractiveness index survey in 2021; 69 out of 84 in the policy perception index; and 24 out of 84 in the best practices mineral potential index.

### **3.3 Ownership**

The Project is wholly owned by Southern Copper Corporation, Sucursal del Perú, which is a majority-owned, indirect subsidiary of Grupo Mexico S.A.B de CV. (Grupo Mexico). An ownership organogram is provided in Figure 3-1.

Project No.: 252233  
6 February 2023

Property Description  
Page 3-6

**wood.**

**Southern Copper**  
 **Grupo México**  
 MINERÍA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

**Figure 3-1: Ownership Organogram**

![img-0.jpeg](img-0.jpeg)

(Source: Southern Copper, 2020)

### 3.4 Mineral Title

The Cuajone mine is located within the mining concession Acumulación Cuajone, which is registered as the mining concession Acumulación Cuajone, No. 010000512L, and registered in the Mining Rights Book of the Real Estate Property Registry of the Zona No. 11294175 of the Mining Rights Book of the Real Estate Property Registry of Zone XXI, Arequipa. Registry Zone N° XXI, Arequipa Branch of the National Superintendence of Public Registries (SUNARP). That registration was completed on 16 July 2021.

Acumulación Cuajone incorporates approximately 15,024.5 ha. Figure 3-2 shows the location of Acumulación Cuajone. Table 3-1 provides the locations of the vertices of points on the perimeter of Acumulación Cuajone.

Mining concessions in Peru are laid out using a grid system delimited by Igemmet.

The annual holding fee is US$3.00/ha.

Project No.: 252233  
 6 February 2023

Property Description  
 Page 3-7

**wood.**

SouthernCopper

GrupoMéxico

MINERÍA

Southern Copper Corporation

Technical Report Summary on Cuajone Operations

Peru

Figure 3-2: Mineral Tenure Location Plan

![img-1.jpeg](img-1.jpeg)

(Source: Wood, 2021)

Project No.: 252233

6 February 2023

Property Description

Page 3-8

wood.

**Southern Copper**  
 **Grupo México**  
 MINERÍA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

**Table 3-1: Acumulación Cuajone Vertex Locations**

| Vertex | Coordinates UTM WGS84 18S |  | Vertex | Coordinates UTM WGS84 18S |  |
| --- | --- | --- | --- | --- | --- |
|  | East (m) | North (m) |  | East (m) | North (m) |
| 1 | 323,813.74 | 8,119,623.45 | 22 | 323,813.79 | 8,108,623.51 |
| 2 | 323,813.75 | 8,118,623.45 | 23 | 321,813.81 | 8,108,623.51 |
| 3 | 323,022.60 | 8,118,623.45 | 24 | 321,813.82 | 8,107,623.52 |
| 4 | 322,813.76 | 8,118,623.45 | 25 | 319,813.84 | 8,107,623.52 |
| 5 | 322,813.76 | 8,118,359.48 | 26 | 319,813.84 | 8,107,520.28 |
| 6 | 322,813.76 | 8,117,623.46 | 27 | 319,366.79 | 8,107,561.96 |
| 7 | 323,813.75 | 8,117,623.46 | 28 | 319,372.52 | 8,107,623.52 |
| 8 | 323,813.76 | 8,115,623.47 | 29 | 314,813.89 | 8,107,623.52 |
| 9 | 322,813.77 | 8,115,623.47 | 30 | 314,813.87 | 8,110,333.86 |
| 10 | 322,813.78 | 8,114,623.48 | 31 | 314,292.77 | 8,110,218.81 |
| 11 | 323,813.77 | 8,114,623.48 | 32 | 314,590.77 | 8,110,187.06 |
| 12 | 323,813.77 | 8,113,623.48 | 33 | 314,378.83 | 8,108,198.35 |
| 13 | 325,813.75 | 8,113,623.48 | 34 | 307,915.49 | 8,108,887.17 |
| 14 | 325,813.76 | 8,112,623.49 | 35 | 308,519.52 | 8,114,555.04 |
| 15 | 327,813.74 | 8,112,623.49 | 36 | 310,813.90 | 8,114,310.51 |
| 16 | 327,813.74 | 8,111,623.50 | 37 | 310,813.88 | 8,116,623.47 |
| 17 | 328,813.73 | 8,111,623.50 | 38 | 314,813.85 | 8,116,623.47 |
| 18 | 328,813.73 | 8,110,623.50 | 39 | 314,813.84 | 8,117,623.46 |
| 19 | 325813.76 | 8110623.50 | 40 | 319813.79 | 8117,623.46 |
| 20 | 325813.76 | 8111623.49 | 41 | 319813.78 | 8119,623.45 |
| 21 | 323813.78 | 8111623.49 | 42 | 323813.74 | 8119,623.45 |

There are two approved beneficiation concessions:

- Cuajone solvent extraction (SX) leach plant.

The Concentradora Botiflaca beneficiation concession was approved on August 14, 1981, by Resolución Directoral No.150-81- EM/DCM, and covered an area of 56 ha. On July 20, 1999, General Director of Mining authorized the operation of the process plant, at a capacity of 87,000 t/d, under report No.266-99-EM-DGM/DPDM. An expansion approval to 90,000 t/d was granted on October 7, 2010, under Resolution N° 379-2010-MEM-DGM/V. Later that year,

Project No.: 252233  
 6 February 2023

Property Description  
 Page 3-9

**wood.**

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

Southern Copper requested that three additional installations be approved, in support of optimization of the crushing process; approval was provided in Directorial Resolution N° 153-2012-MEMDGM-V.

The Cuajone SX leach plant concession (Planta de Lixiviación SX Cuajone) has a 400 ha area, and was granted on May 6, 1996, under Directorial Resolution No.155-96- EM-DGM. The plant capacity approved was 2,100 t/d. An approved plant capacity expansion to 3,100 t/d was approved under Resolution N°988-2009-MEMDGM/V on December 16, 2009.

### **3.5 Surface Rights**

Southern Copper acquired land from private owners in support of the operations. In other areas, surface rights were granted by the Peruvian State in accordance with the law, either by the granting of old mining concessions or by the granting of surface rights (DUTES) for exclusive use.

Most of the surface rights are those granted by the Peruvian State because the operations are situated on uncultivated land owned by the State. Water easements, power lines, tunnels, industrial railroad line and tailings canal are authorized by the Peruvian State, as they are cross uncultivated land that is owned by the State. These surface rights will remain as long as the mining concession remains in force.

Southern Copper holds a “right of free use” on the uncultivated lands in the mining concessions and Quebrada Honda TSF areas. These surface rights will remain current as long as the mining concession remains in force.

There are granted easements covering the TSF and related facilities, the TSF pipelines, and water pipelines from the Suches lagoon to the Cuajone Operations (see also discussion in Chapter 15.10).

Additional surface rights will be required to allow construction and operation of a co-stack (dry-stack) facility that is assumed to be used once the Quebrada Honda TSF capacity is reached in approximately the end of 2036 (refer to Chapter 18.2). There is sufficient time for Southern Copper to obtain the required surface rights and negotiate agreements prior to that date. A provision for these costs has been included in the cashflow analysis in Chapter 19.

### **3.6 Water Rights**

Southern Copper has both groundwater and surface water usage licenses, for a total extraction rate of 1,950 L/s. The rights are summarized in Table 3-2.

Project No.: 252233  
6 February 2023

Property Description  
Page 3-10

**wood.**

**Southern Copper**  
 ![Grupo México logo]() **Grupo México**  
 MINERIA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

**Table 3-2: Water Rights**

| Area | Document Number | Water Right | Date |
| --- | --- | --- | --- |
| Surface water | R.S. N° 534-72-AG | License in process of adaptation of 150 L/s of the waters of the Ticalaya and Quebrada Honda | June 15, 1972 |
|  | R.M. N° 00405-77-AG/DGA | License in the process of adapting the use of 60 L/s of the waters of the Cinto-Quebrada Honda river | April 12, 1977 |
|  | R.D. N° 053-88-AG-DGA | Modification of the R.S. N° 535-72-AG reducing the flow to 300 L/s | April 10, 1988 |
|  | R.D. N° 271-2010-ANA/AAA I C-O | Regularization of the License for the use of surface water, reallocating volumes of the R.M. N° 405-77-AG/DGA | December 31, 2010 |
| Groundwater | R.M. 00899-79-AA-AGAS | License to use a mass of 15,736,464 m3 of groundwater through tubular wells drilled in the “Vizcachas” and “Titijones” hydrographic basins | July 09, 1979 |
|  | R.D. N° 0062-83-AG-DGASI | License to use an annual mass of up to 13,268,966 m3 of groundwater extracted through four tube wells from the “Huaitire” basin | June 15, 1983 |
|  | R.A. N°169-95-DISRAGT-ATDRLIS | License to use groundwater in the Vizcachas basin of up to 360 L/s | July 12, 1995 |
|  | R.A. N° 002-94-DISRAG/ATDRL-S | License for the use of an annual mass of 5,991,840 m3 of groundwater captured from tubular wells TP-11 and TP-12 drilled in the “Huaitire-Gentilar” hydrographic basin | 1994 |
|  | R.A. N° 020-2003-ATDR.M/DRA.MDO | Adequacy of the water use license granted to in the R.M. N° 00899-79-AA/DGAS and R.A. N° 002-94-DISRAG/ATDRL-S up to 9,744,624 m3 | April 1, 2003 |
|  | R.A. N° 034-2005-DRA.T/GR.TAC-ATDRL/S | Groundwater use license with a flow of 162.2 L/s equivalent to an annual mass of 5,115,139 m3 captured by two tubular wells TP-14 and TP-15 located in the Huaitire-Gentilar basin | January 28, 2005 |

Project No.: 252233  
 6 February 2023

Property Description  
 Page 3-11

**wood.**

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

### **3.7 Royalties**

Apart from the mining royalties (see Chapter 3.2.7) there are no other royalty agreements pertinent to the Project.

### **3.8 Encumbrances**

There are currently no encumbrances such as liens, streaming agreements etc. that could affect the LOM plan.

### **3.9 Permitting**

Permitting and permitting conditions are discussed in Chapter 17.5 of this Report.

### **3.10 Violations and Fines**

There are no current material violations or fines, as imposed in the mining regulatory context of the Mine Safety and Health Administration (MSHA) in the United States, that apply to the Cuajone Operations.

### **3.11 Significant Factors and Risks That May Affect Access, Title or Work Programs**

To the extent known to Wood, there are no other significant factors and risks that may affect access, title, or the right or ability to perform work on the Project that are not discussed in this Report.

Project No.: 252233  
6 February 2023

Property Description  
Page 3-12

**wood.**

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

## 4.0 ACCESSIBILITY, CLIMATE, LOCAL RESOURCES, INFRASTRUCTURE AND PHYSIOGRAPHY

### 4.1 Physiography

The Project area ranges in elevation from 2,700-3,800 masl, with the mine situated in an area of very steep terrain. Mine facilities and the pit rim are at about 3,500 masl.

The general direction of water runoff from the area is from the northeast to the southwest. Streams have a dendritic drainage pattern and are typically ephemeral.

Vegetation types vary, depending on terrain elevation and proximity to watercourses. Vegetation commonly consists of scrub and grasslands. Dryer areas are characterized by cacti species. In desert areas, if there is vegetation, it consists of thorny plants and shrubs.

Crops are cultivated along the banks of the watercourses and on flatter land. Hill slopes are used extensively for grazing of goats.

Using classifications developed by the Peruvian-Japanese Center for Seismic Research and Disaster Mitigation (Cismid), the Project area straddles two seismic zones (JCI, 2020):

- *Destructive (VIII intensity)*: slight damage to specialized structures; considerable damage to well-built ordinary structures, with possible collapse; heavy damage to poorly-built structures; seriously damaged or destroyed masonry, and furniture completely moved out of place.
- *Very destructive (IX intensity)*: considerable damage to specialized structures, walls out of plumb; extensive damage to major buildings, with partial building collapse; and buildings displaced off foundations.

### 4.2 Accessibility

The Cuajone mine is accessible by paved road from Lima or Tacna by the Pan-American Highway as follows:

- Lima to Moquegua: 1,140 km
- Moquegua to Cuajone: 42 km
- Tacna to Moquegua: 152 km.

Access within the Project area is via developed roads that are routinely maintained.

Project No.: 252233
6 February 2023

Accessibility, Climate, Local Resources, Infrastructure and Physiography
Page 4-1

wood.

**Southern Copper**  
![Southern Copper logo]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

Puerto de Ilo, the port site and location of the smelter and refinery, is 135 km from the Cuajone mine via paved road.

The Quebrada Honda TSF is about 120 km via local roads, south of the Cuajone Operations. It is accessed via the departmental road MO-107 from the town of Camiara, or via departmental roads MO-105 and MO-107.

Tacna, Moquegua, and Ilo have regularly scheduled air services from Lima.

### 4.3 Climate

Climate conditions vary with altitude, from moderately temperate at lower elevations to intensely cold at high elevations. Monthly temperature averages range from 9-11°C. Wind speeds range, on average, from 1.54-2.06 m/sec.

Average monthly precipitation varies from 0.05-85 mm; however, significantly more rain can fall when the El Niño phenomenon is in force. The dry season typically occurs from June-November, and the wet season generally is confined to the months of December-May.

Mining operations are conducted year-round. Exploration activities are conducted year-round, but may be temporarily curtailed by rare heavy rainfall events.

### 4.4 Infrastructure

Infrastructure that supports the current operations is in place (see also discussions in Chapter 13, Chapter 14, and Chapter 15 of this Report). These Report chapters also discuss water sources, electricity, personnel, and supplies for the LOM plan.

Southern Copper has water rights or licenses for as much as 1,950 liters per second from well fields at the Huaitire, Vizcachas and Titijones aquifers and surface water rights from Lake Suches and two small water sources, Quebrada Honda and Quebrada Tacalaya. Two desalination plants in Ilo produce water for industrial use and domestic consumption.

There is a power purchase agreement in place with the state company Electroperu S.A., for 120 MW, which has a 20-year term, starting in 2017. A second agreement is in place with a private power generator Kallpa Generacion S.A. (Kallpa), which has a 10-year duration, beginning in 2017. Southern Copper has 9 MW of power generation capacity from two small hydro-generating installations at the Cuajone Operations.

Personnel live in mine accommodation villages adjacent the operations.

Tacna is the main source of supplies and fuel.

Project No.: 252233  
6 February 2023

Accessibility, Climate, Local Resources, Infrastructure and Physiography  
Page 4-2

**wood.**

**Southern Copper**  
 **Grupo México**  
 MINERÍA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

## 5.0 HISTORY

The exploration and development history is outlined in Table 5-1.

**Table 5-1: Exploration and Development History**

| Date | Operator | Comment |
| --- | --- | --- |
| 19 th century |  | Brief references in the geographic literature about the existence of copper deposits located in the southwest of Peru and sporadic exploitation of copper on the southern slope of the Torata ravine, where thin layers of copper oxides and sulfides were exploited. |
| 1929 |  | After the border conflict between Peru and Chile was resolved, interest in the area renewed and the Cuajone area claimed by Julio E Gianella. |
| 1937 | Cerro de Pasco Corporation | The Cuajone prospect was considered by A.C. Schmedeman to be a potential porphyry copper deposit. He was exploring for the Cerro de Pasco Corporation. |
| 1942-1945 | Cerro de Pasco | Optioned claims. Drilled 40 holes (12,366 m) |
| 1951-1954 | Newmont/Asarco | SP and resistivity surveys completed; geochemical surveys completed Drilled 88 holes (30,115.6 m), 70 were churn drill holes and 18 were core holes. |
| 1954 | Southern Copper | Feasibility study completed; Southern Peru Copper Corporation formed by Asarco, Marmon Group Inc., Phelps Dodge Overseas Capital Corporation, and Newmont Mining Corporation. Southern Copper owned 88.5% of Cuajone and Billiton BV owned 11.5%. |
| 1956 |  | Preliminary geochemical surveys were completed over the volcanic rocks that covered the deposit. |
| 1965-1970 |  | 122 holes drilled (27,515.43 m) |
| 1969-1970 |  | After 18 months of negotiations, a bilateral agreement was signed with the revolutionary government of the Peruvian armed forces to construct the Cuajone Project. |
| 1970-1976 |  | Construction of mine and ancillary facilities |
| 1976 |  | Copper production began |
| 1980 |  | Core drilling to verify 1950s churn drill data, and to establish the contact between mineralized and post-mineralized cover to the south and southeast of the operations. Completed 26 holes (3,191.89 m) Molybdenum plant operational, generating molybdenum concentrates. |
| 1981 | Billiton B.V. | Sells its interest to Southern Copper |
| 1982-1988 | Southern Copper | 128 core holes (36,130.65 m) for exploration and geotechnical investigations (3 holes) |
| 1991-1994 |  | 24 core holes (4,636.33 m) for geotechnical and hydrogeological investigations. Casagrande piezometers were installed. |

Project No.: 252233  
 6 February 2023

History  
 Page 5-1

**wood.**

**Southern Copper**  
 ![Grupo México logo]() **Grupo México**  
 MINERIA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

| Date | Operator | Comment |
| --- | --- | --- |
| 1993 |  | Regional lithogeochemistry survey (267 points, 255 were in situ rock). Assayed for Cu, Mo, ag, and Au. Two small anomalies were identified. |
| 1993 |  | Induced polarization (IP) study over 1,600 ha |
| 1994 |  | Two geophysical anomalies on the north slope of the Torata River were core drilled to test the anomalies. |
| 1994-1997 |  | 274 holes (125,482.57 m) drilled for exploration, geotechnical, and hydrogeological purposes |
| 1995 | Newmont | Sells its shares to Southern Copper |
| 1997-1999 | Southern Copper | 116 holes (12,536 m) drilled for various purposes of which, 49 were RC (6,014.30 m) for metallurgical tests, inclinometers and evaluation of the tuff crystal. |
| 1998 |  | Cuajone concentrator was expanded to 87,100 t/d |
| 1999 | Grupo Mexico | Acquired the Asarco interest to become the major shareholder |
| 2000-2001 | Southern Copper | 114 core holes (40,902.35 m) to support the mine plan with some geotechnical and condemnation holes |
| 2002-2011 |  | 275 core holes (36,205.33 m) drilled for infill, metallurgist test, geotechnical and piezometers |
| 2007 |  | Incorporated a new mill at the concentrator |
| 2012-2013 |  | 297 core holes drilled (79,986.72 m) to support 15-year plan; principally infill and geotechnical drilling |
| 2013 |  | Installation of high-pressure grind rolls (HPGR) in the concentrator |
| 2014 |  | Integrated the mining division into Americas Mining Corporation for management purposes |
| 2014-2016 |  | 50 core holes (13,283.55 m) for infill and geotechnical purposes |
| 2017-2018 |  | 70 core holes (23,781 m) for infill and geotechnical purposes. Drilled 72 RC holes (3,850 m) to evaluate oxides |
| 2018 |  | Crusher upgrade at the mine and overland conveyor installed |
| 2019 |  | 28 core holes (10,134.05 m) for infill and geotechnical instrumentation installation |
| 2020 |  | 22 core holes (5,763.70 m) for infill and geotechnical instrumentation installation |
| 2021 |  | 37 core holes (12,685.05 m) for infill, metallurgist test and geotechnical |

Project No.: 252233  
 6 February 2023

History  
 Page 5-2

**wood.**

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

## 6.0 GEOLOGICAL SETTING, MINERALIZATION, AND DEPOSIT

### 6.1 Deposit Type and Mineralization

The Cuajone deposit is considered to be an example of a porphyry copper-molybdenum deposit.

Porphyry deposits range in age from Archean to Recent, although most are Jurassic or younger, and form in a variety of tectonic settings. Most copper-molybdenum deposits are associated with low-silica, relatively primitive dioritic to granodioritic plutons that fall on the more oxidized, magnetite-series spectrum.

