Form 6-K ENDEAVOUR SILVER CORP For: Dec 31

January 20, 2022 7:09 AM EST

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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13a-16 OR 15d-16
UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of January 2022

Commission File Number: 001-33153

ENDEAVOUR SILVER CORP.
(Translation of registrant's name into English)

#1130-609 Granville Street
Vancouver, British Columbia, Canada V7Y 1G5

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover Form 20-F or Form 40-F.

[           ] Form 20-F   [ x ] Form 40-F

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): [           ]

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): [           ]

Indicate by check mark whether by furnishing the information contained in this Form, the registrant is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934.

Yes [           ] No [ x ]

If "Yes" is marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2(b): 82- _________


SUBMITTED HEREWITH

Exhibits

Exhibit   Description
     
99.1   NI43-101 Technical Report: Updated Mineral Resource and Reserve Estimates for the Guanaceví Project, Durango State, Mexico
99.2   Consent of Qualified Person


SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

  Endeavour Silver Corp.
  (Registrant)
     
Date: January 20, 2022 By: /s/ Daniel Dickson
    Daniel Dickson
  Title: CEO



Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Certificates of Author

NI43-101 Technical Report:

Updated Mineral Resource and Reserve Estimates for the

Guanaceví Project, Durango State, Mexico

 

 

Report Date:  January 2, 2022

Effective Date:  December 31, 2020 

 

 

Prepared by:

1130 - 609 Granville Street

Vancouver, B.C., Canada, V7Y 1G5

 

Endorsed by QP(s):

Dale Mah, P.Geo

i


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Certificates of Author

Certificate of Qualified Persons

Dale Mah, P.Geo.
Endeavour Silver Corp.
609 Granville St, Suite 1130
Vancouver, British Columbia, Canada, V7Y1G5
Tel: (604) 685-9775

I, Dale Mah, P,Geo, am currently employed as Vice President, Corporate Development with Endeavour Silver Corp. ("Endeavour Silver"), which has its head offices at #1130, 609 Granville Street, Vancouver, BC V7Y 1G5 Canada.

This certificate applies to the technical report titled "NI43-101 Technical Report: Updated Mineral Resource and Reserve Estimates for the Guanaceví Project, Durango State, Mexico", that has an effective date of 31 December, 2020 (the "technical report").

I am a member of the Engineers & Geoscientists, British Columbia, and of the Association of Professional Engineers, Geologists and Geophysicists of Alberta. I graduated from the University of Alberta with a Bachelor of Science (Specialization) degree in Geology in 1996.

I have practiced my profession for over 25 years. In this time I have been directly involved in generating and managing exploration activities, and in the collection, supervision and review of geological, mineralization, exploration and drilling data; geological models; sampling, sample preparation, assaying and other resource-estimation related analyses; assessment of quality assurance-quality control data and databases; supervision of mineral resource estimates; project valuation and cash flow modeling.

As a result of my experience and qualifications, I am a Qualified Person as defined in National Instrument 43-101 Standards of Disclosure for Mineral Projects (NI 43-101).

I visited the Guanacevi Project most recently from 24-28 October, 2018. A personal inspection has not been conducted more recently due to the COVID-19 pandemic and travel restrictions imposed by local and foreign governments. However, once it is safe to do so, a physical site visit will take place as soon as practical.

I am responsible for Sections 1 to 27 of the technical report.

I am not independent of Endeavour Silver as independence is described by Section 1.5 of NI 43-101.

I have been involved with the Guanacevi Project since my employment commenced with Endeavour Silver in June 2016.

I have read NI 43-101 and the sections of the technical report for which I am responsible have been prepared in compliance with that Instrument.

As of the effective date of the technical report, to the best of my knowledge, information and belief, the sections of the technical report for which I am responsible contain all scientific and technical information that is required to be disclosed to make the technical report not misleading.

Dated this 2nd day of January, 2022.

"Signed" Dale Mah, P.Geo.

     
Signature of Qualified Person    

ii


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Table of Contents

Table of Contents

1. EXECUTIVE SUMMARY 1


1.1 Introduction 1
1.2 Property Description and Ownership 1
1.3 Geology and Mineralization 1
1.4 Status of Exploration 2
1.5 Development and Operations 2
1.6 Mineral Resource Estimate 2
1.7 Mineral Reserve Estimate 4
1.8 Conclusions and Recommendations 5
   
2. INTRODUCTION 7


2.1 Issuer and Terms of Reference 7
2.2 Sources of Information 7
2.3 Qualified Persons and Personal Inspection 9
2.4 Units of Measure 9
   
3. RELIANCE ON OTHER EXPERTS 10
   
4. PROPERTY DESCRIPTION AND LOCATION 11


4.1 Project Location 11
4.2 Mineral Tenure, Agreements and Encumbrances 14
4.3 Permits and Environmental Liabilities 15
   
5. ACCESSIBILITY, CLIMATE, LOCAL RESOURCES, INFRASTRUCTURE AND PHYSIOGRAPHY 16


5.1 Access and Climate 16
5.2 Local Resources and Infrastructure 16
5.3 Physiography 17
5.4 Surface Rights 17
   
6. HISTORY 18


6.1 Historical Exploration 18
6.2 Historical Production 18
6.2.1 Mining 18
6.2.2 Production 19
6.3 Historical Mineral Resource and Mineral Reserve Estimates 20
   
7. GEOLOGICAL SETTING AND MINERALIZATION 23


7.1 Regional Geology 23
7.1.1 Guanaceví Formation 23
7.1.2 Lower Volcanic Sequence 24
7.1.3 Upper Volcanic Sequence 24
7.1.4 Structural Setting 26
7.2 Project Geology 27
7.2.1 Local Structure 28
7.2.2 Alteration 28
7.3 Mineralization 28

 

iii


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Table of Contents

7.3.1 Santa Cruz Vein 29
   
8. DEPOSIT TYPES 30
   
9. EXPLORATION 32


9.1 EDR Exploration Prior to 2019 32
9.2 2020 Exploration Activities 32
9.2.1 Sampling Method and Approach 33
9.2.2 2020 Local Field Exploration 33
   
10. DRILLING 34


10.1 Drilling Procedures 34
10.2 EDR Core Logging Procedures 35
10.3 EDR Drilling Programs and Results 35
10.4 EDR Drilling Programs and Results (2020) 36
10.4.1 El Curso 36
   
11. SAMPLE PREPARATION, ANALYSES AND SECURITY 42


11.1 Methods 42
11.1.1 Underground Sampling 42
11.1.2 Exploration Sampling 42
11.2 Sample Preparation and Analysis 43
11.2.1 Underground Channel Samples 43
11.2.2 Exploration Drilling 43
11.3 Quality Control / Quality Assurance (QA/QC) program - UPDATE 45
11.3.1 Underground Channel Sample QA/QC 45
11.3.2 Summary of the 2017 to 2019 Surface and Underground Exploration Programs 51
11.3.3 Underground Exploration (2020) 53
11.4 Adequacy of Data 66
   
12. DATA VERIFICATION 67


12.1 Database Audit 67
12.2 Mechanical Audit 67
12.3 External Data Verification 67
12.4 Adequacy of Data 68
   
13. MINERAL PROCESSING AND METALLURGICAL TESTING 69


13.1 Metallurgical Testing 69
13.1.1 Mineralogy 69
13.1.2 Flotation 70
13.1.3 Hot cyanide leach 70
13.1.4 Leach tests of exploration samples (Milache) 70
13.2 Process Plant 71
13.3 Comments on Section 13 71
   
14. MINERAL RESOURCE ESTIMATES 72
   
14.1 Density 72
14.2 Methodology 72
14.3 Vertical Longitudinal Projection 73


iv


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Table of Contents

14.3.1 Composite Calculations 76
14.3.2 Area and Volume Calculations 76
14.3.3 VLP Mineral Resource Classification 76
14.4 3D Block Model Method 77
14.4.1 Geologic Model 77
14.4.2 Block Model 79
14.4.3 Compositing 81
14.4.4 Capping 82
14.4.5 Variography 85
14.4.6 Estimation Parameters 87
14.4.7 Model Validation 87
14.5 Guanaceví Mineral Resource Statement 94
14.5.1 VLP Mineral Resource Estimate 95
14.5.2 3D Block Model Mineral Resource Estimate 96
14.5.3 Guanaceví Mineral Resource Statement 98
   
15. MINERAL RESERVE ESTIMATES 99


15.1 CALCULATION PARAMETERS 99
15.1.1 Dilution and Mining Recovery 99
15.1.2 Reconciliation of Mineral Reserves to Production 100
15.2 Mineral Reserves 102
15.3 Reserve Classification 106
15.4 Factors that may affect the Reserve Calculation 107
   
16. MINING METHODS 108


16.1 Mining Operations 108
16.2 Geotechnical Factors 108
16.3 Mining Method 109
16.4 Mine Production 110
   
17. RECOVERY METHODS 111


17.1 Production 111
17.2 Mineral Processing 111
   
18. PROJECT INFRASTRUCTURE 114


18.1 Mine Pumping, Ventilation and Electrical 114
   
19. MARKET STUDIES AND CONTRACTS 119
   
20. ENVIRONMENTAL STUDIES, PERMITTING AND SOCIAL OR COMMUNITY IMPACT 122


20.1 Environmental and Sustainability 122
20.2 Closure Plan 122
20.3 Permitting 123
20.4 Social and Community Impact 124
   
21. CAPITAL AND OPERATING COSTS 127


21.1 Capital Costs 127
21.2 Operating Costs 127


v


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Table of Contents

22. ECONOMIC ANALYSIS 128
   
23. ADJACENT PROPERTIES 129
   
24. OTHER RELEVANT DATA AND INFORMATION 130
   
25. INTERPRETATION AND CONCLUSIONS 131


25.1 December 31, 2020 Mineral Resource Estimate 131
25.2 December 31, 2020 Mineral Reserve Estimate 132
25.3 Conclusions 133
   
26. RECOMMENDATIONS 134


26.1 Exploration Program 134
26.2 Geology, Block Modeling, Mineral Resources and Reserves 134
   
27. REFERENCES 136

List of Figures

Figure 4-1  Project Location Map 11
Figure 4-2  Guanaceví Mines Project, Mineral Concessions Map 12
Figure 7-1  Regional Geology Map for the Guanaceví Mining District 25
Figure 7-2  Guanaceví Mines Project Geology Map 27
Figure 8-1  Alteration and Mineral Distributions within a Low Sulphidation Epithermal Vein System 31
Figures 10-1 & 10-2  Versa drill rig in station for drill holes UCM-27 and UCM-28 37
Figure 10-3  Longitudinal Section (looking NE) showing intersection points on Santa Cruz vein in the El Curso area 40
Figure 10-4  Plan View of the El Curso area 41
Figure 10-5  Schematic Cross Section 8,070N, El Curso 41
Figure 11-1  Production Samples Blank Analysis for Silver 46
Figure 11-2  Production Samples Blank Analysis for Gold 47
Figure 11-3  Silver Pulp Duplicates 48
Figure 11-4  Gold Pulp Duplicates 48
Figure 11-5  Silver Reject Duplicates 49
Figure 11-6  Gold Reject Duplicates 49
Figure 11-7  Silver Field Duplicates 50
Figure 11-8  Gold Field Duplicates 50
Figure 11-9  Flow Sheet for Core Sampling, Sample Prep and Analysis 54
Figure 11-10  Control Chart for Gold Assay from the Blank Samples Inserted into the Sample Stream 55
Figure 11-11  Control Chart for Silver Assay from the Blank Samples Inserted into the Sample Stream 55
Figure 11-12 Graph of the Original versus Duplicate Sample for the Gold Assays from EDR's Guanaceví Drilling Program 56
Figure 11-13  Graph of the Original versus Duplicate Sample for the Silver Assays from EDR's Guanaceví Drilling Program 56
Figure 11-14  Control Chart for Gold Assays from the Standard Reference Sample EDR-46 60
Figure 11-15  Control Chart for Silver Assays from the Standard Reference Sample EDR-46 60
Figure 11-16  Control Chart for Gold Assays from the Standard Reference Sample EDR-49 61
Figure 11-17  Control Chart for Silver Assays from the Standard Reference Sample EDR-49 61
   

vi


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Table of Contents

Figure 11-18  Control Chart for Gold Assays from the Standard Reference Sample EDR-51 61
Figure 11-19  Control Chart for Silver Assays from the Standard Reference Sample EDR-51 62
Figure 11-20  Graph of the Original versus Re-Assayed Silver Samples 64
Figure 11-21  Scatter plot of Check Assays for Gold 65
Figure 11-22  Scatter plot of Check Assays for Silver 65
Figure 14-1  VLP Showing the Epsilon - Soto Vein with Indicated (blue), and Inferred (grey) Resource Blocks 75
Figure 14-2  Cross Section Diagram of VLP Method 76
Figure 14-3  Santa Cruz Vein - Milache Area and El Curso Area divided by a green line. Milache HW in red. 77
Figure 14-4  Transverse Section in Milache Area 78
Figure 14-5  Santa Cruz South Veins clipped by concession limits 78
Figure 14-6  Santa Cruz Vein Variogram Models for Silver (left) and Gold (right) 85
Figure 14-7  Silver Search Volume as Defined by the Variogram Model 86
Figure 14-8  Long Section view of Santa Cruz Vein Block Model showing the Estimated Silver Grades and Composites 94
Figure 15-1  Santa Cruz Sur Vein Resource and Reserve Section 104
Figure 17-1  View of Leach Tanks and CCD Circuits 111
Figure 18-1  Portal for the Porvenir 4 Mine 115
Figure 18-2  Aerial View of the Plant and Tailings Facilities of the Guanaceví Mines Project 117
Figure 18-3  Aerial Filtration Circuit Building (left); Two Diemme Filter Presses (right) 117
Figure 18-4  View of the new Rosario Tailings Water Pond with Capacity 10,000 m3 (on the left); View of the Dry Stack Tailings Dam from the Northwest to Southeast (on the right) 118
Figure 18-5  View to Water Extraction Wells (left); and to the South, Water Pond (right) 118

List of Tables

Table 1-1  Mineral Resource Estimate, Effective Date December 31, 2020 3
Table 1-2  Mineral Reserve Estimate 5
Table 4-1  Guanaceví Mines Concessions Controlled by EDR 12
Table 4-2  Guanaceví Mines Concessions Controlled by EDR (Ocampo agreement) 13
Table 4-3  Summary of Endeavour Silver's Surface Access Rights 14
Table 4-4  Summary of Endeavour Silver's Royalties 15
Table 6-1  Summary of the Production for the Guanaceví Property (1991 to 2020) 20
Table 6-2  Historic Mineral Resource Estimate, Effective Date December 31, 2016 21
Table 7-1  Generalized Stratigraphic Column in the Guanaceví Mining District 26
Table 9-1  2016 Regional Exploration, External Concessions, Guanceví 33
Table 10-1  Drilling Summary for Santa Cruz Vein Structure at Guanaceví Mines Project (as of December, 2020) 35
Table 10-2  2020 Drilling Summary, El Curso 36
Table 10-3  2020 Drilling Summary, El Curso (hole extension UCM-20) 37
Table 10-4  2020 Drilling Results, El Curso 38
Table 11-1  Summary of Control Samples Used for Exploration Programs from 2017 to 2019 51
Table 11-2  Summary of the Standard Reference Material Samples Used During the EDR's Drilling Programs (2017 to 2019) at Guanacevi 52
Table 11-3 General Rules for Standard Samples 52
Table 11-4 Summary of Analysis of Standard Reference Materials (2017 to 2019) 52
Table 11-5  Summary of Control Samples Used for the 2020 Underground Exploration Program 53

 

vii


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Table of Contents

Table 11-6  Summary of the Standard Reference Material Samples Used During the EDR's Drilling Programs at Guanacevi 58
Table 11-7  Basis for Interpreting Standard Sample Assays 58
Table 11-8 General Rules for Standard Samples 59
Table 11-9 Summary of Analysis of Standard Reference Materials 59
Table 11-10 Comparative Table of Original vs Re-assays Values 62
Table 13-1  Silver and Gold Distribution in Ore and Leach Residue Samples 69
Table 13-2  Summary of Mineralogical Analysis of Ore and Leach Residue Samples 70
Table 13-3  Results of Bottle Roll Tests on Milache Ore Samples 70
Table 14-1  Statistical Summary of Density Data 72
Table 14-2  Summary of Veins included in the Mineral Resource Estimate 73
Table 14-3  Guanaceví Block Model Parameters 80
Table 14-4  Vein Model Sample Statistics 81
Table 14-5  Composite Silver Summary Statistics within Veins 82
Table 14-6  Composite Gold Summary Statistics within Veins 82
Table 14-7  Summary of Silver and Gold Variogram Parameters 86
Table 14-8  Estimation Parameters 87
Table 14-9  Relative Differences Estimation 88
Table 14-10  Silver Model Descriptive Statistical Comparison 89
Table 14-11  Gold Model Descriptive Statistical Comparison 90
Table 14-12  Cutoff Grade Assumptions for Guanaceví Mine 95
Table 14-13  Polygonal Resource at the Guanaceví, Effective Date of December 31, 2020 96
Table 14-14  3D Block Model Resource at the Guanaceví Mine, Effective Date of December 31, 2020 96
Table 14-15  Mineral Resource Estimate, Effective Date December 31, 2020 98
Table 15-1  Proven and Probable Mineral Reserves, Effective Date December 31, 2020 106
Table 18-1  Standby Mine Generators 115
Table 19-1  Average Annual High and Low COMEX for Gold and Silver from 2000 to 2020 (prices expressed in US$/oz) 119
Table 19-2  Contracts Held by the Guanaceví Project 120
Table 20-1  Reclamation Budget 123
Table 20-2  Summary of Environmental and Mining Permits for the Guanaceví Project 124
Table 21-1  Capital Costs for the Guanaceví Mine 127
Table 21-2  Operating Costs for the Guanaceví Mine 127
Table 25-1  Mineral Resource Estimate, Effective Date December 31, 2020 131
Table 25-2  Mineral Reserve Estimate, Effective Date December 31, 2020 132
Table 26-1  Guanaceví 2021 Exploration Budget 134

viii


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project List of Acronyms

List of Acronyms

3D

Three Dimensional

AA

Atomic Absorption

AES

Atomic Emission Spectrometry

CAHECOMI

Campos Hernandez Contratistas Mineros, S.A. de C.V.

