ERO.TO · 2022-01-06 12:00:00

Ero Copper announces updated mineral reserves and resources for the MCSA Mining Complex and the NX Gold Mine

Resource Estimates

January 6, 2022

Ero Copper announces updated mineral reserves and resources for the MCSA Mining Complex

and the NX Gold Mine

Vancouver, British Columbia – Ero Copper Corp. (TSX: ERO, NYSE: ERO) (“Ero” or the

“Company”) is pleased to announce the results of its 2021 updated National Instrument 43-101

Standards of Disclosure for Mineral Projects (“NI 43-101”) compliant mineral reserve and resource

estimates on its 99.6% owned MCSA Mining Complex located in Bahia State, Brazil and its 97.6%

owned NX Gold Mine, located in Mato Grosso State, Brazil. The updated mineral reserve and mineral

resource estimates incorporate drilling activities and mining depletion on the properties through

September 30, 2021. For the latest mineral reserve and resource update on the Company's Boa

Esperança Project please refer the 2021 Boa Esperança Technical Report (as defined below).

Highlights of the 2021 update include:

• In total, at the same cut-off grades, a 13% increase in total proven and probable mineral reserves

at the MCSA Mining Complex with a significant 56% increase in mineral reserves within the

Deepening Extension Zone of the Pilar Mine that remains open for potential expansion; and,

• A 32% increase in measured and indicated mineral resources ( 25% increase in proven and

probable reserves) for the NX Gold Mine, at the same cut-off grades. These increases are driven

by extensions of the Santo Antonio Vein and the maiden mineral reserve estimate for the

Matinha Vein that remains open for potential expansion and is expected to become an integral

part of the operation in the coming years.

Deepening Extension Zone Highlights, Pilar Mine

• Exceptional drill results continue to demonstrate significant year-on-year increases in the grade

and contained copper of the Deepening Extension Zone of the Pilar Mine since its initial

discovery in 2018, further supporting the Company's decision to construct a larger 6.3 meter

finished diameter external shaft (vs. 4.5 meters previously) to maximize the value of the mine;

◦ Proven and probable mineral reserves within the Deepening Extension Zone increased by

56% to 194.2 kt of contained copper ( 11.0 Mt grading 1.76% copper) compared to 124.6 kt

of contained copper (7.4 Mt grading 1.68% copper) in 2020;

◦ Measured and indicated mineral resources, inclusive of mineral reserves, within the

Deepening Extension Zone increased by 55% year-on-year to 217.1 kt of contained copper

(10.4 Mt grading 2.08% copper) compared to 140.0 kt of contained copper ( 7.5 Mt grading

1.86% copper) in 2020; and,

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◦ Inferred mineral resources within the Deepening Extension Zone increased by 37% to 130.1

kt of contained copper ( 6.1 Mt grading 2.14% copper) compared to 94.8 kt of contained

copper (4.5 Mt grading 2.12% copper) in 2020.

Deepening Extension Mineral Resource Evolution since 2018

(contained copper in kt)

Note: 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 23, 2003 (the “CIM Guidelines”), using geostatistical and/or classical

methods, plus economic and mining parameters appropriate for the deposit. Please see the 2018 Technical Report, 2019

Technical Report or 2020 Technical Report, as applicable and as defined below, for a discussion on the assumptions,

parameters and methods used to estimate the mineral resources and reserves. 2021 mineral resource effective date of

September 30, 2021. Presented indicated mineral resources inclusive of probable mineral reserves. Mineral resources that

are not mineral reserves do not have a demonstrated economic viability. All figures have been rounded to the relative

accuracy of the estimates.

MCSA Mining Complex Highlights, including the Deepening Extension Zone

• Proven and probable mineral reserves increased by 13% to 607.1 kt of contained copper (59.3 Mt

grading 1.02% copper) compared to 536.0 kt of contained copper ( 50.5 Mt grading 1.06%

copper) in 2020;

• Measured and indicated mineral resources, inclusive of mineral reserves, increased 6% to

1,221.1 kt of contained copper ( 104.7 Mt grading 1.17%) compared to 1,154.9 kt of contained

copper (102.8 Mt grading 1.12% copper) in 2020; and,

• Inferred mineral resources increased 21% to 473.4 kt of contained copper ( 43.3 Mt grading

1.09% copper) compared to 390.6 kt of contained copper ( 39.2 Mt grading 1.00% copper) in

2020.