Deposits commonly form irregular, oval, solid or “hollow” cylindrical and inverted cup shapes. Orebodies can occur separately, overlap each other, or be stacked on top of each other. They are characteristically zoned, with barren cores and crudely concentric metal zones that are surrounded by barren pyritic halos with/without peripheral veins, skarns, replacement manto zones and epithermal precious-metal deposits. At the scale of ore deposits, associated structures can result in a variety of mineralization styles, including veins, vein sets, stockworks, fractures, ‘crackled zones’ and breccia pipes.

Pyrite is typically the dominant sulfide mineral, in association with chalcopyrite, bornite, chalcocite, tennantite, enargite, other copper sulfides and sulfosalts, molybdenite and electrum.

### 6.2 Regional Geology

The Cuajone deposit is part of the Eocene porphyry copper belt of the main arc of the Peruvian Andes. The regional geology consists of the Upper Cretaceous/Lower Tertiary Toquepala Group, a sequence of basal volcanic flows and volcano-sedimentary rocks overlain by Miocene to Recent volcanic and volcano sedimentary rocks (Figure 6-1). Toquepala Group rocks are intruded by the late Cretaceous Yarabamba Super Unit of the Costal batholith, characterized by northwest-southeast elongated granodiorite to monzogranite bodies. The final stage of this magmatic event is defined by hypabyssal intrusions that host the lower Tertiary porphyry copper-molybdenum systems in southeastern Peru.

The top of the Toquepala Group is marked by an erosional unconformity. Above that unconformity are numerous post-mineral volcanic and sedimentary formations. Those formations form a cover above the deposit and are not altered or mineralized. Figure 6-2 shows geology in the general Project vicinity.

Project No.: 252233  
6 February 2023

Geological Setting, Mineralization, and Deposit  
Page 6-1

**wood.**

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

Figure 6-1: Regional Geology Map

![img-0.jpeg](img-0.jpeg)

(Source: Southern Copper, 2021). Note: Grid shown is South latitude and West longitude lines.

Project No.: 252233
6 February 2023

Geological Setting, Mineralization, and Deposit
Page 6-2

wood.

SouthernCopper

[Non-Text]

GrupoMéxico

MINERÍA

Southern Copper Corporation

Technical Report Summary on Cuajone Operations

Peru

Figure 6-2: Regional and Project Geology

![img-1.jpeg](img-1.jpeg)

LEGEND

| CENOZOIC | MIDCENE | Moquegua Formation | PN-mo_x | Polymictic conglomerates, coarse sandstones stratified, in the upper levels lithic tufts. |  |  |
| --- | --- | --- | --- | --- | --- | --- |
|  |  |  | PN-mo_y |  |  |  |
| PALEOCENE | PALEOCENE | Tinajones Member | KsP-tm | Yellowish-white porphyritic lava of rhyolitic composition. | Coastal Bathutith Varabamba Superund | Diorite |
|  |  | Yanto Member | KsP-yam | Pink-gray porphyritic lavas of rhyolitic composition. |  |  |
| CRETACEOUS | UPPER | Quellaveco Formation | Carpanto Member | KsP-yam | Doleritic Andesites. | KsP-yalgh |
|  |  | Asana Member | Asana Member | KsP-asm | Porphyritic lavas of rhyolitic composition. | KsP-yamz |
|  |  | Samanape Member | Samanape Member | KsP-sa/tb | Light gray porphyritic lavas. | KoZ-yo/mz |
|  |  | Paralaque Formation | Ks-pa/tb+th | Welded lithic tufts. |  |  |
|  |  | Inagoya Formation | Ks-pa/tb | Sandstones with intercalation of pyroclastic flows and gray-green conglomerates. |  |  |
| Huaracane Formation | Huaracane Formation | Ks-hu/cz+th | As-hu/cz+th | Andesite, Dacite, Agglomerates with nodacitic tufts. |  |  |
|  |  | Ks-hu/tb+cz+td | As-hu/tb+th |  |  |  |

(Source: Southern Copper, 2022)

Project No.: 252233

6 February 2023

Geological Setting, Mineralization, and Deposit

Page 6-3

wood.

**Southern Copper**  
![Southern Copper logo]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

## 6.3 Local Geology

### 6.3.1 Lithologies and Stratigraphy

The major sedimentary and intrusive rock types in the general Cuajone Operations area are summarized in Table 6-1 and Table 6-2, respectively. A summary of the breccia types in the deposit area is provided in Table 6-3. A stratigraphic column is provided in Figure 6-3.

### 6.3.2 Structure

The regional-scale Incapuquio fault system influenced the location of the Late Cretaceous-Early Paleogene magmatism of the Toquepala Group. The “Cuajone Alignment” (Manrique and Plazolles, 1975) follows the structural pattern defined by the Incapuquio fault system. The geometry of the porphyritic stocks, the magmatic-hydrothermal breccias, as well as the dykes are oriented and controlled by pre- and inter-mineral faults that were later sealed by magmatic and hydrothermal activity with a preferential orientation of N40-50° W. Post-mineral reactivations follow the same structural model with components orthogonal to the northeast and east-west, with generally steep dips.

### 6.3.3 Alteration

Alteration is primarily recognized in association with the Cuajone deposit and is described in Chapter 6.4.4.

## 6.4 Property Geology

### 6.4.1 Deposit Dimensions

The deposit is approximately 2,300 m long, 900 m wide, and averages 1,000 m in thickness. Mineralization has been drill tested to a depth of 2,255 m. The deposit remains open at depth.

Project No.: 252233  
6 February 2023

Geological Setting, Mineralization, and Deposit  
Page 6-4

**wood.**

**Southern Copper**  
 ![Grupo México logo]() **Grupo México**  
 MINERIA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

**Table 6-1: Sedimentary and Volcanic Lithology Table**

| Unit | Age | Comment |
| --- | --- | --- |
| - | Quaternary | Alluvial deposits in river beds and colluvial deposits on hill slopes. Moraines |
| Chuntacala Formation | Mid-Late Miocene | Pyroclastic flows and welded tuffs with volcanoclastic flow deposits and lahars. Pink to brown tuffs and agglomerates |
| Huaylillas Formation | Early Miocene | Post-mineral volcaniclastic succession with interspersed pyroclastic intervals. White, grey, and pink dacitic and rhyolitic tuffs |
| Moquegua Formation | Late Oligocene to early Miocene | Unconformably overlies the Toquepala Group. In mine area, consists of sandy to conglomeratic, continental sedimentary rocks; and also rhyolitic conglomerate-doleritic conglomerate |
| Toquepala Group | Cretaceous to lower Tertiary | Toquepala, Inogoya, Paralaque and Quellaveco Formations. Volcanic sequence of andesite, rhyolite and dacite flows |

**Table 6-2: Intrusive Lithology Table and Mineralization Description**

| Unit | Age (Ma) | Comment |
| --- | --- | --- |
| Dikes | - | Two compositions predominate: quartz-feldspathic granitoids and to a lesser extent hypabyssal andesite. Orientation of these dikes is controlled by a N46°W and east-west trend, with steep dips to the northeast and north respectively. Exhibit a spaced parallelism with lengths to 830 m and variable thicknesses to 6 m |
| Latite Porphyry 3 | 53 | Monzogranite to granodiorite stock and dikes with bipyramidal quartz phenocrystals without Cu-Mo mineralization. It is weakly altered with a predominance of sericite and to a lesser extent, clays; weakly disseminated pyrite and sporadic veinlets |
| Latite Porphyry 2 | 56 | Coarse-grained with hornblende phenocrysts and/or plagioclase to 1 cm and very low density of granular quartz veins. It is considered to be an intra-mineral intrusion. Weak to moderate argillic alteration and sericitization superimposed on earlier potassic alteration characterized by granular silica veins with K-feldspar halos |
| Latite Porphyry 1 | 55-51 | The stock is elongate northwest to southeast. Cu and Mo mineralization are related spatially and temporally to this stock. It is characterized by a medium to coarse grain porphyritic texture, phenocrysts of plagioclase, hornblende, biotite, and quartz, with moderate to high density of granular quartz veins. Sulfides are mainly disseminated and in quartz veins. The ratio pyrite to chalcopyrite varies depending on the location within the system |
| Granodiorite | 65-58 | This pluton extends to the west and northwest of the porphyritic stocks, cutting lava sequences of andesite and rhyolite (Toquepala Group) and is partially covered by pyroclastic deposits of the Huaylillas Formation. Hydrothermal granodiorite breccias developed in the Cuellar sector are weakly mineralized in intra-clastic cavities, showing weak to no rotation of clasts |
| Diorite | 66 | Crops out in an elongate north-south trend east of the current pit. Cuts most of the units of the Toquepala Group |

Project No.: 252233  
 6 February 2023

Geological Setting, Mineralization, and Deposit  
 Page 6-5

**wood.**

**Southern Copper**  
 **Grupo México**  
 MINERÍA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

**Table 6-3: Breccia Type Table**

| Breccia Type | Comment and Mineralization Description |
| --- | --- |
| Rupture breccia | Synonymous with “stockwork”, “shatter breccia”, “fracture breccia” and “crackle breccia” and is characterized by a multitude of randomly crisscrossing cracks, the same ones that, when crossing and joining each other, divide the original rock into angular fragments, caused by hydraulic fracturing. The most distinctive characteristic of the rupture breccia is that its individual fragments do not detach, displace, slide or rotate among themselves. |
| Hydrothermal breccia | Predominantly angular clasts, arranged chaotically in a matrix of strongly altered porphyritic latite and mineral sulfides |
| Magmatic-hydrothermal breccias | Ore Brecha, Ore Brecha Silicea, Brecha Silicea, Blind Brecha in LP2 and Brecha de Cubes. Form elongated sub-vertical chimneys with diameters that vary from 58 to 244 m. They are characterized by the rotation and/or transport of their angular to sub-rounded clasts in a matrix of granular quartz and sulfides. The breccia is typically inter-mineral and Cu-Mo mineralization is most common within the breccia itself. A molybdenite-bearing breccia is characterized by the fact that the upper part of the chimney has tabular fragments of latite porphyry 2, aligned parallel to the cupola, defining a “shingle breccia” with quartz-molybdenite cement. Its formation is attributed to exfoliation of the wall rock and its fall towards the interior of the magmatic chamber. Intra-clastic cavities contain calcite and ankerite druse due to the circulation of fluids with high calcium content and contain high-grade copper mineralization due to its intrinsic permeability. |
| Intrusive breccias | Associated with emplacement of quartz-feldspathic intrusive rocks (not hydrothermal). These are characterized by incorporated clasts of wall rocks as xenoliths. Clasts are angular to subrounded in a crystalline igneous matrix. These are not genetically related to a mineralizing process; however, they may be mineralized. |
| Phreatic breccias | Non-mineralized breccias, commonly <3 m wide |

## 6.4.2 Lithologies

A geology map is provided as Figure 6-4. Example lithological cross-sections through the deposit are included as Figure 6-5 and Figure 6-6.

The geology summary that follows is sourced from Portergeo (2021).

Mineralization and alteration at the Cuajone deposit is directly related to a multi-stage latite porphyry that intrudes basaltic andesites and the overlying 370 m of rhyolite porphyries of the Toquepala Group.

Project No.: 252233  
 6 February 2023

Geological Setting, Mineralization, and Deposit  
 Page 6-6

**wood.**

Southern Copper

[Non-Text]

Grupo México

MINERÍA

Southern Copper Corporation

Technical Report Summary on Cuajone Operations

Peru

Figure 6-3: Stratigraphic Column

| SERIES |  | DATE(Ma) | FORMATION | LITHOLOGY |  |  |
| --- | --- | --- | --- | --- | --- | --- |
| HOLOCENE |  | 0.01 | ALLUVIAL | AL | ALLUVIUM, COLLUVIUM, TALL |  |
| PLEISTOCENE | UPPER |  |  | 3rd EROSIVE PERIOD |  |  |
|  | MIDDLE | 1.60 |  |  |  |  |
|  | LOWER |  |  |  |  |  |
| PLIOCENE | UPPER | 3.30 |  |  |  |  |
|  | LOWER | 9.00-5.30 |  |  |  |  |
| MIOCENE | UPPER | 11.00 | CHUNTACALA FORMATION | TS | ANDESITE PORPHYRY |  |
|  |  |  |  | AS | UPPER AGGLOMERATE |  |
|  | MIDDLE |  |  | TS | UPPER TUFF |  |
|  |  |  |  | AI | LOWER AGGLOMERATE |  |
|  |  |  |  | TI | LOWER TUFF |  |
|  | LOWER | 16.20 |  | TC | CRYSTAL TUFF |  |
|  |  |  |  |  | 2nd EROSIVE PERIOD | BASAL AGGLOMERATE |
|  |  |  |  |  |  | TUFF |
|  |  | HUAYLILLAS FORMATION |  | AT | GRAY AGGLOMERATE |  |
| AG |  |  |  | CONGLOMERATE TRACHYTE TUFF TRACHYTE |  |  |
| OLIGOCENE |  | 23.00 |  | TY | TUFF |  |
|  |  |  |  | TR | RHYOLITIC CONGLOMERATE |  |
| EOCENE |  | 36.50 |  | 1st EROSIVE PERIOD |  |  |
| PALEOCENE |  | 53.00 | TOQUEPALA GROUP | QUELLAVECO VOLCANICS | TOQUEPALA DOLERITE |  |
| UPPER CRETACEOUS |  | 65.00 |  | PARALAQUE VOLCANICS | RP | RHYOLITE |
|  |  |  |  |  | BA | BASALT |
|  |  | 95.00 |  | BA | DI - RHYOLITIE LP - LATITE PORPHYRY BX - BRECCIA |  |

(Source: Southern Copper, 2021)

Project No.: 252233

6 February 2023

Geological Setting, Mineralization, and Deposit

Page 6-7

wood.

SouthernCopper

GrupoMéxico

MINERÍA

Southern Copper Corporation

Technical Report Summary on Cuajone Operations

Peru

Figure 6-4: Geology Map

![img-2.jpeg](img-2.jpeg)

(Source: Wood, 2022)

Project No.: 252233

6 February 2023

Geological Setting, Mineralization, and Deposit

Page 6-8

wood.

Southern Copper

Grupo México

MINERÍA

Southern Copper Corporation

Technical Report Summary on Cuajone Operations

Peru

Figure 6-5: Lithology Cross-section (R-R')

![img-3.jpeg](img-3.jpeg)

(Source: Wood, 2022)

Project No.: 252233

6 February 2023

Geological Setting, Mineralization, and Deposit

Page 6-9

wood.

Southern Copper

Grupo México

MINERÍA

Southern Copper Corporation

Technical Report Summary on Cuajone Operations

Peru

Figure 6-6: Lithology Cross-section (32-32')

![img-0.jpeg](img-0.jpeg)

(Source: Wood, 2022)

Project No.: 252233

6 February 2023

Geological Setting, Mineralization, and Deposit

Page 6-10

wood.

SouthernCopper

GrupoMéxico
MINERÍA

Southern Copper Corporation

Technical Report Summary on Cuajone Operations

Peru

The first, pre-mineral intrusive in the mine area, situated approximately 1-2 km to the west of the deposit, was a north-south-elongated, 0.7 x 0.35 km, grey to grey-green holocrystalline to equigranular, medium grained, porphyritic diorite stock. This was followed by emplacement of three latite porphyry stages, producing a 2.5 x 0.7 km, northwest-southeast-elongated intrusive body. The latite multiphase intrusion hosts the mineralization.

The first magmatic pulse of the latite porphyry was concentrated in the southeastern part of the multiple intrusive mass and was responsible for the introduction of the bulk of the hypogene copper and molybdenite mineralization in the Cuajone orebody and the associated intense alteration of both the latite and surrounding Toquepala Group andesites and rhyolites. The intrusion is a porphyry with phenocrysts of quartz to 4 mm in diameter and laths of feldspar in a cryptocrystalline matrix. Alteration takes the form of a potassic core, characterized by biotite-magnetite-K feldspar-silica, grading upwards and outwards to biotite-magnetite-silica, which passes laterally into an extensive outer envelope of chlorite-epidote-calcite-pyrite propylitic alteration which has a radial extent of 4 km from the center of the deposit. The intensity of this alteration has masked the boundary between the latite porphyry and the surrounding Toquepala Group lithologies.

The second intrusive phase formed two bodies, a larger, ovoid 850 x 550 m mass immediately to the northwest of the first pulse, while a smaller 300 x 200 m plug occurs within the outcrop of the first pulse. Both exposures have only weak associated alteration and very minor, low-level copper and molybdenum mineralization. Breccia bodies were developed along the intrusive contacts with the other latite pulses and country rocks. These breccias comprise heterolithic clasts that range from well-rounded to angular within a matrix of latite porphyry.

The third magmatic pulse covers a surface area of around 800 m in diameter immediately to the northwest of the main primary latite porphyry outcrop and has only weak associated alteration and no copper or molybdenum mineralization. It is porphyritic with quartz grains up to 2 cm across in a microcrystalline to cryptocrystalline matrix.

At a late stage in the emplacement of the latite porphyry complex, and during an initial erosive period, the interaction of downward-percolating meteoric waters with the rising hypogene hydrothermal fluids produced an intense phyllic silica-sericite-pyrite zone that was superimposed on the upper parts of the mineralized system associated with the first latite porphyry pulse to develop a higher grade zone of copper-molybdenum ore with grades of >0.4% Cu as chalcopyrite and molybdenite. This alteration and mineralization style is principally developed within the Latite Porphyry and the Toquepala Group rhyolites, and only to a minor degree in the underlying andesites.

Project No.: 252233

6 February 2023

Geological Setting, Mineralization, and Deposit

Page 6-11

wood.

**Southern Copper**
**Grupo México**
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

The Huaylillas Formation was deposited after the mineralizing event ended. It consists of conglomerate, tuff, vitrophyre, and trachyte, and is as thick as 230 m.

#### **6.4.3 Structure**

The regional structural trend is northwest-southeast. Those faults are shown in Figure 6-4.

#### **6.4.4 Alteration**

The Cuajone porphyry deposit exhibits a zoned alteration pattern that includes potassic, propylitic, sericitic and intermediate argillic hydrothermal alteration styles. The alteration halo extends for about 3-4 km diameter. An alteration map is provided in Figure 6-7. Example cross-sections showing the alteration are included as Figure 6-8 and Figure 6-9. The major alteration types are summarized in Table 6-4.

#### **6.4.5 Mineralization**

A mineralization map is provided as Figure 6-10. Example mineralization cross-sections are included as Figure 6-11 and Figure 6-12.

##### **6.4.5.1 Supergene Mineralization**

The 900 m wide hypogene ore zone was overlain by a secondary enrichment blanket that was about 20 m thick and averaged more than 0.75% Cu (PorterGeo, 2021).

The main chalcocite layer was overlain by 15-40 m of partially-oxidized upper zone averaging 0.60% Cu, where remnant chalcocite was apparent, but malachite and chrysocolla dominated. These were in turn overlain by a partially-preserved (maximum of 120 m thick) hematite-bearing leached cap that graded 0.01-0.12% Cu. Argillic alteration associated with the supergene ores included kaolinite, montmorillonite, illite and dickite.

##### **6.4.5.2 Hypogene Mineralization**

Hypogene mineralization is distributed as follows:

- Basaltic andesite: 51%
- Latite porphyry: 47%
- Toquepala Group rhyolite: 1%
- Mineralized breccias: 1%

Project No.: 252233
6 February 2023

Geological Setting, Mineralization, and Deposit
Page 6-12

**wood.**

SouthernCopper

[LOGO]

GrupoMéxico

MINERÍA

Southern Copper Corporation

Technical Report Summary on Cuajone Operations

Peru

The mineralogy is typically simple and consists of pyrite, chalcopyrite, and bornite, with sparse sphalerite, galena, and enargite. Hypogene mineralization represents >98% of the remaining mineralization within the Cuajone open pit.