CCD

Counter-Current Decantation

CEMEFI

Mexican Center for Philanthropy

CIM

Canadian Institute of Mining, Metallurgy and Petroleum

CL

Control Limit

CMC

Compañia Minera del Cubo S.A. de C.V.

CV

Coefficient Variation

EDR

Endeavour Silver Corp.

ESR

Socially Responsible Company

FSE

Frankfurt Stock Exchange

g/t

Grams per Tonne

HDPE

High Density Polyethylene

HP

Horsepower

HRC

Hard Rock Consulting

ICP

Inductively Coupled Plasma

ID

Inverse Distance

LL

Lower Control Limit

LOM

Life of Mine

MG

Metalurgica Guanaceví

MSO

Mineable Shape Optimizer

NN

Nearest Neighbor

NYSE

New York Stock Exchange

OK

Ordinary Kriging

QA/QC

Quality Assurance/Quality Control

REE

Rare Earth Element

RQD

Rock Quality Designation

SRM

Standard Reference Material

TSF

Tailings Storage Facility

TSX

Toronto Stock Exchange

UL

Upper Control Limit

VLP

Vertical Longitudinal Projection

WGM

Watts, Griffis & McQuat, Ltd

ix


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Executive Summary

1. EXECUTIVE SUMMARY

1.1 Introduction

Mr. Dale Mah, P.Geo., has prepared this Technical Report (the Report) on the Guanacevi Project (Guanacevi) for Endeavour Silver Corp. (EDR). Guanacevi is located northwest of the capital city of Durango, Durango State, Mexico.

This report provides updated information on the operation of the Guanacevi Project, including an updated Mineral Resource and Mineral Reserve estimate. The information will be used to support disclosures in Endeavour Silver's Annual Information Form (AIF). Units used in the report are metric units unless otherwise noted. Monetary units are in United States dollars (US$) unless otherwise stated. This report was prepared in accordance with the requirements and guidelines set forth in National Instrument 43-101 (NI43-101), Companion Policy 43-101CP and Form 43-101F1 (June 2011), and the mineral resources and reserves presented herein are classified according to Canadian Institute of Mining, Metallurgy and Petroleum ("CIM") Definition Standards - For Mineral Resources and Mineral Reserves, prepared by the CIM Standing Committee on Reserve Definitions and adopted by CIM Council on May 10, 2014. The mineral resource and mineral reserve estimates reported here are based on all available technical data and information as of December 31, 2020.

1.2 Property Description and Ownership

The Guanaceví Project is located in the northwest portion of the Mexican state of Durango, approximately 3.6 km west of the town of Guanaceví and 260 km northwest of the capital city of Durango. The approximate geographic center of the Project is 105°58'20"W longitude and 25°54'47"N latitude. At present, the Project is comprised of 51 mineral concessions for a total property area of 4,171.5546 ha.

EDR controls the Guanaceví Project through its 100% owned Mexican subsidiary, Endeavour Gold Corporation S.A. de C.V. (Endeavour Gold). Endeavour Gold holds the project through its two 100% owned subsidiaries, Minera Plata Adelante S.A. de C.V. (Minera Plata Adelante) and Refinadora Plata Guanaceví S.A. de C.V. (Refinadora Plata Guanaceví).

1.3 Geology and Mineralization

The Guanaceví silver-gold district hosts classic, high-grade silver-gold, epithermal vein deposits characterized by low sulphidation mineralization and adularia-sericite alteration. The Guanaceví veins are typical of many epithermal silver-gold vein deposits in Mexico in that they are primarily hosted in the Tertiary Lower Volcanic series of andesite flows, pyroclastics and epiclastics, overlain by the Upper Volcanic series of rhyolite pyroclastics and ignimbrites. Evidence is accumulating in the Guanaceví mining district that the mineralization is closely associated with a pulse of silicic eruptions that either signaled the end of Lower Volcanic Sequence magmatism or the onset of Upper Volcanic Sequence activity.

Mineralization at Guanaceví occurs in association with an epithermal low sulphidation, quartz-carbonate, fracture-filling vein hosted by a structure trending approximately N45°W, dipping 55° southwest. The Santa Cruz vein is the principal host of silver and gold mineralization at Guanaceví, and is located on the west side of the horst of the Guanaceví Formation. The mineralized vein is part of a major fault system that trends northwest and principally places the Guanaceví Formation in the footwall against andesite and/or rhyolite in the hanging wall. The fault and vein comprise a structural system referred to locally as the Santa Cruz vein structure or Santa Cruz vein fault. The Santa Cruz vein itself has been traced for 5 km along trend, and averages approximately 3.0 m in width. High-grade mineralization in the system is not continuous but occurs in steeply northwest-raking shoots up to 200 m in strike length. A secondary mineralized vein is located sub-parallel and subjacent to the Santa Cruz vein, in the footwall, and while less continuous is economically significant in the Porvenir Dos and North Porvenir portions of the Project. 


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Executive Summary

1.4 Status of Exploration

In 2020, EDR spent US $916,935 (including property holding costs) on exploration activities, primarily in the El Curso Claim. Underground drilling program focused on exploring the Santa Cruz vein the El Curso property, and included a total of 7,200m in 24 holes, with a total of 1,205 samples submitted for assays. Field exploration activities over a third-party claim (Los Angeles), located northwest of Guanacevi town, and a total of 55 rock samples were collected.

Since acquisition of the Guanaceví Project in 2004, and prior to the 2020 exploration season, EDR had completed 793 diamond drill holes totaling 216,810 m and 22 reverse circulation drill holes totaling 2,977 m on the entire Guanaceví Project. Of this total, approximately 173,412 m of diamond drilling in 607 holes were completed on the Santa Cruz vein structure. Holes were drilled from both surface and underground drill stations, and 64,865 samples were collected and submitted for assay.

1.5 Development and Operations

Mining methods used at Guanacevi include long-hole stoping and conventional cut and fill mining. Cut and fill stopes are generally mined 15m along strike and in 1.5 - 1.8m high cuts, and long hole stopes are 15m long and 20m high (20m between levels floor to floor). Access to the stoping areas is provided by a series of primary and secondary ramps located in the footwall of the principal structure, the Santa Cruz vein. The ramps have grades from minus 15% to plus 12%, with plus or minus 12% as standard. The ramps and crosscuts are generally 4 m by 4 m.

In 2020, the total ore production was 329,892 tonnes at an average grade of 321 g/t Ag and 0.86 g/t Au. The 4 operating mine areas were Santa Cruz Sur (26% production), El Porvenir (14% production), El Curso (37% production) and Milache (22% production).

As of December 31, 2020, the Guanaceví mines project had a roster of 512 employees and an additional 413 contractors. The mine operates on two 10-hour shifts, 7 days per week, whereas the mill operates on a 24/7 schedule, two 10 hour shifts per day.

1.6 Mineral Resource Estimate

Dale Mah, P.Geo., of EDR is responsible for the mineral resource estimate presented in this report. Mr. Mah is a Qualified Person as defined by NI 43-101, and is not independent of EDR. The mineral resources and mineral reserves reported herein are classified as Measured, Indicated and Inferred according to CIM Definition Standards.


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Executive Summary

EDR estimated the mineral resource for the Guanaceví Project based on channel samples and drillhole data constrained by geologic vein boundaries with an Ordinary Krige ("OK") algorithm. Vulcan® V10.1.5 ("Datamine") software was used to complete the resource estimate. The metals of interest at Guanaceví are gold and silver.

The Guanaceví mineral resource is comprised of 13 individual models or veins. The veins are further subdivided by area and modeling method. The mineral resources have been estimated using either a Vertical Longitudinal Projection (VLP) polygonal method (4 veins) or as 3-dimensional ("3D") block model (9 veins).

The resources based on the 2D polygonal methods are estimated by using a fixed distance VLP from sample points. The VLPs are created by projecting vein geology and underground workings onto a vertical 2D long section. The 2D estimates were classified based on the distance to the nearest sample. Measured mineral resources are the area of the defined resource blocks within 10 meters of a sample. Indicated mineral resources are the area of the defined resource blocks within 20 meters of a sample. Inferred mineral resources are those blocks greater than 20 meters from a sample and have a value for estimated silver.

Vein wireframes were created using both implicit and explicit modeling methods.  Explicit modeling involved using cross-sections orthogonal to the strike of the vein to select intervals from drillholes representing the vein material. Level sections were used to select vein material from channel samples. Points representing the hanging wall and footwall contacts were extracted by the software to interpolate hanging wall and footwall surfaces. These surfaces were used to delineate each vein solid. The surfaces were evaluated in 3-dimensions to ensure that both the down dip and along strike continuity was maintained throughout the model. Veins were clipped against younger veins, topography, and the concession boundaries. Implicit models were created initially in Leapfrog software, but then edited by the geological team to ensure boundaries are accurate.

The mineral resource estimate includes all data obtained as of December 31, 2020. Mineral resources are not mineral reserves and may be materially affected by environmental, permitting, legal, socio-economic, political, or other factors. Mineral resources are reported above a silver equivalent grade of 198 gpt, assuming a silver price of $16.51 and a gold price of $1465 per ounce. EDR used a cutoff grade to test for reasonable prospects for economic extraction.

The mineral resources for the Guanaceví mine as of December 31, 2020, are summarized in Table 1-1. The resources are exclusive of the mineral reserves.

Table 1-1  Mineral Resource Estimate, Effective Date December 31, 2020

Classification

Tonnes

Silver

Gold

Silver_Equivalent

g/t

oz.

g/t

oz.

g/t

oz.

Measured

95,360

405

1,240,207

0.88

2692

475

1,455,576

Indicated

565,975

363

6,603,002

0.82

14,920

428

7,796,568

Measured + Indicated

661,335

369

7,843,209

0.83

17,612

435

9,252,143

Inferred

865,804

495

13,765,421

1.18

32,737

589

16,384,411

TOTAL

1,527,139

440

21,608,629

1.03

50,349

522

25,636,554



Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Executive Summary

1. Measured, Indicated and Inferred Mineral Resource cut-off grades are based on a 225 g/t silver equivalent for Santa Cruz Sur of Guanacevi and 222 g/t silver equivalent for Santa Cruz, 237 g/t silver equivalent for  Milache and 280 g/t silver equivalent for Ocampo and Porvenir Norte of Guanaceví.

2. Mineral resources are not mineral reserves and do not have demonstrated economic viability. There is no certainty that all or any part of the mineral resources estimated will be converted into mineral reserves.

3. Metallurgical recoveries were 84.6% silver and 85.7% gold.

4. Silver equivalents are based on a 80:1 silver: gold ratio

5. Price assumptions are $16.51 per ounce for silver and $1,465 per ounce for gold for resource cutoff calculations.

6. Mineral resources are estimated exclusive of and in addition to mineral reserves.

1.7 Mineral Reserve Estimate

Dale Mah, P.Geo., of EDR is responsible for the mineral reserve estimate presented in this report. Mr. Mah is a Qualified Person as defined by NI 43-101, and is not independent of EDR. The mineral reserves reported herein are classified as Proven and Probable according to CIM Definition Standards.  The mineral reserve estimate for EDR's Guanaceví Project has an effective date of December 31st, 2020.  The mineral reserve estimate includes the Santa Cruz and Milache areas of the mine and the ore stockpiles at the mill site.  Stope designs for reporting the mineral reserves were created utilizing the updated resources and cutoffs established for 2020.  All the stopes are within readily accessible areas of the active mining areas.  Ore is processed in the on-site mill, leaching circuit and Merrill Crowe process capable of processing 1,300 tpd.

Measured and Indicated mineral resources within mineable areas have been converted to Proven and Probable mineral reserves as defined by CIM. Inferred mineral resources are classified as waste. Dilution is applied to Measured and Indicated resource blocks depending on the mining method chosen. Mining stopes were created based solely on Measured and Indicated resources above the calculated cutoff grade which have reasonable prospects of economic extraction after applying certain modifying factors:

  • Cutoff Grades:  237 g/t AgEq for Milache; 225 g/t AgEq for Santa Cruz Sur and 280 g/t AgEq for El Curso and El Porvenir including the royalties payable
  • Minimum Mining Width:  0.8m.
  • External Dilution Cut and Fill:  15%
  • External Dilution Long Hole:  30%
  • Silver Equivalent:  80:1 silver to gold
  • Gold Price:  US $1,465/oz.
  • Silver Price:  US $16.51/oz.
  • Gold Recovery:  85.7%
  • Silver Recovery:  84.6%

The Guanaceví Project mineral reserves are derived and classified according to the following criteria:

  • Proven mineral reserves are the economically mineable part of the Measured resource for which mining and processing / metallurgy information and other relevant factors demonstrate that economic extraction is feasible. For Guanaceví Project, this applies to blocks located within approximately 10m of existing development and for which EDR has a mine plan in place.

Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Executive Summary
  • Probable mineral reserves are those Measured or Indicated mineral resource blocks which are considered economic and for which EDR has a mine plan in place. For the Guanaceví mine project, this is applicable to blocks located a maximum of 35m either vertically or horizontally from development with one exception in the main lower Santa Cruz vein the maximum distance to development was extended to 110m as this area is currently being developed.

The Proven and Probable mineral reserves for the Guanaceví mine as of December 31, 2020 are summarized in Table 1-2.  The reserves are exclusive of the mineral resources reported in Section 14 of this report.

Table 1-2  Mineral Reserve Estimate

Classification

Vein

Tonnes

Silver

Gold

Silver_Equivalent

Dilution

g/t

oz.

g/t

oz.

g/t

oz.

%

Proven

El CURSO SUR

69,092

359

796,517

0.90

2009

431

957,227

38%

MILACHE

6,333

242

49,204

0.69

141

297

60,486

35%

MILACHE B1

5,770

407

75,561

1.04

193

491

91,005

35%

SANTA CRUZ SUR

31,194

218

218,516

0.67

671

271

272,210

30%

STOCK PILE

28,444

334

305,442

0.76

695

395

361,044

0%

Total Proven

 

140,832

319

1,445,240

1

3,709

385

1,741,971

35%

Probable

El CURSO SUR

525,763

426

7,200,253

1.08

18227

512

8,658,384

38%

MILACHE

42,226

285

387,523

0.90

1222

357

485,271

35%

MILACHE B1

29,491

286

271,557

0.77

727

348

329,712

35%

SANTA CRUZ SUR

350,755

239

2,694,498

0.77

8643

300

3,385,922

30%

Total Probable

 

948,236

346

10,553,831

0.95

28,818

422

12,859,288

35%

Total Proven + Probable Reserves

1,089,068

343

11,999,071

0.93

32,527

417

14,601,259

35%

1. Cutoff Grades:  237 g/t AgEq for Milache; 225 g/t AgEq for Santa Cruz Sur and 280 g/t AgEq for El Curso and Porvenir Norte including the royalties payable.

2. Minimum Mining Width:  0.8m.

3. External Dilution Cut and Fill:  15%

4. External Dilution Long Hole:  30%

5. Silver Equivalent:  80:1 silver to gold

6. Gold Price:  US $1,465/oz.

7. Silver Price:  US $16.51/oz.

8. Recovery:  85.7% silver and 85.4% gold.

9. Mineral resources are estimated exclusive of and in addition to mineral reserves.

10. Figures in table are rounded to reflect estimate precision; small differences generated by rounding are not material to estimates.

1.8 Conclusions and Recommendations

The QP considers the Guanaceví resource and reserve estimates presented here to conform with the requirements and guidelines set forth in Companion Policy 43-101CP and Form 43-101F1 (June 2011), and the mineral resources and reserves presented herein are classified according to Canadian Institute of Mining, Metallurgy and Petroleum ("CIM") Definition Standards - For Mineral Resources and Mineral Reserves, prepared by the CIM Standing Committee on Reserve Definitions and adopted by CIM Council on May 10, 2014.  These resources and reserves form the basis for EDR's ongoing mining operations at the Guanaceví Project.


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Executive Summary

The QP is unaware of any significant technical, legal, environmental or political considerations which would have an adverse effect on the extraction and processing of the resources and reserves located at the Guanaceví Mines Project. Mineral resources which have not been converted to mineral reserves, and do not demonstrate economic viability shall remain mineral resources.  There is no certainty that all or any part of the mineral resources estimated will be converted into mineral reserves.

The QP considers that the mineral concessions in the Guanaceví mining district controlled by EDR continue to be highly prospective both along strike and down dip of the existing mineralization.

EDR's Guanaceví Project has an extensive mining history with well-known silver and gold bearing vein systems. Ongoing exploration has continued to identify additional resources at the project and within the district surrounding the mine. Since EDR took control of the Guanaceví properties, new mining areas identified have enabled EDR to increase production by providing additional sources of mill feed.  EDR's operation management teams continue improving efficiency, lowering costs and researching and applying low-cost mining techniques. This report demonstrates that the project has positive cash flow, and mineral reserve estimates can be supported.