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NX Gold Mine Highlights

• Proven and probable mineral reserves increased 25% to 306.8 koz of contained gold (1,104 kt

grading 8.64 gpt gold) compared to 244.7 koz of contained gold (862 kt grading 8.83 gpt gold) in

2020;

• Measured and indicated mineral resources, inclusive of mineral reserves, increased 32% to 357.3

koz of contained gold (1,081 kt grading 10.28 gpt gold) compared to 269.9 koz of contained gold

(770 kt grading 10.90 gpt gold) in 2020;

• Within the Santo Antonio Vein, proven and probable mineral reserves increased by 13% to 277.5

koz of contained gold (958 kt grading 9.01 gpt gold) compared to 244.7 koz of contained gold

(862 kt grading 8.83 gpt gold) in 2020;

• Within the Santo Antonio Vein, measured and indicated mineral resources, inclusive of mineral

reserves, increased by 20% to 322.4 koz of contained gold (950 kt grading 10.56 gpt gold)

compared to 269.2 koz of contained gold (763 kt grading 10.97 gpt gold) in 2020, driven

primarily by conversion of inferred mineral resources delineated in 2020; and,

• Within the Matinha Vein, maiden mineral reserve estimate with probable mineral reserves of

29.4 koz gold (146 kt grading 6.26 gpt gold) while inferred mineral resources increased by 79%

to 104.2 koz of contained gold (310 kt grading 10.47 gpt gold) compared to 58.2 koz of

contained gold (149 kt grading 12.15 gpt gold) in 2020.

Commenting on the re sults, David Strang, CEO, st ated, “The meaningful growth of our asset base, as

reflected i n o ur 2 021 mi neral r eserve a nd r esource update continues to dem onstrate o ur a bility t o

deliver or ganic growt h and gene rate s hareholder value t hrough explorat ion. Our annual results are

highlighted b y t he significant increase s i n the m ineral r eserves a nd resource s w ithin t he Dee pening

Extension Zone.

“Over the last year, the Deepening Extension Zone continued to exceed our own lofty expectations with

respect to mineral re serve and resource size and q uality. The demonstrated year-on-year growth in the

high-grade s uperpod t hrough o ur ongoing dri ll c ampaigns since 2018 highli ghts the pote ntial of t he

zone, which remains open. These results support our decision in 2021 to undertake a larger redesign of

the ne w e xternal shaft. T he re design doe s require a g reater upfront i nvestment but w ill, ov er time ,

enhance the pr oject's v alue and provide opt ionality ov er the long-te rm as w e c ontinue to l ook to

increase overall production volumes from the Pilar Mine.

"In addition t o significant growth in the Dee pening Extension Zone's mineral reserves and resources,

drilling throughout t he y ear at t he V ermelhos M ine and t hroughout the broader C uraçá V alley

continued to deliver growth in overall mineral reserves and resources. These additions were more than

sufficient to replace depletion during the year relative to our 2020 update, ev en as we increased our

annual copper production rate.

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“At the NX Gold Mine, demonstrated extensions of the Santo Antonio Vein and Matinha Vein during the

year both serve as further evidence of the intrinsic value and exploration potential of the broader land

package surrounding the mine. In 2022, we will focus on extending mineralization within the Matinha

Vein as we integrate it into our operations as an additional feed source for the mill.

"As a core tenet of our organic growth strategy, we are pleased to see our investment in exploration

continue to generate a pipeline of high-return actionable growth projects across our portfolio. Looking

ahead to 2022, our in- and near-mine exploration plans for the year include expanded drilling activities

in the upper levels of the Pilar Mine in support of a two-mine system, extending the known limits of the

high-grade Vermelhos Mine main orebodies to depth and continuing to define several growth projects

throughout the MCSA Mining Complex and the NX Gold Mine."