Figure 6-7: Alteration Map

![img-1.jpeg](img-1.jpeg)

(Source: Wood, 2022)

Project No.: 252233

6 February 2023

Geological Setting, Mineralization, and Deposit

Page 6-13

wood.

Southern Copper

Grupo México

MINERÍA

Southern Copper Corporation

Technical Report Summary on Cuajone Operations

Peru

Figure 6-8: Alteration Section (R-R')

![img-2.jpeg](img-2.jpeg)

(Source: Wood, 2022)

Project No.: 252233

6 February 2023

Geological Setting, Mineralization, and Deposit

Page 6-14

wood.

Southern Copper

Grupo México

MINERÍA

Southern Copper Corporation

Technical Report Summary on Cuajone Operations

Peru

Figure 6-9: Alteration Section (32-32')

![img-3.jpeg](img-3.jpeg)

(Source: Wood, 2022)

Project No.: 252233

6 February 2023

Geological Setting, Mineralization, and Deposit

Page 6-15

wood.

SouthernCopper

[LOGO]

GrupoMéxico

MINERÍA

Southern Copper Corporation

Technical Report Summary on Cuajone Operations

Peru

Table 6-4: Alteration Assemblages

| Alteration Type | Description |
| --- | --- |
| Potassic | An alteration assemblage of secondary biotite, magnetite, chlorite and some anhydrite. Primarily associated with the basaltic andesite and latite porphyry units. |
| Phyllic | Largely a retrograde alteration consisting of quartz, white mica (sericite), and pyrite. Chlorite, illite and secondary biotite occur more rarely. Best developed in the latite porphyry stock. |
| Argillic | Alteration assemblage of kaolinite, montmorillonite, dickite, and illite. Argillic alteration is almost exclusive to the basaltic andesite and seems to be of both hypogene and supergene origin. |
| Propylitic | Occurs mostly on the margins of the mineralized body and covers a halo of approximately 4 km. The mineral assemblage epidote, calcite, pyrite, and chlorite. |
| Silicic | Intense silicification is found within the non-leached rhyolite in the south of the ore zone, silica alteration has almost totally obliterated the original texture/mineralogy. The central breccia zone is also highly silicified, as are certain areas within the latite porphyry. In addition to matrix silicification, multiple quartz-veining stages are found in this alteration type. |

Figure 6-10: Mineralization Map

![img-4.jpeg](img-4.jpeg)

(Source: Wood, 2022)

Project No.: 252233

6 February 2023

Geological Setting, Mineralization, and Deposit

Page 6-16

wood.

SouthernCopper

GrupoMéxico

MINERÍA

Southern Copper Corporation

Technical Report Summary on Cuajone Operations

Peru

Figure 6-11: Cross-section Showing Mineralization (R-R')

![img-5.jpeg](img-5.jpeg)

(Source: Wood, 2022)

Project No.: 252233

6 February 2023

Geological Setting, Mineralization, and Deposit

Page 6-17

wood.

Southern Copper

Grupo México

MINERÍA

Southern Copper Corporation

Technical Report Summary on Cuajone Operations

Peru

Figure 6-12: Cross-section Showing Mineralization (32-32')

![img-6.jpeg](img-6.jpeg)

(Source: Wood, 2022)

Project No.: 252233

6 February 2023

Geological Setting, Mineralization, and Deposit

Page 6-18

wood.

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

## **7.0 EXPLORATION**

### **7.1 Exploration**

#### **7.1.1 Grids and Surveys**

The topographic survey used for the present mineral resource estimate includes field surveys completed as of September 19, 2022 with a projection of mining advance to the end of December 2022.

Collar surveys are in the local Cuajone mine grid system; however, much of the information has been updated to UTM coordinates. The current block model is based on local mine grid coordinates. Future model updates are planned to use UTM coordinates.

The conversion from the mine grid to UTM was conducted in four phases, and completed in December, 2021. A cartographic LiDAR survey was completed using Leica ALS 70 HA equipment. In addition, coordinate transformation software for was developed. The final conversion has a rotation and translation of coordinates in the X and Y directions and an increase from 0 to 2 m in the Z direction due to the geoid model update.

Topographic survey data used to delimit topographic surfaces for mineral resource and mineral reserve estimates were acquired by the mine survey department using a differential GPS Trimble R8 Series 3 instrument.

#### **7.1.2 Geological Mapping**

A 1:100,000 scale geological map of the deposit area was prepared in 1968.

Pit mapping is conducted at 1:5,000 scale. Maps are used for ore control, geotechnical purposes, and updating the short-term mine models.

#### **7.1.3 Geochemistry**

A total of 267 rock chip samples were taken in 1993 and assayed for copper, molybdenum, silver, and gold. The results obtained indicated prospective anomalies in the northwest sector where the current open pit is located.

Project No.: 252233  
6 February 2023

Exploration  
Page 7-1

**wood.**

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

#### **7.1.4 Geophysics**

Between 1951 and 1952, self-potential and resistivity surveys were completed (Figure 7-1). The anomalous responses outside the pit area were drill-tested by Asarco and Newmont.

An induced polarization (IP) geophysical survey was completed in 1993 with the purpose of complementing existing information and delimiting mineralization in the northwest sector of the Cuajone pit (Figure 7-2).

The more intense anomalies coincided with the mineralized body that was explored by a 1987-1988 drilling campaign. Northwest of the Torata River, two small IP anomalies were drilled in 1994, but yielded very low copper values.

#### **7.1.5 Qualified Person’s Interpretation of the Exploration Information**

The mine has been operating since 1976, and all exploration data generated prior to mine start-up is long superseded by mining and drill data.

#### **7.1.6 Exploration Potential**

The deepest drill hole testing the Cuajone deposit at 2,380 m and encountered low-grade copper mineralization. The deposit remains open at depth.

### **7.2 Drilling**

#### **7.2.1 Overview**

Drilling totals 1,600 core, churn and reverse circulation (RC) drill holes (446,593 m) and is summarized in Table 7-1. Drilling that supports mineral resource estimation consists of 870 core, churn and RC drill holes, (301,037 m). Drilling used in the mineral resource estimate is provided in Table 7-2. Drill collar locations are shown on a Project-basis in Figure 7-3 and the collars of those drill holes used in mineral resource estimation are shown in Figure 7-4.

Churn drill data were validated by twinning with core holes. RC holes were used for infill drilling within the pit.

Project No.: 252233  
6 February 2023

Exploration  
Page 7-2

**wood.**

Southern Copper

Grupo México

MINERÍA

Southern Copper Corporation

Technical Report Summary on Cuajone Operations

Peru

Figure 7-1: Self Potential and Resistivity Summary Map (% sulfide)

![img-0.jpeg](img-0.jpeg)

(Source: Southern Copper, 2021). Note: North is to top of map.

Project No.: 252233

6 February 2023

Exploration

Page 7-3

wood.

Southern Copper

Grupo México

MINERÍA

Southern Copper Corporation

Technical Report Summary on Cuajone Operations

Peru

Figure 7-2: Induced Polarization: Chargeability

![img-1.jpeg](img-1.jpeg)

(Source: Southern Copper, 2021). Note: North is to top of map, grid is 1,000 m.

Project No.: 252233

6 February 2023

Exploration

Page 7-4

wood.

**Southern Copper**  
 **Grupo México**  
 MINERÍA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

**Table 7-1: Project Drill Summary Table**

| Year | Operator | No. of Drill Holes |  |  | Drilled Length (m) |  |  | Total Drill Holes | Total Drilled Length (m) |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  |  | Churn | Core | RC | Churn | Core | RC |  |  |
| 1942 | Cerro De Pasco | - | 40 | - | - | 12,366 | - | 40 | 12,366 |
| 1952 | Newmont and Asarco | 70 | 18 | - | 26,545 | 3,570 | - | 88 | 30,116 |
| 1965 | Southern Copper | - | 121 | - | - | 27,067 | - | 121 | 27,067 |
| 1980 |  | - | 43 | - | - | 11,592 | - | 43 | 11,592 |
| 1982 |  | - | 127 | - | - | 36,086 | - | 127 | 36,086 |
| 1991 |  | - | 24 | - | - | 4,636 | - | 24 | 4,636 |
| 1994 |  | - | 215 | 43 | - | 112,032 | 10,928 | 258 | 122,961 |
| 1998 |  | - | 60 | 48 | - | 5,678 | 5,815 | 108 | 11,494 |
| 2000 |  | - | 90 | - | - | 36,146 | - | 90 | 36,146 |
| 2002 |  | - | 7 | - | - | 1,561 | - | 7 | 1,561 |
| 2003 |  | - | 14 | - | - | 1,365 | - | 14 | 1,365 |
| 2004 |  | - | 29 | - | - | 2,089 | - | 29 | 2,089 |
| 2005 |  | - | 25 | - | - | 3,336 | - | 25 | 3,336 |
| 2006 |  | - | 46 | - | - | 4,673 | - | 46 | 4,673 |
| 2007 |  | - | 33 | - | - | 4,239 | - | 33 | 4,239 |
| 2008 |  | - | 20 | - | - | 3,295 | - | 20 | 3,295 |
| 2009 |  | - | 22 | - | - | 3,769 | - | 22 | 3,769 |
| 2010 |  | - | 37 | - | - | 4,503 | - | 37 | 4,503 |
| 2011 |  | - | 201 | - | - | 52,719 | - | 201 | 52,719 |
| 2012 |  | - | 31 | - | - | 6,857 | - | 31 | 6,857 |
| 2013 |  | - | 58 | - | - | 4,012 | - | 58 | 4,012 |
| 2014 |  | - | 21 | - | - | 5,825 | - | 21 | 5,825 |
| 2015 |  | - | 11 | - | - | 3,581 | - | 11 | 3,581 |
| 2016 |  | - | 14 | - | - | 3,407 | - | 14 | 3,407 |
| 2017 |  | - | 34 | - | - | 11,044 | - | 34 | 11,044 |
| 2018 |  | - | 32 | - | - | 12,622 | - | 32 | 12,622 |
| 2019 |  | - | 28 | - | - | 10,134 | - | 28 | 10,134 |
| 2020 |  | - | 14 | - | - | 3,900 | - | 14 | 3,900 |
| 2021 |  | - | 24 | - | - | 11,200 | - | 24 | 11,200 |
| Total |  | 70 | 1,438 | 91 | 26,545 | 403,105 | 16,743 | 1,600 | 446,593 |

Project No.: 252233  
 6 February 2023

Exploration  
 Page 7-5

**wood.**

**Southern Copper**  
 **Grupo México**  
 MINERÍA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

**Table 7-2: Drilling Supporting Mineral Resource Estimation**

| Year | Operator | No. of Drill Holes |  |  | Drilled Length (m) |  |  | Total Drill Holes | Total Drilled Length (m) |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  |  | Churn | Core | RC | Churn | Core | RC |  |  |
| 1942 | Cerro de Pasco | - | 39 | - | - | 12,167 | - | 39 | 12,167 |
| 1952 | Newmont and Asarco | 70 | 17 | - | 26,545 | 3,449 | - | 87 | 29,995 |
| 1980 | Southern Copper | - | 17 | - | - | 8,400 | - | 17 | 8,400 |
| 1982 |  | - | 1 | - | - | 276 | - | 1 | 276 |
| 1991 |  | - | 1 | - | - | 201 | - | 1 | 201 |
| 1994 |  | - | 208 | 39 | - | 110,977 | 10,308 | 247 | 121,285 |
| 1998 |  | - | 1 | 1 | - | 152 | 315 | 2 | 467 |
| 2000 |  | - | 85 | - | - | 35,284 | - | 85 | 35,284 |
| 2004 |  | - | 20 | - | - | 1,644 | - | 20 | 1,644 |
| 2005 |  | - | 8 | - | - | 1,005 | - | 8 | 1,005 |
| 2006 |  | - | 39 | - | - | 3,704 | - | 39 | 3,704 |
| 2007 |  | - | 24 | - | - | 3,082 | - | 24 | 3,082 |
| 2008 |  | - | 5 | - | - | 813 | - | 5 | 813 |
| 2009 |  | - | 2 | - | - | 565 | - | 2 | 565 |
| 2010 |  | - | 31 | - | - | 3,739 | - | 31 | 3,739 |
| 2011 |  | - | 140 | - | - | 36,201 | - | 140 | 36,201 |
| 2012 |  | - | 7 | - | - | 2,308 | - | 7 | 2,308 |
| 2013 |  | - | 13 | - | - | 2,350 | - | 13 | 2,350 |
| 2014 |  | - | 20 | - | - | 5,425 | - | 20 | 5,425 |
| 2015 |  | - | 11 | - | - | 3,581 | - | 11 | 3,581 |
| 2016 |  | - | 12 | - | - | 2,996 | - | 12 | 2,996 |
| 2017 |  | - | 20 | - | - | 7,550 | - | 20 | 7,550 |
| 2018 |  | - | 21 | - | - | 10,400 | - | 21 | 10,400 |
| 2019 |  | - | 18 | - | - | 7,600 | - | 18 | 7,600 |
| Total |  | 70 | 760 | 40 | 26,545 | 263,869 | 10,623 | 870 | 301,037 |

Project No.: 252233  
 6 February 2023

Exploration  
 Page 7-6

**wood.**

SouthernCopper

[LOGO]

GrupoMéxico

MINERÍA

Southern Copper Corporation

Technical Report Summary on Cuajone Operations

Peru

Figure 7-3: Property Drill Collar Location Plan

![img-2.jpeg](img-2.jpeg)

(Source: Wood, 2021)

Project No.: 252233

6 February 2023

Exploration

Page 7-7

wood.

SouthernCopper

[LOGO]

GrupoMéxico

MINERÍA

Southern Copper Corporation

Technical Report Summary on Cuajone Operations

Peru

Figure 7-4: Drill Collar Location Plan for Drilling Supporting Mineral Resource Estimates

![img-3.jpeg](img-3.jpeg)

(Source: Wood, 2021)

Project No.: 252233

6 February 2023

Exploration

Page 7-8

wood.

**Southern Copper**
**Grupo México**
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

Selected intervals were ignored by Hexagon, a third-party contractor to Southern Copper, in the construction of the mineral resources model, DHUSE=2. Such intervals were identified by using four filters that were the result of checks on vertical sections:

- Assays which are approximately 15 m in length, due to concerns over sample intervals crossing lithological contacts or not aligning with mining benches
- Drill holes with a single assay or drill holes with highly variable assay intervals (long and short assays). The average assay interval length of these holes was 29 m.
- Drill holes without assays
- Assay intervals with lengths >5 m were omitted, in addition to the filters described above.

Wood does not agree with Hexagon's exclusion of this data, because data with variable lengths can be dealt with through the selection of an appropriate composite length. Wood completed a check on the impact of removing these data and concluded that the mineral resource estimate was not materially affected.

### 7.2.2 Drill Methods

Core drilling was the dominant form of drilling for all exploration. Where known, drill contractors included Boyles Brothers, Boart Longyear, Geotec Asociados, Britton Hermanos Perforaciones del Perú, Geodrill, and rigs operated by Southern Copper staff. The only rig type recorded is a Longyear 44 drill rig. Core diameters included HQ (63.5 mm), NQ (47.6 mm), HQ3 (61.1 mm), and NQ3 (45.1 mm).

Some RC drilling was completed. Drilling contractors and bit diameters are not recorded. Limited churn drilling was completed from 1952-1954. Those data are used to support mineral resource estimation because they were verified by core drilling.

Blasthole sampling, while used to validate the resource estimation, is not used in the estimation of grades for the resource model.

Holes are generally drilled vertically and collared on section lines spaced 50 m apart. A program with inclined core holes was completed in 1982. Holes were inclined at 45°-60°. The azimuth of these holes was on a 50° azimuth. Those drill holes were drilled to define the orientation and extents of various intrusive lithologies within the Cuajone deposit.

Project No.: 252233
6 February 2023

Exploration
Page 7-9

wood.

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

### 7.2.3 Logging

Geological logs, at a minimum, record: logger name, date, coordinates of the hole, name of the hole, start-date of logging, azimuth, dip, logging interval equivalent to 3 m, core diameter, rock type, intensity of alteration minerals, rock quality designation (RQD), recovery, mineralization, and other information deemed important by the geologist responsible for the log. Log formats varied with time; but the basic information was always recorded. From 1942-2017, geological logging was done on paper:

- From 1942-1988, the same format was used; depth, assays, geology, mineralization, type of casing and recovery were recorded.
- From 1991-1999, the logging format changed to provide more detail to the alteration minerals, type of structure, RQD and types of limonite.
- In 2001 and continuing to 2017, the logging format eliminated the option of types of limonite, added detail for mineral occurrence, grade estimate, rock hardness, and a log summary. More detail for alteration was required and structure was minimized.
- From 2017 on, physical logging changed from paper to digital logging using GVMapper.

### 7.2.4 Recovery

Core recovery in most lithological units is >80%. Alluvium, upper tuff, basal conglomerate, rhyolitic conglomerate, and white agglomerate have recoveries <80%, but lithologies are on the edges of the mineralization and the poor recovery does not affect mineral resource estimation.

### 7.2.5 Collar Surveys

Collar surveys for the 2015-2021 drilling were performed by mine surveyors using Trimble R12 GPS instruments. No formal survey certificates were produced so the survey data in the database cannot be verified against an original hard-copy document.

The collar survey method for the earlier campaigns is not known and there is no original hard copy data to verify the collar locations in the database. Southern Copper has, whenever possible, picked up historical collar locations with modern equipment. Such surveys have largely confirmed the drill hole collar locations.

### 7.2.6 Downhole Surveys

The majority of the drill holes were vertical. The database does not record why certain drill holes and not others, were down-hole surveyed.

Project No.: 252233
6 February 2023

Exploration
Page 7-10

wood.

**Southern Copper**
**Grupo México**
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

Downhole surveys were not systematically performed during the pre-2011 drill campaigns, with exception of some drill holes completed during the 2000 drill campaign.

Where information is available in the database, it is summarized below:

- From 1942-1980, downhole surveys were performed using Sperry Sun single- and multi-shot instruments. Survey intervals were typically spaced at about 50 m intervals.
- From 1982-1996, the Sperry Sun single-shot instruments were used for downhole surveys. Survey intervals were typically about 100 m.
- Records suggest that from 1996-2001, Eastman, CBC Welany, Christensen, Sperry Sun and WhipStock GmbH single-shot instruments were used.
- From 2011 to 2013, Flexit and Peewee instruments were used.
- Since 2013, downhole surveys were performed with Flexit instruments (3 m intervals; to about 2012), Devishot (50 m intervals; to about 2017) and Stockholm Precision Tools gyroscope (10 m intervals; to present).
- There is no record of declination corrections that must be applied to determine true north from magnetic instruments. In 1942, declination was about 5.33°E and it is now 6.45°W so the adjustment is not trivial. Wood cannot verify that declination was applied properly. This introduces a risk that the azimuth of angled drill holes is not accurate and thus samples are not accurately located which will cause estimated grades to be misplaced.

Gyroscopic downhole surveys were performed for 30% of the drill holes remaining (below current topography) in the mineral resource database. Of the drill holes below the end-of-year topography, 55% have directional surveys.

### 7.2.7 Comment on Material Results and Interpretation

The term “true thickness” is not generally applicable to porphyry-style deposits as the entire rock mass is potentially mineralized and there is often no preferred orientation to the mineralization so there is no “true thickness” in the sense of layered deposits. Thickness of mineralization in drill holes accurately reflects the “thickness” of the mineralization at the location of the hole.