For 2021, approved exploration budget for Guanaceví includes 11,500 meters of drilling, which is estimated to be approximately US $2,025,000.

The QP recommends that the continuation of the conversion of all resource models from 2D polygons to 3D block models be continued.  Between 2017 and 2020, considerable progress was made in this regard. Additional modeling efforts should be made to define the mineralized brecciated areas as they have been an import source of economic material encountered in the current operation and could continue to provide additional tonnage to support the mine plan. Work programs should continue to focus on areas to explore for mine life extensions.


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Introduction

2. INTRODUCTION

2.1 Issuer and Terms of Reference

Endeavour Silver Corp. ("EDR") is a Canadian based mining and exploration company actively engaged in the exploration, development, and production of mineral properties in Mexico. EDR is headquartered in Vancouver, British Columbia with management offices in Leon, Mexico, and is listed on the Toronto (TSX:EDR), New York (NYSE: EXK) and Frankfurt (FSE:EJD) stock exchanges. EDR has three currently active mining properties in Mexico, the Guanaceví Property in northwest Durango State, the Bolañitos property in Guanajuato State, and the El Compas property in Zacatecas State. The El Compas property has ceased mining operations since the Effective Date of this Report.

Endeavour Silver is using the provision for producing issuers, whereby the QP for this technical report is not required to be prepared by or under the supervision of an independent QP. Mr. Dale Mah, P.Geo, is employed as VP Corporate Development for Endeavour Silver and supervised the preparation of the mineral resource and reserve estimate and is not independent.

This report was prepared in accordance with the requirements and guidelines set forth in NI 43-101 Companion Policy 43-101CP and Form 43-101F1 (June 2011), and the mineral resources and reserves presented herein are classified according to Canadian Institute of Mining, Metallurgy and Petroleum ("CIM") Definition Standards - For Mineral Resources and Mineral Reserves, prepared by the CIM Standing Committee on Reserve Definitions and adopted by CIM Council on May 10, 2014. The mineral resource and mineral reserve estimates reported here are based on all available technical data and information as of December 31, 2020.

2.2 Sources of Information

A portion of the information and technical data for this study was obtained from the following previously filed NI 43-101 Technical Reports:

Hard Rock Consulting LLC (2016). NI 43-101 Technical Report: Updated Mineral Resource and Mineral Reserve Estimates for the Guanaceví Project, Durango State, Mexico.

Munroe, M.J., (2015). NI 43-101 Technical Report, Resource and Reserve Estimates for the Guanaceví Mines Project, Durango State, Mexico.

Munroe, M.J., (2014). NI43-101 Technical Report, Resource and Reserve Estimates for the Guanaceví Mines Project, Durango State, Mexico.

EDR also relied in part on background information presented in the following unpublished technical reports prepared on behalf of EDR: 

Lewis, W.J., Murahwi, C., and San Martin, A.J., (2013). NI 43-101 Technical Report Resource and Reserve Estimates for the Guanaceví Mines Project, Durango State, Mexico: unpublished NI 43-101 technical report prepared by Micon International for Endeavour Silver, effective date December 15, 2012.


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Introduction

Lewis, W.J., Murahwi, C., and San Martin, A.J., (2012). NI 43-101 Technical Report Resource and Reserve Estimates for the Guanaceví Mines Project, Durango State, Mexico: unpublished NI 43-101 technical report prepared by Micon International for Endeavour Silver, effective date December 31, 2011.

Lewis, W.J., Murahwi, C., Leader, R.J. and Mukhopadhyay, D.K., (2011). NI 43-101 Technical Report Audit of the Resource and Reserve Estimates for the Guanaceví Mines Project, Durango State, Mexico: unpublished NI 43-101 technical report prepared by Micon International for Endeavour Silver, effective date December 31, 2010.

Lewis, W.J., Murahwi, C., Leader, R.J. and Mukhopadhyay, D.K., (2010). NI 43-101 Technical Report Audit of the Resource and Reserve Estimates for the Guanaceví Mines Project, Durango State, Mexico: unpublished NI 43-101 technical report prepared by Micon International for Endeavour Silver, effective date December 31, 2009.

Lewis, W.J., Murahwi, C., Leader, R.J. and Mukhopadhyay, D.K., (2009). NI 43-101 Technical Report Audit of the Resource and Reserve Estimates for the Guanaceví Mines Project, Durango State, Mexico: unpublished NI 43-101 technical report prepared by Micon International for Endeavour Silver, effective date December 31, 2008.

Devlin, B.D., (2008). NI 43-101 Technical Report on the Resource and Reserve Estimates for the Guanaceví Mines Project, Durango State, Mexico: unpublished NI 43-101 technical report prepared by B. Devlin, V.P. Exploration for Endeavour Silver, effective date December 31, 2007.

Lewis, W.J. Leader, R.J. and Mukhopadhyay, D.K., (2007). NI 43-101 Technical Report Audit of the Resource and Reserve Estimates for the Guanaceví Mines Project, Durango State, Mexico: unpublished NI 43-101 technical report prepared by Micon International for Endeavour Silver, effective date December 31, 2006.

Olson, A. E., (2006). Technical Report, Mineral Resource and Mineral Reserve Estimate, Guanaceví Mines Project, Durango, Mexico: unpublished NI 43-101 technical report prepared by Range Consulting for Endeavour Silver, effective date March 31, 2006.

Spring, V., (2005). A Technical Review of the North Porvenir Zone, Santa Cruz Mine, Guanaceví Mines Project in Durango State, Mexico: unpublished NI 43-101 technical report prepared by Watts, Griffis, McOuat for Endeavour Silver, effective date May 10, 2005.

The information contained in current report Sections 4 through 8 was largely presented in, and in some cases, is excerpted directly from, the technical reports listed above. EDR has reviewed this material in detail, and finds the information contained herein to be factual and appropriate with regard to guidance provided by NI 43-101 and associated Form NI 43-101F1.


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Introduction

2.3 Qualified Persons and Personal Inspection

This report is endorsed by the following Qualified Person, as defined by NI 43-101: Mr. Dale Mah, P.Geo., VP Corporate Development of Endeavour Silver Corp.

As Qualified Persons and representative of EDR, Mr. Mah has visited the mining operations on numerous occasions. His most recent visit was conducted on October 24-28, 2018. During his visit, he viewed selected drill core, underground mining operations, visited waste rock storage facilities, toured mineral processing facilities, viewed infrastructure, and discussed aspects of mine planning, budgeting, geology, exploration and mining practices with site personnel. A personal inspection has not been conducted more recently due to the COVID-19 pandemic travel restrictions imposed by local and foreign governments. However, once it is safe to do so, a physical site visit will take place as soon as practical.

2.4 Units of Measure

Unless otherwise stated, all measurements reported here are in U.S. Commercial Imperial units, and currencies are expressed in constant 2020 U.S. dollars.


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Reliance on Other Experts

3. RELIANCE ON OTHER EXPERTS

This section is not relevant to this report.


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Property Description and Location

4. PROPERTY DESCRIPTION AND LOCATION

4.1 Project Location

The Guanaceví Project is located in the northwest portion of the Mexican state of Durango, approximately 3.6 km west of the town of Guanaceví and 260 km northwest of the capital city of Durango (Figure 4-1). The approximate geographic center of the Project is 105°58'20"W longitude and 25°54'47"N latitude.

Figure 4-1  Project Location Map

The Project is comprised of 51 mineral concessions for a total property area of 4,171.5546 ha (Figure 4-2) and 2 concessions associated to an exploitation agreement with Ocampo Mining (Ocampo), which covers an area of 55.3472 hectares. The mineral concessions vary in size and are not all contiguous.  The annual 2021 concession tax for the Guanaceví Properties is estimated to be approximately 21,186,396 Mexican pesos (pesos), which is equal to about US $59,320 at an exchange rate of 20.00 pesos to US $1.00. Mineral concession information is summarized in Tables 4-1 and 4-2.

The Guanaceví Project consists of the milling facility just outside of the town of Guanaceví and 3 active mines (Milache-El Curso, North Porvenir and Santa Cruz Sur), which all are on the Santa Cruz vein.  The mines are approximately 5 km from the plant.  The Milache-El Curso mines are accessed using the same portal as the old Porvenir 4 mine, while the North Porvenir and Santa Cruz Sur mines are located 2 km and 4.5 km, respectively, south of the Porvenir 4 portal. 


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Property Description and Location

Figure 4-2  Guanaceví Mines Project, Mineral Concessions Map

Table 4-1  Guanaceví Mines Concessions Controlled by EDR

Concession Name

Title Number

Term of Mineral Concession

Hectares

2021 Annual Taxes (pesos)

From

To

1st Half

2nd Half

Santa Cruz Dos

191773

19/12/1991

18/12/2041

113.5387

19,971

19,971

El Pelayo Y Anexas

193392

19/12/1991

18/12/2041

56.2519

9,895

9,895

Unif. Santa Cruz

186577

24/04/1990

23/04/2040

28.5896

5,029

5,029

San Guillermo

179601

11/12/1986

10/12/2036

5.0000

880

880

Unificacion Flora

189233

05/12/1990

04/12/2040

36.5506

6,429

6,429

San Marcos

185486

14/12/1989

13/12/2039

5.5469

976

976

San Vicente

187020

29/05/1990

28/05/2040

8.0000

1,407

1,407

Nuestra Senora

185412

14/12/1989

13/12/2039

5.6000

985

985

San Pedro Uno

191143

29/04/1991

28/04/2041

49.8437

8,768

8,768

El Porvenir Dos

161449

10/04/1975

09/04/2025

30.0000

5,277

5,277

La Sultana

162915

08/08/1978

07/08/2028

11.5889

2,038

2,038

El Milache

163509

10/10/1978

09/10/2028

42.8866

7,544

7,544

Veronica

167013

11/08/1980

10/08/2030

11.7648

2,069

2,069

El Desengaño

187018

29/05/1990

28/05/2040

19.4747

3,426

3,426

El Calvario

191733

19/12/1991

18/12/2041

1.3098

230

230



Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Property Description and Location

Concession Name

Title Number

Term of Mineral Concession

Hectares

2021 Annual Taxes (pesos)

From

To

1st Half

2nd Half

Elizabeth

180568

13/06/1987

12/06/2037

16.9973

2,990

2,990

El Rocio

227665

28/07/2006

27/07/2056

51.2334

9,012

9,012

La Brisa 3

236564

16/07/2010

15/07/2060

715.8666

125,921

125,921

La Gloria

238353

23/09/2011

22/09/2061

309.9369

54,518

54,518

La Brisa 4

240296

17/05/2012

16/05/2062

1584.4986

158,371

158,371

La Brisa 4, Fracc.

239873

29/02/2012

28/02/2062

51.8008

5,177

5,177

La Brisa 5

239874

29/02/2012

28/02/2062

214.6744

21,457

21,457

Ampl. Al Bajo Del Nvo. P.

184074

15/02/1989

14/02/2039

7.3062

1,285

1,285

La Mazatleca

186475

02/04/1990

01/04/2040

14.1797

2,494

2,494

La Guirnalda

187771

17/09/1990

16/09/2040

46.7611

8,225

8,225

La Guirnalda 2

219707

03/04/2003

02/04/2053

5.9915

1,054

1,054

San Pablo

216716

28/05/2002

27/05/2052

3.3972

598

598

Ana Maria

214167

18/08/2001

17/01/2051

3.2320

569

569

El Martir

215925

02/04/2002

01/04/2052

8.8675

1,560

1,560

Ampl. Del Soto

191987

19/12/1991

18/12/2041

3.9998

704

704

IDA

191659

19/12/1991

18/12/2041

4.9086

863

863

Epsilon

195079

25/08/1992

24/08/2042

7.0622

1,242

1,242

El Terremoto

193869

19/12/1991

18/12/2041

12.0000

2,111

2,111

Alajaa

183881

23/11/1988

22/11/2038

11.2050

1,971

1,971

Barradon 7

214162

18/08/2001

17/01/2051

37.1376

6,533

6,533

Santa Isabel

204725

25/04/1997

24/04/2047

84.0000

14,776

14,776

Noche Buena

167563

26/11/1980

25/11/2030

79.8962

14,054

14,054

El Porvenir Cuatro

168105

13/02/1981

12/02/2031

30.0000

5,277

5,277

La Brisa

224158

19/04/2005

18/04/2055

25.5518

4,495

4,495

El Cambio

205475

17/09/1997

16/09/2047

11.9962

2,110

2,110

La Onza

211502

30/05/1991

29/05/2041

18.2376

3,208

3,208

San Nicolas

191543

19/12/1991

18/12/2041

4.4838

789

789

Ampl. de San Nicolas

191675

19/12/1991

18/12/2041

2.5934

456

456

Garibaldi

224396

04/05/2005

03/05/2055

165.4490

29,102

29,102

Santa Cruz Ocho

215911

19/03/2002

18/03/2052

165.6280

29,134

29,134

El Pelayo

219709

03/04/2003

02/04/2053

5.8881

1,036

1,036

El Aguaje De Arriba

170158

17/03/1982

16/03/2032

5.0000

880

880

A. El Aguaje De Arriba

170159

17/03/1982

16/03/2032

7.0000

1,231

1,231

La Plata

170156

17/03/1982

16/03/2032

2.0000

352

352

La Prieta

148479

29/10/2017

28/10/2067

7.0000

1,231

1,231

San Fernando

165045

23/08/1979

22/08/2029

19.8279

3,488

3,488

Totals

 

 

 

4,171.5546

593,198

593,198

Table 4-2  Guanaceví Mines Concessions Controlled by EDR (Ocampo agreement)

Concession Name

Title Number

Term of Mineral Concession

Hectares

From

To

El Porvenir

168488

13/05/1981

12/05/2031

15.0000

El Curso

214316

06/09/2001

05/09/2051

40.3472

Totals

 

 

 

55.3472



Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Property Description and Location

4.2 Mineral Tenure, Agreements and Encumbrances

EDR controls the Guanaceví Project through its 100% owned Mexican subsidiary, Endeavour Gold Corporation S.A. de C.V. (Endeavour Gold). Endeavour Gold holds the project through its three 100% owned subsidiaries, Minera Plata Adelante S.A. de C.V. (Minera Plata Adelante), Minera Santa Cruz SA de CV (Minera Santa Cruz) and Refinadora Plata Guanaceví S.A. de C.V. (Refinadora Plata Guanaceví).

EDR has executed a number of agreements with respect to the Guanaceví Project over the years. During 2019, EDR acquired a 10-year right to explore and exploit the El Porvenir and El Curso concessions from Ocampo Mining SA de CV ("Ocampo"), a subsidiary of Grupo Frisco.  EDR agreed to meet certain minimum production targets from the properties, subject to various terms and conditions and pay Ocampo a $12 fixed per tonne production payment plus a variable net smelter return royalty based on the spot silver price. EDR pays a 4% royalty on sales below $15.00 per ounce, 9% above $15.00 per ounce 13% above $20.00 per silver ounce, and a maximum 16% above $25.00 per silver ounce, based on then current realized prices.

EDR also maintains access agreements with various private landowners and two local ejidos (Del Hacho and San Pedro) to ensure access for exploration and mining. Surface access agreements as of December 31, 2020 are summarized in Table 4-3.

Table 4-3  Summary of Endeavour Silver's Surface Access Rights

Owner

Type

Area Name

Validity

Term

Drill Pads

ANNUAL

(Pesos)

PAYMENT
(PESOS)

Ejido Arroyo Del Hacho

Exploitation / Exploration

Guanaceví

10 Years

27/12/2017 - 2027

None

1,820,000

Rosa Elena Rivera

Exploitation / Exploration

Santa Cruz Sur

10 Years

21/04/2015 - 2025

None

1,311,188

Comunidad de San Pedro

Exploitation / Exploration

San Pedro

10 Years

09/10/2018 - 2028

None

2,005,000

Royalties currently associated with the Guanaceví Project are summarized in Table 4-4


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Property Description and Location

Table 4-4  Summary of Endeavour Silver's Royalties

Agreement

NSR

Concession Name

Title Number

Hectares

Minera Las Albricias

1%

Ampl. Al Bajo Del Nvo. P.

184074

7.3062

La Mazatleca

186475

14.1797

La Guirnalda

187771

46.7611

La Guirnalda 2

219707

5.9915

San Pablo

216716

3.3972

Ana María

214167

3.2320

El Martir

215925

8.8675

Ampl. Del Soto

191987

3.9998

Ida

191659

4.9086

Epsilon

195079

7.0622

El Terremoto

193869

12.0000

Alajaa

183881

11.2050

Barradon 7

214162

37.1376

Santa Isabel

204725

84.0000

Noche Buena

167563

79.8962

Minera Capela

3%

Santa Cruz Dos

191773

113.5387

El Pelayo y Anexas

193392

56.2519

Unif. Santa Cruz

186577

28.5896

San Guillermo

179601

5.0000

Unificación Flora

189233

36.5506

San Marcos

185486

5.5469

San Vicente

187020

8.0000

Nuestra Señora

185412

5.6000

San Pedro Uno

191143

49.8437

Ignacio Barraza

2%

Garibaldi

224396

165.4490

Ocampo Mining

4% if Ag price <= $15 per oz
9% if Ag price >$15 <$20 per oz
13% if Ag price >$20 <$25 per oz
16% if Ag price >$25 per oz

El Porvenir

168488

15.0000

El Curso

214316

40.3472

4.3 Permits and Environmental Liabilities

EDR holds all environmental and mine permits required to conduct planned exploration and mining operations on the Guanaceví Project and is in compliance with all environmental monitoring requirements and applicable safety, hygiene and environmental standards. Environmental permitting and liabilities are discussed in greater detail in Section 20 of this report.

