In 2017, we designed a detailed process for the preparation of technical reports required for the declaration of our mineral reserves and mineral resources in all of our mines and greenfield projects, which were in accordance with the standards set forth in Canada’s National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”) and the U.S. Securities and Exchange Commission (“SEC”) Industry Guide 7.
In October 2018, the Securities and Exchange Commission (“SEC”) adopted amendments to its current disclosure rules to modernize the mineral property disclosure requirements for mining registrants. The amendments include the adoption of a new subpart 1300 of regulation S-K (“S-K 1300”), which will govern disclosure for mining registrants (the “SEC Mining Modernization Rules”). The SEC Mining Modernization Rules replace the historical property disclosure requirements for mining registrants that were included in the SEC’s Industry Guide 7 and better align disclosure with international industry and regulatory practices, including the NI 43-101.
Nexa notes that it has voluntarily adopted the SEC’s new disclosure requirements for mining reserves and resources under S-K 1300 for the financial year ended December 31, 2020, which are required to be adopted by registrants in annual reports for the fiscal year beginning on or after January 1, 2021.
We are always working on the updated of our mineral reserves and mineral resources, as presented below. The technical reports, mining reports and press releases related to mineral reserves and mineral resources are available on www.sedar.com and www.sec.gov.
Mineral Reserves and Mineral Resources
Nexa Resources announced on March 27, 2024, the publication of updated information relating to mineral reserves and resources as of December 31, 2023. All Mineral Reserve and Mineral Resource estimates of the Company disclosed or referenced in this news release have been prepared in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum (“CIM”) Definition Standards on Mineral Reserves and Mineral Resources dated May 10, 2014 (“2014 CIM Definition Standards”), whose definitions are incorporated by reference in NI 43-101, for the metals indicated per mine and project. Accordingly, such information may not be comparable to the information that is presented in our annual report on Form 20-F prepared in accordance with S-K 1300.
| Mineral Reserves – NI 43-101 | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Grade | Contained Metal | ||||||||||||
| Interest
|
Ownership (%) |
Class
|
Tonnage (1) | Zinc | Copper | Silver | Lead | Gold | Zinc | Copper | Silver | Lead | Gold |
| (Mt) | (%) | (%) | (g/t) | (%) | (g/t) | (kt) | (kt) | (koz) | (kt) | (koz) | |||
|
Cerro Lindo (2) |
83.48% |
Proven | 26.15 | 1.68 | 0.61 | 21.2 | 0.20 | – | 439.7 | 158.8 | 17,803 | 52.8 | – |
| Probable | 15.00 | 1.15 | 0.45 | 25.2 | 0.24 | – | 172.9 | 68.1 | 12,163 | 35.9 | – | ||
| Subtotal | 41.15 | 1.49 | 0.55 | 22.6 | 0.22 | – | 612.6 | 226.9 | 29,966 | 88.7 | – | ||
|
El Porvenir (3) |
83.48% |
Proven | 3.92 | 4.09 | 0.24 | 75.2 | 1.29 | – | 160.3 | 9.5 | 9,472 | 50.3 | – |
| Probable | 10.73 | 4.11 | 0.22 | 72.1 | 1.17 | – | 441.6 | 24.0 | 24,867 | 125.3 | – | ||
| Subtotal | 14.65 | 4.11 | 0.23 | 72.9 | 1.20 | – | 601.9 | 33.5 | 34,338 | 175.7 | – | ||
|
Atacocha |
75.96% |
Proven | 1.71 | 3.86 | 0.34 | 84.9 | 1.45 | – | 65.8 | 5.7 | 4,654 | 24.6 | – |
| Probable | 3.96 | 4.54 | 0.43 | 77.7 | 1.29 | – | 179.8 | 16.9 | 9,886 | 51.1 | – | ||
| Subtotal | 5.66 | 4.33 | 0.40 | 79.8 | 1.34 | – | 245.6 | 22.6 | 14,540 | 75.7 | – | ||
|
Atacocha |
75.96% |
Proven | 1.91 | 1.02 | – | 38.2 | 1.16 | 0.25 | 19.5 | – | 2,342 | 22.2 | 15.2 |
| Probable | 2.47 | 0.97 | – | 32.4 | 1.14 | 0.29 | 24.0 | – | 2,577 | 28.1 | 22.9 | ||
| Subtotal | 4.38 | 0.99 | – | 34.9 | 1.15 | 0.27 | 43.5 | – | 4,919 | 50.3 | 38.1 | ||
|
Total |
Proven | 33.69 | 2.03 | 0.52 | 31.6 | 0.44 | 0.05 | 685.3 | 174.0 | 34,271 | 149.9 | 15.2 | |
| Probable | 32.16 | 2.54 | 0.34 | 47.9 | 0.75 | 0.07 | 818.3 | 109.0 | 49,493 | 240.4 | 22.9 | ||
| Total | 65.85 | 2.28 | 0.43 | 39.6 | 0.59 | 0.06 | 1,503.6 | 283.0 | 83,764 | 390.3 | 38.1 | ||
Notes: The estimation of Mineral Reserves involves assumptions as to future commodity prices and as to technical mining matters. Numbers and totals may not sum due to rounding. The qualified person responsible for the Mineral Reserve estimates are not aware of any mining, metallurgical, infrastructure, permitting, or other relevant factors that could materially affect the Mineral Reserve estimate. The El Porvenir, Atacocha Underground and Atacocha Open Pit mines are part of the Cerro Pasco Complex.