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2021 MINERAL RESERVE AND RESOURCE UPDATE

2021 Mineral Reserves &

Resources

2020 Mineral Reserves &

Resources Change

Tonnes

(kt)

Grade

(Cu %)

Contained

Cu (kt)

Tonnes

(kt)

Grade

(Cu %)

Contained

Cu (kt)

Contained

Cu (kt) %

Deepening Extension Zone, Pilar Mine

Proven Reserves 19 1.56 0.3 — — — 0.3 NA

Probable Reserves 10,996 1.76 193.9 7,432 1.68 124.6 69.3 56

Proven & Probable Reserves1 11,016 1.76 194.2 7,432 1.68 124.6 69.6 56

Measured Resources 4 1.77 0.1 — — — 0.1 NA

Indicated Resources 10,439 2.08 217.0 7,527 1.86 140.0 76.9 55

Measured & Indicated Resources 10,442 2.08 217.1 7,527 1.86 140.0 77.0 55

Inferred Resources 6,095 2.14 130.1 4,476 2.12 94.8 35.3 37

MCSA Mining Complex, including Deepening Extension Zone

Underground, including Deepening Extension Zone

Proven Reserves 9,177 1.49 136.8 9,707 1.63 158.2 (21.4) (14)

Probable Reserves 20,797 1.42 295.6 17,516 1.34 235.6 60.1 25

Proven & Probable Reserves1 29,974 1.44 432.4 27,224 1.45 393.8 38.7 10

Measured Resources 30,355 1.63 493.7 33,888 1.56 527.3 (33.7) (6)

Indicated Resources 39,005 1.33 519.9 34,292 1.23 420.6 99.3 24

Measured & Indicated Resources 69,360 1.46 1,013.6 68,180 1.39 947.9 65.7 7

Inferred Resources 40,331 1.14 458.3 36,271 1.05 379.8 78.5 21

Open Pit

Proven Reserves 15,680 0.59 92.0 11,757 0.60 70.1 21.9 31

Probable Reserves 13,627 0.61 82.7 11,474 0.63 72.2 10.6 15

Proven & Probable Reserves 29,306 0.60 174.7 23,230 0.61 142.3 32.4 23

Measured Resources 16,777 0.61 103.0 15,270 0.63 96.6 6.5 7

Indicated Resources 18,563 0.56 104.5 19,335 0.57 110.5 (5.9) (5)

Measured & Indicated Resources 35,340 0.59 207.5 34,605 0.60 207.0 0.5 —

Inferred Resources 3,000 0.50 15.1 2,930 0.37 10.8 4.3 40

Total MCSA Mining Complex, including Deepening Extension Zone

Proven Reserves 24,857 0.92 228.8 21,464 1.06 228.3 0.5 —

Probable Reserves 34,423 1.10 378.3 28,990 1.06 307.7 70.6 23

Proven & Probable Reserves 59,280 1.02 607.1 50,454 1.06 536.0 71.1 13

Measured Resources 47,132 1.27 596.7 49,158 1.27 623.9 (27.2) (4)

Indicated Resources 57,568 1.08 624.4 53,627 0.99 531.0 93.4 18

Measured & Indicated Resources 104,700 1.17 1,221.1 102,785 1.12 1,154.9 66.2 6

Inferred Resources 43,331 1.09 473.4 39,201 1.00 390.6 82.8 21

1. In the mine design of the Pilar and Vermelhos underground mines, certain stopes include measured and indicated as well as

inferred resource blocks. In these instances, inferred resource blocks within the defined mining shape were assigned zero

grade. Development occurring within marginal ore, above the operational cut-off grade, has also been included in the

mineral reserve estimate. See below notes on mineral reserve and resource estimates for additional technical and scientific

information.

2. 2021 mineral reserve and resource estimates are effective as at September 30, 2021. Presented mineral resources inclusive

of mineral reserves. Mineral resources that are not mineral reserves do not have a demonstrated economic viability. See

below notes on mineral reserve and resource estimates for additional technical and scientific information.