There are no existing or anticipated significant factors which might affect access, title, or the right or ability to perform work on the Guanaceví Project.


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Accessibility, Climate, Local Resources, Infrastructure and Physiography

5. ACCESSIBILITY, CLIMATE, LOCAL RESOURCES, INFRASTRUCTURE AND PHYSIOGRAPHY

5.1 Access and Climate

The Guanaceví Property is readily accessible from the city of Durango via paved roads. Primary access is provided by State Highway 45 north from Durango to the town of Canatlan, continuing on State Highway 23 through Santiago Papasquiaro and Tepehuanes to the town of Guanaceví. The total distance between Durango and the town of Guanaceví is approximately 260 km, which requires roughly 4.5 hours of drive time. Guanaceví has a small, unmaintained airport with a 1,000-m unpaved landing strip capable of handling light aircraft.

The Guanaceví Project is located just 3.6 km from the town of Guanaceví, which is economically dependent on regional mining and milling operations. The town of Guanaceví boasts a population of approximately 3,000 (2015 census) and all standard modern services. The town, mine and plant are connected to the national land-based telephone system that provides reliable national and international direct dial telephone communications, as well as stable internet connections and satellite television.

The local climate poses no limitations to the length of the operating season at the Guanaceví Project. The dry season runs from October through June, and the wet season from July to September. Total average annual rainfall varies from about 65 to 105 mm. Winter temperatures vary from a maximum of 15°C to a minimum of -14°C, while summer temperatures range from a minimum of 20°C to a maximum of 30°C. Freezing temperatures can occur overnight, but quickly warm to above freezing during daylight hours. Occasional snow does occur in the area but quickly melts on all but the most protected slopes.

5.2 Local Resources and Infrastructure

The city of Durango is the closest major population center to the Guanaceví Project, with a population of approximately 580,000. Durango is a mining, agricultural, commercial and tourist center with all of the associated municipal amenities, including an international airport with numerous international and regional flights to other major Mexican cities and the United States.

At each of the mine sites, the water required is supplied from the dewatering of the mines. Industrial water for the flotation and cyanide plant is recycled, and additional water (60,000 m3/y of fresh water) is obtained from a nearby underground mine. The tailings facility at the plant is set up to recycle all water back into the ore processing plant.

Electrical power from the Federal Power Authority (34 kV) supplies both the plant and mine. In 2011, EDR completed an upgrade of the power to the mine and mill sites by installing a second line into main power supply.

An upgrade to the tailings dam was completed in 2010, and EDR began placing filtered tailings in compacted lifts. After a planned expansion in the coming year or two, current tailings storage facility (TSF) capacity will be sufficient for many years of production.


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Accessibility, Climate, Local Resources, Infrastructure and Physiography

Apart from offices, warehouses and other facilities, EDR also provides living accommodations for employees working on a rotational schedule. Much of the labor work force lives in Guanaceví and nearby communities. The area has a rich tradition of mining and there is ample supply of skilled personnel sufficient to man both the underground mining operations and the surface facilities.

5.3 Physiography

The town of Guanaceví is located on the altiplano at about 2,170 m elevation. Both the town and the Project lie east of the Sierra Madre Occidental mountain range among low, rounded mountains with relief of about 650 m from the valley bottoms (~2,100 m) to the mountain crests (~2,750 m). The mountains are predominately covered by scrub oak, pine trees and occasional cactus, with the pine trees more prevalent at the higher elevations. Wildlife in the area consists generally of deer, badgers, foxes, coyotes, squirrels, rabbits, and mice.

5.4 Surface Rights

EDR has negotiated access and the right to use surface lands sufficient for many years of operation. Sufficient area exists at the property for all needed surface infrastructure related to the life-of-mine plan, including processing, maintenance, fuel storage, explosives storage and administrative offices. Once the tailings facility expansion planned for 2021 is completed, there will be sufficient capacity in existing tailings impoundment for many years.


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project History

6. HISTORY

6.1 Historical Exploration

The extent of historical exploration on the Guanaceví Project is relatively unknown. Prior to management by EDR, production was supported by three mines without the benefit of any systematic exploration drilling, geological mapping or mine planning. Documented historical exploration activities are summarized as follows:

  • During the 1920's, Peñoles purchased several mines including the Santa Cruz mine, where from 1921 to 1924, the 330-m inclined shaft and several kilometers of underground workings on Levels 6, 7, 8, 10, 11 and 13 were developed that partially explored the vein ore shoots.

  • The Guanaceví Mining Company operated from the 1930's until production ceased in 1942. In the 1970's, the Comisión de Fomento Minero (Federal Mining Commission) (Fomento Minero), a Federal government agency charged with the responsibility of assisting the small-scale Mexican mining industry, constructed a 400 t/d flotation plant, now the MG plant.

  • In the early 1960's, Engineer Mejorado of Peñoles Mining Company recommended additional exploration to prove up the mineral resource estimate at the time. Engineer P. Sanchez Mejorado mapped and sampled the mine underground and recommended diamond drilling below Level 13. Watts, Griffis and McOuat Limited (WGM) noted that the exploration works conducted by Peñoles consisted of channel sampling across the mineralized zone coupled with short, lateral, approximately 1-inch diameter diamond drillholes, and detailed surveying and geological mapping of the underground workings (WGM,2005). WGM (2005) further noted that the limited exploration by Peñoles was well conducted and blocked out several areas of potential resources, but also stated that more than half of the areas of potential resources, except for those below the water table (below Level 13), had been mined out.

  • In the early 1990's, Fomento Minero started construction of a 600 t/d cyanide leach plant but construction ceased when it was only 30% complete due to the lack of funding.

  • In 1992, MG, a private company, purchased the Fomento Minero facilities and completed the leach plant construction. MG used the leach circuit to process the old tailings from the flotation plant.  During 2002, total plant production included 170 t/d to 250 t/d coming from the three mines: Santa Cruz, Barradón and La Prieta mines, with approximately 700 to 800 t/d of additional feed purchased from other small-scale operations.

  • Pan American Silver Corp. (Pan American) conducted an eight-month evaluation program in 2003 that consisted of an extensive, systematic, underground channel sampling and surveying program and included three diamond drillholes in the North Porvenir area.

6.2 Historical Production

6.2.1 Mining

The Guanaceví mining district and the Guanaceví Mines Project area are riddled with mine openings and old workings which occur in a haphazard fashion near ground surface, representing the earliest efforts at extraction, and more systematic fashion at depth, which is indicative of later, better organized and formal planned mining. Associated with these openings and workings are a number of old ruins representing the remains of historic mine buildings and other structures.


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project History

Many waste dumps and historically material extracted through the tunnels, shafts and winzes from underground operations can be seen scattered over the hillsides and beneath the foundations of the ruins and modern buildings. Historically, individual veins or deposits had separate owners and, in the case of some of the larger veins or deposits, had several owners along the strike length which resulted in a surfeit of adits and shafts and very inefficient operations. The mines within the Guanaceví mining district have been developed primarily by using open stope/shrinkage and cut-and-fill underground mining methods.

Both the ground conditions, which vary from good to poor, and the deposit geometries tend to favor the higher cost, cut-and-fill mining method, with development waste used for backfill.

6.2.2 Production

Mining in the Guanaceví district extends back to at least 1535 when the mines were first worked by the Spanish. During the late sixteenth century silver production accounted for 80% of all exports from Nueva España (New Spain), although, by the mid-seventeenth century silver production collapsed when mercury, necessary to the refining process, was diverted to the silver mines of Potosí in present day Bolivia. Collapse of the seventeenth century mining led to widespread bankruptcy among the miners and hacienda owners; however, in the latter half of the seventeenth century silver mining began to recover in Nueva España. By the start of the 18th century, Guanaceví had become an important mining center in the Nueva Vizcaya province. The peasant uprisings of 1810 to 1821 were disastrous to the Mexican mining industry with both the insurgents' soldiers and royalist troops all but destroying the mining production in Mexico, and the Guanaceví mining district was not spared during this period.

The vast majority of production came prior to the 1910 Mexican Revolution with the Guanaceví mining district being known for its high silver grades. Previous reports noted that the official production records indicate that a total value of 500 million pesos, or approximately 500 million ounces of silver and silver equivalents, with a present-day value of about US $3.25 billion, had been extracted from this mining district. This makes the Guanaceví district one of the top five silver mining districts in Mexico on the basis of past production, though production has been sporadic since the 1910 Revolution.

Table 6-1 includes estimated historical production at the Guanaceví Mines Project for the years 1991 to 2003, prior to Endeavour Silver, plus 2004 to 2020 during Endeavour Silver's ownership.


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project History

Table 6-1  Summary of the Production for the Guanaceví Property (1991 to 2020)

Year

Tonnes

Silver (g/t)

Gold (g/t)

1991 (from July)

2,306 est.

470 est.

1.0 est.

1992

10,128

340 est.

1.3 est.

1993

12,706

320 est.

0.8 est.

1994

18,256

190 est.

0.5 est.

1995 (until May)

5,774

280 est.

0.5 est.

1996

11,952

315

0.74

1997

13,379

409

0.87

1998

11,916

550

0.92

1999

6,466

528

0.84

2000

18,497

538

1.01

2001

13,150

510

1.09

2002

NA

NA

NA

2003

1,531

550

8,902

2004

NA

NA

NA

2005

102,617

385

0.88

2006

117,255

449

0.90

2007

291,561

319

0.87

2008

255,656

318

0.58

2009

230,632

322

0.80

2010

312,087

324

0.74

2011

363,076

311

0.69

2012

418,287

249

0.76

2013

435,922

253

0.60

2014

423,251

314

0.65

2015

431,431

295

0.62

2016

367,441

232

0.51

2017

321,113

230

0.53

2019

322,988

234

0.65

2020

346,679

314

0.96

6.3 Historical Mineral Resource and Mineral Reserve Estimates

2016 HRC completed the most recent estimate of the mineral resource for the Guanaceví Project in December 2016.  The process was based on drillhole data constrained by geologic vein boundaries with an Inverse Distance Weighted ("ID") algorithm.

The mineral resource included 22 individual veins, 4 of which were estimated using a Vertical Longitudinal Projection (VLP) polygonal method and the remaining 18 veins as 3-dimensional ("3D") block model.


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project History

The resources based on the 2D polygonal methods were estimated by using a fixed distance VLP from sample points. The VLPs were created by projecting vein geology and underground workings onto a vertical 2D long section. The 2D estimates were classified using distance to the nearest sample. Measured mineral resources include resource blocks within 10 meters of a sample. Indicated mineral resources include resource blocks within 20 meters of a sample. Inferred mineral resources include those blocks greater than 20 meters from a sample and have a value for estimated silver.

HRC constructed the 3D vein models using Leapfrog. Eighteen veins were modeled using a linear interpolation methodology and sample intervals.  Cross-sections orthogonal to the strike of the vein were used to select intervals from drillholes representing the vein material. Level sections were used to select vein material from channel samples. Points representing the hanging wall and footwall contacts were extracted by the software to interpolate hanging wall and footwall surfaces. These surfaces were used to delineate each vein solid. The surfaces were evaluated in 3-dimensions to ensure that both the down dip and along strike continuity was maintained throughout the model. Veins were clipped against younger veins, topography, and the concession boundaries.

The mineral resource estimate included all analytical data obtained as of December 31, 2016.

Table 6-2  Historic Mineral Resource Estimate, Effective Date December 31, 2016

Classification

Tonnes

Silver Equivalent

Silver

Gold

g/t

g/t

oz.

g/t

oz.

Measured

69,000

284

248

550,300

0.47

1,000

Indicated

2,271,000

351

296

21,595,600

0.72

52,800

Measured + Indicated

2,340,000

349

295

22,145,900

0.71

53,800

Inferred

638,000

441

379

7,769,400

0.82

16,900

  • Measured, Indicated and Inferred resource cut-off grades were 198 g/t silver equivalent at Guanaceví.

  • Metallurgical recoveries were 82.5% silver and 85.4% gold.

  • Silver equivalents are based on a 75:1 silver: gold ratio

  • Price assumptions are $16.29 per ounce for silver and $1,195 per ounce for gold for resource cutoff calculations.

  • Mineral resources were estimated exclusive of and in addition to mineral reserves.

The Guanaceví Project mineral reserves were derived and classified according to the following criteria:

  • Proven mineral reserves were the economically mineable part of the Measured resource for which mining and processing / metallurgy information and other relevant factors demonstrate that economic extraction is feasible. For Guanaceví Project, this applies to blocks located within approximately 10m of existing development and for which EDR has a mine plan in place.

  • Probable mineral reserves are those Indicated mineral resource blocks which are considered economic and for which EDR has a mine plan in place. For the Guanaceví mine project, this was applicable to blocks located a maximum of 35m either vertically or horizontally from development with one exception in the main lower Santa Cruz vein the maximum distance to development was extended to 110m as this area is currently being developed.


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project History

The Proven and Probable mineral reserves for the Guanaceví mine as of December 31, 2016

Table [1-2]  Historic Mineral Reserve Estimate as of 31 Dec 2016

Classification

Tonnes 

(t x 1,000)

AgEq g/t

Ag g/t

Ag (oz) * 1,000

Au g/t

Au (oz) * 1,000

% Dilution

Proven

86.5

284

247

686.2

0.49

1.37

26%

Probable

508.2

311

262

4,285.20

0.64

10.48

30%

Total Proven and Probable Reserves

594.7

307

260

4,971.40

0.62

11.84

29%

  • Reserve cut-off grades are based on a 198 g/t silver equivalent.

  • Metallurgical Recoveries were 82.5% silver and 85.4% gold.

  • Mining Recoveries of 95% were applied.

  • Minimum mining widths were 1.4 meters.

  • Dilution factors averaged 29%. Dilution factors are calculated based on internal stope dilution calculations and external dilution factors of 15% for cut and fill and 30% for long hole.

  • Silver equivalents are based on a 75:1 silver:gold ratio.

  • Price assumptions are $16.29 per ounce for silver and $1,195 per ounce for gold.

  • Mineral resources are estimated exclusive of and in addition to mineral reserves.

  • Figures in table are rounded to reflect estimate precision; small differences generated by rounding are not material to estimates.


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Geological Setting and Mineralization

7. GEOLOGICAL SETTING AND MINERALIZATION

The regional and local geology of the Guanaceví Project is described in detail in several existing internal and previously published technical reports. The following descriptions of geology and mineralization are included and/or modified from HRC (2015, 2016) and Munroe (2014). The QP has reviewed the available geologic data and information, and finds the information presented here in reasonably accurate and suitable for use in this report.

7.1 Regional Geology

The rock types of the Guanaceví district can be divided into three principal stratigraphic groups based on stratigraphic studies by the Consejo de Recursos Minerales and observations of drill core during exploration programs carried out by EDR.

7.1.1 Guanaceví Formation

The oldest unit in the district is the Guanaceví Formation, a polymictic basal conglomerate composed of angular to sub-angular fragments of quartz and metamorphic rocks set in a sandy to clayey matrix within sericitic and siliceous cement. It is assigned to the Upper Jurassic or Lower Cretaceous periods on the basis of biostratigraphic indicator fossils mentioned but not detailed in the Durango State Geological Reference Report (1993). At least 450 m of thickness has been reported in the Guanaceví area for this basal unit, the lower contact of which has not been observed. In most areas, the upper contact is structural on high-angle normal faults but, in the San Pedro area, the upper contact is abrupt from Guanaceví conglomerate rocks to fairly fresh, dark colored andesitic flows of the Lower Volcanic Sequence that appear conformable to the underlying Guanaceví Formation. The Jurassic assignment of the Guanaceví Formation has been in question, and at least two reports in the 1990's considers it to be Tertiary (Durning and others, unpublished reports). A Tertiary age for the unit mitigates the idea of a transitional unit persisting through the Cretaceous; alternatively, it is possible that paraconformities in the package may be present but unreported to date.

Regional studies in Mexico demonstrate that Mesozoic rocks basal to the Tertiary section are strongly deformed with the development of sericitic alteration, shearing and microfolding in local shear zones and stronger deformation associated with overthrust nappe folds of Laramide age (late Cretaceous to end of the Paleocene). This type of strong deformation is not visible in the Guanaceví Formation, further raising questions about the validity of a Mesozoic assignment for this unit.

The Guanaceví Formation has been structurally defined as a horst, occupying the central portion of the northwest trending Guanaceví erosional window and flanked by sets of northwest striking normal faults that offset the Upper and Lower Volcanic Sequences down to the southwest and northeast on corresponding sides of the window. Mineralization within the horst is hosted by the conglomerate, both as dilatational high-angle fracture-filled structures and, in the San Pedro area, as manto-like replacement bodies below the upper contact of the conglomerate with overlying andesitic units of the Lower Volcanic Sequence.


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Geological Setting and Mineralization

7.1.2 Lower Volcanic Sequence

Using an inherited stratigraphic framework for the area, andesitic rocks and associated sedimentary units are placed in a loosely defined package of flows and volcaniclastic sediments correlated with Eocene volcanism throughout the Sierra Madre of Mexico. No radio isotope age determinations have been made on volcanic units of the Guanaceví district, and lithological correlations to the Lower Volcanic Sequence appear to be reasonable for the andesitic flows and associated volcaniclastic units.