(1) The tonnage and content amounts presented in this table have not been adjusted to reflect our ownership interest. The information presented in this table includes 100% of the Mineral Resources estimates of our consolidated subsidiaries and of our joint ventures, certain of which are not wholly owned, as set out in this ownership interests’ column.
(2) Cerro Lindo
The Qualified Person for the Mineral Reserves estimate is Cristovao Teofilo dos Santos, B.Eng., FAusIMM, a Nexa employee. Subpart 1300 of Regulation S-K definitions were followed for Mineral Reserves, which also are consistent with the CIM (2014) definitions. Mineral Reserves are estimated at an NSR break-even cut-off value of US$40.86/t processed. Some incremental material with values between US$32.99/t and US$40.86/t was included. Mineral Reserves estimates are based on average long-term metal prices of: zinc: US$2,799.04/t (US$1.27/lb); copper: US$7,669.61/t (US$3.48/lb); lead: US$2,000.29/t (US$0.91/lb); and silver: US$21.17/oz. Metallurgical recoveries are accounted for in NSR calculations based on historical processing data and are variable as a function of head grade. Recoveries at Life of Mine average head grades are 88.36% for Zn, 85.23% for Cu, 66.53% for Pb, and 68.78% for Ag. A minimum mining width of 5.0 m was used. Dilution and extraction factors are applied based on stope type and location. Bulk density varies depending on mineralization domain.
(3) El Porvenir
The Qualified Person for the Mineral Reserves estimate is SLR Consulting (Canada) Ltd., an independent mining consulting firm. Subpart 1300 of Regulation S-K definitions were followed for Mineral Reserves, which also are consistent with the CIM (2014) definitions. Mineral Reserves are estimated at NSR cut-off grade values ranging from US$63.77/t to US$67.04/t for SLS areas and US$65.77/t to US$69.04/t for C&F areas depending on the zone. Mineral Reserves estimates are based on average long-term metal prices of: zinc: US$2,799.04/t (US$1.27/lb); copper: US$7,669.61/t (US$3.48/lb); lead: US$2,000.29/t (US$0.91/lb); and silver: US$21.17/oz. Metallurgical recoveries are accounted for in NSR calculations based on historical processing data and are variable as a function of head grade. Recoveries at Life of Mine average head grade are 89.21% for Zn, 14.60% for Cu, 80.01% for Pb, and 77.51% for Ag. Minimum mining width of 5.0 m for C&F mining and 4.0 m for SLS mining were used for reserves shapes and development design and are reported inclusive of extraction losses and dilution.
(4) Atacocha (Underground)
The Qualified Person for the Mineral Reserves estimate is SLR Consulting (Canada) Ltd., an independent mining consulting firm. Subpart 1300 of Regulation S-K definitions were followed for Mineral Reserves, which also are consistent with the CIM (2014) definitions. The Mineral Reserves were estimated at a NSR cut-off of US$69.00/t for SLS areas and US$71.07/t for C&F areas depending on the zone. A number of incremental material (with values between US$45.09/t and US$69.00/t for SLS and values between US$47.16/t and US$71.07/t for C&F mining were included in estimate. Mineral Reserves estimates are based on average long-term metal prices of: zinc: US$2,799.04/t (US$1.27/lb); copper: US$7,669.61/t (US$3.48/lb); lead: US$2,000.29/t (US$0.91/lb); and silver: US$21.17/oz. Metallurgical recoveries are accounted for in NSR calculations based on historical processing data and are variable as a function of head grade. Recoveries at Life of Mine average head grades are 89.30% for Zn, 15.73% for Cu, 80.02% for Pb, and 77.51% for Ag. Minimum mining width of 5.0 m for C&F mining and 4.0 m for SLS mining were used for reserves shapes and development design and are reported inclusive of extraction losses and dilution.
