Reserves & Resources

Ore Classification Ore (000 tonnes) Grade (%Cu) Contained Copper (000 tonnes)
Mineral Reserves      
Proven 30,674 0.89% 273.2
Probable 12,378 0.67% 83.3
Total Proven & Probable 43,052 0.83% 356.6
Mineral Resources (Pit Constrained, Including Reserves)    
Measured (High-Grade) 7,117 2.16% 153.6
Indicated (High-Grade) 1,661 2.27% 37.6
Measured & Indicated (High-Grade) 8,778 2.18% 191.3
Measured (Low-Grade) 25,476 0.60% 152.0
Indicated (Low-Grade) 13,434 0.51% 68.4
Measured & Indicated (Low-Grade) 38,909 0.57% 220.4
Total Measured & Indicated  47,687 0.86% 411.7
Inferred Resources    
Inferred (Pit Constrained, High-Grade) 40 2.69% 1.1
Inferred (Pit Constrained, Low-Grade) 514 0.49% 2.5
Inferred (Pit Constrained) 555 0.65% 3.6
Inferred (Unconstrained High-Grade Outside Pit Limits) 1,354 2.24% 30.4
Inferred (Unconstrained Low-Grade Outside Pit Limits) 9,681 0.60% 58.2
Inferred (Unconstrained Mineralization Outside Pit Limits) 11,035 0.80% 88.6
Total Inferred 11,590 0.80% 92.2

Mineral Reserves Notes:

  1. Effective Date of August 31, 2021.
  2. Mineral Reserves included within stated Mineral Resources. Stated mineral resources are inclusive of mineral reserves. All figures have been rounded to the relative accuracy of the estimates. Summed amounts may not add due to rounding. High-grade and low-grade mineral resources defined as greater than or equal to 1.00% copper and less than 1.00% copper, respectively.
  3. A 3D geologic model was developed for the Boa Esperança Project. Geologically constrained copper grade shells were developed using a copper cut-off grade of 0.20% and 0.51% for pit constrained and unconstrained mineral resources, respectively, to generate a 3D mineralization model of the Boa Esperança Project. Within grade shells, mineral resources were estimated using ordinary kriging within a 2.0 meter by 2.0 meter by 4.0 meter block size. Open pit constrained, unconstrained and marginal cut-off grades are based upon a copper price of US$6,400 per tonne with cost parameters appropriate to the deposit. The mineral resource estimates were prepared in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum (“CIM”) Definition Standards for Mineral Resources and Mineral Reserves, adopted by the CIM Council on May 10, 2014 (the “CIM Standards”), and the CIM Estimation of Mineral Resources and Mineral Reserves Best Practice Guidelines, adopted by CIM Council on November 29, 2019 (the ‘CIM Guidelines”), using geostatistical and/or classical methods, plus economic and mining parameters appropriate to the deposit
  4. Mineral reserve estimates were prepared in accordance with the CIM Standards and the CIM Guidelines, using geostatistical and/or classical methods, plus economic and mining parameters appropriate for the deposit. Mineral reserves are based on a long-term copper price of US$6,613 per tonne; concentrate grade of 27% copper; average metallurgical recoveries of 91.3%; copper concentrate logistics costs of US$108.20 per wet metric tonne ("wmt"); transport losses of 0.2%; copper concentrate treatment charges of US$59.50 per dry metric tonne ("dmt"), refining charges of U$0.0595 per pound of copper; copper payability of 96.3%; average mining cost of US$2.47 per tonne mined; processing cost of US$7.74 per tonne processed and G&A costs of US$3.83 per tonne processed; average pit slope angles that range from 30º for saprolite to 50º for fresh rock and a 2% CFEM government royalty.
  5. Mineral reserves were classified according to the CIM Standards and the CIM Guidelines by Mr. Carlos Guzman, RM CMC (0119) and FAusIMM (229036), an employee of NCL Ingenieria y Construcion SpA ("NCL") and an independent qualified person as such term is defined under NI 43-101. NCL is independent of the Company. Please refer to the Company’s press release, dated September 28, 2021 for additional technical information.

Mineral Resources Notes:

  1. Please refer to the Technical Report for the Tucumã Project for additional scientific and technical information, available on this website and on SEDAR (www.SEDAR.com) and EDGAR (www.sec.gov).
  2. Effective Date of August 31, 2021.
  3. Presented Mineral Resources inclusive of Mineral Reserves. Summed amounts may not add due to rounding. High-grade and low-grade mineral resources defined as greater than or equal to 1.00% copper and less than 1.00% copper, respectively
  4. A 3D geologic model was developed for the Project. Geologically constrained grade shells were developed using various copper cut-off grades to generate a 3D mineralization model of the Project. Within the grade shells, mineral resources were estimated using ordinary kriging within a 2.0 meter by 2.0 meter by 4.0 meter block size. Within the optimized resource open pit limits, a cut-off grade of 0.20% copper was applied based upon a copper price of US$6,400 per tonne, net smelter return ("NSR") of 94.53%, average metallurgical recoveries of 90.7%, mining recovery of 95.0%, dilution of 5.0%, mining costs of US$3.10 per tonne mined run of mine ("ROM"), processing and transportation costs of US$5.65 per tonne ROM, and G&A costs of US$2.66 per tonne ROM. Unconstrained inferred mineral resources have been stated at a cut-off grade of 0.51% copper with a marginal cut-off grade of 0.32% copper based upon a copper price of US$6,400 per tonne, NSR of 94.53%, mining recovery of 100%, average metallurgical recoveries of 90.7%, mining costs of US$14.71 per tonne ROM, processing and transportation costs of US$5.70 per tonne ROM, and G&A costs of US$2.60 per tonne ROM.
  5. Block model tonnage and grade estimates for the Project were classified according to the CIM Standards and the CIM Guidelines by Mr. Emerson Ricardo Re, RM CMC (0138) and MAusIMM (CP) (305892), an employee of Ero Copper Corp. and a qualified person as such term is defined under National Instrument 43-101, Standards of Disclosure for Mineral Projects ("NI 43-101"). Please refer to the Company’s press release, dated September 28, 2021 for additional technical information. 

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