It has been observed in the rocks that host the Porvenir and Santa Cruz mine workings that the andesite occurs as a pale green to nearly black volcanic flow ranging from aphyric to plagioclase-hornblende phyric. Plagioclase is the common phenocryst type with crystals ranging from 1 to 2 mm up to 10 mm. Hornblende phenocrysts are 1 mm to 4 mm in length. In porphyritic andesites, feldspar phenocryst abundance approaches 5%, and hornblende abundance is generally less than 3%.

The sequence of rock types in the Lower Volcanic Sequence, as presently understood, is a coarsening-upward series of volcaniclastic sediments capped by an andesite flow as described above. The sedimentary lithologies are siltstones overlain by sandstone with minor intercalations of conformable conglomerate beds. The siltstone-sandstone sequence becomes transitionally dominated by conglomeratic beds at the top of the volcaniclastic package. Overall thickness of the siltstone-sandstone beds is up to 120 m.

Conglomerate beds of the Lower Volcanic Sequence are from a few centimeters to 150 m thick at the top of the package and differ from the conglomerates of the Guanaceví Formation in that Lower Volcanic Sequence clasts are mainly andesite of varying textural types.

7.1.3 Upper Volcanic Sequence

The Upper Volcanic Sequence consists of rhyolite crystal-lapilli tuff units unconformably overlying the andesites which are generally structurally disrupted and altered by oxidation and silicification. The rhyolite is strongly argillically altered with silicification overprinting argillic alteration in the immediate hanging wall of quartz veins and other silicified structures. The rhyolite commonly contains rounded quartz 'eyes' up to 4 mm in diameter, and the matrix consists of adularia, kaolinite and quartz. Local concentrations of biotite crystals up to 2 mm are not uncommon. The rhyolite has variable textures from thin-bedded ash flows to coarse lapilli tuffs with lithic clasts of andesite or rhyolite up to 50 cm in diameter. These latter commonly exhibit alteration rims indicating high temperatures and fluids in the volcanic environment. The thickness of the rhyolite tuff assemblage has not been measured at this time, but appears to exceed 300 m.

Geochemically, the lower portion of the rhyolites has been demonstrated by rare earth element (REE) data, from a series of samples taken from East Santa Cruz drilling, to be magmatically linked to the underlying andesites. The similarity between REE patterns of the rhyolite crystal-lapilli tuff and the andesitic rock units in this data set suggests a common source for the two volcanic packages that is difficult to reconcile with the idea of many millions of years of volcanic quiescence (from Lower Volcanic to Upper Volcanic Sequences). This raises the possibility that regional correlations for Guanaceví rhyolite based on radio isotope age determinations may result in assignment of the rhyolite (of the Santa Cruz/Porvenir mine area) to the Lower Volcanic Sequence rather than the Upper. In the San Martin de Bolaños district of Jalisco and also in the Topia district of Durango State, uppermost volcanic lithologies of the Lower Volcanic Sequence are rhyolitic and directly associated with mineralization. This may be true for the Guanaceví mining district as well.


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Geological Setting and Mineralization

See Figure 7-1 for a map of the regional geology in the area surrounding the Guanaceví mining district. See Table 7-1 for a generalized stratigraphic column in the Guanaceví mining district.

Figure 7-1 Regional Geology Map for the Guanaceví Mining District


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Geological Setting and Mineralization

Table 7-1   Generalized Stratigraphic Column in the Guanaceví Mining District

Geological Age

Stratigraphic Units and Lithologies

Thickness (m)

Tertiary

Oligocene

Upper Volcanic Sequence

300

Rhyolitic tuffs and ignimbrites

Eocene

Lower Volcanic Sequence

 

Andesite porphrytic flow

< 70

Andesite conglomerate

< 150

Volcanic sandstone/siltstone

< 120

Jurassic ()

(Late)

Guanaceví Formation

450

Note: Table reproduced from the March, 2006 Technical Report by Range Consulting

7.1.4 Structural Setting

Figure 7-1 shows major faults of the Guanaceví mining district on a simplified geologic map of the region. The map pattern constitutes an erosional window caused by crustal uplift apparently centered about 3 km west of Guanaceví. With some exceptions, fracture-filling vein mineralization is localized on the flanks of the uplift center, suggesting a genetic relationship between uplift and mineralization. The three principal trends of high-angle normal faults that characterize the region are as follows:

  • The dominant structural trend in the region is northwest, with significant north-northeast faults in a likely conjugate relationship. This generation of structures hosts most of the mineralization in the district.

  • Northeast faults postdate the mineralized structures.

  • East-west faults appear last.

This pattern sequence would appear to indicate an early extension in a northeast-southwest direction, followed by a later extension in an east-northeast-west-southwest direction, followed by a northwest-southeast extension and finally ending with the latest extension in a north-south direction. This clockwise evolution of principal stress directions is similar to that of other regions in the American Cordillera, including the Sierra Madre of Mexico.

Timing of uplift of the Guanaceví window is constrained by the following considerations:

  • Dilatational fractures flanking the uplift are dominantly northwest trending, with subordinate north and north-northeast components. Northeast and east-west fractures are not significant in controlling the uplift pattern. Thus, uplift is early in the structural evolution described above.

  • The northeast-southwest extension in Mexico is generally associated with opening of the Gulf of California, and dated as Oligocene to Miocene.

  • Uplift therefore may be coeval with the onset of silicic volcanism of the Upper Volcanics, which are considered Oligocene in age.

It is reasonable to conclude that uplift occurred at the onset of Upper Volcanic Sequence eruptions (Oligocene), northeast-southwest extension, and was coeval with mineralization. The cause of uplift, however, is left unexplained by these considerations. Alternative explanations include magmatic upwelling at depth, resurgent doming within a cryptic caldera, or tectonic transpression resulting from large-scale lateral displacement


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Geological Setting and Mineralization

7.2 Project Geology

The Santa Cruz mine property, which forms part of the main portion of the Guanaceví Mines Project, covers about a 3.0 km strike length of the Santa Cruz fault/vein system. The Santa Cruz vein is similar in many respects to other veins in the Guanaceví district, except that it is the only one to lie on the west side of the horst of Guanaceví Formation and associated facies, and it dips west instead of east. See Figure 7-2 for the Guanaceví Mines Project geology map.

Figure 7-2  Guanaceví Mines Project Geology Map

In the Porvenir Dos area and the Deep Santa Cruz mine workings, a low angle rhyolite crystal-lapilli tuff and andesitic contact occurs high in the hanging wall of the Santa Cruz vein indicating a fault contact with Guanaceví Formation, which obviously cuts the contact.


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Geological Setting and Mineralization

7.2.1 Local Structure

The Santa Cruz vein, the principal host of silver and gold mineralization, is located on the west side of the horst of the Guanaceví Formation. The mineralized vein is part of a major fault system that trends northwest and principally places the Guanaceví Formation in the footwall against andesite and/or rhyolite in the hanging wall. The vein/fault presents a preferred strike of N45°W with dips from 45° to 70° to the southwest. From Santa Cruz Sur to Milache, it extends a distance of 6.5 km and averages approximately 3 m in width.

The broader and higher-grade mineralized ore shoots tend to occur along flexures in the Santa Cruz vein structure, where sigmoidal loops are developed both along strike and down dip. The vein in Deep Santa Cruz for instance splays into two, three or four separate mineralized structures with the intervening wall rocks also often well mineralized, giving mining widths up to 20 m in some places. These sigmoidal loops tend to develop with some regularity along strike and all of the ore shoots at the Santa Cruz mine have about a 60° plunge to the northwest. A shallow northwest plunging striation, raking at 15°-30°, is noted on a number of fault planes within the Santa Cruz structure; these striations appear to be consistent with an observed sinistral movement seen on minor faults which produce small offsets of the Santa Cruz vein.

Particularly around the peripheral ore zones the vein is observed to develop imbricate structures, either as imbricate lenses shallowly oblique to the principal Santa Cruz trend or as vein segments offset by similarly trending minor faults. The trend of these structural features is generally slightly more westerly than the Santa Cruz vein/fault trend and steeper dipping. Veining is also often affected by north-south structures, which rarely seem to offset the main fault but do cause minor jogs in the vein; often the north-south structures are associated with manganese oxide concentrations and elevated silver grades.

7.2.2 Alteration

The sedimentary and volcanic rocks are hydrothermally altered with propylitization (chlorite) the most widespread, up to 150 m from the veins, with narrower bands of potassic and argillic alteration (kaolinite and adularia) typically up to 25 m thick in the hanging wall and with silicification near the veins. Phyllic alteration, however, is absent in the Guanaceví district.

7.3 Mineralization

The principal mineralization within the Santa Cruz-Porvenir mines is an epithermal low-sulfidation, quartz-carbonate, fracture-filling vein hosted by a fault-structure that trends approximately N45°W and dips 55° southwest. The fault and vein comprise a structural system referred to locally as the Santa Cruz vein structure or Santa Cruz vein fault. The Santa Cruz vein structure has been traced for 6.5 km along the trend and averages about 3 m in width. Mineralization in the system is not continuous but occurs in steeply northwest-raking shoots up to 200 m in strike length. A second vein, sub-parallel to the Santa Cruz vein but less continuous, is economically significant in the Porvenir Dos zone, the northern portion of deep North Porvenir, in the Milache zone and finally in the Santa Crus Sur zone. It is referred to in these areas as the "Footwall vein".


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Geological Setting and Mineralization

7.3.1 Santa Cruz Vein

The Santa Cruz vein is a silver-rich structure with lesser amounts of gold, lead and zinc. Mineralization has averaged 500 g/t silver and 1 g/t gold over 3 m true width. The minerals encountered are argentite-acanthite, limited gold, galena, sphalerite, pyrite and manganese oxides. Gangue minerals noted are barite, rhodonite, rhodochrosite, calcite, fluorite and quartz. The mineralization down to Level 6 in the Santa Cruz mine is mainly oxidized, with a transition zone of oxides to sulfides occurring between Levels 6 to 8, although some sulfide ore was mined above Level 6.

Mineralization exhibits evidence of episodic hydrothermal events which generated finely banded textures. The higher-grade mineralization in the district is commonly associated with multiple phases of banding and brecciation. The first phase, deposition of white quartz, white calcite and pyrite in stockwork structures, often exhibits horse-tail structures bifurcating both in the horizontal and vertical sense to form imbricate pods. The second phase deposited semi translucent quartz with argentite, scarce gold, and oxides of manganese (2%) and rare lead and zinc sulfide (4%), the latter particularly in the lower part of the hydrothermal system. The second phase was accompanied by the deposition of barite, rhodonite, rhodochrosite, fluorite and calcite.

This second phase comprises multiple pulses of mineralization expressed in the vein structures as bands of massive, banded or brecciated quartz. Massive and massive-to-banded quartz are commonly associated with carbonate which is predominantly manganoan calcite and calcitic rhodochrosite. Rhodonite is much less abundant than carbonates but is not uncommon.

According to results obtained through diamond drilling, the lead and zinc mineralization occurs more commonly in the vein below the water table which, in the Santa Cruz mine, is just below the 13 Level.


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Deposit Types

8. DEPOSIT TYPES

The type of mineral deposit which is the target of exploration and mining activity at the Guanaceví Project is described in detail in a number of existing internal and previously published technical reports. The following description of the mineral deposit type is excerpted and/or modified from Munroe (2014).

The Guanaceví silver-gold district comprises classic, high-grade silver-gold, epithermal vein deposits, characterized by low sulphidation mineralization and adularia-sericite alteration. The Guanaceví veins are typical of most other epithermal silver-gold vein deposits in Mexico in that they are primarily hosted in the Tertiary Lower Volcanic series of andesite flows, pyroclastics and epiclastics, overlain by the Upper Volcanic series of rhyolite pyroclastics and ignimbrites. Evidence is accumulating in the Guanaceví mining district that the mineralization is closely associated with a pulse of silicic eruptions that either signaled the end of Lower Volcanic Sequence magmatism or the onset of Upper Volcanic Sequence activity.

Low sulphidation epithermal veins in Mexico typically have a well-defined, sub-horizontal ore horizon about 300 m to 500 m in vertical extent where the bonanza grade ore shoots have been deposited due to boiling of the hydrothermal fluids. Neither the top nor the bottom of the Santa Cruz ore horizon has yet been found but, given that high-grade mineralization occurs over a 400-m vertical extent from the top of the Garibaldi shaft (south of the Santa Cruz mine) to below Level 13 in Santa Cruz, it is likely that erosion has not removed a significant extent of the ore horizon.

Low sulphidation deposits are formed by the circulation of hydrothermal solutions that are near neutral in pH, resulting in very little acidic alteration with the host rock units. The characteristic alteration assemblages include illite, sericite and adularia that are typically hosted by either the veins themselves or in the vein wall rocks. The hydrothermal fluid can travel either along discrete fractures where it may create vein deposits or it can travel through permeable lithology such as a poorly welded ignimbrite flow, where it may deposit its load of precious metals in a disseminated deposit. In general terms, this style of mineralization is found at some distance from the heat source. Figure 8-1 illustrates the spatial distribution of the alteration and veining found in a hypothetical low sulphidation hydrothermal system.


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Deposit Types

Figure adapted from Berger & Eimon (1983), Buchanan (1981), Corbett & Leach (1996) and Hollister (1985) and others and dated December, 2013.

Figure 8-1  Alteration and Mineral Distributions within a Low Sulphidation Epithermal Vein System


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Exploration

9. EXPLORATION

9.1 EDR Exploration Prior to 2019

Exploration activities conducted by EDR in recent years prior to 2019 are summarized in the following paragraphs and are discussed in greater detail in the technical reports prepared by Hard Rock Consulting (2015,2016) and Munroe (2013, 2014). Exploration field activities carried out during 2017 to 2019, which have not been included in previous technical reports, are also summarized below.

During 2013, surface geological mapping and sampling was conducted by EDR at Guanaceví focused, from north to south, on San Pedro (El Cambio-PP), Milache, El Rocio and Santa Cruz South. Regionally, a total of 17 exploration targets were defined in a radius of approximately 70 km around the Guanaceví Project.

During 2014, exploration field activities were conducted by EDR at Guanaceví mainly in the Rocio-Pelayo, Porvenir 4, El Aguaje Mine and Santa Cruz South areas. These activities were undertaken to define targets of interest with possible potential of mineralization in order to develop possible drilling programs. A total of 655 samples were collected and submitted for assays.

In 2015, EDR conducted exploration activities, including drilling, at the Guanaceví Project. Local field exploration activities in 2015 included geological mapping, sampling, and interpretation in the La Guirnalda, Santa Cruz West, and Garibaldi claim areas.

During 2016, EDR conducted Regional Exploration over several concessions located around the Guanacevi Properties, mainly focused on discovering possible mineralization which could be of interest for Endeavour. In addition, EDR conducted both surface and underground drilling programs.

During 2017, exploration field activities were conducted in the Guanaceví Project, including underground drilling. Geological mapping over the projection on surface of the La Negra vein, and regionally over several concessions peripheral to the Guanaceví Project, with the intent of identifying mineralized zones for which additional exploration and drilling might be warranted.

During 2018, little exploration conducted by EDR around the Guanacevi Properties, with the objective of identifying mineralized bodies that could be of interest for EDR. In addition, underground and surface drilling conducted by EDR.

In 2019, exploration activities were conducted by EDR, including underground drilling. Geological mapping carried out by EDR over the projection of Santa Cruz vein, south of the Santa Cruz Sur mine and regional field activities over several concessions peripheral to the Guanaceví Project

9.2 2020 Exploration Activities

In 2020, EDR spent US $916,935 (including property holding costs) on exploration activities, including drilling at the Guanaceví Project, focused primarily on the definition of the Santa Cruz vein within El Curso claim. Exploration field activities were conducted in a third-party property, located northwest of the town of Guanaceví


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Exploration

9.2.1 Sampling Method and Approach

To establish exploration drill hole targets, EDR has collected surface outcrop, underground channel, surface channel samples, and conducted numerous surface geologic mapping campaigns.

9.2.1.1 Surface Channel Samples

Chip channel samples are marked by a line at each end of the channel and are collected across zones of mineralization, alteration, and structure by taking continuous (approximately 10 cm width) chips from a geologically defined traverse. The sample is chipped from the face with a mallet and chisel and captured by a large canvas. The canvas is cleaned after each sample has been taken and a lithologic description is recorded.  The samples range from 1 to 2 meters long, depending on degree of mineralization and weigh approximately 3 to 6 kilograms. Their location is recorded by a hand-held GPS unit.

9.2.1.2 Rock Chip Samples

As with the channel samples, single point rock chip samples are collected from an area of 1 to 2 meters in diameter. Multiple chips are collected from different points in the sampling area with a resulting weight from 1 to 3 kilograms.  The chips are bagged and the same protocol is applied as with the channel samples. The location is recorded with a hand-held GPS unit.

9.2.1.3 Soil Chip Samples

The soil sample method is primarily utilized in areas with a higher degree of weathering. Where appropriate, soil samples were taken from just below the organic horizon in pits dug by hand with shovels; in other areas, soil samples constituted fine-grained material collected from weathered slopes.  Soil samples constituted approximately 400 g to 600 g of material with as much organic matter removed as possible by screening or hand-picking.  Soil sampling typically occurred on lines or grids with one sample taken every 50 m to 100 m. The grids or lines are oriented perpendicular to the structure being tested. Samples and sample location were described by the geologist / sampling technician and location recorded by handheld GPS.