Drilling and surveying were conducted in accordance with industry standard practices at the time the drill data were collected and provide suitable coverage of the mineralization. The collar and downhole survey methods used provide reliable sample locations; however, there are a number of holes without downhole surveys and it is not clear from the record if declination corrections were properly applied. The lack of downhole surveys for some older drill holes and

Project No.: 252233
6 February 2023

Exploration
Page 7-11

wood.

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

uncertainty about declination is potential source of error in the location of deeper drillhole intersections. The majority of drill holes are vertical so the lack of surveys is not considered to be a significant issue for the initial 100-200 m drilled depth.

The interpretation of the drilling results is summarized in representative drill sections illustrated in Figures 6-5, 6-6, 6-8, 6-9, 6-11 and 6-12.

In Wood's opinion, while there are uncertainties about downhole surveys for some holes, there are a sufficient number of properly surveyed holes to provide confidence that the quantity and quality of existing drilling data are sufficient to support mineral resource estimation. Wood recommends that all holes have well documented, proper collar and downhole surveys.

Geological and geotechnical logging procedures provide consistency in descriptions.

### 7.3 Hydrogeology

A conceptual hydrogeological model was produced for the Cuajone pit that serves as input for the geotechnical model in the pit. To understand hydrogeological dynamics, the following topics were analyzed:

- Analysis of hydrometeorological data
- Determination of the recharge and discharge to the system
- Evolution of groundwater levels in the area
- Analysis of permeabilities correlating to lithology
- Definition of hydrogeological units
- Groundwater movement and flow mechanisms.

#### 7.3.1 Sampling Methods and Laboratory Determinations

The Cuajone pit drainage system consists mainly of natural channel control, construction of horizontal drains and pumping from the bottom of the pit. Hydraulic conductivities of the main hydrogeological units were estimated based on field tests.

No chemical analysis of groundwater have been performed so no water quality data exist.

Project No.: 252233
6 February 2023

Exploration
Page 7-12

wood.

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

### 7.3.2 Groundwater Models

A two-dimensional hydrogeological numerical model was built and calibrated to estimate the pore pressure in the slopes of the Cuajone open pit. Results of this modeling allowed generation of necessary input for stability analyses at inter-ramp and global level.

Over time a cone of depression has been generated around the pit from dewatering programs. The current groundwater flow is about 2.4 L/s.

### 7.3.3 Water Balance

A water balance was generated for the mine, using the formula:

$$\text{Precipitation} = \text{evaporation} + \text{infiltration} + \text{surface runoff} + \text{mine drainage}$$

The average annual rainfall is 137 mm/a, while evaporation reaches 2,055 mm/a. The average annual potential infiltration is about 14.1 mm/a, which is equivalent to an annual average potential infiltration flow, for the 23.1 km2 area of the Cuajone Operations sub-basin, of the order of 10.4 L/s. Not all of the potential infiltration actually infiltrates. A portion of the flow is captured by mine drainage systems, leaving a potential infiltration flow of 7.8 L/s.

### 7.3.4 Comment on Results

The hydrological data support the current pit dewatering parameters and assumptions.

## 7.4 Geotechnical

Open pit slope geotechnical analysis and design is supported by data gathered from 2001-2013 geotechnical drilling, laboratory testing, and bench-scale structural conducted by SRK (2016).

In the most recent geotechnical review and analysis of the 15-year pit (to 2028) that was used to support the production plan and final pit configuration, Southern Copper generated an updated geotechnical block model. That block model was based on historical geological and geotechnical information and updated geological/geotechnical, structural, and hydrogeological data derived from drilling and bench mapping. Various basic geotechnical units were also updated.

The updated structural model resulted in improved structural domains, and a conceptual hydrogeological model was produced based on those data.

Project No.: 252233  
6 February 2023

Exploration  
Page 7-13

**wood.**

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

#### 7.4.1 Sampling Methods and Laboratory Determinations

Geological logging was used to develop rock mass rating (RMR) criteria (Bieniawski, 1976).

A program of laboratory testing of the samples obtained during geotechnical drilling was initiated in support of stability analysis of the bench level, inter-ramp and global mining designs. Testwork included unconfined compressive strength, point load, and direct shear tests. The laboratory used for the work is not recorded.

This work was used to generate the rock material parameters that were used for derivation of strength parameters in rock mass characterization and slope stability analyses.

A three-dimensional 3DEC model of the 15-year pit was compiled to verify the generation of potential macro-blocks or macro-wedges.

#### 7.4.2 Comment on Results

Lithological and geomechanical logging protocols, and laboratory test equipment used, and quality assurance/quality control (QA/QC) checks on the logging and laboratory tests were not available for review by Wood.

Based on the 2016 SRK report:

- There is no information available as to any quality assurance or QA/QC procedures that may have been in place during data collection.
- No procedures and protocols for mine design are currently in place.
- No geotechnical risk register or seismic management plan is mentioned.

Wood's review of summaries of the field investigation and laboratory testing data presented in SRK (2016) indicate that the information used to support the SRK (2016) design of the open pit slopes appears to be consistent with generally-accepted industry standard practice for the level of geotechnical effort required to support pre-feasibility level open pit designs (Read & Stacey, 2010).

Project No.: 252233
6 February 2023

Exploration
Page 7-14

wood.

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

## 7.4.3 Facilities

### 7.4.3.1 Heap Leach Geotechnical

There are multiple heap leach facilities at the site. The most recent geotechnical investigations by Anddes (2018) relate to the design of the physical stabilization of the solvent extraction heap leach facility. Previous geotechnical campaigns supported the original facility designs. Available geotechnical data included sampling at specified locations and borrow sources, test pits, in-situ density tests, cone penetration tests, seismic cone penetration tests, along with 7 seismic refraction lines.

A review performed by Anddes (2020) and checks of the as-built plans presented by SKEX (2016) confirmed that a stability berm was proposed in the detailed engineering for the solvent extraction heap leach facility (GreEngField-Anddes, 2014a), and confirmed in the technical memorandum prepared by Anddes (2015), was not built.

The heap leach facility Phase IV design was supported by geotechnical evaluations completed in 2014 and 2020. Testwork included test pits into the limits of the foundation, borrow source areas and waste material, in-situ density tests, natural density tests of soil liner material, Schmidt hammer tests, 23 seismic refraction lines, a multichannel analysis of surface waves (MASW) survey, surface samplings of potential borrow and ore materials. No geotechnical drilling was conducted within the footprint of the existing Phase IV facilities. Given the proximity to the open pit, geological structures (faults) may exist under the footprint of this facility.

### 7.4.3.2 Waste Rock Storage Facilities

Geotechnical investigation campaigns, consisting of test pits, in-situ density tests, and grain size distribution tests, were conducted to support the designs of the WRSFs and for closure planning purposes in 2008 and 2012. There is no information regarding the original design of the WRSFs.

Project No.: 252233  
6 February 2023

Exploration  
Page 7-15

**wood.**

**Southern Copper**  
![Southern Copper logo]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

## **8.0 SAMPLE PREPARATION, ANALYSES, AND SECURITY**

### **8.1 Sampling Methods**

Core was sampled on 3 m intervals. A geologist put a “cut line” on the core to guide core cutting. Core was cut with a diamond saw.

RC samples were sampled on 3 m intervals and split to 300-400 g. The splits were sent to the sample preparation laboratory.

Blasthole samples are sampled by cutting four channels on opposite sides of the cuttings pile. Samples are scraped from the walls of the channels and placed in a bag.

### **8.2 Sample Security Methods**

Sample security from drill point to laboratory relied upon the fact that samples were either always attended to, or stored in a secure area prior to shipment to the external laboratory. Chain-of-custody procedures consisted of completing sample submittal forms to be sent to the laboratory with sample shipments to ensure that all samples were received by the laboratory.

### **8.3 Density Determinations**

Density samples were 10-15 cm in length. There are a total of 24,174 measurements available in the database, obtained using the water displacement method.

A density quality control report included results for 210 control samples tested by the Certimin laboratory from drill samples completed in 2017-2019. Wood evaluated the obtained results using reduced major axis (RMA) plot and a reasonable correlation between the Southern Copper data and Certimin results was observed. Certimin results were 3.4% high than the Southern Copper data.

### **8.4 Analytical and Test Laboratories**

Table 8-1 summarizes, to the extent known, the sample preparation and analytical laboratories used.

Project No.: 252233  
6 February 2023

Sample Preparation, Analyses, and Security  
Page 8-1

**wood.**

**Southern Copper**  
 **Grupo México**  
 MINERÍA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

**Table 8-1: Summary of Preparation and Analysis Laboratories**

| Date | Operator | Laboratory | Accreditations | Sample Preparation | Sample Analysis | Independent |
| --- | --- | --- | --- | --- | --- | --- |
| 1942-1945 | Cerro De Pasco | Unknown | Unknown | Unknown | Unknown | Unknown |
| 1952-1954 | Asarco | Unknown | Unknown | Unknown | Unknown | Unknown |
| 1965-1970 | Southern Copper | Ilo Southern Copper Central Laboratory | none | Moquegua | Ilo Southern Copper Central Laboratory | no |
| 1982-1988 | Southern Copper | Ilo Southern Copper Central Laboratory | none | Moquegua | Ilo Southern Copper Central Laboratory | no |
| 1991-1996 | Southern Copper | Ilo Southern Copper Central Laboratory | none | Moquegua | Ilo Southern Copper Central Laboratory | no |
| 1997-2002 | Southern Copper | Ilo Southern Copper Central Laboratory | none | Moquegua | Ilo Southern Copper Central Laboratory | no |
| 2004-2011 | Southern Copper | Ilo Southern Copper Central Laboratory | none | Moquegua | Ilo Southern Copper Central Laboratory | no |
| 2011-2019 | Southern Copper | Ilo Southern Copper Central Laboratory | none | Moquegua | Ilo Southern Copper Central Laboratory | no |
| 2013 | Southern Copper | ALS Global | ISO 14001; ISO9001 | Lima | Lima | yes |
| 2014-2019 | Southern Copper | Inspectorate Services Perú, S.A.C. | ISO 14001; ISO9001; ISO 17026 | Arequipa | Lima | yes |
| 2019 | Southern Copper | Bureau Veritas | ISO 14001; ISO9001; ISO 17025 | Arequipa | Lima | yes |
| 2017-2019 | Southern Copper | Certimin | ISO 14001; ISO9001; ISO 17026 | Arequipa | Lima | yes |

Project No.: 252233  
 6 February 2023

Sample Preparation, Analyses, and Security  
 Page 8-2

**wood.**

**Southern Copper**  
![Grupo México logo]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

## 8.5 Sample Preparation

Sample preparation procedures at laboratories other than the Cuajone mine laboratory prior to 2017, were not provided to Wood.

Sample preparation in the Cuajone mine laboratory consisted of drying the sample, crushing, splitting in a riffle splitter to 100-150 g, and pulverization to 95% passing 105 μm (140 mesh).

Sample preparation from 2017 to the Report date at Certimin consisted of crushing to 90% passing 6 mm, crushing to 90% passing 2 mm (10 mesh), splitting to 200 g, and pulverization to 95% passing 105 μm (140 mesh).

## 8.6 Analysis

The Cuajone mine laboratory (1965-2021) performed a multi-element determination with an aqua regia digestion and atomic absorption spectrometry (AAS) finish on submitted exploration and blast hole samples. Components analyzed were total copper (CuT), acid soluble copper (CuS), cyanide soluble copper (CuCN), molybdenum, iron, iron oxide (FeOx), zinc, silver, and lead.

The Ilo smelter laboratory also performed multielement determinations for CuT, CuS, CuCN, molybdenum, silver, iron, Fe, iron oxide (FeOx), and zinc, using the same procedures as the Cuajone mine laboratory.

In 2013, ALS used a four-acid digestion with an inductively-coupled plasma (ICP) optical emission spectroscopy (OES finish) (method ME-ICP61) for CuT, iron, molybdenum, lead, zinc, arsenic and silver.

Certimin (2017-2019) performed multi-element determinations with a four-acid digestion and ICP-OES/ICP mass spectrometry (MS) finishes, and AAS. Elements such as CuT, CuS, CuCN, and FeOx were finished by AAS. All other elements except CO$_{3}$ and chlorine were finished by ICP. Carbonate was analyzed by LECO and chlorine was assayed with an ultraviolet absorption method.

## 8.7 Quality Assurance and Quality Control

Quality control programs for pre-2017 drill campaigns are not recorded. Southern Copper selected 160 samples (80 one-half core samples; 80 pulp samples) from 69 holes drilled in 1980, 1994, 2000, 2006, and 2011-2015 and sent them to Certimin for check-assaying. Accuracy was judged by Wood to be generally acceptable, with bias for copper in core samples at -6.3% which

Project No.: 252233  
6 February 2023

Sample Preparation, Analyses, and Security  
Page 8-3

**wood.**

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

is just outside the $\pm 5\%$ limits generally accepted by the industry. This result is acceptable considering the age of some of the drill core.

Quality control programs for exploration core holes and bast holes were implemented in 2017 with insertion of certified reference materials (standards), coarse blanks, fine blanks, twin samples, coarse duplicates, and pulp duplicates. The use of check samples was also adopted.

Sampling precision, sub-sampling precision and analytical precision were evaluated using twin samples, coarse duplicates, and fine duplicates, respectively. Southern Copper used the hyperbolic method for assessing sampling, sub-sampling and analytical precision. Max-min plots were constructed for copper and molybdenum. Precision is considered to be acceptable.

The standards used by Southern Copper were prepared by Target Rocks Perú S.A.C. using material from the Cuajone deposit. Standard certificates were provided by Smee & Associates Consulting Ltd. The standards showed acceptable bias. Some apparently out of control samples were observed; however, these are likely due to sample mix-ups and should be investigated.

Bureau Veritas Perú (Bureau Veritas) was sent a total of 268 pulp samples to evaluate the quality of the internal Ilo laboratory facility. These samples were obtained from 48 drill holes completed in 1982, 2009, 2011, 2012, 2017, and 2018. Results were processed by Wood using RMA plots, comparing the Ilo laboratory data against the Bureau Veritas results. Biases of the Ilo data relative to Bureau Veritas were acceptable for copper (-1.6%) and questionable for molybdenum (-6.3%).

Southern Copper personnel collected 40 samples per month during the months of December 2020 to March 2021 to send to Certimin to evaluate the quality of the primary Ilo laboratory. Results indicate acceptable correspondence between the two laboratories.

Coarse blanks and fine blanks analytical results do not indicate any significant contamination for copper and molybdenum in the period from 2017-2019.

Selected blasthole pulps from late 2020 and early 2021 that were analyzed at the internal Ilo laboratory were submitted to the Inspectorate laboratory in Lima (Inspectorate) for check assay. The results of the blasthole check assays are good. Means of the original and check assay results are close and the reproducibility of the original assays from the Ilo laboratory with the check assays from the external laboratory is good.

Selected drill hole sample pulps and archived core intervals from resource drill programs from the late 1990s to 2021, which were analyzed at the Cuajone mine laboratory until 2016 and at the Ilo laboratory from 2016 to 2020, were submitted to Inspectorate for check assay. Reproducibility of the samples from before 2016 is poorer than expected, suggesting potential

Project No.: 252233  
6 February 2023

Sample Preparation, Analyses, and Security  
Page 8-4

**wood.**

**Southern Copper**  
![Southern Copper logo: a stylized blue and white 'C' shape.]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

issues with sampling, sample preparation, assaying or database integrity for the samples analyzed at the Cuajone mine laboratory before the implementation of QA/QC programs and use of the Ilo laboratory.

## **8.8 Database**

Data are currently managed using an acQuire database. User profiles and passwords are used to limit editorial access to the database. All data entry is validated using data masks that impose reasonable limits on the data. Data outside the limits are not allowed in the database and must be corrected.

## **8.9 Qualified Person’s Opinion on Sample Preparation, Security, and Analytical Procedures**

In Wood QP’s opinion, the sample preparation, security, and analytical procedures, and QA/QC protocols for the samples are acceptable to support mineral resource estimation and are acceptable for the other purposes used in the Report.

Project No.: 252233  
6 February 2023

Sample Preparation, Analyses, and Security  
Page 8-5

**wood.**

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

## 9.0 DATA VERIFICATION

### 9.1 Data Verification by Qualified Person

#### 9.1.1 Site Visit

Representatives from Wood visited the Cuajone Operations, as outlined in Chapter 2.4. Observations from the visit were incorporated into Wood QP's conclusions as appropriate to the discipline areas in this Report, or incorporated into the recommendations in Chapter 23.

#### 9.1.2 Database Audit

Absence of original hard copy survey and assay certificates makes evaluation of database integrity impossible for data that predates 2017. Some data exist and those were used to verify data.

To assess data integrity, Wood QPs performed comparisons of the Cuajone dataset and its available original sources including collar, survey, density, assay certificates and reports. A summary of the comparison follows:

- Collar location records for 47 drillholes were compared. No significant discrepancies were observed. Collar certificates for three drillholes were not available for review. In general, collar certificates formats are not adequate, lack of following information was observed: used equipment, signature of the person in charge, date, drill hole depth.
- Discrepancies during downhole survey records review were observed at least five drill holes, which represent 10% drill holes reviewed. Southern Copper concluded that any the discrepancies were due to the methodology used to upload data in MineSight.
- Wood QPs compared 6,425 assay records from 48 drill holes against their respective assay certificates for copper and molybdenum which represent 4% of total records included in the database. No significant discrepancies were observed.
- 298 holes with copper grades were found to be excluded from the mineral resource estimate.
- A small number of discrepancies were noted in recovery and RQD data. Those were resolved and were not considered to have any impact on the mineral resource estimate.
- Wood QPs compared 9,340 logging records against their respective log reports. Discrepancies for 515 records were observed, which represent an error rate of 6%. These discrepancies are, as yet, not resolved. The impact is that geological interpretations based

Project No.: 252233
6 February 2023

Data Verification
Page 9-1

wood.

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

on the records with discrepancies may cause local anomalies of geological contacts and thus possibly mislocate mineralization or other geological features. Such discrepancies result in a lower confidence in the geological model than if no such discrepancies were observed.

- Wood QPs compared 2,158 density records from 36 drill holes against their respective density reports. Three discrepancies were observed, which represent an error rate of 0.14%. Of the 50 drill holes selected for review, 14 do not have density data in the database (28%).

### 9.1.3 Peer Review

Wood QPs requested that information, conclusions, and recommendations presented in the body of this Report be peer reviewed by Wood’s subject matter experts or experts retained by Wood in each discipline area as a further level of data verification.

Peer reviewers reviewed the information in the areas of their expertise as presented in this Report. This could include checks of numerical data, consistency of presentation of information between the different Report chapters, consistency of interpretation of the data between different discipline areas, checked for data omissions, verified that errors identified during Wood’s gap analyses were appropriately addressed or mitigated, and reviewed the appropriateness of the individual QP’s opinions, interpretations, recommendations, and conclusions as summarized by the QP Firm.

## 9.2 Qualified Person’s Opinion on Data Adequacy

Wood QPs consider that a reasonable level of verification has been completed, and that no material issues would have been left unidentified from the programs undertaken.

Wood QPs are of the opinion that the data verification programs for Project data adequately support the geological interpretations, the analytical and database quality, and therefore support the use of the data in mineral resource estimation, mineral reserve estimates, and the mine plans.

Project No.: 252233  
6 February 2023

Data Verification  
Page 9-2

**wood.**

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

## **10.0 MINERAL PROCESSING AND METALLURGICAL TESTING**

### **10.1 Test Laboratories**

Historical testwork on which the plant designs were originally based are not available.

Two different laboratories were used to perform metallurgical testwork. The Southern Copper-operated Cuajone concentrator was used from 2007-2012, and is not independent. Inmet Chapi in Arequipa (Inmet) was used in 2008 and is an independent laboratory. There is no international standard of accreditation provided for metallurgical testing laboratories or metallurgical testing techniques.