(5) Atacocha (Open pit)
The Qualified Person for the Mineral Reserves estimate is SLR Consulting (Canada) Ltd., an independent mining consulting firm. Subpart 1300 of Regulation S-K definitions were followed for Mineral Reserves, which also are consistent with the CIM (2014) definitions. Mineral Reserves are estimated at a NSR cut-off values of US$16.21/t. Mineral Reserves estimates are based on average long-term metal prices of: zinc: US$2,799.04/t (US$1.27/lb); lead: US$2,000.29/t (US$0.91/lb); silver: US$21.17/oz; and gold: US$1,630.93/oz. Metallurgical recoveries are accounted for in NSR calculations based on historical processing data and are variable as a function of head grade. Recoveries at Life of Mine average heads grade are 70.44% for Zn, 83.97% for Pb, 75.76% for Ag and 65.46% for Au.
| Mineral Resources – NI 43-101 (Mines) | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Grade | Contained Metal | ||||||||||||
| Interest
|
Ownership (%) |
Class
|
Tonnage (1) | Zinc | Copper | Silver | Lead | Gold | Zinc | Copper | Silver | Lead | Gold |
| (Mt) | (%) | (%) | (g/t) | (%) | (g/t) | (kt) | (kt) | (koz) | (kt) | (koz) | |||
|
Cerro Lindo (2) |
83.48% |
Measured | 4.40 | 1.93 | 0.65 | 23.1 | 0.24 | – | 84.9 | 28.6 | 3,268 | 10.6 | – |
| Indicated | 3.30 | 1.06 | 0.47 | 24.4 | 0.22 | – | 35.0 | 15.5 | 2,589 | 7.3 | – | ||
| Subtotal | 7.70 | 1.56 | 0.57 | 23.7 | 0.23 | – | 119.9 | 44.1 | 5.857 | 17.9 | – | ||
| Inferred | 9.28 | 1.54 | 0.25 | 32.6 | 0.42 | – | 142.9 | 23.2 | 9,726 | 39.0 | – | ||
|
El Porvenir (3) |
83.48% |
Measured | 0.66 | 3.47 | 0.27 | 57.7 | 0.95 | – | 22.9 | 1.8 | 1,225 | 6.3 | – |
| Indicated | 3.22 | 3.25 | 0.20 | 63.2 | 0.97 | – | 104.7 | 6.4 | 6,540 | 31.2 | – | ||
| Subtotal | 3.88 | 3.29 | 0.21 | 62.2 | 0.97 | – | 127.6 | 8.2 | 7,765 | 37.5 | – | ||
| Inferred | 11.06 | 3.83 | 0.24 | 82.9 | 1.32 | – | 423.6 | 26.5 | 29,471 | 146.0 | – | ||
|
Atacocha |
75.96% |
Measured | 1.05 | 3.47 | 0.27 | 55.0 | 0.98 | – | 36.4 | 2.8 | 1,857 | 10.3 | – |
| Indicated | 2.52 | 3.30 | 0.36 | 54.9 | 0.92 | – | 83.2 | 9.1 | 4,448 | 23.2 | – | ||
| Subtotal | 3.57 | 3.35 | 0.33 | 54.9 | 0.94 | – | 119.6 | 11.9 | 6,305 | 33.5 | – | ||
| Inferred | 8.06 | 4.09 | 0.56 | 77.3 | 1.21 | – | 329.7 | 45.1 | 20,031 | 97.5 | – | ||
|
Atacocha |
75.96% |
Measured | 1.80 | 1.28 | – | 31.4 | 0.87 | 0.19 | 36.1 | – | 1,818 | 15.7 | 11.0 |
| Indicated | 3.88 | 1.05 | – | 29.0 | 0.90 | 0.24 | 87.3 | – | 3,616 | 34.9 | 29.9 | ||
| Subtotal | 5.68 | 1.12 | – | 29.8 | 0.89 | 0.22 | 123.4 | – | 5,434 | 50.6 | 40.9 | ||
| Inferred | 1.70 | 1.27 | – | 32.7 | 1.15 | 0.22 | 18.6 | – | 1,787 | 19.6 | 12.0 | ||
|
Total Mines |
Measured | 7.90 | 2.12 | 0.42 | 32.2 | 0.54 | 0.14 | 167.2 | 33.2 | 8,168 | 42.9 | 11.0 | |
| Indicated | 12.92 | 2.04 | 0.24 | 41.4 | 0.75 | 0.23 | 263.6 | 31.0 | 17,193 | 96.6 | 29.9 | ||