9.2.2 2020 Local Field Exploration

In 2020, field exploration activities over a third party claim (Los Angeles), located 5.4km northwest, in a straight line, from the town of Guanacevi, with the objective of identifying a possible mineralized zone which could be of interest for EDR. A total of 55 rock samples were collected from both surface (over the trace of the Los Angeles vein) and underground (Los Angeles mine). Table 9-1 shows the summary of the external concession.

Table 9-1 2016 Regional Exploration, External Concessions, Guanceví

Project

Owner

Location

Number of
Samples
Taken

Concession

Title

Los Angeles

Manuel Macho

NW Guanaceví town

55

Los Angeles

163686



Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Sample Preparation, Analyses and Security

10. DRILLING

Diamond drilling the Guanacevi Project is conducted under the exploration staff. Underground drilling is predominantly concerned with definition and extension of the known mineralized zones to guide development and mining. Surface drilling is conducted further from the active mining area with the goal of expanding the resource base. Drilling results from both programs were used in the mineral resource and mineral reserve estimates presented in this report. To date, all drilling completed at the mine has been diamond core.

10.1 Drilling Procedures

Surface drillholes are generally oriented to intersect the veins as close to perpendicular as possible. The drillholes are typically drilled from the hanging wall, perpendicular to, and passing through the target structure into the footwall, and no drilling is designed for intercepts with angles less than about 30° to the target. Drillholes extend an average of 50 m beyond the target zone. 

Underground drillholes are typically drilled from the hanging wall, but due to limitations of infrastructure may be drilled from the footwall. Drill orientation are ideally perpendicular to structures, but oblique intersection may be required in some instances due to limitations of the drill station. Underground positive angled holes (up holes) are generally drilled from the footwall using the same criteria. All holes are designed to pass through the target and into the hanging or footwalls. Both surface and underground drillholes are typically HQ to NQ in size.

On the drill site, the drill set-up is surveyed for azimuth, inclination and collar coordinates, with the drilling subject to daily scrutiny and coordination by EDR geologists. Since 2010, surface holes are surveyed using a Reflex multi-shot down-hole survey instrument normally at 50 m intervals from the bottom of the hole back up to the collar. At underground drill stations, azimuth orientation lines are surveyed in prior to drilling. Inclination of underground holes is collected using the Reflex EX-Shot® survey device prior to starting drilling.

The survey data obtained from the drillholes are transferred to databases in Vulcan® and AutoCAD®, and are corrected for local magnetic declination, as necessary. Information for each drillhole is stored in separate folders.

Drill core is collected daily and is transported to the core logging facility under EDR supervision. The core storage facilities at Guanaceví are well protected by high level security fences, and are under 24-hour surveillance by security personnel to minimize any possibility of tampering with the dill cores.

When assay results are received from the laboratory, they are merged into an Excel® spreadsheet for importation and interpretation in Vulcan® and AutoCAD® software. The starting and ending point of each vein and/or vein/vein breccia intercept is determined from a combination of geology notes in the logs and assay results. Using approximate vein and drillhole orientation information a horizontal width is calculated for the intercept to be used as part of a Vertical Longitudinal Projection ("VLP").


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Sample Preparation, Analyses and Security

The center point of the intercept, horizontal width, and gold and silver assay values are plotted on VLPs of each vein. These are used to guide further drilling, interpret mineralization shoots, and as the basis of polygonal resource estimation.

10.2 EDR Core Logging Procedures

As the core is received at the core facility, geotechnical data is logged manually on paper sheets and entered into Excel®. The core is then manually logged for geological data and marked for sampling. Geological data and sample information are entered directly into Excel® spreadsheets.

10.3 EDR Drilling Programs and Results

Since acquisition of the Guanaceví Project in 2004, and prior to the 2020 exploration season, EDR had completed 793 diamond drill holes totaling 216,810 m and 22 reverse circulation drill holes totaling 2,977 m on the entire Guanaceví Project (Table 10-1). Of this total, approximately 173,412 m of diamond drilling in 607 holes were completed on the Santa Cruz vein structure. Holes were drilled from both surface and underground drill stations, and 64,865 samples were collected and submitted for assay.

Table 10-1  Drilling Summary for Santa Cruz Vein Structure at Guanaceví Mines Project (as of December, 2020)

Project

Diamond Drill
Holes

Metres

North Porvenir

265

73,218

Porvenir Dos

24

5,062

Porvenir Cuatro

38

10,100

La Prieta

12

2,627

Santa Cruz

146

35,703

Alex Breccia

27

8,614

Milache

51

24,931

Santa Cruz South

23

8,902

El Curso

21

4,254

Total

607

173,412

EDR's drilling exploration programs through 2016 are well described in previous technical reports (HRC, 2015, 2016; Munroe 2013, 2014; Micon 2006, 2008, 2009, 2010, 2011, 2012; Devlin 2007). Exploration programs carried out in 2017 to 2019 have not been included in previous technical reports, to provide continuity, a brief description of these programs is provided in the following paragraphs.

In 2017, underground drilling conducted at Guanaceví focused on exploring the Santa Cruz vein in the (deep) Santa Cruz Mine area (below levels 3352 and 3358) and at the (deep) Central part of the North Porvenir area (between Porvenir and Santa Cruz Mines, below level 3105) (Figure 10‐1). The underground drilling program included a total of 6,794 m in 29 holes, with 2,995 samples submitted for assays.

In 2018, surface and underground drilling were conducted by EDR in the Guanacevi Project. The surface drilling program with the objective to test the Santa Cruz vein at the shallow part of the Porvenir "Comedor" area, totaling 875m in 3 holes and 125 samples collected. The underground drilling program conducted in the both the deep parts of the North Porvenir (below levels 3133 and 3157) and Santa Cruz (below level 3359) mines, the program included a total of 4,816m in 21 drill holes and 1,704 samples submitted for analysis.


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Sample Preparation, Analyses and Security

In 2019, EDR carried out underground drilling programs at the (deep) Central and North part of the North Porvenir area (below levels 3105 and 3157) and at the (deep) Santa Cruz mine area (below level 3355), totaling 2,258m in 10 holes, with 894 samples collected and submitted for analysis. In addition, with the acquisition of two mining concessions from Ocampo, EDR started drilling the El Curso claim from the footwall, using some loaders ("cargaderos") as drill stations, located in the ramp that connect the Porvenir 4 and Milache mines, a total of 21 drill holes completed with 4,254m and 1,301 samples collected.

10.4 EDR Drilling Programs and Results (2020)

In 2020, underground drilling conducted by EDR at Guanacevi, focused on exploring the Santa Cruz vein the El Curso property, and included a total of approximately 7,150 m in 24 holes.

The results, since the beginning of the drilling in the El Curso area, have been mostly favorable, reporting high grade values in 87% of the intercepts of the Santa Cruz vein. In 2020, most of the holes drilled intercepted the structure with high grade values ranging from 194 gpt to 2,559 gpt AgEq.

10.4.1 El Curso

In 2020, EDR resumed the underground diamond drilling program in the El Curso area, with the objective to continue defining the mineralized body along the Santa Cruz vein. The underground drilling program included a total of 7,150 m.  (including one-hole extension of 48.8m, from 309.00 to 357.8m in hole UCM-20) in 24 holes and 1,205 samples collected and submitted for analysis to the commercial laboratory SGS, in Durango, México.

Drilling was conducted by Versa Perforaciones S.A. de CV ("Versa"). Versa is a contract drilling company and is independent of EDR.

Tables 10-2 and 10-3 show the details of the holes drilled in the El Curso area.

Table 10-2  2020 Drilling Summary, El Curso

Hole

Azimuth

Dip

Diameter

Total Depth (m)

Start Date

Finish Date

UCM-22

226 º

(+)24.5

HQ

216.00

20/01/2020

24/01/2020

UCM-23

226 º

(-)22

HQ

342.00

24/01/2020

03/02/2020

UCM-24

226 º

(-)27.5

HQ

375.00

03/02/2020

13/02/2020

UCM-25

213 º

(-)28

HQ

383.00

14/02/2020

24/02/2020

UCM-26

236 º

(-)27

HQ

354.00

25/02/2020

04/03/2020

UCM-27

222 º

(-)33

HQ

383.60

04/03/2020

14/03/2020

UCM-28

222 º

(-)38

HQ

414.00

17/03/2020

29/03/2020

UCM-29

214 º

(-)22

HQ

293.30

04/08/2020

12/08/2020

UCM-30

215 º

(-)29

HQ

318.00

12/08/2020

25/08/2020



Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Sample Preparation, Analyses and Security

Hole

Azimuth

Dip

Diameter

Total Depth (m)

Start Date

Finish Date

UCM-31

228 º

(-)28.5

HQ

229.50

28/08/2020

03/09/2020

UCM-32

227 º

(-)41.5

HQ

336.00

03/09/2020

12/09/2020

UCM-33

205 º

(-)37.5

HQ

318.00

14/09/2020

21/09/2020

UCM-34

220 º

(-)38

HQ

296.00

21/09/2020

28/09/2020

UCM-35

238 º

(-)32.5

HQ

282.00

28/09/2020

05/10/2020

UCM-36

250 º

(-)29

HQ

300.00

05/10/2020

10/10/2020

UCM-37

222 º

(-)33.5

HQ

258.00

12/10/2020

16/10/2020

UCM-38

239 º

(-)38

HQ

319.50

16/10/2020

24/10/2020

UCM-39

224 º

(-)25.5

HQ

234.00

26/10/2020

03/11/2020

UCM-40

209 º

(-)24

HQ

208.50

04/11/2020

09/11/2020

UCM-41

238 º

(-)23

HQ

216.00

09/11/2020

13/11/2020

UCM-42

250 º

(-)21

HQ

205.00

13/11/2020

18/11/2020

UCM-43

246 º

(-)29

HQ

275.50

19/11/2020

26/11/2020

UCM-44

255 º

(-)28

HQ

288.00

27/11/2020

05/12/2020

UCM-45

264 º

(-)26

HQ

306.00

05/12/2020

15/12/2020

 

 

 

Total

7,150.90

 

 

Table 10-3  2020 Drilling Summary, El Curso (hole extension UCM-20)

Hole

Azimuth

Dip

Diameter

Total Depth (m)

Start Date

Finish Date

UCM-20

203 º

(-)29.5

HQ

357.80

29/11/2019 - 28/07/2020

07/12/2019 - 04/08/2020

Figures 10-1 & 10-2  Versa drill rig in station for drill holes UCM-27 and UCM-28

The drilling campaign was carried out from the ramp connecting the Porvenir 4 and Milache mines, from the footwall of the structure of interest, in order to define the Santa Cruz vein in the El Curso claim.

In 2020, the exploration program was mainly focused on the continuity of the mineralized body discovered in 2019, over an area of 550m long by 200m deep (in a grid of approximately 40m centres).


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Sample Preparation, Analyses and Security

The results successfully identified a mineralized body between elevations 2,000 and 2,200 masl, between sections 7,750N and 8,300. N. In addition, the mineralized zone extended the Porvenir 4 ore-body between the elevations 2,200 and 2,400 masl.

In 2019 an area where the structure disappeared was defined between sections 8,000N and 8,100N and elevation 2,300 masl. Hole UCM-22, like holes UCM-16 and UCM-18, carried out in 2019, intersected only the andesitic contact, which continues to confirm the wedging of the structure towards the surface from section 8,000N to the north.

The Santa Cruz vein mainly consisted of white and gray quartz, with smaller amounts of calcite and sometimes there is quartz-fluorite or quartz-calcite. Breccia textures are predominantly observed, while the central part of the vein shows massive-banded textures. Structurally, the vein is hosted in andesites in the south-central part of this area and towards the north, close to the limits with the Milache area the structure is in the contact of conglomerate and andesite.

Common minerals observed include, quartz, calcite, fluorite, rhodonite, rhodochrosite, traces of barite, sulfides such as pyrite, chalcopyrite, traces of galena and silver sulfosalts. In the parts where the Santa Cruz fault is close to the vein, minerals such as sericite and other clays are common. Hematite, siltstone and sometimes manganese occur in shallow, near surface sections of core.

Significant results from the Santa Cruz vein are shown in Table 10-4.

Table 10-4 shows the summary of the results of the underground carried out in the El Curso area during 2020. The impacts of the Santa Cruz vein are shown in the longitudinal section in Figure 10-3, as well as the location of the holes in the plan view in Figure 10-4; and typical cross section in Figure 10-5.

Table 10-4  2020 Drilling Results, El Curso

Drill Hole
ID

Structure

Mineralized Interval

Assay Results

From (m)

To (m)

Core Length
(m)

True Width
(m)

Silver (g/t)

Gold (g/t)

UCM-20

Santa Cruz Vein

304.35

313.60

9.25

4.97

484

1.18

Santa Cruz Composite

309.00

315.15

6.15

3.30

763

1.88

Including

312.85

313.60

0.75

0.40

1,673

4.85

UCM-22

Santa Cruz Vein

177.20

178.95

1.75

1.73

<2

<0.005

Santa Cruz Composite

177.20

178.40

1.20

1.19

<2

<0.005

Including

177.20

177.65

0.45

0.44

<2

<0.005

UCM-23

Santa Cruz Vein

304.30

312.75

8.45

4.91

339

1.04

Santa Cruz Composite

307.90

312.75

4.85

2.82

570

1.78

Including

308.05

308.60

0.55

0.32

2,422

5.80

UCM-24

Santa Cruz Vein

338.50

352.70

14.20

7.63

314

1.55

Santa Cruz Composite

344.25

351.00

6.75

3.63

614

3.15

Including

350.00

351.00

1.00

0.54

2,264

15.16

UCM-25

Santa Cruz Vein

339.40

348.40

9.00

4.84

986

1.43

Including

347.55

348.40

0.85

0.46

7,451

7.30

UCM-26

Santa Cruz Vein

309.65

319.95

10.30

6.27

630

1.52

Santa Cruz Composite

311.55

319.95

8.40

5.11

762

1.87

Including

315.35

316.35

1.00

0.61

2,026

3.50



Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Sample Preparation, Analyses and Security

Drill Hole
ID

Structure

Mineralized Interval

Assay Results

From (m)

To (m)

Core Length
(m)

True Width
(m)

Silver (g/t)

Gold (g/t)

UCM-27

Santa Cruz Vein

320.70

339.30

18.60

10.93

995

2.97

Santa Cruz Composite

322.80

339.85

17.05

10.02

1,085

3.25

Including

335.65

336.50

0.85

0.50

5,500

14.88

UCM-28

Santa Cruz Vein

364.05

373.20

9.15

5.05

389

1.15

Including

372.65

373.20

0.55

0.30

986

1.31

UCM-29

Santa Cruz Vein

263.00

267.80

4.80

3.21

2,307

3.15

Including

264.20

265.10

0.90

0.60

5,002

5.17

UCM-30

Santa Cruz Vein

299.30

306.05

6.75

4.02

1,106

2.45

Santa Cruz Composite

300.80

306.05

5.25

3.12

1,409

3.13

Including

305.55

306.05

0.50

0.30

5,454

13.35

UCM-31

Santa Cruz Vein

178.00

184.05

6.05

3.25

102

0.34

Santa Cruz Composite

179.50

181.35

1.85

0.99

172

0.70

Including

179.50

180.05

0.55

0.30

274

0.88

UCM-32

Santa Cruz Vein

294.55

303.70

9.15

3.43

54

0.14

Santa Cruz Composite

299.30

301.45

2.15

0.81

171

0.36

Including

300.80

301.45

0.65

0.24

302

0.57

UCM-33

Santa Cruz Vein

257.90

267.65

9.75

3.81

369

0.80

Santa Cruz Composite

261.00

267.65

6.65

2.60

516

1.14

Including

266.75

267.65

0.90

0.35

1,953

4.81

UCM-34

Santa Cruz Vein

245.40

253.65

8.25

3.62

333

0.66

Santa Cruz Composite

240.50

252.95

12.45

5.44

336

0.60

Including

250.00

250.85

0.85

0.37

1,244

2.32

UCM-35

Santa Cruz Vein

231.60

234.60

3.00

1.45

167

0.34

Including

233.80

234.60

0.80

0.39

247

0.46

UCM-36

Santa Cruz Vein

244.90

251.05

6.15

3.17

274

1.10

Santa Cruz Composite

239.25

261.65

22.40

11.54

381

0.65

Including

256.30

256.70

0.40

0.21

3,789

5.78

UCM-37

Santa Cruz Vein

203.30

210.15

6.85

2.98

769

1.42

Santa Cruz Composite

203.90

212.50

8.60

4.10

653

1.24

Including

206.45

207.00

0.55

0.26

1,603

2.80

UCM-38

Santa Cruz Vein

272.70

274.15

1.45

0.65

40

0.05

Santa Cruz Composite

272.70

274.95

2.25

1.00

31

0.05

Including

273.35

274.15

0.80

0.36

44

0.06

UCM-39

Santa Cruz Vein

172.35

179.40

7.05

4.48

1,553

3.56

Santa Cruz Composite

173.10

179.40

6.30

4.01

1,726

3.96

Including

177.65

178.30

0.65

0.41

8,105

8.05

UCM-40

Fw Santa Cruz Vein

162.55

164.80

2.25

1.37

323

0.52

Fw Santa Cruz Composite

162.55

164.30

1.75

1.07

395

0.64

Including

162.80

163.35

0.55

0.33

856

1.26

Santa Cruz Vein

168.75

170.55

1.80

1.10

1,446

3.40

Including

169.60

170.55

0.95

0.58

1,868

4.51

UCM-41

Santa Cruz Vein

181.85

185.15

3.30

2.05

64

0.10

Santa Cruz Composite

183.15

185.15

2.00

1.25

97

0.16

Including

183.90

184.50

0.60

0.37

228

0.39

UCM-42

Santa Cruz Vein

197.70

198.30

0.60

0.34

66

0.14

Santa Cruz Composite

197.70

199.70

2.00

1.15

42

0.06

Including

197.70

198.30

0.60

0.34

66

0.14

UCM-43

Santa Cruz Vein

234.60

237.30

2.70

1.49

397

1.09

Santa Cruz Composite

235.35

237.30

1.95

1.08

518

1.50

Including

236.85

237.30

0.45

0.25

1,069

3.82



Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Sample Preparation, Analyses and Security

Drill Hole
ID

Structure

Mineralized Interval

Assay Results

From (m)

To (m)

Core Length
(m)

True Width
(m)

Silver (g/t)

Gold (g/t)

UCM-44

Santa Cruz Vein

248.50

254.40

5.90

3.43

273

0.68

Santa Cruz Composite

251.15

254.40

3.25

1.65

530

1.31

Including

253.75

254.40

0.65

0.33

1,361

4.02

UCM-45

Santa Cruz Vein

269.20

273.10

3.90

1.71

620

1.36

Santa Cruz Composite

270.25

275.30

5.05

2.21

572

1.27

Including

272.55

273.10

0.55

0.24

2,304

5.60

Figure 10-3  Longitudinal Section (looking NE) showing intersection points on Santa Cruz vein in the El Curso area 


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Figure 10-4  Plan View of the El Curso area

Figure 10-5  Schematic Cross Section 8,070N, El Curso


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Guanaceví Project Sample Preparation, Analyses and Security

11. SAMPLE PREPARATION, ANALYSES AND SECURITY

The sample data relied upon during completion of the mineral resource and reserve estimates presented in this report are from diamond drill core and underground chip channel samples.