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2021 Mineral Reserves &

Resources

2020 Mineral Reserves &

Resources Change

Tonnes

(kt)

Grade

(Au gpt)

Contained

Au (koz)

Tonnes

(kt)

Grade

(Au gpt)

Contained

Au (koz)

Contained

Au (koz) %

NX Gold Mine

Santo Antonio Vein

Proven Reserves — — — — — — — NA

Probable Reserves 958 9.01 277.5 862 8.83 244.7 32.8 13

Proven & Probable Reserves 958 9.01 277.5 862 8.83 244.7 32.8 13

Measured Resources — — — — — — — NA

Indicated Resources 950 10.56 322.4 763 10.97 269.2 53.2 20

Measured & Indicated Resources 950 10.56 322.4 763 10.97 269.2 53.2 20

Inferred Resources 248 2.99 23.9 268 13.08 112.6 (88.7) (79)

Matinha Vein

Proven Reserves — — — — — — — NA

Probable Reserves 146 6.26 29.4 — — — 29.4 NA

Proven & Probable Reserves 146 6.26 29.4 — — — 29.4 NA

Measured Resources — — — — — — — NA

Indicated Resources 124 8.55 34.1 — — — 34.1 NA

Measured & Indicated Resources 124 8.55 34.1 — — — 34.1 NA

Inferred Resources 310 10.47 104.2 149 12.15 58.2 46.0 79

Brás & Buracão Veins

Proven Reserves — — — — — — — NA

Probable Reserves — — — — — — — NA

Proven & Probable Reserves — — — — — — — NA

Measured Resources — — — — — — — NA

Indicated Resources 7 3.36 0.7 7 3.36 0.7 — —

Measured & Indicated Resources 7 3.36 0.7 7 3.36 0.7 — —

Inferred Resources 157 4.71 23.8 157 4.71 23.8 — —

Total, NX Gold Mine

Proven Reserves — — — — — — — NA

Probable Reserves 1,104 8.64 306.8 862 8.83 244.7 62.2 25

Proven & Probable Reserves 1,104 8.64 306.8 862 8.83 244.7 62.2 25

Measured Resources — — — — — — — NA

Indicated Resources 1,081 10.28 357.3 770 10.90 269.9 87.3 32

Measured & Indicated Resources 1,081 10.28 357.3 770 10.90 269.9 87.3 32

Inferred Resources 714 6.61 151.9 574 10.55 194.6 (42.7) (22)

1. 2021 mineral reserve and resource estimates are effective as at September 30, 2021. Presented mineral resources inclusive

of mineral reserves. Mineral resources that are not mineral reserves do not have a demonstrated economic viability. See

below notes on mineral reserve and resource estimates for additional technical and scientific information.

6 Ero Copper Corp

NOTES ON MINERAL RESERVE AND RESOURCE TABLES

Mineral reserves are presented inclusive of mineral resources. All figures have been rounded to the

relative accuracy of the estimates. Summed amounts may not add correctly due to rounding. Mineral

resources that are not mineral reserves do not have a demonstrated economic viability.

Estimates for the MCSA Mining Complex and the NX Gold Mine are prepared by or under the

supervision of and verified by Mr. Emerson Ricardo Re, MSc, MBA, MAusIMM (CP) (No. 305892),

Registered Member (No. 0138) (Chilean Mining Commission) and Resource Manager of the Company,

who is a Qualified Person as such term is defined under NI 43-101. The technical and scientific

information in this news release has been prepared in accordance with NI 43-101 and has been reviewed,

verified and approved by Mr. Emerson Ricardo Re.

Reference herein of $ or USD is to United States dollars and BRL is to Brazilian reais. Mineral Reserves

for all active mines have been estimated using metal prices of $2.75/lb copper and $1,650/oz gold. The

exchange rates used were USD/BRL 5.23 for mineral reserve and mineral resource estimates for the

MCSA Mining Complex and USD/BRL 5.00 for mineral reserve and mineral resource estimates for the

NX Gold Mine.

MCSA Mining Complex

Mineral reserve and mineral resource estimates are effective as at September 30, 2021.

Underground mineral resource estimates have been constrained within newly developed 3D lithology

models applying a 0.45% and 0.20% copper grade envelope for high and marginal grade, respectively.