| Total | 20.82 | 2.07 | 0.31 | 37.9 | 0.67 | 0.20 | 430.8 | 64.2 | 25,361 | 139.5 | 40.9 | ||
| Inferred | 30.10 | 3.05 | 0.31 | 63.0 | 0.94 | 0.04 | 917.8 | 94.8 | 61,015 | 284.1 | 12.0 | ||
| Mineral Resources – NI 43-101 (Zinc Projects) | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Grade | Contained Metal | ||||||||||||
| Interest
|
Ownership (%) |
Class
|
Tonnage (1) | Zinc | Copper | Silver | Lead | Gold | Zinc | Copper | Silver | Lead | Gold |
| (Mt) | (%) | (%) | (g/t) | (%) | (g/t) | (kt) | (kt) | (koz) | (kt) | (koz) | |||
|
Hilarión (6) |
83.48% |
Measured | 14.54 | 3.39 | – | 30.9 | 0.69 | – | 492.9 | – | 14,445 | 100.3 | – |
| Indicated | 34.03 | 3.62 | – | 27.0 | 0.54 | – | 1,231.9 | – | 29,540 | 183.8 | – | ||
| Subtotal | 48.57 | 3.55 | – | 28.2 | 0.58 | – | 1,724.8 | – | 43,985 | 284.1 | – | ||
| Inferred | 42.17 | 4.06 | – | 25.0 | 0.41 | – | 1,712.1 | – | 33,895 | 172.9 | – | ||
|
Florida Canyon Zinc (7) |
50.93% |
Measured | 0.81 | 11.32 | – | 15.4 | 1.40 | – | 91.7 | – | 401 | 11.3 | – |
| Indicated | 1.63 | 10.28 | – | 14.9 | 1.31 | – | 167.6 | – | 781 | 21.4 | – | ||
| Subtotal | 2.44 | 10.63 | – | 15.1 | 1.34 | – | 259.3 | – | 1.182 | 32.7 | – | ||
| Inferred | 14.86 | 9.63 | – | 11.3 | 1.26 | – | 1.431.0 | – | 5,399 | 187.2 | – | ||
|
Total Zinc Projects |
Measured | 15.35 | 3.81 | – | 30.1 | 0.73 | – | 584.6 | – | 14,846 | 111.6 | – | |
| Indicated | 35.66 | 3.91 | – | 26.4 | 0.58 | – | 1,399.5 | – | 30,321 | 205.2 | – | ||
| Subtotal | 51.01 | 3.89 | – | 27.5 | 0.62 | – | 1,984.1 | – | 45,167 | 316.8 | – | ||
| Inferred | 57.03 | 5.51 | – | 21.4 | 0.63 | – | 3,143.1 | – | 39,294 | 361.1 | – | ||
| Mineral Resources – NI 43-101 (Copper Projects) | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Grade | Contained Metal | ||||||||||||||
| Interest
|
Ownership (%) |
Class
|
Tonnage (1) | Zinc | Copper | Silver | Lead | Gold | Moly | Zinc | Copper | Silver | Lead | Gold | Moly |
| (Mt) | (%) | (%) | (g/t) | (%) | (g/t) | (%) | (kt) | (kt) | (koz) | (kt) | (koz) | (kt) | |||
|
Magistral (8) |
83.48% |
Measured | 98.69 | – | 0.52 | 2.8 | – | – | 0.050 | – | 513.2 | 8,884 | – | – | 49.3 |
| Indicated | 90.68 | – | 0.43 | 2.8 | – | – | 0.040 | – | 389.9 | 8,163 | – | – | 36.3 | ||
| Subtotal | 189.37 | – | 0.48 | 2.8 | – | – | 0.045 | – | 903.1 | 17,047 | – | – | 85.6 | ||
| Inferred | 11.06 | – | 0.38 | 3.1 | – | – | 0.050 | – | 42.0 | 1,103 | – | – | 5.5 | ||
Notes: The estimation of Mineral Resources involves assumptions as to future commodity prices and as to technical mining matters. Numbers and totals may not sum due to rounding. Mineral Resources are reported exclusive of those Mineral Resources that were converted to Mineral Reserves, and Mineral Resources are not Mineral Reserves and do not have demonstrated economic viability. The El Porvenir, Atacocha Underground and Atacocha Open Pit mines are part of the Cerro Pasco Complex.