11.1 Methods

11.1.1 Underground Sampling

Sampling intervals in each channel range from about 0.3m to 2.5m, with most in the 0.5m to 1.5m range. EDR's geologists use geological criteria to select sample intervals. Quartz vein material is separated from hanging wall and footwall horizons, and internal vein samples are broken out by texture type. Three principal types of vein textures are recognized: (a) massive, (b) banded and (c) brecciated. As much as possible, vein samples are selected to represent mineralization episodes.

Mine samples are collected principally for grade control purposes but are also used to build up a channel sample database for resource estimation purposes. Samples are collected from sill-development and in stopes. Sill-development samples are taken from the face on a blast-by-blast basis. All sampling starts from the footwall and proceeds towards the hanging wall, with sample limits based on geological contacts. In stopes, and in sill development if time permits, samples are taken from the back and footwall sidewall. In general, footwall waste samples are not taken systematically, although at least one footwall sample is normally taken in a sampling session, depending on wherever the footwall is veined or sulfide rich. If the vein or breccia is present in the footwall sidewall, it is sampled. Side-wall channel samples are measured vertically, whilst back samples are measured horizontally. Spacing between channels is generally at 3.0 m intervals but can be increased to 5 m intervals in areas where the geology and grade distribution are well known. Samples are taken using a hammer and chisel.

Sample locations underground are measured from a known reference point, usually an identified topographic control point installed by EDR surveyors. All grade control samples are bagged in heavy duty polyurethane bags with a commercially prepared sample ticket inserted in the bag, and the sample number marked on the bag exterior with marker pen. All sample information is noted in a field notebook and later transferred to daily information sheets in the office. Basic sample information is also noted on sample ticket slips which are stored in the mine geology department office.

11.1.2 Exploration Sampling

EDR's exploration staff are responsible for regional and mine exploration within the Guanaceví mining district, including the management, monitoring, surveying, and logging of surface and underground diamond drilling.

Regardless of which program the core comes from, the process is the same. Core from diamond drilling is placed in boxes which are sealed shut at the drill site. EDR personnel transport the core to the core facility. Sample handling at the core facility follows a standard general procedure, during which depth markers are checked and verified; the outside of the boxes are labeled with interval information; core is washed and photographed; and the recovery and modified rock quality designation (RQD) are logged for each drillhole.


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Guanaceví Project Sample Preparation, Analyses and Security

All of EDR's surface and underground exploration drillholes are processed at the exploration core facility.

A cutting line is drawn on the core with a colored pencil, and sample tags are stapled in the boxes or denoted by writing the sample number with a felt tip pen.

11.2 Sample Preparation and Analysis

11.2.1 Underground Channel Samples

Mine production sampling including plant feed samples and doré, are sent to EDR's in-house Metalurgica Guanaceví (MG) assay laboratory. The MG laboratory has previously been ISO certified (this has not been renewed last year due to COVID travel restrictions) and is set up in a single facility at the Guanaceví mine with separate enclosed sections for sample preparation, fire assay with gravimetric finish, and atomic absorption facilities. The facilities are located within the Guanaceví plant compound and operate 24 hours per day.

Grade control channel samples, which are used for stope-based reserve estimates, are prepared and analyzed at the in-house laboratory. The sample preparation procedure for samples is as follows: Samples are received and checked in by laboratory staff; moist samples are dried for 2 to 4 hours; otherwise samples are crushed to -½ inch in a primary jaw crusher; samples are split using a 1 inch or ½ inch Jones splitter; 100 to 150 g of sample is retained for pulverizing and is put in a metal tray, along with a pulp envelope; remaining coarse rejects are returned to their original bag along with the sample ticket and stored; the 150 g crushed sample is then dried at a temperature of 100° C. The dried sample is pulverized in a ring pulverizer to -80 mesh; the pulverized sample is stored in a numbered envelope. The procedures for the mine channel sample preparation have been the same since 2008.

11.2.2 Exploration Drilling

All exploration drill core is transported under supervision of the EDR's geologist to the secure core storage facility at the Santa Cruz mine site. Sampling procedures typically begin with splitting by either a wheel-driven manual splitting device or an electric diamond-bladed core saw. The wheel-driven manual splitting device is generally used only when the core is badly broken-up and cannot be effectively cut by the diamond-bladed core saw. One half of the core is replaced in the original core box with depth markers, and the other half is bagged with sample tickets and recorded in the sample record. Once samples are bagged, they are transported to an outside laboratory using industry standard chain of custody procedures.

During 2020, all of EDR's exploration samples of rock and drill core were bagged and tagged at the Guanaceví warehouse and shipped to the SGS preparation and analysis laboratory in Durango, Mexico.

Upon arrival at the SGS laboratory, all of the samples are logged into the laboratory's tracking system (LOG-02). The sample is dried at 105 +/-5°C, if received wet or if requested by client. Drying temperatures can vary based on client specific requests or when mercury determination is requested. The next step involves crushing to reduce the sample size to typically 2mm/10meshes (9 mesh Tyler). The sample is then split via a riffle splitter continuously in order to divide the sample into typically a 250g sub-sample for analysis and the remainder is stored as a reject. A rotary sample divider may also be used to split the sample. Pulverizing is done using pots made of either hardened chrome steel or mild steel material. Crushed material is transferred into a clean pot and the pot is placed into a vibratory mill. Samples are pulverized to typically 75 microns/200 mesh or otherwise specified by the client.


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EDR uses a two-phase analysis process of the samples to reduce.

11.2.2.1 First phase

Gold determination with AAS finish (GE_FAA313). Fire Assay consisting of two consecutive pyrometallurgical processes. Results are reported in ppm. In ranges from 0.005 to 10 ppm.

The analytical procedure for Silver and multi-elements is ICP14B and consists of a nitric and hydrochloric acid digestion (aqua regia) with an inductively coupled plasma optical emission spectrometry (ICP-OES) finish. The detection range for silver is 2 to 100 ppm.

11.2.2.2 Second Phase

The method for evaluation of higher-grade silver (+/- gold) mineralization consists of fire assay followed by a gravimetric finish. All samples originally assaying >100 ppm silver and >10 ppm gold are then re-assayed using the methods GO_FAG313 (Ag determination only) and GO_FAG303 (Gold determination only). A 30-g nominal pulp sample weight is used. Lower detection limits are 0.5 ppm for the gold assay and 10 ppm for the silver assay.

As an economical tool for first pass exploration geochemistry, the pulps are sometimes subjected to aqua regia digestion and inductively coupled plasma (ICP) multi-element analysis. The data reported from an aqua regia leach are considered to represent the leachable portion of the particular analyte. These analytical methods are optimized for low detection limits. Over-limits (>10,000 ppm) determined for copper, lead and zinc by ICP are re-analyzed using optical emission spectroscopy (OES). The method ICP90Q consists of a sodium peroxide of fusion and extracted with nitric acid with ICP-OES finish. The detection ranges are 0.01% to 30% for copper, lead and zinc.

SGS is an independent, ISO-certified, analytical laboratory company which services the mining industry around the world. SGS employs a rigorous quality control system in its laboratory methodology as well as a system of analytical blanks, standards and duplicates.

SGS Minerals Services in Durango is accredited by the Standards Council of Canada (SCC) for specific mineral tests listed on the scope of accreditations to the ISO/IEC 17025 standard. The methods FAA313, GE_ICP14B, FAG313, FAG303 and ICP90Q are currently listed on the scope. ISO/IEC addresses both the quality management system and the technical aspects of operating a testing laboratory. You can get a copy of the current scope in the SCC website www.scc.ca.


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11.3 Quality Control / Quality Assurance (QA/QC) program

QA/QC processes are divided into two separate programs. One for in mine channel grade control samples which have only a minor influence on the resource and reserve calculations at the end of each year as only the most recent samples at the margins of developed and mined areas influence the block model. The exploration drilling and sampling follows a separate QA/QC regime.

11.3.1 Underground Channel Sample QA/QC

In order to monitor the sampling, preparation and assaying process EDR has established a QA/QC program, in an effort to control or minimize possible errors, including the use of duplicate, blanks, standards and cross checks.

The QA/QC protocol for production samples involves repeat assays on pulp and coarse reject material, along with in-house prepared blanks and control samples. No commercially available standards were used in 2020 as part of the Geology Department QA/QC program however, the laboratory does use these as part of its internal QA/QC monitoring process (as well as its own blanks). EDR creates standards in-house using selected pulp rejects which are prepared by a third-party laboratory. Roughly 3% to 5% of production grade control sample are submitted for re-assay.

11.3.1.1 Blank Performance

In August 2009, the geology department began collecting and sending blanks along with production samples. This practice is ongoing. Currently, blanks are inserted at a frequency of approximately 1 sample per day. Blanks are collected as run-of-mine material from waste headings such as the development ramps. These samples are usually of sufficiently low silver grade to be useful in detecting laboratory errors such as sample swaps and contamination, however, there is always the possibility that the samples will contain anomalous values. Blanks are submitted blind, that is, they are inserted into the sample stream using the same sample sequence and identifiers as any other sample collected.

Results of the blank assays are shown in Figures 11-1 and 11-2. Approximately 2.5% of the 550 samples sent for assay in 2020 returned silver grades greater than 20 times the detection for silver and 4.5% were between 5 and 20 times the detection limit for silver. Sample values less than 25 g/t (5x detection) are considered acceptable.


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Figure 11-1  Production Samples Blank Analysis for Silver

Gold values were slightly better with only 1.5% of the 358 samples sent for assay returning gold grades greater than 20 times the detection, and 3.3% between 5 and 20 times the detection limit for gold. Sample values less than 0.15 g/t (5x detection) are considered acceptable.


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Figure 11-2  Production Samples Blank Analysis for Gold

11.3.1.2 Precision Demonstrated by Duplicate Results

Maximum-minimum scatter plots for duplicate samples are shown in Figure 11-3 through Figure 11-8. In general, results of the duplicate re-assays indicate a good correlation for silver and moderate to poor correlation for gold. Acceptable variance for pulp duplicates is 10%. Silver pulps show a 11% failure rate while gold shows a 23% failure rate.

Acceptable variance rate for coarse reject duplicates is 20%. Silver rejects show a 28% failure rate while gold shows a 24% failure rate.

Finally, variance for mine re-sample duplicates is 30%. Silver duplicates show a 46% failure rate while gold shows a 28% failure rate.

Silver pairs with a mean value of 10x the detection limit were excluded. Gold pairs with a mean value of 15x the detection limit were excluded. The higher failure rate may be caused by low precision near the origin. Eliminating pairs that are close to detection will reduce the failure rate. Overall the results are acceptable but could be improved


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Figure 11-3  Silver Pulp Duplicates

Figure 11-4  Gold Pulp Duplicates


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Figure 11-5  Silver Reject Duplicates

Figure 11-6  Gold Reject Duplicates


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Figure 11-7  Silver Field Duplicates

Figure 11-8  Gold Field Duplicates


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11.3.1.3 Mine Standard Reference Material

No mine standards are used in the grade control sampling QA/QC program at Guanacevi.

11.3.1.4 Accuracy Demonstrated by Check Assays

Check assaying is performed to check the precision and accuracy of the primary laboratory, and to identify errors due to sample handling. Check assaying consists of sending pulps and rejects to a secondary lab for analysis and comparison against the primary lab.

For the mine grade control sampling no check assays were sent to secondary labs for analysis in 2020.

11.3.2 Summary of the 2017 to 2019 Surface and Underground Exploration Programs

A summary of the surface and underground drilling programs carried out during 2017 to 2019 is described below.

The protocols and procedures are the same as those used by EDR to date and are shown in chapter 11.3.3.

The summary of the control samples used during these programs is shown in Table 11-1.

Table 11-1  Summary of Control Samples Used for Exploration Programs from 2017 to 2019

Samples

2017

2018

2019

No. of Samples

Percentage (%)

No. of Samples

Percentage (%)

No. of Samples

Percentage (%)

Duplicate

106

5.1%

85

5.2%

106

4.8%

Blank

121

5.8%

95

5.8%

112

5.1%

Standard

108

5.2%

81

4.9%

94

4.3%

Normal

1978

94.8%

1568

95.1%

1,883

85.8%

Total

2086

100%

1649

100%

2,195

100%

Cross Check

122

5.8%

87

5.3%

115

5.2%

In general, the QA/QC programs had acceptable behaviors, a summary of the blanks, duplicate, standard reference material and check assays is described below:

For blanks, from 2017 to 2019, only one sample returned outside the upper limit during the 2017 QA/QC program, but is not associated to a mineralized zone, and the value is not significant comparing the contiguous samples in the hole.

Graphical analysis of the duplicate samples, showed moderate correlation coefficients for gold (0.6 & 0.5) during the 2017 and 2018 programs, due to most of the values are near the detection limit and any variation between the original and duplicate value is magnified, the correlation coefficients for silver are good to high (0.84 & 0.93). Correlations coefficients for the 2019 program are excellent for both gold and silver (>0.99).

The standard reference materials used during EDR's drilling programs (2017 to 2019) are described in Table 11-2.


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Guanaceví Project Sample Preparation, Analyses and Security

Table 11-2  Summary of the Standard Reference Material Samples Used During the EDR's Drilling Programs (2017 to 2019) at Guanacevi

Year

Reference
Standard

Reference
Number

Reference
Source

Control Limits

Certified Mean
Value Au (g/t)

Certified Mean
Value Ag (g/t)

Re-calculated
Mean Value Au
(g/t)

Re-calculated
Mean Value Ag
(g/t)

2017

EDR-39

CDN-ME-1305

Cdn Resource Lab

1.92

231

1.9

227

EDR-43

CDN-ME-1307

Cdn Resource Lab

1.02

54

1.02

55

EDR-44

CDN-ME-1407

Cdn Resource Lab

2.12

245

2.12

240

2018

EDR-46

CDN-ME-1413

Cdn Resource Lab

1.01

52

1.03

52.13

EDR-47

CDN-ME-1604

Cdn Resource Lab

2.51

299

2.59

302.72

2019

EDR-46

CDN-ME-1413

Cdn Resource Lab

1.01

52.2

1.02

52.51

EDR-49

CDN ME-1605

Cdn Resource Lab

2.85

269

2.83

271.64

EDR's general rules for the Standard Samples and the required actions are described in Table 11-3.

Table 11-3 General Rules for Standard Samples.

Value

Status

Mineralized Zone

Action

< 2 SD

Acceptable

N/A

No action required

< 2 - 3 SD from CL

Acceptable

N/A

No action required

(Single result; not consecutive)

< 2 - 3 SD

Warning

YES

Re-Analyse samples

(Two or more consecutive samples)

NO

No action required

> 3 SD

Warning

YES

Re-Analyse samples

(Single result; not consecutive)

NO

No action required

> 3 SD

Failure

N/A

Re-Analyse samples

(Consecutive Samples)

N/A    Not Applicable

 

 

 

Results of each standard are reviewed separately and the analysis of the behavior of these materials and the taken actions are summarized in Table 11-4.

Table 11-4 Summary of Analysis of Standard Reference Materials (2017 to 2019).

Year

Standard
Reference

Element

Observations

Comments

2017

EDR-39

Au

One sample (DH56848) between plus two to three standard deviations from CL, not consecutive.

No action required

EDR-43

Ag

Two samples (DH57914 and DH59095) between plus two to three standard deviations, not consecutive.

No action required

EDR-44

Ag

One sample (DH58485) between plus two to three standard deviations, not consecutive.

No action required

2018

EDR-46

Au

Within established limits.

No action required

Ag

Within established limits.

No action required

EDR-47

Au

Within established limits.

No action required

Ag

One sample (DH59645) between plus two to three standard deviations, not consecutive.