Leach Inc., a metallurgical consultancy, was retained to provide advice to the Southern Copper metallurgical team.

### **10.2 Metallurgical Testwork**

A total of 222 samples from the different mineralized zones were tested for Bond ball mill work index values (BWi), 201 at the Cuajone concentrator, and 21 at Inmet. Values ranged from 13.10-21.37 kWh/t.

A total of 300 samples from different mineralized zones were subjected to copper and molybdenum flotation testing by the Cuajone concentrator, using standard plant conditions, aimed to replicate plant operations. The results of this testing campaign were used to develop a recovery model for copper and molybdenum. Recovery results versus grade by lithology for copper and molybdenum are shown in Figure 10-1 to Figure 10-5. The variability in copper recovery is less than the variability of molybdenum for all major lithologies.

### **10.3 Oxide Recovery Estimates**

#### **10.3.1 Copper Recovery Equation**

Predicting the copper production of the leach plant is based on an estimate of the grade of the ore to be processed, a testwork-obtained correlation between the three copper phases (acid soluble, cyanide soluble and insoluble), and the length of time the ore is leached. Corrections to the estimated recovery are made for the percentage minus 100 mesh and the percent carbonate ($\text{CO}_3^{2-}$) in the ore.

Project No.: 252233  
6 February 2023

Mineral Processing and Metallurgical Testing  
Page 10-1

**wood.**

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

Figure 10-1: Cu and Mo Recovery - Basaltic Andesite

![img-0.jpeg](img-0.jpeg)

(Source: Southern Copper, 2021)

Figure 10-2: Cu and Mo Recovery - Breccia

![img-1.jpeg](img-1.jpeg)

(Source: Southern Copper, 2021)

Project No.: 252233
6 February 2023

Mineral Processing and Metallurgical Testing
Page 10-2

wood.

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

Figure 10-3: Cu and Mo Recovery - Intrusive Andesite

![img-2.jpeg](img-2.jpeg)

(Source: Southern Copper, 2021)

Figure 10-4: Cu and Mo Recovery - Porphyritic Latite

![img-3.jpeg](img-3.jpeg)

(Source: Southern Copper, 2021)

Project No.: 252233
6 February 2023

Mineral Processing and Metallurgical Testing
Page 10-3

wood.

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

**Figure 10-5: Cu and Mo Recovery - Porphyritic Rhyolite**

![img-4.jpeg](img-4.jpeg)

(Source: Figure prepared by Southern Copper, 2021)

Project No.: 252233
6 February 2023

Mineral Processing and Metallurgical Testing
Page 10-4

wood.

**Southern Copper**  
 **Grupo México**  
 MINERÍA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

The estimated copper recovery was based on 2001 column testwork, and the sum of the recovery of each of the three copper phases. The equation for the base recovery is:

- % Recovered Cu = $$\frac{\text{leach time}}{(\text{leach time} + 8.12) \cdot \text{fraction of copper that is acid soluble} + \text{leach time}}{(1.06 \cdot \text{leach time} + 16.16) \cdot \text{fraction of copper that is cyanide soluble after removing acid soluble copper} + \text{leach time} / (6.12 \cdot \text{leach time} + 220.15) \cdot \text{fraction of copper that is insoluble in acid or cyanide}}$$

Oxide ore is leach for a period of 60 to 66 days. Table 10-1 lists the copper recovery for each of the three copper phases for 60, 66 and 70 days.

The derived equation is for a typical ore, however, and the recovery calculated by the above equation must be corrected for fines and carbonate concentrations.

The LOM head grade and copper recovery are expected at 0.52% (including the ore from the existing stockpile) and 48.2% respectively.

**Table 10-1: Copper Recovery by Phase**

| Time (d) | Cu Recovery (%) |  |  |
| --- | --- | --- | --- |
|  | CuS | CNCu | InsolCu |
| 60 | 88.1 | 54.8 | 10.8 |
| 66 | 89.0 | 59.7 | 11.3 |
| 70 | 89.6 | 63.0 | 11.6 |

Note: CNCu = cyanide-soluble copper; InsolCu = copper that is not soluble in copper or acid

### 10.3.2 Fines Adjustment

The basic copper recovery equation assumes that the crushed ore contains 13% minus 100 mesh. Copper recovery from ores containing more or less than this amount will have copper recoveries greater or less than that predicted by the equation. If the ore contains less than 13% minus 100 mesh, then the following equation is used to calculate an adjustment to the calculated recovery:

- Adjustment factor = $$35.075 \cdot (\% - 100\#)^3 + 3.527 \cdot (\% - 100\#)^2 - 0.0726 \cdot (\% - 100\#) - 0.1315$$

If the percentage of minus 100 mesh is greater than 13%, then the following equation is used to calculate an adjustment to the base recovery:

- Adjustment factor = $$-0.3297 \cdot (\% - 100\#)^2 - 0.3442 \cdot (\% - 100\#) - 0.0075$$

Project No.: 252233  
 6 February 2023

Mineral Processing and Metallurgical Testing  
 Page 10-5

**wood.**

**Southern Copper**  
![Grupo México logo]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

The adjustment factors given by the two equations require an understanding of the percentage of minus 100 mesh in the crushed ore that will be leached in the future.

An average obtained from historical data is used to estimate recoveries for short- and long-term production planning. Fines are about 21% minus 100 mesh historically.

The correlation coefficients for each of the two equations relating the percentage of minus 100 mesh to recovery exceed 0.99.

### 10.3.3 Carbonate Adjustment

The basic copper recovery equation is adjusted for the percentage of carbonate in the ore in addition to the amount of minus 100 mesh in the crushed ore. This adjustment is necessary only if the CO3= content is >2.7%. If the ore contains >2.7% CO3= then the following equation is used to calculate reduction applied to the calculated recovery:

$$\text{Recovery factor} = -498.83 * (\text{CO}_3\text{)}^3 + 25.728 * (\text{CO}_3\text{)}^2 + 8.7246 * (\text{CO}_3\text{)} - 0.2438$$

Unlike the percentage of minus 100 mesh in the crushed ore, the carbonate content is a characteristic of the ore that can be included in the geological model, and therefore can be used in a model for estimating the copper recovery that can be expected from heap leaching.

## 10.4 Sulfide Recovery Estimates

### 10.4.1 Throughput Models

A mathematical model for throughput prediction was developed based on the work index and grind size as defined by the weight percentage retained on a 65-mesh screen. This model, together with a copper and molybdenum flotation model for grade forecasting, was used to predict daily copper and molybdenum production.

A total of 167 measurements were made on the product of the two grinding circuits. The larger circuit comprises two large diameter mills with a combined capacity of about 29,750 dmt/d. The smaller circuit consists of small diameter mills which have a total capacity of about 57,500 dmt/d. Information recorded included the plant work index, percent operating time, and percent plus 65 mesh in the mill product for both the large and the small mills.

Project No.: 252233  
6 February 2023

Mineral Processing and Metallurgical Testing  
Page 10-6

**wood.**

**Southern Copper**
**Grupo México**
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

Mill production was then defined as:

- Large circuit: dmt/day = 40,627.6 - 1,117.05 * work index (large mills) + 358.817 * % +65 mesh (large mills)
- Small circuit: dmt/day = 86,655.3 - 3,028.41 * work index (general) + 835.838 * % +65 mesh (general)

The adjusted correlation coefficients for these equations were 0.7284 and 0.7803 for the small and large mills, respectively.

Leach Inc. reproduced the equations, with the following defined:

- Large circuit: dmt/day = 40,638.77 - 1,117.22 * work index (large mills) + 358.464 * % +65 mesh (large mills)
- Small circuit: dmt/day = 86,675.48 - 3,025.24 * work index (general) + 833.253 * % +65 mesh (general).

The adjusted correlation coefficients for these equations were 0.7280 and 0.7795 for the small and large mills, respectively. Differences between Leach Inc. and Southern Copper equations were attributed to a combination of different statistical packages used to derive the equations and rounding. The equations indicate that actual production will be within about 6% of the predicted production 95% of the time.

Additional analytical work by Southern Copper on the throughput model concluded that at a 23.5% of +65 mesh the liberation of the copper species is adequate and good copper recoveries can be achieved. It was concluded that that the percentage of +65 mesh in the equation can be replaced by a constant value of 23.5%.

The equations developed by Leach Inc. were adjusted as follows:

- Large circuit: dmt/day = 49,062.67 - 1,117.22 * work index (large mills)
- Small circuit: dmt/day = 106,256.93 - 3,025.24 * work index (small mills)

However, as the equations proposed by Leach Inc. are valid for a plant availability close to 100%, they were revised to adjust by an availability factor in accordance with the operational results, thus the resulting equations are as follows:

- Large circuit: dmt/day = (49,062.67 - 1,117.22 * work index) * % Availability (large mills)
- Small circuit: dmt/day = (106,256.93 - 3,025.24 * work index) * % Availability (small mills)

Project No.: 252233
6 February 2023

Mineral Processing and Metallurgical Testing
Page 10-7

wood.

SouthernCopper

GrupoMéxico
MINERÍA

Southern Copper Corporation

Technical Report Summary on Cuajone Operations

Peru

The initial equations included an additional increase in throughput of 4% because of the start-up of the high-pressure grinding rolls (HPGR) in the grinding circuit. However, operational results to date have shown that the plant throughput has increased by an average of 5.7%, therefore the throughput prediction equations were adjusted to correct for this factor.

The equations currently used by Southern Copper to predict the plant throughput are:

- Large circuit: dmt/d = (49,062.67 - 1,117.22 * work index) * (% Availability * 1.057/1.040) (large mills)
- Small circuit: dmt/d = (106,256.93 - 3,025.24 * work index) * (% Availability * 1.057/1.040) (small mills)

Figure 10-1 to Figure 10-5 show the variability of the copper and molybdenum recovery in relation to the percentage of copper and molybdenum content of the head grade by lithology for the 300 samples tested from different zones of the mine. The variation of the copper recovery was observed to be less significant than the molybdenum recovery for the major lithologies.

### 10.4.2 Copper Recovery Model

A 300-sample flotation test program was undertaken by Southern Copper to develop a mathematical relationship between the chemical composition of the ore and the rougher flotation recovery of copper and molybdenum. A standard flotation test protocol was used. Each test sample was assayed for CuT, CuS, molybdenum, iron, zinc, and acid-soluble iron (ASFe).

An empirical equation was selected and tested using multivariate regression analysis to determine which combination of the six independent variables generated the model equation which best fitted the laboratory-measured rougher copper recovery. Models for the three ore types, basaltic andesite, intrusive andesite and latite porphyry, were separately developed.

Both Southern Copper and Leach Inc. personnel developed recovery equations as follows:

- Basaltic andesite:

- Southern Copper: Cu Recovery, % = 84.41 + 2.39 CuT - 189.8 CuS + 58.04 Mo - 0.2420 Fe + 34.23 Zn + 3.854 ASFe
- Leach Inc.: Cu Recovery, % = 83.85 + 2.06 CuT - 188.7 CuS + 65.76 Mo + 31.60 Zn + 3.471 ASFe

Project No.: 252233

6 February 2023

Mineral Processing and Metallurgical Testing

Page 10-8

wood.

SouthernCopper

GrupoMéxico
MINERÍA

Southern Copper Corporation

Technical Report Summary on Cuajone Operations

Peru

• Intrusive andesite:

- Southern Copper: Cu Recovery, % = 96.12 - 9.67 CuT - 77.21 CuS + 0.2067 Fe - 63.89 Zn - 4.82 ASFe
- Leach Inc.: Cu Recovery, % = 97.30 - 9.66 CuT - 93.63 CuS - 64.37 Zn - 4.11 ASFe

• Latite porphyry

- Southern Copper: Cu Recovery, % = 90.12 + 6.51 CuT - 88.80 CuS - 60.35 Mo + 0.4788 Fe - 82.31 Zn - 0.6148 ASFe
- Leach Inc.: Cu Recovery, % = 90.06 + 6.39 CuT - 98.15 CuS - 60.19 Mo - 79.07 Zn + 0.4344 ASFe

• All ore types:

- Southern Copper: Cu Recovery, % = 88.94 + 7.20 CuT - 189.3 CuS - 0.9374 Fe + 13.69 CuSCN + 1.745 ASFe
- Leach Inc.: Cu Recovery, % = 88.92 + 7.20 CuT - 189.2 CuS - 0.9374 Fe + 13.69 CuSCN + 1.745 ASFe

A scale up factor of -3.2 was added to the all-ore-type equation to better reflect the plant metallurgical performance.

The LOM expected copper recovery is estimated at 84.4% (including the ore from the existing stockpile). Copper recovery from ore stockpiled (70.8 Mt with 0.28% copper grade and 0.012% molybdenum grade) and assumed to be treated in the last years of the LOM was reduced in 10% as a provision to account for potential metallurgical degradation. The forecast LOM copper concentrate grade is 25.34%.

### 10.4.3 Molybdenum Recovery Model

The molybdenum recovery was assumed to be a function of the flotation feed grade for molybdenum only; no other ore constituents were included in the model. Flotation test samples were divided into five groups based on the molybdenum grade of the sample, and an average molybdenum recovery was calculated for each of the five groups. In addition, 1,871 daily measurements were made of the plant recovery together with the daily molybdenum feed grade. The average molybdenum recovery in the laboratory test for feed samples containing more than 0.02% Mo in the plant data was 82.8% and had a standard deviation of 3.7%.

Project No.: 252233

6 February 2023

Mineral Processing and Metallurgical Testing

Page 10-9

wood.

**Southern Copper**  
 **Grupo México**  
 MINERÍA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

Further model development work that was completed by Southern Copper established two scale-up factors to better predict molybdenum recovery in the plant. These factors were defined based on operational experience and are:

- Molybdenum plant factor = 0.92

The predicted plant recovery was estimated as follows:

- % Mo plant recovery = % Mo rougher recovery * regrind factor * molybdenum plant factor

Further development work based on plant data for the period March 2014 to January 2021 determined that an additional scale up factor should be issued to improve the prediction of the molybdenum recovery from the laboratory data (Table 10-2).

The model recovery is very close to the actual plant recovery for the period indicated, which supports the use of this model in production plan forecasts.

The LOM expected molybdenum recovery is estimated at 62.5% (including ore from the existing stockpile). Molybdenum recovery from ore stockpiled (70.8 Mt with 0.28% copper grade and 0.012% molybdenum grade) and assumed to be treated in the last years of the LOM was reduced in 10% as a provision to account for potential metallurgical degradation. The LOM molybdenum concentrate grade forecast is 54.05%

**Table 10-2: Molybdenum Recoveries, Test vs. Plant Actual**

| Head Grade Range (% Mo) |  | Add. Factor | Mo Recovery (%) |  |
| --- | --- | --- | --- | --- |
|  |  |  | Model | Plant |
|  | <0.007 | 0.96 | 54.84 | 54.87 |
| 0.008 | 0.012 | 0.90 | 59.74 | 60.06 |
| 0.013 | 0.016 | 0.89 | 62.96 | 62.91 |
| 0.017 | 0.020 | 0.90 | 65.03 | 64.83 |
|  | >0.021 | 0.87 | 63.76 | 63.85 |

## 10.5 Metallurgical Variability

A significant number of samples were selected by rock type/alteration for comminution and flotation testing (Figure 10-6 and Figure 10-7).

Project No.: 252233  
 6 February 2023

Mineral Processing and Metallurgical Testing  
 Page 10-10

**wood.**

**Southern Copper**  
 **Grupo México**  
 MINERÍA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

Tests were performed on samples that are considered to be representative of the different orebodies/zones and the mineralogy and alteration styles.

**Figure 10-6: Copper Grade Variability Tests**

![img-0.jpeg](img-0.jpeg)

(Source: Southern Copper, 2021)

**Figure 10-7: Molybdenum Grade Variability Tests**

![img-1.jpeg](img-1.jpeg)

(Source: Southern Copper, 2021)

Project No.: 252233  
 6 February 2023

Mineral Processing and Metallurgical Testing  
 Page 10-11

**wood.**

**Southern Copper**  
 **Grupo México**  
 MINERÍA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

## 10.6 Deleterious Elements

The copper and molybdenum concentrates are considered clean concentrates as they do not contain significant amounts of deleterious elements.

Average chemical and mineralogical compositions of the copper and molybdenum monthly concentrate composites for the period 2020 to 2022 are provided in Table 10-3, Table 10-4, Table 10-5, and Table 10-6, respectively.

**Table 10-3: Copper Concentrate Average Grades, 2020-2022**

| Item | Composites |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  | %Cu | %Ins | %Fe | %Mo | %CuSAc | %CuS CN | % Ca | %Zn |
| Minimum | 24.160 | 9.180 | 24.490 | 0.058 | 0.251 | 1.540 | 0.220 | 0.535 |
| Maximum | 26.600 | 14.24 | 28.670 | 0.202 | 0.557 | 6.220 | 0.786 | 1.692 |
| Average | 25.400 | 11.786 | 26.860 | 0.098 | 0.371 | 3.545 | 0.325 | 0.945 |
|  | Composites |  |  |  |  |  |  |  |
|  | %S | % SiO 2 | %Al 2 O 3 | %ASFe | %Pb | %K | %Ni | %Co |
| Minimum | 26.190 | 6.936 | 0.960 | 0.280 | 0.098 | 0.009 | 0.001 | 0.003 |
| Maximum | 34.950 | 11.080 | 4.720 | 0.790 | 0.301 | 0.040 | 0.009 | 0.010 |
| Average | 30.590 | 8.840 | 2.851 | 0.575 | 0.167 | 0.021 | 0.003 | 0.007 |
|  | Composites |  |  |  |  |  |  |  |
|  | %Mn | %Mg | %As | %Na | Oz Ag | %CO 3 = | ppm Cl- |  |
| Minimum | 0.006 | 0.092 | 0.040 | 0.012 | 2.510 | 0.520 | 0.444 |  |
| Maximum | 0.033 | 0.218 | 0.228 | 0.025 | 4.400 | 1.580 | 6.245 |  |
| Average | 0.017 | 0.144 | 0.096 | 0.017 | 3.427 | 1.205 | 3.396 |  |

Note: Ins = insoluble ; CNCu = cyanide-soluble copper

**Table 10-4: Copper Concentrate Average Mineralogical Composition, 2020-2022**

| Item | Composites |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- |
|  | %Sulfides | %Chalcocite | %Chalcopyrite | % Pyrite | Py/Cpy Ratio | %Molybdenite |
| Minimum | 23.90 | 1.93 | 55.99 | 8.08 | 0.12 | 0.10 |
| Maximum | 26.04 | 7.79 | 66.83 | 22.21 | 0.38 | 0.34 |
| Average | 25.03 | 4.44 | 62.05 | 15.90 | 0.26 | 0.16 |

Project No.: 252233  
 6 February 2023

Mineral Processing and Metallurgical Testing  
 Page 10-12

**wood.**

**Southern Copper**  
 **Grupo México**  
 MINERÍA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

**Table 10-5: Molybdenum Concentrate Average Grades, 2020-2022**

| Item | Composites |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  | %Cu | %Ins | %Fe | %Mo | %CuS | %CNCu | %Ca | %Zn |
| Minimum | 0.412 | 1.860 | 1.620 | 52.043 | 0.005 | 0.084 | 0.118 | 0.021 |
| Maximum | 0.854 | 4.600 | 4.500 | 55.699 | 0.021 | 0.268 | 0.483 | 0.051 |
| Average | 0.686 | 2.919 | 2.584 | 54.111 | 0.010 | 0.181 | 0.183 | 0.034 |
|  | Composites |  |  |  |  |  |  |  |
|  | %S | % SiO 2 | %Al 2 O 3 | %ASFe | %Pb | %K | %Ni | %Co |
| Minimum | 26.560 | 1.190 | 0.378 | 0.010 | 0.036 | 0.002 | 0.001 | 0.001 |
| Maximum | 42.770 | 3.800 | 2.490 | 0.080 | 0.060 | 0.018 | 0.004 | 0.009 |
| Average | 38.76 | 2.136 | 0.788 | 0.038 | 0.049 | 0.005 | 0.002 | 0.005 |
|  | Composites |  |  |  |  |  |  |  |
|  | %Mn | %Mg | %As | %Na | Oz Ag | %CO 3 * | ppm Cl - |  |
| Minimum | 0.003 | 0.036 | 0.005 | 0.009 | 0.500 | 0.140 | 0.657 |  |
| Maximum | 0.021 | 0.100 | 0.032 | 0.029 | 1.190 | 0.880 | 5.259 |  |
| Average | 0.007 | 0.061 | 0.012 | 0.018 | 0.756 | 0.404 | 2.386 |  |

Note: Ins = insoluble; CNCu = cyanide-soluble copper

**Table 10-6: Molybdenum Concentrate Average Mineralogical Composition, 2020-2022**

| Item | Composites |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- |
|  | %Sulfides | %Chalcocite | %Chalcopyrite | % Pyrite | Py/Cpy Ratio | %Molybdenite |
| Minimum | 0.40 | 0.11 | 0.72 | 2.25 | 1.26 | 86.83 |
| Maximum | 0.83 | 0.34 | 1.79 | 8.75 | 11.96 | 92.93 |
| Average | 0.68 | 0.23 | 1.43 | 4.54 | 3.48 | 90.28 |

## 10.7 Qualified Person’s Opinion on Data Adequacy

A significant amount of testwork have been performed on the sulfide and oxide ore that has allowed to develop a plant throughput, and a copper and molybdenum recovery models for the sulfide ore, and a copper recovery model for the oxide ore. Furthermore, the developed models have been improved and updated with time to take into account actual plant performance.