(1) The tonnage and content amounts presented in this table have not been adjusted to reflect our ownership interest. The information presented in this table includes 100% of the Mineral Resources estimates of our consolidated subsidiaries and of our joint ventures, certain of which are not wholly owned, as set out in this ownership interests’ column.
(2) Cerro Lindo
Mineral Resources are effective date as of December 31, 2023. The Qualified Person for the Mineral Resources estimate is Jerry Huaman Abalos, B.Geo., MAusIMM CP (Geo), a Nexa employee. Subpart 1300 of Regulation S-K definitions were followed for Mineral Resources, which also are consistent with the CIM (2014) definitions. Mineral Resources are reported on a 100% ownership basis. Nexa owns 83.48%. Mineral Resources are estimated at an NSR cut-off value of US$40.86/t. Mineral Resources estimates are based on average long-term metal prices of: zinc: US$3,218.90/t (US$1.46/lb); copper: US$8,820.05/t (US$3.48/lb); lead: US$2,300.33/t (US$1.04/lb); and silver: US$24.35/oz. Metallurgical recoveries are accounted for in NSR calculations based on historical processing data and are variable as a function of head grade. Recoveries at Life of Mine average head grades are 88.36% for Zn, 85.23% for Cu, 66.53% for Pb, and 68.78% for Ag. A minimum mining width of 4.0 m was used to create resource shapes. Bulk density varies depending on mineralization domain
(3) El Porvenir
Mineral Resources are effective date as of December 31, 2023. The Qualified Person for the Mineral Resources estimate is Jerry Huaman Abalos, B.Geo., MAusIMM CP (Geo), a Nexa employee. Subpart 1300 of Regulation S-K definitions were followed for Mineral Resources, which also are consistent with the CIM (2014) definitions. Mineral Resources are reported on a 100% ownership basis. Nexa owns 83.48%. Mineral Resources are estimated at NSR cut-off grade values ranging from of US$63.77/t to US$67.05/t for SLS areas and US$65.77/t to US$69.04for C&F areas depending on the zone. Mineral Resources estimates are based on average long-term metal prices of: zinc: US$3,218.90/t (US$1.46/lb); copper: US$8,820.05/t (US$3.48/lb); lead: US$2,300.33/t (US$1.04/lb); and silver: US$24.35/oz. Metallurgical recoveries are accounted for in NSR calculations based on historical processing data and are variable as a function of head grade. Recoveries at Life of Mine average head grades are 89.21% for Zn, 14.60% for Cu, 80.01% for Pb, and 77.51% for Ag. A minimum mining width of 4.0 m was used for C&F and 3.0 m was used for SLS resource stopes shapes respectively. Bulk density varies depending on mineralization domain.
(5) Atacocha (Underground)
Mineral Resources are effective date as of December 31, 2023. The Qualified Person for the Mineral Resources estimate is Jerry Huaman Abalos, B.Geo., MAusIMM CP (Geo), a Nexa employee. Subpart 1300 of Regulation S-K definitions were followed for Mineral Resources, which also are consistent with the CIM (2014) definitions. Mineral Resources are reported on a 100% ownership basis. Nexa owns 75.96%. Mineral Resources are estimated at a NSR cut-off value of US$69.00/t for SLS, and US$71.07/t for C&F. Mineral Resources estimates are based on average long-term metal prices of: zinc: US$3,218.90/t (US$1.46/lb); copper: US$8,820.05/t (US$3.48/lb); lead: US$2,300.33/t (US$1.04/lb); and silver: US$24.35/oz. Metallurgical recoveries are accounted for in NSR calculations based on historical processing data and are variable as a function of head grade. Recoveries at Life of Mine average head grades are 89.30% for Zn, 14.60% for Cu, 80.02% for Pb, and 77.51% for Ag. A minimum mining width of 4.0 m was used for resources shape. Density was assigned based on rock type.