Within these envelopes, mineral resources for underground deposits were constrained using varying

stope dimensions of up to 20m by 10m by 35m applying a 0.51% copper cut-off grade, as well as a

0.32% copper marginal (or operational) cut-off grade. Mineral resources have been estimated using

ordinary kriging inside 5m by 5m by 5m block sizes. The mineral resource 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 to the deposit.

A low-grade envelope using a cut-off grade of 0.20% copper for underground deposits was used to

develop a dilution envelope and development block model that was included to define the grade of

blocks within the dilution envelope in the planning and design of stopes within the mineral resources

and mineral reserve estimate.

Open pit mineral resource estimates have been constrained within newly developed 3D lithology models

using a 0.21% copper cut-off grade for open pit deposits. Mineral resources have been estimated using

ordinary kriging inside 5m by 5m by 5m block sizes. The mineral resource 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 to the deposit.

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Mineral reserves are the economic portion of the measured and indicated mineral resources. Mining

dilution and recovery factors vary for specific mineral reserve sources and are influenced by factors such

as deposit type, deposit shape, stope orientation and selected mining method. In the mine design of the

Pilar and Vermelhos underground mines, certain stopes include measured and indicated as well as

inferred resource blocks. In these instances, inferred resource blocks within the defined mining shape

were assigned zero grade. In 2021, inferred blocks assigned zero grade totaled approximately 159,000

tonnes for the Deepening Extension Zone, 296,500 tonnes for the Pilar Underground Mine and

approximately 80,000 tonnes for the Vermelhos Underground Mine. Development occurring within

marginal ore, above the operational cut-off grade, has also been included in the mineral reserve estimate.

Dilution occurring from measured and indicated resource blocks was assigned grade based upon the

mineral resource grade of the blocks included in the dilution envelope.

Please refer to the NI 43-101 technical report entitled "2020 Updated Mineral Resources and Mineral

Reserves Statements of Mineração Caraíba’s Vale do Curaçá Mineral Assets, Curaçá Valley" dated

January 14, 2021 with an effective date of October 1, 2020, prepared by Porfirio Cabaleiro Rodrigues,

FAIG, Bernardo Horta de Cerqueira Viana, MAIG, Paulo Roberto Bergmann, FAusIMM, Fábio Valério

Câmara Xavier, MAIG and Dr. Augusto Ferreira Mendonça, RM SME all of GE21 Consultoria Mineral

Ltda. (“GE21”) and Dr. Beck (Alizeibek) Nader, FAIG of BNA Mining Solutions (the “2020 Technical

Report”) for technical information and assumptions related to the 2020 mineral reserve and mineral

resource estimate. Where applicable, please refer to the NI 43-101 technical report entitled "2019

Updated Mineral Resources and Mineral Reserves Statements of Mineração Caraíba’s Vale do Curaçá

Mineral Assets, Curaçá Valley" dated November 25, 2019 with an effective date of September 18, 2019,

prepared by Rubens Jose De Mendonça, MAusIMM, of Planminas – Projectos e Consultoria em

Mineração Ltd. (“Planminas”), and Porfirio Cabaleiro Rodrigues, MAIG, Leonardo de Moraes Soares,

MAIG, and Bernardo Horta de Cerqueira Viana, MAIG, all of GE21 (the “2019 Technical Report”) for

technical information and assumptions related to the 2019 mineral reserve and mineral resource

estimate. Where applicable, please refer to the NI 43-101 technical report entitled "2018 Updated

Mineral Resources and Mineral Reserves Statements of Mineração Caraíba’s Vale do Curaçá Mineral

Assets, Curaçá Valley" dated October 17, 2018 with an effective date of August 1, 2018, prepared by

Rubens Jose De Mendonça, MAusIMM, of Planminas, and Porfirio Cabaleiro Rodrigues, MAIG, Fábio

Valério Cãmara Xavier, MAIG, and Bernardo Horta de Cerqueira Viana, MAIG, all of GE21 (the “2018

Technical Report”) for technical information and assumptions related to the 2018 mineral reserve and

mineral resource estimate.

Please refer to the table below for details related to the mineral reserve and resource growth of the

Deepening Extension Zone within the Pilar Underground Mine from 2018 to 2021.

8 Ero Copper Corp

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