Testwork on the sulfide ore was performed on selected samples representing the main five rock types. The testing program included comminution and flotation testing for the sulfide ore. Sulfides samples prepared for flotation testing cover a wide range of copper and molybdenum content. Testwork on the oxide ore included column leach testing.

Project No.: 252233  
 6 February 2023

Mineral Processing and Metallurgical Testing  
 Page 10-13

**wood.**

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

The available metallurgical testwork information is considered by the QP to be of an acceptable quality to at least pre-feasibility level of study, and are considered adequate to support the metallurgical inputs to the mineral resources, mineral reserves, and the economic analysis.

The copper concentrate produced is considered to be a clean concentrate and no penalties are expected as the concentrate does not contain any significant amounts of deleterious elements.

Project No.: 252233  
6 February 2023

Mineral Processing and Metallurgical Testing  
Page 10-14

**wood.**

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

## 11.0 MINERAL RESOURCE ESTIMATES

### 11.1 Introduction

Mineral resources were prepared by third-party consultants Hexagon, and reviewed, adjusted and endorsed by Wood qualified persons in accordance with definitions under S-K 1300. A probability assisted constrained kriging (PACK) approach was used to estimate copper and molybdenum grades in the mineral resource model:

- Proportions of 12 lithology domains were calculated for each block using the lithology model wireframes.
- Proportions of regular and anomalous grades were estimated for each lithology domain using an indicator set at the anomalous grade threshold. A hard boundary was used for blocks and composites above or below the top of the primary sulfide horizon.
- Grades were kriged for the normal and anomalous portions of each lithological unit present in every block. A hard boundary was used for blocks and composites above or below the top of primary sulfide horizon.
- Final grades were calculated by weighting the proportion of normal and anomalous grades and proportion of each lithology domain in the block.

### 11.2 Exploratory Data Analysis

#### 11.2.1 Anomalous Cu (total)

Hexagon completed a manual, subjective classification of assays in to anomalous (higher-grade) and non-anomalous (lower-grade or background) categories.

Non-anomalous values were classified based upon total copper grades whose distribution behavior was considered to be characteristic of the type of lithology (pre-mineral, post-mineral, and mineralizing lithology groups).

Anomalous values were classified using the following criteria:

- ROCKV = 1. Total copper values in this code are hosted by pre- and post-mineral lithologies and are characterized by intervals with significantly higher total copper grades with respect to adjacent intervals. These intervals can be explained by the presence of mineralized veinlets in pre-mineralizing lithology or fragments of mineralization in post-mineralized lithologies.

Project No.: 252233
6 February 2023

Mineral Resource Estimates
Page 11-1

wood.

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

- ROCKV = 2. The total copper values in this code are hosted by pre-mineral lithologies displaying continuous intervals of mineralization.
- ROCKV = 3. The total copper values in this code are hosted by mineralizing lithologies with higher total copper grade intervals in comparison to adjacent intervals and are characterized by intervals with high total copper grade followed by intervals of lower total copper grades, either as continuous or isolated intervals.

### 11.2.2 Acid and Cyanide Soluble Cu

Acid soluble copper (CuS) and cyanide soluble copper (CuCN) were determined on some, but not all samples. Four cases were identified:

- CuS assay only
- CuCN assay only
- CuS and CuCN assays
- No CuS or CuCN assays.

CuS and CuCN were normalized to CuT (total copper) when CuS + CuCN > CuT in the oxide and transition zones. The solubility indices of CuS and CuCN were calculated as was the residual copper. The solubility indices that individually exceeded a value of 1.0 and the negative values of residual copper were coded as follows:

- Solubility index for CuS > 1.0 were encoded "1".
- Solubility index for CuCN > 1.0 were encoded "2".
- Negative residual copper (CuS + CuCN > CuT) values were encoded with "3".

The normalization of the grades of CuS and CuCN was performed as follows:

- CuS grades were set to the total copper values.
- CuCN grades were set to total copper values.
- Values were normalized using a factor derived from the two soluble copper grades.

### 11.2.3 Lithology Grouping

For estimation of CuT, CuS, CuCN, molybdenum and silver, lithology domains were consolidated into items SEC1 and SEC2.

The SEC1 item grouped post-mineralization and pre-mineralization lithologies with a non-anomalous classification. They were coded with codes 10 and 20. Lithologies excluded

Project No.: 252233
6 February 2023

Mineral Resource Estimates
Page 11-2

wood.

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

from the grouping due to the presence of anomalous total copper grades had their estimations made independently considering these anomalies and retained their original codes.

The SEC2 item grouped remaining post-mineralization and pre-mineralization lithologies with a non-anomalous classification in code 30. The unbundled lithologies kept their original codes.

### 11.3 Geological Models

Three dimensional models of lithology, alteration, and mineralization type were constructed in Leapfrog. Each block was assigned a percentage of each lithology, mineralization, and alteration type. Intervals of logged lithology and alteration were used to construct respective models. To add additional control, in-pit mapping data of specific geological contacts on bench plans at 15 m elevations were also used. Model blocks were coded with the 3D solids, created in Leapfrog and then imported into MineSight 3D. The deposit lithology was divided into the following categories:

- Cover (overburden)
- Post mineralization
- Syn-mineralized
- Pre-mineralization.

Southern Copper interpreted eight geometric solids, comprising:

- Oxides
- Enriched
- Transitional
- Primary
- Leached capping
- Sterile
- Sterile post-mineralization
- Dump.

Eight geometric alteration solids were interpreted:

- Argillic
- Phyllic/potassic
- Potassic
- Phyllic
- Phyllic propylitic

Project No.: 252233
6 February 2023

Mineral Resource Estimates
Page 11-3

wood.

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

- Unaltered

Geometallurgical zones were assigned based on the percentages of lithology, alteration, and mineralization types in each block.

## 11.4 Density Assignment

Lithology, alteration and mineralization domains were combined to produce geometallurgical domains for estimation of work index and for bulk density assignment.

The mean value of bulk density determinations was assigned to each geometallurgical domain for tonnage estimation.

Near surface zones of oxidized material, mining fill and unconsolidated overburden have SG values of <2.0. Domains that have SGs between 2.00-2.60 are near-surface agglomerates or conglomerates. Also included in this group are lithologies that have undergone some degree of moderate oxidation. Domains with SG values >2.6 are hypogene lithologies. The pre-mineralization lithologies have the highest SG values, of >2.70.

Figure 11-1 shows the work index geometallurgical domains. Table 11-1 shows the densities assigned to each work index geometallurgical domain.

## 11.5 Grade Capping/Outlier Restrictions

No capping or outlier restriction was used by Hexagon during mineral resource estimation. Wood checked the model on section and in plan and found minor evidence of over-projection of high grades. For future estimation, Wood recommends that Southern Copper complete a capping study and use an outlier restriction to control grade estimation.

Project No.: 252233  
6 February 2023

Mineral Resource Estimates  
Page 11-4

**wood.**

Southern Copper

Grupo México

MINERÍA

Southern Copper Corporation

Technical Report Summary on Cuajone Operations

Peru

Figure 11-1: Work Index Geometallurgical Domains

![img-2.jpeg](img-2.jpeg)

(Source: Southern Copper, 2021). Note: 405 = potassic-altered porphyritic latite; 414 = argillic-altered porphyritic rhyolite; 416 = potassic-altered andesite breccia; 423 = phyllic-altered intrusive andesite; 425 = silicified intrusive andesite; 434 = phyllic-altered porphyritic rhyolite; 442 = propylitic-altered basaltic andesite; 458 = tuffaceous agglomerate; 463 = gray agglomerate; 471 = diorite; 480 = trachytic tuff; 487 = fill; 499 = fresh rhyolite.

Project No.: 252233

6 February 2023

Mineral Resource Estimates

Page 11-5

wood.

**Southern Copper**  
 ![Grupo México logo]() **Grupo México**  
 MINERIA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

**Table 11-1: Specific Gravity by Work Index Assigned**

| Lithology | Alteration | Work-Index Code | Specific Gravity |
| --- | --- | --- | --- |
| Rhyolite porphyry | Phyllic | 401 | 2.65 |
| Breccia of rhyolite porphyry | Quartz-sericite | 402 | 2.50 |
| Latite porphyry | Silicification | 403 | 2.65 |
| Latite porphyry | Lattice structure | 404 | 2.66 |
| Latite porphyry | Potassic | 405 | 2.65 |
| Latite porphyry | Moderate silicification | 406 | 2.63 |
| Latite porphyry | Quartz-sericite | 407 | 2.63 |
| Latite porphyry | Fresh | 408 | 2.67 |
| Breccia of latite porphyry | Silicification | 409 | 2.65 |
| Breccia of barren latite porphyry | Silicification | 410 | 2.65 |
| Latite porphyry breccia | Silicification | 411 | 2.66 |
| Breccia of latite porphyry | Quartz-sericite | 412 | 2.64 |
| Breccia of barren latite porphyry fresh | Silicification | 413 | 2.63 |
| Rhyolite porphyry | Argillic | 414 | 2.54 |
| Basaltic andesite | Potassic | 416 | 2.69 |
| Basaltic andesite | Phyllic-potassic | 417 | 2.70 |
| Basaltic andesite | Argillic | 419 | 2.60 |
| Intrusive andesite | Phyllic-potassic | 420 | 2.68 |
| Intrusive andesite | Phyllic | 423 | 2.72 |
| Intrusive andesite | Lattice structure | 424 | 2.67 |
| Intrusive andesite | Silicification | 425 | 2.69 |
| Breccia of intrusive andesite | Argillic-potassic | 426 | 2.68 |
| Intrusive andesite | Phyllic | 427 | 2.64 |
| Intrusive andesite | Phyllic | 428 | 2.67 |
| Intrusive andesite | Phyllic-silicification | 430 | 2.69 |
| Breccia of rhyolite porphyry | Silicification | 431 | 2.69 |
| Basaltic andesite | Silicification | 432 | 2.66 |
| Latite porphyry | Phyllic-potassic | 433 | 2.69 |
| Rhyolite porphyry | Phyllic-propylitic | 434 | 2.64 |
| Breccia of basaltic andesite | Phyllic | 435 | 2.70 |
| Basaltic andesite | Propylitic | 442 | 2.75 |
| Coffee tuff |  | 450 | 1.74 |
| Alluvium |  | 451 | 1.25 |
| Upper agglomerate |  | 452 | 1.88 |
| Upper tuff |  | 453 | 2.25 |

Project No.: 252233  
 6 February 2023

Mineral Resource Estimates  
 Page 11-6

**wood.**

**Southern Copper**  
 ![Grupo México logo]() **Grupo México**  
 MINERIA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

| Lithology | Alteration | Work-Index Code | Specific Gravity |
| --- | --- | --- | --- |
| Lower agglomerate |  | 454 | 2.04 |
| Lower tuff |  | 455 | 1.85 |
| Crystal tuff |  | 456 | 2.36 |
| Basal conglomerate |  | 457 | 2.36 |
| Tuffaceous agglomerate |  | 458 | 2.01 |
| White tuff |  | 459 | 1.79 |
| Yellow/green conglomerate |  | 460 | 1.50 |
| Trachyte |  | 461 | 2.33 |
| Salmon tuff |  | 462 | 1.92 |
| Grey agglomerate |  | 463 | 2.14 |
| Rhyolite conglomerate |  | 464 | 2.20 |
| Granodiorite |  | 465 | 2.65 |
| Diorite |  | 471 | 2.65 |
| Andesite porphyry |  | 472 | 2.40 |
| Breccia pebble |  | 473 | 2.05 |
| Latite |  | 474 | 2.65 |
| Dike |  | 478 | 2.69 |
| Micaceous tuff |  | 479 | 1.40 |
| Trachyte tuff |  | 480 | 1.91 |
| Trachyte agglomerate |  | 481 | 1.66 |
| Colluvial |  | 482 | 1.80 |
| Doleritic conglomerate |  | 484 | 2.34 |
| Dump |  | 487 | 1.80 |
| Trachyte conglomerate |  | 488 | 1.68 |
| Dolerite |  | 490 | 2.67 |
| Crystal tuff vitrophyre |  | 494 | 2.29 |
| Trachyte Vitrophyre |  | 496 | 2.21 |
| Reworked Tuff |  | 497 | 1.90 |
| White Agglomerate |  | 498 | 2.26 |
| Rhyolite Fresh |  | 499 | 2.56 |

## 11.6 Composites

More than 90% of the intervals of the exploratory holes have a length of 3 m. Data were composited to 3 m.

Project No.: 252233  
 6 February 2023

Mineral Resource Estimates  
 Page 11-7

**wood.**

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

Four sets of composites were prepared:

- CuT grade estimation
- Hypogene CuS, CuCN, molybdenum and silver
- Solubility indices
- Secondary elements.

Histograms and cumulative probability plots were prepared for each composite set.

## 11.7 Variography

Variograms were prepared for the CuT, solubility index for CuS (ROX), solubility index for CuCN (RSUL), CuS (CUSAC), CuCN (CUSCN), molybdenum, silver, iron, and soluble Fe (FESAC). Ten sets of variograms were constructed.

Once the variogram maps for each element were completed, the orthogonal orientations were adjusted to each axis and the various directional variograms were exported, which were mostly modeled with two structures. To obtain the nugget effect, downhole variograms were created. In domains with a small number of samples, a generic isotropic 150 m variogram was used.

## 11.8 Estimation/interpolation Methods

The dimensions of the block in the three-dimensional model are 20 x 20 x 15 m. The block model covers an area of 4.8 km by 4.8 km in plan view, and 1.74 km vertically.

The elements, parameters and estimation methods used in the mineral resource model were:

- Variables: copper, CUSAC, CUSCN, molybdenum, iron, arsenic, antimony, bismuth, lead, zinc, potassium, magnesium, sodium, calcium, AL2O3, chlorite, CO3, manganese, FESAC, sulfur, selenium, SiO2, and silver were estimated with ordinary kriging (OK). Blocks that were not estimated were assigned a mean grade according to their corresponding estimation domain.
- Indicators of anomalous (higher-grade) total copper were estimated using OK.

To complement the global statistical reviews, estimates were constructed using polygonal and inverse distance to the second power (ID2) methods.

Project No.: 252233
6 February 2023

Mineral Resource Estimates
Page 11-8

wood.

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

## 11.9 Validation

Wood completed visual inspection of copper and molybdenum models and geostatistical validation of global bias (comparison of OK and nearest neighbor (NN) models), local trends in grade profiles (swath plots using ID2 and NN estimates and declustered composites) and change of support for each estimation domain. Reconciliation was also used as a validation tool.

## 11.10 Confidence Classification of Mineral Resource Estimate

### 11.10.1 Mineral Resource Confidence Classification

Mineral resource classification was based on the distance from the block center to the closest estimation composite. Within the mined-out volume of 2015 through 2019, distances to the closest three and two holes for blocks were examined. For all quarters mined, except two of 18, the average three-hole distance approximated or was <50 m and the average two-hole distance was <45 m. Therefore, an average distance to the nearest two holes of 60 m was used to classify indicated mineral resources.

The final classification was:

- Indicated: 60 m average distance to the closest two drill holes; 30 m extrapolation around single drill holes
- Inferred: maximum 300 m average distance to the closest two drill holes; restricted to 120 m average distance to the three closest composites to avoid classifying blocks with assigned grades as inferred mineral resources.

No measured mineral resources were classified.

Once blocks were flagged as indicated mineral resources with the above parameters, a smoothing exercise using a dilation/erosion methodology in the easting and northing directions, by bench was completed to assimilate and concentrate areas that were mostly indicated.

Project No.: 252233
6 February 2023

Mineral Resource Estimates
Page 11-9

wood.

**Southern Copper**  
![Grupo México logo]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

### **11.10.2 Uncertainties Considered During Confidence Classification**

Following the analysis that classified the mineral resource estimates into the confidence categories, uncertainties regarding sampling and drilling methods, data processing and handling, geological modeling, and estimation were incorporated into the classifications assigned. The areas with the most uncertainty were assigned to the inferred category, and the areas with fewer uncertainties were classified as indicated.

## **11.11 Reasonable Prospects of Economic Extraction**

### **11.11.1 Input Assumptions**

Wood's QP constrained the mineral resource estimate within a conceptual pit shell using a Lerchs-Grossmann algorithm and the parameters summarized in Table 11-2.

### **11.11.2 Commodity Prices and Market**

Long-term commodity prices used in resource estimation are based on Southern Copper's internal price forecast based on analyst and bank forecasts and are stated in Table 11-2. An explanation of the derivation of the commodity prices is provided in Chapter 16.5. The estimated timeframe used for the price forecasts is the 48-year LOM that supports the mineral reserve estimates.

The market for the mine production is discussed in Chapter 16.1.

### **11.11.3 Cut-off**

The cut-off grade for mineral resources was determined to be 0.112% Cu for sulfide mineralization. The cut-off grade for mineral resources sent to the leach pad was 0.149 %Cu. The inputs to the cut-off grades are shown in Table 11-2. Operating costs were based on actual costs and data from Southern Copper's operating mines in Peru, Wood's experience and the proposed mine and process plans. Wood used slightly more optimistic assumptions on costs for mineral resources than those used for mineral reserves. Along with 15% higher long-term metal price assumptions for the mineral resource inputs the slightly more optimistic assumptions ensured the mineral reserves would be a sub-set of the mineral resources,

Wood QPs consider those blocks within the constraining resource pit shell and above the cut-offs applied have reasonable prospects for economic extraction.