(6) Atacocha (Open Pit)
Mineral Resources are effective date as of December 31, 2023. The Qualified Person for the Mineral Resources estimate is Jerry Huaman Abalos, B.Geo., MAusIMM CP (Geo), a Nexa employee. Subpart 1300 of Regulation S-K definitions were followed for Mineral Resources, which also are consistent with the CIM (2014) definitions. Mineral Resources are reported on a 100% ownership basis. Nexa owns 75.96%. Mineral Resources are reported within optimized pit shell. Mineral Resources are estimated at a NSR cut-off value of US$22.44/t. Mineral Resources estimates are based on average long-term metal prices of: zinc: US$3,218.90/t (US$1.46/lb); lead: US$2,300.33/t (US$1.04/lb); silver: US$24.35/oz; and gold: US$1,875.57/oz. Metallurgical recoveries are accounted for in NSR calculations based on historical processing data and are variable as a function of head grade. Recoveries at Life of Mine average head grades are 70.44% for Zn, 83.97% for Pb, 75.76% for Ag, and 65.46% for Au. Mineral resources are reported within open pit shell. Density was assigned based on rock type.
(7) Hilarion
Mineral Resources have effective date as of December 31, 2022. The Qualified Person for the Mineral Resources estimate is Jerry Huaman Abalos, B.Geo., MAusIMM CP (Geo), a Nexa Resources employee. Mineral Resources are reported on a 100% ownership basis. Nexa owns 83.48%. Mineral Resources are estimated at a NSR cut-off value of US$45.00/t for SLS resource shapes for the Hilarión deposit, and US$50.00/t for Room & Pillar (R&P) resource shapes for the El Padrino deposit. Mineral Resources estimates are based on average long-term metal prices of: zinc: US$3,245.91/t (US$1.47/lb); lead: US$2,332.46/t (US$1.06/lb); and silver: US$22.66/oz. Mineral Resources are reported within underground mining shapes. A minimum mining width of 3.0 m was used for Hilarión and El Padrino. Bulk density varies depending on mineralization domain.
(8) Florida Canyon Zinc
Mineral Resources have effective date as of October 30, 2020. The Qualified Person for the Mineral Resources estimate is Jerry Huaman Abalos, B.Geo., MAusIMM CP (Geo), a Nexa Resources employee. Mineral Resources are reported on a 100% ownership basis. Nexa owns 50.93%. Mineral Resources are reported using a cut-off values of US$41.40/t NSR for SLS, US$42.93/t for C&F and US$40.61/t for Room & Pillar mine areas. Forecast long term metal prices used for the NSR calculation are Zn: US$ 2,816.35/t (US$ 1.28/lb); Pb: US$ 2,196.50/t (US$ 1.00/lb) and Ag: US$ 19.38/oz. Average metallurgical recoveries for the resource are Zinc (80%), Lead (74%) and Silver (52%). Mineral Resources are reported within underground mining shapes. Minimum thickness is 3.0 m for SLS and C&F, and 4.0 m for Room & Pillar. Bulk density varies depending on mineralization domain.
(9) Magistral
Mineral Resources have effective date as of December 31, 2021. The Qualified Person for the Mineral Resources estimate is Jerry Huaman Abalos, B.Geo., MAusIMM CP (Geo), a Nexa Resources employee. Mineral Resources are reported on a 100% ownership basis. Nexa owns 83.48%. Mineral Resources are estimated at NSR cut-off values of US$5.99/t for porphyry, US$5.51/t for mixed, and US$5.48/t for skarn rock types. Metallurgical recoveries are accounted for in the NSR calculations based on metallurgical data and vary from 79.3% in skarn to 92.5% in San Ernesto porphyry for Cu, 51.3% in skarn and 79.2% in San Ernesto porphyry for Mo, and 70% for Ag. Mineral Resources are estimated using an average long term metal prices of US$7,193.45/t Cu, US$21.34/oz Ag, and US$9.90/lb of Mo. Mineral Resources are reported constrained within a Whittle optimized pit shell. Mineral Resources are stated considering dilution into the regularized block. Bulk density varies depending on mineralization domain.