Project No.: 252233  
6 February 2023

Mineral Resource Estimates  
Page 11-10

**wood.**

**Southern Copper**  
 ![Grupo México logo]() **Grupo México**  
 MINERIA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

**Table 11-2: Input Parameters, Mineral Resource**

| Parameter | Unit | Value |
| --- | --- | --- |
| Price |  |  |
| Copper | US$/lb | 3.80 |
| Molybdenum | US$/lb | 11.50 |
| Mining |  |  |
| Reference mining cost* | US$/t | 1.76 |
| Incremental haulage cost up | US$/t | - |
| Incremental haulage cost down | US$/t | - |
| Processing |  |  |
| Concentration process cost* | US$/t | 7.05 |
| Leaching process cost* | US$/t | 5.26 |
| Selling* |  |  |
| Concentrate Cu payable price** | US$/lb | 3.36 |
| Concentrate Mo payable price*** | US$/lb | 9.72 |
| Leach Cu payable price*** | US$/lb | 3.77 |
| Minimum Modified Mining Royalty*** | % NSR | 1 |
| Average LOM recovery |  |  |
| Concentrate | % | 84.8 |
| Leaching | % | 42.4 |
| Cut-offs |  |  |
| Sulfide cut-off | % Cu | 0.112 |
| Leachable cut-off | % Cu | 0.149 |
| Pit slopes |  |  |
| Pit slope angles | Variable inter-ramp, degree | 40-50 |

Note: Numbers have been rounded.

* Excluding sustaining capital costs.

** Concentrate Cu payable price per pound produced includes the following: smelting & refining recoveries (99.4% and 99.9% respectively) and treatment costs (US$0.311/lb Cu, excluding sustaining costs), copper selling cost (US$-0.0024/lb Cu), and 1% NSR royalty.

*** Concentrate Mo payable price per pound produced includes the following: molybdenum selling cost (US$1.679/lb Mo), and 1% NSR royalty.

*** Leach Cu payable price per pound produced includes the following: cathode ocean freight cost (US$0.032/lb Cu), copper cathode premium (US$0.041/lb Cu), and 1% NSR royalty.

*** As per current Peruvian mining taxation regime.

Project No.: 252233  
 6 February 2023

Mineral Resource Estimates  
 Page 11-11

**wood.**

**Southern Copper**  
 **Grupo México**  
 MINERÍA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

## 11.12 Mineral Resource Estimate

### 11.12.1 Mineral Resource Statement

Mineral resources are reported using the mineral resource standards and definitions set out in S-K 1300, and are reported exclusive of those mineral resources converted to mineral reserves. The selected point of reference for the mineral resource estimate is in place (before mining). The mineral resource estimate is current as at 31 December, 2022.

The indicated mineral resource estimates for the Cuajone Operations are provided in Table 11-3. The inferred mineral resource estimates are included in Table 11-4. Wood is the QP Firm responsible for the estimate and the estimates have been prepared by, or under the supervision of qualified persons.

**Table 11-3: Indicated Mineral Resource Statement**

| Process Type | Tonnage (Mt) | Cu (%) | Mo (%) | Contained Cu (Mlb) | Contained Mo (Mlb) |
| --- | --- | --- | --- | --- | --- |
| Sulfide | 331.6 | 0.46 | 0.017 | 3,381.5 | 121.7 |
| Oxide | 0.2 | 0.62 | - | 3.2 | - |
| Total | 331.8 | 0.46 | - | 3,384.7 | 121.7 |

**Table 11-4: Inferred Mineral Resource Statement**

| Process Type | Tonnage (Mt) | Cu (%) | Mo (%) | Contained Cu (Mlb) | Contained Mo (Mlb) |
| --- | --- | --- | --- | --- | --- |
| Sulfide | 850.9 | 0.31 | 0.011 | 5,901.7 | 201.8 |
| Oxide | 0.3 | 0.51 | - | 3.4 | - |
| Total | 851.2 | 0.31 | - | 5,905.1 | 201.8 |

Note: (1) Mineral resources are reported in place and are current as at December 31, 2022. Mineral resources are reported exclusive of mineral reserves. Wood is the QP Firm responsible for the estimate.

(2) Mineral resources are constrained within an optimized pit shell based on copper and molybdenum only. Mineral resources are reported within a conceptual pit shell that use the following input parameters: metal prices of US$3.80/lb Cu and US$11.50/lb Mo; average metallurgical recovery assumptions of 84.8% for copper and 62.9% for molybdenum from a process plant and 42.4% copper recovery from a heap leach; based mining cost of US$1.76/t, mill process operating costs of US$7.05/t processed, leach costs of US$5.26/t processed; copper concentrate payable price of US$3.36/lb Cu, molybdenum concentrate payable price of US$9.72/lb Mo, and leach copper payable price of US$3.77/lb Cu.

(3) No estimates for molybdenum are reported for leachable material as this element cannot currently be recovered using the leach process envisaged.

(4) Numbers in the table have been rounded. Totals may not sum due to rounding.

Project No.: 252233  
 6 February 2023

Mineral Resource Estimates  
 Page 11-12

**wood.**

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

### 11.12.2 Uncertainties (Factors) That May Affect the Mineral Resource Estimate

Areas of uncertainty that may materially impact all of the mineral resource estimates include:

- Changes to long-term metal price and exchange rate assumptions
- Changes in local interpretations of mineralization geometry such as presence of unrecognized mineralization off-shoots; faults, dikes, and other structures; and continuity of mineralized zones
- Changes to geological and grade shape, and geological and grade continuity assumptions
- Changes to metallurgical recovery assumptions
- Changes to the input assumptions used to derive the open pit shell that is used to constrain the estimates
- Changes to the cut-off values applied to the estimates
- Variations in geotechnical (including seismicity), hydrogeological and mining assumptions
- Changes to environmental, permitting and social license assumptions.

Wood identified several factors that may result in poor validation results and other risks in the 2021 model:

- Issues with geological modeling especially the shapes and volumes of high-grade breccia units and lower grade dykes potentially having an impact on grade and tonnage above cut-off at bench-scale in the resource model used for long-range planning
- Weakness in geological and spatial consistency of alteration modeling
- Over-projection (blowouts) of higher-grade mineralization in areas of sparse drilling around the edges of the main mineralized zone, narrower zones and especially at depth in blocks flagged as inferred mineral resources
- Predominantly vertical drilling does not ideal for defining vertical lithological contacts, ore-waste boundaries, and gradients in grade
- Use of unnecessarily short (3 m) composites given the selective mining unit dimensions for the Cuajone Operations led to rejection of approximately 30% of drill data having sample lengths >3 m, resulting in a reduction in the confidence of mineral resource estimates because fewer data are used in grade estimation.

There are a number of blocks, primarily in lower-grade material that were not estimated with the parameters used and the average grade was assigned to these blocks. This risk was mitigated by modifying the distance used in classifying inferred mineral resources to a maximum distance of 120 m.

Project No.: 252233
6 February 2023

Mineral Resource Estimates
Page 11-13

wood.

**Southern Copper**  
![Grupo México logo]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

### 11.12.3 QP Statement

Wood is of the opinion that any issues that arise in relation to relevant technical and economic factors likely to influence the prospect of economic extraction can be resolved with further work. Porphyry-copper style deposits are a well-known and studied deposit type, and Southern Copper has more than 45 years’ experience with mining the Cuajone deposit.

Project No.: 252233  
6 February 2023

Mineral Resource Estimates  
Page 11-14

**wood.**

**Southern Copper**  
![Grupo México logo]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

## 12.0 MINERAL RESERVE ESTIMATES

### 12.1 Introduction

Indicated mineral resources were converted to mineral reserves by applying the modifying factors within a prefeasibility level mining study of the Cuajone mine operations. The life of mine plan for the Cuajone mining operations are considered by the Wood QPs to be technically achievable and economically viable and is a reasonable basis for determining the mineral reserves. Inferred mineral resources were set to waste.

### 12.2 Development of Mining Case

#### 12.2.1 Pit Optimization

Pit optimization was performed using the Lerchs-Grossmann (LG) algorithm in GEOVIA Whittle software. A summary of the economic and operational parameters used for the pit optimization of the Cuajone deposit is presented in Table 12-1.

Nested pit shells were run from revenue factors (RF) ranging from 0.2 to 1.0 (Figure 12-1 and Figure 12-2). The revenue factor is a multiplier applied to the base metal price and, subsequently, used in the pit optimization. For example, a RF of 1.0 corresponds to a copper base price of US$3.30/lb. A revenue factor of 0.5 multiplies the base metal price by 0.5 to determine the price used in the optimization and pit shells.

For final pit selection Southern Copper’s corporate guidelines dictates that total life-of-mine (LOM) production and metal content are maximized. As such, the revenue factor 1.0 pit shell was selected as the guide for the final pit design, a cut-off strategy to define material destination was used in mine planning.

#### 12.2.2 Block Model

The block model was updated as part of the 2021 fiscal year-end mineral reserve estimation incorporating some agreed modifications, see discussion in Chapter 12.2.3. These modifications in the block model were reviewed and approved by Southern Copper prior to the pit optimization step.

Project No.: 252233  
6 February 2023

Mineral Reserve Estimates  
Page 12-1

**wood.**

**Southern Copper**  
 **Grupo México**  
 MINERÍA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

**Table 12-1: Input Parameters Mineral Reserve Pit Shell**

| Parameter | Unit | Value |
| --- | --- | --- |
| Price |  |  |
| Copper | US$/lb | 3.30 |
| Molybdenum | US$/lb | 10.00 |
| Mining |  |  |
| Reference mining cost | US$/t-mined | 2.34 |
| Incremental haulage cost above reference level | US$/t-mined | 0.012 |
| Incremental haulage cost below reference level | US$/t-mined | 0.020 |
| Processing |  |  |
| Concentration process cost | US$/t-processed | 7.97 |
| Leaching process cost | US$/t-processed | 9.06 |
| Selling |  |  |
| Concentrate Cu payable price* | US$/lb-produced | 2.81 |
| Concentrate Mo payable price** | US$/lb-produced | 8.24 |
| Leach Cu payable price*** | US$/lb-produced | 3.28 |
| Average LOM Cu recovery |  |  |
| Concentrate*** | % | 84.8 |
| Leaching*** | % | 46.9 |
| Minimum Modified Mining Royalty *** | % NSR | 1 |

Note: Numbers have been rounded. All costs and metal prices assumptions are fixed over the 48-year life of mine.

* Concentrate Cu payable price per pound produced includes the following: smelting & refining recoveries (99.4% and 99.9% respectively) and treatment costs (US$0.382/lb Cu), copper selling cost (US$-0.0024/lb Cu), and 1% NSR royalty.

** Concentrate Mo payable price per pound produced includes the following: molybdenum selling cost (US$1.679/lb Mo), and 1% NSR royalty.

*** Leach Cu payable price per pound produced includes the following: cathode ocean freight cost (US$0.032/lb Cu), copper cathode premium (US$0.041/lb Cu), and 1% NSR royalty.

*** Average Cu metallurgical recovery, excluding ore currently stockpiled at the site.

*** As per current Peruvian mining taxation regime.

Project No.: 252233  
 6 February 2023

Mineral Reserve Estimates  
 Page 12-2

**wood.**

**Southern Copper**  
 **Grupo México**  
 MINERÍA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

**Figure 12-1: Nested Pit Shells from Pit Optimization (Plan View)**

![img-0.jpeg](img-0.jpeg)

(Source: Wood, 2022)

**Figure 12-2: Nested Pit Shells from Pit Optimization (Section View)**

![img-1.jpeg](img-1.jpeg)

(Source: Wood, 2021). Note: Elevation is in metres. Pit reference levels: 3295 (for sulfide), 3430 (for oxide), and 3430 (for waste)

Project No.: 252233  
 6 February 2023

Mineral Reserve Estimates  
 Page 12-3

**wood.**

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

### **12.2.3 Adjustment Factors to Mineral Reserves**

No mining dilution was applied based on grade reconciliation data completed as part of the 2021 mineral reserve estimation, showing no requirement for application of a dilution factor to the model. Mineralization extensions, which had been classified as indicated mineral resources were re-classified to inferred because of their limited grade estimation support. This resulted in a 20% reduction of indicated mineral resources and a corresponding reduction of mineral reserves for those blocks.

A 100% mining recovery was used because no reductions due to operational issues were identified, and the reconciliation from mine to mill completed as part of the 2021 mineral reserve estimation, showed mining recovery losses were adequately addressed in the mineral resource estimates.

### **12.2.4 Topography**

Surface topography was provided by Southern Copper and corresponds to the forecasted topography to the end of 2022. This surface was used to code the rock percentage in the block model item TOPO. Blocks above the surface were given a value of 0, blocks below the surface were given a value of 100, and blocks on the surface were given a value between 0-100 based on their percentage below topography.

### **12.2.5 Slope Angles**

Geotechnical zones used for the pit optimization were based on guidance provided by SRK (2016).

Block model item GTZN was used to code the different geotechnical zones and corresponds to an overall slope angle assigned in GEOVIA Whittle software. Overall slope angles (OSA) were estimated based on the 2022 optimized reserve pit design developed by Southern Copper (Table 12-2).

Project No.: 252233  
6 February 2023

Mineral Reserve Estimates  
Page 12-4

**wood.**

**Southern Copper**  
 **Grupo México**  
 MINERÍA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

**Table 12-2: Overall Slope Angle by Geotechnical Zones**

| Zone | GTZN Code | OSA (degree) |
| --- | --- | --- |
| NW | 1 | 40.0 |
| N | 2 | 34.0 |
| E1 | 3 | 36.0 |
| E2 | 4 | 31.0 |
| SE1 | 5 | 36.0 |
| SE2 | 6 | 33.0 |
| W1 | 7 | 38.0 |
| W2 | 8 | 37.0 |
| Pit bottom E | 9 | 37.0 |
| Pit bottom W | 10 | 39.0 |
| Fill | 11 | 30.0 |

Note: OSA calculated based on the 2022 optimized reserve pit design developed by Southern Copper. Fill code was used for blocks with undefined GTZN code.

### 12.2.6 Metallurgical Recoveries

Copper metallurgical recoveries were included in the block model for concentration and leaching processes, using formulas provided by SCC. These formulas were also used for the 2021 mineral reserve estimate.

The concentration metallurgical recovery for molybdenum was included in the block model using a formula provided by SCC. This formula was also used for the 2021 mineral reserve estimate.

The smelting recovery was set at 97.4%, and the refining recovery was 99.9%. Both values represent the average of historical smelting and refining recoveries at the Ilo smelter and refinery between 2018-2020. These recoveries were also used for the 2021 mineral reserve estimate.

### 12.2.7 Mining Costs

The base mining cost used was US$1.763/t mined, which was estimated from the 2021 year-end mineral reserve estimate LOM mining cost and the incremental haulage costs. The mining sustaining cost used was US$0.574/t mined, and included mining equipment and mining maintenance capital costs.

Project No.: 252233  
 6 February 2023

Mineral Reserve Estimates  
 Page 12-5

**wood.**

**Southern Copper**  
![Grupo México logo]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

The pit reference levels used were 3,295 masl for sulfide material, 3,430 masl for oxide material, and 3430 for waste material. An incremental haulage cost of US$0.012/t mined was applied for each bench above the pit reference level and US$0.020/t mined was applied for each bench below the pit reference level.

### **12.2.8 Processing Costs**

The concentration operating cost used was US$5.877/t-processed which corresponds to the 2021 year-end mineral reserve estimate LOM average concentration operating cost. The concentration sustaining cost used was US$0.387/t-processed for concentration material, which included primary crusher relocation, concentrator ongoing sustaining, and concentrator maintenance capital costs.

The tailings operating cost used was US$1.169/t-processed for concentration material, and corresponds to the 2021 year-end mineral reserve estimate LOM average conventional and filtered tailings disposal operating costs. The tailing sustaining cost used was US$0.538/t-processed for concentration material, which included existing TSF, filtering tailings plant and supporting infrastructure, and waste dumps (land acquisition) capital costs.

The leaching and SX/EW operating cost used was US$5.256/t-processed for leaching material, and corresponds to the 2021 year-end mineral reserve estimate LOM average leaching and SX/EW operating costs. The leaching and SX/EW sustaining cost used was US$3.805/t-processed for leaching material, which included leach pad expansion, leaching and SX/EW ongoing sustaining and maintenance capital costs.

The smelting and refining operating cost used was US$0.311/lb of copper cathode produced, and corresponds to the 2021 year-end mineral reserve estimate LOM average smelting and refining (Ilo) operating costs. The smelting and refining sustaining cost used was US$0.071/lb of copper cathode produced, which included Ilo smelter and refinery ongoing sustaining and maintenance, and other ongoing sustaining and maintenance capital costs.

### **12.2.9 Selling Costs for Concentration Process**

The copper selling cost included metallurgical deduction and allowance, ocean freight cost, and a copper cathode premium. The cathode premium reduced the selling cost, obtaining a final negative selling cost of -US$0.0024/lb of copper cathode produced.

A selling cost of US$1.679/lb-Mo was used for molybdenum, which included freight and roasting costs.

Project No.: 252233  
6 February 2023

Mineral Reserve Estimates  
Page 12-6

**wood.**

**Southern Copper**  
![Grupo México logo]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

### **12.2.10 Selling Costs for Leaching Process**

An ocean freight cost of US$0.032/lb of copper cathode produced was assumed, which corresponds to the average cost from 2020 to August 2022, using normalized values to Q3 2022, of shipping the material to the Americas, Europe, and Asia.

A copper cathode premium of US$0.041/lb produced was applied, average from 2020 to August 2022, using normalized values to Q3 2022.

### **12.2.11 Royalties**

A 1.0% NSR royalty was applied to copper and molybdenum for the pit optimization, which corresponds to the minimum Modified Mining Royalty (refer to discussion in Chapter 3.2.7).

### **12.2.12 Commodity Prices and Market**

Southern Copper is currently engaged in and has established a market for selling products from the Cuajone mine. A summary of the market is discussed in Chapter 16.1. Long-term metal prices of US$3.30/lb Cu and US$10.00/lb Mo were used to estimate mineral reserves over the life of the mine, and were provided by Southern Copper. Supporting information related to these prices can be found in Chapter 16.5.

### **12.2.13 Cut-offs**

To define the ultimate reserve pit for a concentration process it was considered a variable NSR cut-off value ranging from US$10.31/t to US$11.39/t. To define destination of the material it was based on a NSR cut-off ranging from US$7.791/t to US$8.079/t.

For heap leach it was considered a variable NSR cut-off value ranging from US$11.40/t to US$11.74/t. To define destination of the material it was based on a NSR cut-off of US$9.061/t.

Currently there are two crushers at the Cuajone operation, a main crusher for sulfide material at the entrance to the pit, and another crusher for oxide material adjacent to the Torata West waste rock storage facility (WRSF) by year 2042 because of mine development a new crusher for sulfide will be used. Since the oxide crusher is close to the WRSF, no differential cost between sending the material to the leach pad or to the WRSF was applied.

Project No.: 252233  
6 February 2023

Mineral Reserve Estimates  
Page 12-7

**wood.**

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

The formulas used to calculate the concentration and leaching mineral reserve NSR cut-off values were:

- CCO = (MC - MCW) + CC + TC
- LCO = (MC - MCW) + LSEC

where:

- CCO: concentration cut-off value (US$/t-processed for concentration material)
- LCO: leaching cut-off value (US$/t-processed for leaching material)
- MC: mining cost for mineralized material (US$/t mined)
- MCW: mining cost for waste material (US$/t mined)
- CC: concentration cost (US$/t-processed for concentration material)
- TC: tailing cost (US$/t-processed for concentration material)
- LSEC: leaching and SX/EW cost (US$/t-processed for leaching material).

The mine plan considers a strategy of elevated cut-off for years 2023 to 2026 of the mine plan with the purpose of increasing early cash flows. Using this strategy, the following approach to cut-off grade for Cu was used to define the material that goes directly to mill/concentrator:

- Year 2023 to 2025: ≥ 0.25 % of Cu
- Year 2026: ≥0.24 % of Cu
- Year 2027 to end of mine life: COG (≈0.15 %) of Cu

Material below the specific COG is sent to a stockpile if it is above the COG of ≈0.15 %Cu.

Cost assumptions are stated in the footnotes to Table 12-3 and are based on actual mine operational data and are fixed over the 48-year life of mine.

### 12.2.14 Pit Design

Figure 12-3 shows a plan view of the final pit design obtained for the Cuajone deposit. This final pit is the result of the extraction of nine mining phases, which are described in more detail in Chapter 13.4.

Project No.: 252233
6 February 2023

Mineral Reserve Estimates
Page 12-8

wood.

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

Figure 12-3: Final Pit Design (Plan View)

![img-2.jpeg](img-2.jpeg)

(Source: Wood, 2022)

### 12.2.15 Ore Versus Waste Determinations

The criteria for the determination of ore and waste included the following:

- Sulfide material was evaluated for treatment by a concentration process. The economical and marginal sulfide material above the concentration NSR cut-off value was defined as concentration/sulfide material.
- Oxide material was evaluated for leaching process. The economical and marginal oxide material above the leaching NSR cut-off value was defined as leaching/oxide material.
- The uneconomical sulfide material below the concentration NSR cut-off value was defined as waste material. The uneconomical oxide material below the leaching NSR cut-off value was defined as waste material. All other materials were also defined as waste material.

Project No.: 252233
6 February 2023

Mineral Reserve Estimates
Page 12-9

wood.

**Southern Copper**
**Grupo México**
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

- The mine plan considers an elevated cut-off strategy where material below the selected COG, but above the cut-off is sent to a stockpile, to be finally reclaimed at the end of LOM.

The formulas used to calculate the concentration and leaching material NSRs were:

- CNSR = CUG * CCUR * SMCUR * RFCUR * (CUP - CUSC - SMRFC) * (1 - ROY) * CF + MOG * CMOR * (MOP - MOSC) * (1 - ROY) * CF
- LNSR = CUG * LCUR * SECUR * (CUP - COFC + CUCP) * (1 - ROY) * CF

where:

- CNSR: concentration material NSR (US$/t-processed for concentration material)
- LNSR: leaching material NSR (US$/t-processed for leaching material)
- CUG: copper grade (%), MOG: molybdenum grade (%)
- CCUR: concentration copper recovery (%)
- CMOR: concentration molybdenum recovery (%)
- LCUR: leaching copper recovery (%)
- SMCUR: smelting copper recovery (%)
- RFCUR: refining copper recovery (%)
- SECUR: SX/EW copper recovery (%)
- CUP: copper price (US$3.3 /lb)
- MOP: molybdenum price (US$10/lb)
- CUSC: copper selling cost (US$/lb Cu)
- MOSC: molybdenum selling cost (US$/lb Mo)
- SMRFC: smelting and refining cost (US$/lb Cu)
- COFC: cathode ocean freight cost (US$/lb Cu)
- CUCP: copper cathode premium (US$/lb Cu)
- ROY: NSR royalty (Modified Mining Royalty) (1 %)
- CF: conversion factor between units (2,204.62 lb/t).

All costs and metal prices used in the mineral reserve determination were fixed over the life of mine.

Project No.: 252233
6 February 2023

Mineral Reserve Estimates
Page 12-10

wood.

**Southern Copper**  
 **Grupo México**  
 MINERÍA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

## 12.3 Mineral Reserve Estimate

### 12.3.1 Mineral Reserve Statement

Mineral reserves are reported using the mineral reserve definitions set out in S-K 1300. The selected point of reference for the mineral estimate is at delivery to the process facility. Mineral reserves are summarized in Table 12-3. No proven mineral reserves have been estimated.

Wood is the QP Firm responsible for the mineral reserve estimates and were prepared by, or under the supervision of appropriately qualified persons. The estimates are current as of December 31, 2022. The concentration and leach type ore currently stockpiled at the site is reported as concentration and leach ore from stockpile.

**Table 12-3: Probable Mineral Reserve Statement**

| Process Type | Tonnes (Mt) | Copper Grade (%) | Molybdenum Grade (%) | Contained Copper (Mlb) | Contained Molybdenum (Mlb) |
| --- | --- | --- | --- | --- | --- |
| Concentration | 1,307.0 | 0.48 | 0.017 | 13,956.7 | 497.5 |
| Concentration from stockpile | 29.1 | 0.41 | 0.017 | 260.0 | 10.8 |
| Leach | 0.4 | 0.68 | - | 5.6 | - |
| Leach from stockpile | 21.1 | 0.51 | - | 238.9 | - |
| Total | 1,357.6 | 0.48 | - | 14,461.2 | 508.3 |

Note: (1) Mineral reserves are current as of December 31, 2022. Wood is the QP Firm responsible for the estimate.

(2) Mineral reserves are constrained within an engineered pit based on copper and molybdenum revenues only. The following parameters were used in estimation: assumed open-pit mining methods; assumed concentration and leaching processes; copper price of US$3.30/lb, molybdenum price of US$10.00/lb; variable NSR cut-off values of US$7.791-US$8.079/t-processed for concentration material, and a NSR cut-off value of US$9.061/t-processed for leaching material; mining recovery of 100%; variable metallurgical recoveries (average LOM recoveries of 84.4% for copper by concentration, 62.5 % for molybdenum by concentration, and 48.2% for copper by leaching, including concentration and leach ore existing in stockpiles); average copper recoveries of 97.4% for smelting and 99.9% for refining; variable mining costs that range from US$2.337-US$3.417/t-mined; average process costs of US$7.971/t-processed for concentration material, and US$9.061/t for leaching material; average smelting and refining cost of US$0.382/lb Cu; selling costs of US$-0.0024/lb Cu for concentration process, US$1.679/lb Mo for concentration process, and US$-0.009/lb Cu for leaching process; and 1% NSR royalty applied to the for Cu and Mo.

(3) Numbers in the table have been rounded. Totals may not sum due to rounding.

Project No.: 252233  
 6 February 2023

Mineral Reserve Estimates  
 Page 12-11

**wood.**

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

### 12.3.2 Uncertainties (Factors) That May Affect the Mineral Reserve Estimate

In the opinion of the Wood QPs, areas of uncertainty that may materially impact the mineral reserve estimates include:

- Changes to long-term metal price and exchange rate assumptions
- Changes to metallurgical recovery assumptions
- Changes to the geological model supporting the mineral resource estimates
- Changes to the input assumptions used to derive the mineable shapes applicable to the open pit mining methods used to constrain the mineral reserve estimates
- Changes to the forecast dilution and mining recovery assumptions
- Changes to the NSR cut-off values applied to the estimates for example the material subject to the elevated cut-off strategy
- Variations in geotechnical (including seismicity), hydrogeological and mining method assumptions
- Changes to environmental, permitting, and social license assumptions.

To assess the impact of a number of these uncertainties on the mineral reserves, a pit optimization sensitivity analysis was performed in GEOVIA Whittle software for the sulfide and oxide mineralization in the Cuajone life of mine plan by varying the metal price, mining cost, process cost, and metallurgical recovery.

Variations in the metal price and metallurgical recovery generate the greatest impact on the mineral reserve estimates. Conversely, a variation in mining and process costs does not generate a significant impact on the mineral reserve estimates.

Project No.: 252233
6 February 2023

Mineral Reserve Estimates
Page 12-12

wood.

**Southern Copper**  
![Logo of Grupo México]() **Grupo México**  
MINERÍA

Southern Copper Corporation  
Technical Report Summary on Cuajone Operations  
Peru

## **13.0 MINING METHODS**

### **13.1 Introduction**

The Cuajone Operations use conventional truck-and-shovel open pit mining methods.

### **13.2 Geotechnical Considerations**

Geotechnical criteria used in the pit optimization were provided in Chapter 12.2.5. The geotechnical zones in relation to the pit outline are shown in Figure 13-1, and the pit slopes used in mine design are included in Table 13-1.

The fill material parameters were used by default for all blocks with an undefined GTZN code.

### **13.3 Hydrogeological Considerations**

Water that accumulates in the base of the pit is pumped out of the pit; the pumping system is capable of extracting 44 L/s. The water is used for dust suppression.

### **13.4 Operations**

#### **13.4.1 Pit Phases**

The open pit mine has a circular conical shape with a diameter of approximately 3.0 km. Currently, the highest elevation of the pit walls is on the southeast wall at 3,865 masl. The current bottom of the pit is at 2,955 masl, while the depth of the final pit design will be in 2,575 masl.

Nine pit phases remain in the life-of-mine (LOM) plan, starting with phase 6 and ending with phase 10C. The parameters used in the phase designs are summarized in Table 13-2. The final pit is shown by phase in Figure 13-2 and in cross-section view in Figure 13-3.

#### **13.4.2 Throughput**

The mine plan assumed a maximum mining capacity of 158 Mt of annual movement and a nominal processing rate of 90 kt/d of sulfide material at the milling/concentration facility.

Project No.: 252233  
6 February 2023

Mining Methods  
Page 13-1

**wood.**

Southern Copper

[LOGO]

Grupo México

MINERÍA

Southern Copper Corporation

Technical Report Summary on Cuajone Operations

Peru

Figure 13-1: Geotechnical Zones Projected to Final Pit Design Surface

![img-0.jpeg](img-0.jpeg)

(Source: Wood, 2022)

Table 13-1: Pit Slope Design Criteria by Geotechnical Zones

| Zone | GTZN Code | Bench Height (m) | Bench Face Angle (degree) | Inter-Ramp Angle (degree) | Catch Berm Width (m) | Maximum Inter-Ramp Height (m) |
| --- | --- | --- | --- | --- | --- | --- |
| NW | 1 | 15 | 70 | 49 | 7.6 | 180 |
| N | 2 | 15 | 60 | 42 | 8.0 | 180 |
| E1 | 3 | 15 | 60 | 42 | 8.0 | 150 |
| E2 | 4 | 15 | 70 | 44 | 10.1 | 150 |
| SE1 | 5 | 15 | 60 | 40 | 9.2 | 150 |
| SE2 | 6 | 15 | 70 | 44 | 10.1 | 150 |
| W1 | 7 | 15 | 60 | 45 | 6.3 | 180 |
| W2 | 8 | 15 | 70 | 44 | 10.1 | 180 |
| Pit bottom E | 9 | 15 | 65 | 47 | 7.0 | 180 |
| Pit bottom W | 10 | 15 | 65 | 50 | 5.6 | 180 |
| Fill | 11 | 15 | 38 | 38 | 0.0 | 90 |

Project No.: 252233

6 February 2023

Mining Methods

Page 13-2

wood.

**Southern Copper**  
 **Grupo México**  
 MINERÍA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

**Table 13-2: Pit Design Criteria Summary**

| Design Criteria | Unit | Value |
| --- | --- | --- |
| Bench height | m | 15 |
| Minimum mining width | m | 80 |
| Ramp width | m | 40 |
| Ramp gradient | % | 10 |
| Inter-ramp height | m | See Table 13-1 |
| Geotechnical berm width | m | 30-40 |
| Bench face angle | degree | See Table 13-1 |
| Inter-ramp angle | degree | See Table 13-1 |
| Catch berm width | m | See Table 13-1 |

**Figure 13-2: LOM Pit Phases**

![img-1.jpeg](img-1.jpeg)

(Source: Wood, 2022)

Project No.: 252233  
 6 February 2023

Mining Methods  
 Page 13-3

**wood.**

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

Figure 13-3: LOM Pit Phases (Section View)

![img-2.jpeg](img-2.jpeg)

(Source: Wood, 2022)

### 13.4.3 Operations

The mining operations are shown in the flow diagram in Figure 13-4.

Mining is conducted using two 12-h shifts. The mining operations can be summarized as:

- Initial drilling and blasting
- Loading, using shovels, of the blasted material into haul trucks
- Transport of ore and waste, depending on destination to WRSFs, stockpiles, oxide crusher, and sulfide crusher.

The current sulfide crusher is located at elevation 3,295 masl in the northern zone of the pit. Material is supplied to the crusher by haul trucks directly from the pit. Only at the end of the LOM material will also be supplied to the crusher from a sulfide stockpile. From the crusher, the crushed material is transported using a 7 km long conveyor belt to the concentrator plant. The sulfide crusher throughput is a nominal 90 kt/d. A new sulfide crusher located at level 3,385 is expected to be fully operational by year 2041 when development of phase 10B reaches level 3,295.

Project No.: 252233
6 February 2023

Mining Methods
Page 13-4

wood.

**Southern Copper**  
 **Grupo México**  
 MINERÍA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

Material destined for the heap leach pad can be sent either directly to an oxide stockpile, or to the oxide crusher that is located at elevation 3,480 masl, 5.9 km southwest of the pit. Once crushed, the material is rehandled by loaders and trucks and deposited on a heap leach pad approximately 1.0 km northeast of the oxide crusher.

**Figure 13-4: Mine Operation Flow Diagram**

![img-3.jpeg](img-3.jpeg)

(Source: Wood, 2022)

#### 13.4.4 Production Plan

The LOM plan assumes that all material that will be processed by concentration goes to the current sulfide crusher and to the new sulfide crusher by year 2042. All material that will be processed by heap leaching goes to the oxide crusher. The point of transfer from mining to processing is at the point of the conveyor or delivery to the oxide crusher.

Three pit phases will be operational at any one time, to ensure that production rates can be met. A maximum mining capacity per phase of 110 Mt/a is assumed, with a maximum vertical advance rate of 10 benches per year. The mine plan assumes:

- 2023: phases 6, 7, and 8 are in the production stage and phase 9A is undergoing stripping.

Project No.: 252233  
 6 February 2023

Mining Methods  
 Page 13-5

**wood.**

Southern Copper
Grupo México
MINERÍA

Southern Copper Corporation
Technical Report Summary on Cuajone Operations
Peru

- 2024: phase 9B will commence stripping, and phases 6, 7, and 8 will be in production.
- 2028: phase 10B will commence stripping, and phases 7 and 9A will be in production.
- 2030: phase 10A will commence stripping, and phases 7, 9A, and 9B will be in production.
- 2038: phase 9C will be in production.
- 2059: phase 10C will be in production.

Four WRSFs will be used:

- The Torata east WRSF will be used from 2025 to 2026, and will receive material from phase 9A.
- The Cuajone WRSF will be used from 2023 to 2052, and will receive material mainly from phases 9A and 10B.
- The Cocotea west WRSF will be used from 2024 to 2040, and will receive material mainly from phases 9A and 10A.
- The Torata west WRSF will be used from 2023 to 2068, and will receive material mainly from phases 9B, 10A, and 10B.

The material movement envisaged in the LOM plan is provided in Figure 13-5.

Mill availability can vary, and Southern Copper has a formula that is used to predict the amount of material that can be fed to the plant based on a combination of the material work index and mill availability. This was used to estimate the amount of time needed to mill each block, and the mine plan was optimized to try and fill the mills based on the available time.

The mine plan considers a strategy of elevated cut-off for years 2023 to 2026 of the mine plan with the purpose of increasing early cash flows.

Figure 13-6 shows that the mine plan is expected to obtain a variable feed to the sulfide crusher ranging from approximately 22-31 Mt/a. The average copper grades are expected vary from 0.2-0.7%. During almost the entire LOM, the feed will be direct from the mine, except for the last 3 years where the feed will also include material from the sulfide stockpile.

The oxide crusher will operate at a maximum effective capacity of 1.2 Mt/a (Figure 13-7). The feed will be mainly with material from the existing oxide stockpile, except in the years where material from the mine will also be included in the feed.

Table 13-3, Table 13-4, and Table 13-5 show the material movement on an annualized basis.

The final LOM pit layout plan is provided in Figure 13-8.

Project No.: 252233
6 February 2023

Mining Methods
Page 13-6

wood.

**Southern Copper**  
 **Grupo México**  
 MINERÍA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

**Figure 13-5: LOM Material Movement by Destinations**

![img-4.jpeg](img-4.jpeg)

(Source: Wood, 2022)

**Figure 13-6: LOM Feed to Sulfide Crusher**

![img-5.jpeg](img-5.jpeg)

(Source: Wood, 2022)

Project No.: 252233  
 6 February 2023

Mining Methods  
 Page 13-7

**wood.**

SouthernCopper

[LOGO]

GrupoMéxico

MINERÍA

Southern Copper Corporation

Technical Report Summary on Cuajone Operations

Peru

Figure 13-7: LOM Feed to Oxide Crusher

![img-6.jpeg](img-6.jpeg)

(Source: Wood, 2022)

Project No.: 252233

6 February 2023

Mining Methods

Page 13-8

wood.

**Southern Copper**  
 **Grupo México**  
 MINERÍA

Southern Copper Corporation  
 Technical Report Summary on Cuajone Operations  
 Peru

**Table 13-3: LOM Material Movement Plan (Sulfide Material)**

| Year | Direct Feed to Sulfide Crusher |  |  |  |  |  | Reclaimed Feed to Sulfide Crusher |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  | Tonnage (Mt) | Work Index (kWh/st) | Grade |  | Recovery |  | Tonnage (Mt) | Work Index (kWh/st) | Grade |  | Recovery |  |  |
|  |  |  | Cu (%) | Mo (%) | Cu (%) | Mo (%) |  |  | Cu (%) | Mo (%) | Cu (%) | Mo (%) |  |
|  | 2023 | 26.1 | 17.6 | 0.58 | 0.020 | 85.1 | 63.1 | - | - | - | - | - | - |
| 2024 | 28.7 | 16.9 | 0.64 | 0.022 | 85.8 | 63.3 | - | - | - | - | - | - |  |
| 2025 | 28.0 | 18.0 | 0.67 | 0.021 | 84.9 | 63.3 | - | - | - | - | - | - |  |
| 2026 | 28.8 | 17.4 | 0.63 | 0.023 | 85.5 | 63.4 | - | - | - | - | - | - |  |
| 2027 | 28.4 | 16.9 | 0.49 | 0.026 | 85.1 | 63.4 | - | - | - | - | - | - |  |
| 2028 | 29.2 | 17.1 | 0.39 | 0.018 | 85.0 | 62.8 | - | - | - | - | - | - |  |
| 2029 | 28.6 | 17.5 | 0.38 | 0.015 | 84.1 | 62.2 | - | - | - | - | - | - |  |
| 2030 | 26.7 | 18.9 | 0.40 | 0.009 | 82.8 | 59.8 | - | - | - | - | - | - |  |
| 2031 | 26.7 | 18.9 | 0.41 | 0.009 | 83.1 | 60.2 | - | - | - | - | - | - |  |
| 2032 | 26.6 | 19.0 | 0.46 | 0.011 | 83.3 | 61.6 | - | - | - | - | - | - |  |
| 2033 | 27.2 | 18.5 | 0.45 | 0.010 | 83.1 | 61.2 | - | - | - | - | - | - |  |
| 2034 | 27.9 | 18.0 | 0.55 | 0.014 | 84.0 | 62.4 | - | - | - | - | - | - |  |
| 2035 | 27.8 | 18.0 | 0.56 | 0.016 | 84.3 | 62.8 | - | - | - | - | - | - |  |
| 2036 | 28.4 | 17.6 | 0.58 | 0.016 | 84.4 | 62.8 | - | - | - | - | - | - |  |
| 2037 | 29.0 | 17.2 | 0.61 | 0.016 | 84.9 | 62.9 | - | - | - | - | - | - |  |
| 2038 | 28.7 | 17.4 | 0.64 | 0.018 | 84.6 | 62.9 | - | - | - | - | - | - |  |
| 2039 | 29.7 | 16.8 | 0.63 | 0.020 | 85.6 | 63.3 | - | - | - | - | - | - |  |
| 2040 | 30.9 | 16.0 | 0.61 | 0.022 | 86.4 | 63.4 | - | - | - | - | - | - |  |

Project No.: 252233  
 6 February 2023

Mining Methods  
 Page 13-9

**wood.**

**Time limit hit – remaining pages or documents were skipped.**