No action required

2019

EDR-46

Au

Within established limits.

No action required

Ag

One sample (DH61541) between plus two to three standard deviations, not consecutive.

No action required

EDR-49

Au

Within established limits.

No action required

Ag

Two samples (DH61473 & DH61799) between plus two to three standard deviations, not consecutive.

No action required



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During the 2017 to 2019 programs, all standard samples within established protocols.

Check analyses at a secondary laboratory showed high correlation coefficients (>0.93) for both gold and silver during the 2017 to 2019 programs.

11.3.3 Underground Exploration (2020)

During 2020, drilling was supported by a QA/QC program to monitor the integrity of assay results. Each batch of 20 samples included one blank, one duplicate and one standard. Check assaying is also conducted at a frequency of approximately 5%. Discrepancies and inconsistencies in the blank and duplicate data are resolved by re-assaying either the pulp or reject or both.

A total of 1,205 samples, including control samples, were submitted during Endeavour Silver's underground drilling program at Guanaceví from January 2020 through March 2020 and from July 2020 to December 2020, as shown in Table 11-5.

This year, for Guanaceví, preparation and analysis were carried out at the SGS de México Laboratory, in Durango, México.

A total of 64 pulps were also submitted for check assaying to ALS Minerals (preparation facility in Zacatecas, México and analysis at ALS Vancouver).

Table 11-5  Summary of Control Samples Used for the 2020 Underground Exploration Program

Samples

No. of Samples

Percentage (%)

Duplicate

51

4.2%

Blank

60

5.0%

Standard

58

4.8%

Normal

1,036

86.0%

Total

1,205

100%

Cross Check

64

5.3%



Endeavour Silver Corp. NI 43-101 Technical Report
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EDR's sampling process, including handling of samples, preparation and analysis, is shown in the quality control flow sheet, Figure 11-9.

Figure 11-9  Flow Sheet for Core Sampling, Sample Prep and Analysis

11.3.3.1 Underground Exploration Blank Performance

Blank samples were inserted to monitor possible contamination during the preparation process and analysis of the samples in the laboratory. The blank material used for EDR's drilling programs at the Guanacevi project comes from a non-mineralized rhyolite quarry located in the Porvenir 4 area. The results of previous sampling show that the values are below the detection limit and thus adequate to be used in the exploration programs. Blank samples are inserted randomly into the sample batch and given unique sample numbers in sequence with the other samples before being shipped to the laboratory.

Blank samples were inserted at an average rate of approximately 1 for each 20 original samples, with a total of 60 blank samples (5%) submitted.


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The control limit for Blank samples is 10 times the minimum limit of detection of the assay method of the element. For gold is 0.05 ppm and for silver 20 ppm (graphically showed 4 ppm).

No blank samples returned assay values above the tolerance limit for both gold and silver, which is why it is considered that the assay results for the drilling programs are for the most part free of any significant contamination (Figures 11-10 and 11-11).

Figure 11-10  Control Chart for Gold Assay from the Blank Samples Inserted into the Sample Stream

Figure 11-11  Control Chart for Silver Assay from the Blank Samples Inserted into the Sample Stream

11.3.3.2 Precision Demonstrated by Duplicate Results

Duplicate samples were used to monitor (a) potential mixing up of samples and (b) variability of the data as a result of laboratory error or the lack of homogeneity of the samples.

Duplicate core samples were prepared by EDR personnel at the core storage facility at the Guanaceví mines project. Preparation first involved randomly selecting a sample interval for duplicate sampling purposes. The duplicates were then collected at the time of initial sampling. This required first splitting the core in half and cut again in half and then select the opposite quarters to be sent to the laboratory separately. The duplicate samples were ticketed with the consecutive number following the original sample. One duplicate sample was collected for each batch of 20 samples.

A total of 51 duplicate samples were taken, representing 4.2% of the total samples.


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Discrepancies and inconsistencies in the duplicate sample data are resolved by re-assaying either the pulp or reject or both.

For the duplicate samples, graphical analysis shows high correlation coefficient for both gold (>0.98) and silver (>0.91). Scatter diagrams for core duplicate samples are shown in Figures 11-12 and 11-13.

Figure 11-12 Graph of the Original versus Duplicate Sample for the Gold Assays from EDR's Guanaceví Drilling Program

Figure 11-13  Graph of the Original versus Duplicate Sample for the Silver Assays from EDR's Guanaceví Drilling Program


Endeavour Silver Corp. NI 43-101 Technical Report
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Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Sample Preparation, Analyses and Security

11.3.3.3 Underground Exploration Standard Reference Material

EDR uses commercial reference standards to monitor the accuracy of the laboratories. Standard reference material (SRM) has been purchased from an internationally recognized company (CDN Resource Laboratories Ltd.). Each standard reference sample was prepared by the vendor at its own laboratories and shipped directly to EDR, along with a certificate of analysis for each standard purchased.

In 2020, a total of 58 standard reference samples were submitted at an average frequency of 1 for each batch of 20 samples. The standard reference samples were ticketed with pre-assigned numbers in order to avoid inadvertently using numbers that were being used during logging.

Three different standards were submitted and analyzed for gold and silver. The reference standards used during EDR's drilling programs are described in Table 11-6.

Table 11-6  Summary of the Standard Reference Material Samples Used During the EDR's Drilling Programs at Guanacevi

Reference
Standard

Reference
Number

Reference
Source

Control Limits

Certified Mean
Value Au (g/t)

Certified Mean
Value Ag (g/t)

Re-calculated Mean
Value Au (g/t)

Re-calculated
Mean Value Ag
(g/t)

edr-46

CDN-ME-1413

Cdn Resource Lab

1.01

52.2

NA

NA

edr-49

CDN ME-1605

Cdn Resource Lab

2.85

269.0

NA

NA

edr-51

CDN ME-1806

Cdn Resource Lab

3.43

365

3.40

374.62

NA= Not Applicable

 

 

 

 

 

For each of the three standards used with greater than 25 sample results from the primary lab (SGS) it was recalibrated the mean and standard deviation using available data. This is an acceptable practice implemented by some Companies to strengthen the control limits (CL) utilized in an ongoing QC program, with a larger dataset being more reliable than the smaller number of round robin results used to calculate certified values.

For graphical analysis, results for the standards were scrutinized relative to the mean or control limit (CL), and a lower control limit (LL) and an upper control limit (UL), as shown in Table 11-7.

Table 11-7  Basis for Interpreting Standard Sample Assays

Limit

Value

UL

Plus 2 standard deviations from the mean

CL

Recommended or calculated value (mean) of standard reference material

LL

Minus 2 standard deviations from the mean



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EDR's general rules for the Standard Samples and the required actions are described in Table 11-8.

Table 11-8 General Rules for Standard Samples.

Value

Status

Mineralized Zone

Action

< 2 SD

Acceptable

N/A

No action required

< 2 - 3 SD from CL

Acceptable

N/A

No action required

(Single result; not consecutive)

< 2 - 3 SD

Warning

YES

Re-Analyse samples

(Two or more consecutive samples)

NO

No action required

> 3 SD

Warning

YES

Re-Analyse samples

(Single result; not consecutive)

NO

No action required

> 3 SD

Failure

N/A

Re-Analyse samples

(Consecutive Samples)

N/A    Not Applicable

 

 

 

Results of each standard are reviewed separately and the analysis of the behavior of these materials and the taken actions are summarized in Table 11-9.

With the exception of the cases mentioned in Table 11-9, most values for gold and silver were found to be within the control limits, and the results are considered satisfactory. The mean of the SGS assays agrees well with the mean value of the standard.

Examples of control charts generated by EDR are shown in Figures 11-14 to 11-19 for the standard reference materials.

Table 11-9 Summary of Analysis of Standard Reference Materials.

Reference

Standard

Element

Observations

Comments

EDR-46

Au

Within established limits.

No action required

Ag

One sample (DH63870) between plus two to three standard deviations from CL, not consecutive.

No action required

One sample (DH64302) between plus two to three standard deviations from CL, consecutive with DH63910 (>3 std), mineralized zone.

Batch Re-Assayed

One sample (DH63699) greater than 3 standard deviations, not consecutive, no mineralized zone.

No action required

One sample (DH63910) greater than 3 standard deviations, mineralized zone.

Batch Re-Assayed

       


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Reference

Standard

Element

Observations

Comments

EDR-49

Au

One sample (DH64259) greater than 3 standard deviations, not consecutive, no mineralized zone.

No action required

Ag

Two samples (DH63890 and DH64259) between plus two to three standard deviations, not consecutive.

No action required

Two samples (DH63643 and DH63778) greater than 3 standard deviations, not consecutive, no mineralized zone.

No action required

One sample (DH64214) greater than 3 standard deviations, mineralized zone.

Batch Re-Assayed

EDR-51

Au

One sample (DH64359) between plus two to three standard deviations, not consecutive.

No action required

Ag

Three samples (DH64590, DH64678 and DH64712) between plus two to three standard deviations, not consecutive.

No action required

Two samples (DH64338 and DH64570) greater than 3 standard deviations, not consecutive, no mineralized zone.

No action required

Two samples (DH64381 and DH64401) greater than 3 standard deviations, consecutive.

Batchs Re-Assayed

Figure 11-14  Control Chart for Gold Assays from the Standard Reference Sample EDR-46

Figure 11-15  Control Chart for Silver Assays from the Standard Reference Sample EDR-46

 


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Sample Preparation, Analyses and Security

Figure 11-16  Control Chart for Gold Assays from the Standard Reference Sample EDR-49

Figure 11-17  Control Chart for Silver Assays from the Standard Reference Sample EDR-49

Figure 11-18  Control Chart for Gold Assays from the Standard Reference Sample EDR-51


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Sample Preparation, Analyses and Security

Figure 11-19  Control Chart for Silver Assays from the Standard Reference Sample EDR-51

Re-Assays

The recommended value showed some values of silver to be outside the tolerance limits, thus, five batches, totaling 63 samples, were re-analyzed (SGS).

The scatter diagrams for silver show high correlation coefficient (>0.99), which indicates that the original values are validated.

Note that in the batch were inserted again the corresponding standard (EDR-46, EDR-49, or EDR-51) for analysis.

Table 11-10 show the original vs re-assays values of the re-analyzed batches.

Figure 11-20 shows the correlation between the values of Silver.

Table 11-10 Comparative Table of Original vs Re-assays Values.

Sample

SGS_Au

SGS_Ag

ReSGS_Au

ReSGS_Ag

Standard
Reference

DH63905

1.35

627.8

1.30

619.0

 

DH63906

1.34

534.2

1.27

531.1

 

DH63907

2.75

566.9

2.46

567.8

 

DH63908

1.84

710.5

1.65

738.0

 

DH63909

1.03

362.7

1.04

360.3

 

DH63910

1.12

61.0

0.96

55.0

EDR-46

DH63911

0.88

262.2

0.84

255.5

 

DH63912

1.31

985.9

1.39

1029.2

 

DH63913

0.05

119.2

0.04

121.6

 

DH63914

0.06

59.0

0.05

64.0

 

DH63915

0.15

59.0

0.13

59.0

 

DH63916

0.03

33.0

0.02

34.0

 

DH64296

1.13

310.3

1.09

297.5

 

DH64297

3.10

363.2

3.11

347.7

 

DH64298

0.28

34.0

0.27

36.0

 



Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Sample Preparation, Analyses and Security

Sample

SGS_Au

SGS_Ag

ReSGS_Au

ReSGS_Ag

Standard
Reference

DH64299

2.25

201.3

2.38

172.0

 

DH64300

2.30

600.5

2.18

585.1

 

DH64301

0.21

65.0

0.20

77.0

 

DH64302

1.02

56.0

1.08

59.0

EDR-46

DH64303

0.28

127.6

0.26

124.8

 

DH64304

1.05

377.7

1.02

369.5

 

DH64305

1.20

323.3

1.18

307.1

 

DH64306

1.65

987.7

1.59

991.8

 

DH64307

0.03

249.5

0.04

242.1

 

DH64209

0.16

136.3

0.16

135.7

 

DH64210

1.01

601.4

1.03

598.4

 

DH64211

0.67

502.5

0.65

490.3

 

DH64212

0.15

125.6

0.15

121.9

 

DH64213

0.26

214.6

0.27

193.8

 

DH64214

2.98

296.5

2.87

277.3

EDR-49

DH64215

0.03

113.7

0.03

112.9

 

DH64216

0.01

65.0

0.02

68.0

 

DH64217

0.02

61.0

0.01

55.0

 

DH64218

0.05

20.0

0.06

24.0

 

DH64219

0.38

129.7

0.39

117.9

 

DH64220

0.39

163.5

0.40

159.8

 

DH64375

0.01

4.0

0.01

3.0

 

DH64376

0.01

<2

0.01

<2

 

DH64377

0.01

<2

0.01

<2

 

DH64378

0.01

4.0

0.01

5.0

 

DH64379

0.01

3.0

<0.005

3.0

 

DH64380

0.02

<2

0.01

<2

 

DH64381

3.56

403.6

3.55

361.7

EDR-51

DH64382

0.05

4.0

0.05

4.0

 

DH64383

0.02

<2

0.01

<2

 

DH64384

0.05

<2

0.05

<2

 

DH64385

0.06

<2

0.06

<2

 

DH64386

0.11

<2

0.10

<2

 

DH64387

0.06

2.0

0.06

<2

 

DH64394

0.02

16.0

0.02

13.0

 

DH64395

0.02

15.0

0.02

15.0

 

DH64396

0.02

5.0

0.01

4.0

 

DH64397

0.05

35.0

0.05

30.0

 

DH64398

0.06

44.0

0.05

49.0

 

DH64399

0.04

15.0

0.03

17.0

 

DH64400

0.01

3.0

0.02

3.0

 

DH64401

3.38

398.7

3.15

378.5

EDR-51

DH64402

0.02

<2

0.01

<2

 



Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Sample Preparation, Analyses and Security

Sample

SGS_Au

SGS_Ag

ReSGS_Au

ReSGS_Ag

Standard
Reference

DH64403

0.01

<2

0.01

<2

 

DH64404

0.03

17.0

0.02

13.0

 

DH64405

0.02

3.0

0.01

2.0

 

DH64406

0.04

36.0

0.05

35.0

 

DH64407

0.01

6.0

0.01

12.0

 

Figure 11-20  Graph of the Original versus Re-Assayed Silver Samples

11.3.3.4 Underground Accuracy Demonstrated by Check Assays

To evaluate the accuracy of the primary laboratory, EDR periodically conducts check analyses. Random pulps are selected from original core samples and send to a second laboratory to verify the original assay and monitor any possible deviation due to sample handling and laboratory procedures. EDR uses the ALS-Minerals laboratory, for check analyses.

A total of 64 pulps were sent to a third-party laboratory (ALS) for check analysis. This amounts to approximately 5.3% of the total samples taken during the drilling program.

Correlation coefficients are high (>0.86) for both silver and gold, showing a high level of agreement between the original SGS assay and the ALS-Minerals check assay. Figure 11-21 and Figure 11-22 show the correlation between the values of Gold and Silver.


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Sample Preparation, Analyses and Security

Figure 11-21  Scatter plot of Check Assays for Gold

Figure 11-22  Scatter plot of Check Assays for Silver


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Sample Preparation, Analyses and Security

11.4 Adequacy of Data

EDR's QP concludes that the exploration and production sample preparation, security and analytical procedures are correct and adequate for the purpose of this technical report.  The sample methods and density are appropriate, and the samples are of sufficient quality to comprise a representative, unbiased database.


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Data Verification

12. DATA VERIFICATION

The mineral resource estimate presented in report Section 14 is based on the following information with an effective date of December 31, 2020:

  • Discussions with EDR personnel;

  • Personal investigation of the Guanaceví Project office;

  • A surface exploration and underground drilling database received as csv files;

  • Production channel sample database received as csv files;

  • 3D vein models for 9 veins;

  • Polygonal 2D vein models for Epsilon-Soto, La Blanca, Mi Niña, and Buena Fe with resource and reserve calculations;

  • The Technical Report "NI43-101 Technical Report: Updated Mineral Resource and Reserve Estimates for the Guanaceví Project Durango State Mexico" dated March 3, 2017 and authored by Hard Rock Consulting, LLC;

12.1 Database Audit

The surface drilling, underground drilling, and underground channel samples were combined into a single database for mineral resource estimation. The QP conducted a thorough audit of the current EDR exploration and operation sample databases.  The following tasks were completed as part of the audit:

  • Performed a mechanical audit of the database;

  • Validated the geologic information compared to the paper logs;

  • Validated the assay values contained in the exploration database with assay certificates from the EDR Guanaceví mine laboratory; and

  • Validated the assay values contained in the 2D polygonal long sections by comparing with select, relevant historical assays and the original drawings.

The audit was limited to the lithology, assay, drillhole collar, and survey data contained in the exploration database as those fields have the greatest impact on mineral resource estimation.

12.2 Mechanical Audit

A mechanical audit of the combined database was completed using Leapfrog Geo® software. The database was checked for overlaps, gaps, duplicate channel samples total drillhole length inconsistencies, non-numeric assay values, and negative numbers. No material deficiencies were identified.

12.3 External Data Verification

A number of independent technical reports were prepared on the project prior to 2020. These are listed in section 2.2. No material issues were identified in these reports.


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Data Verification

12.4 Adequacy of Data

The QP has reviewed check assay programs, including continuous QA/QA checks conducted by the geology team and believes the programs provide adequate confidence in the data.  Samples that are associated with failures and the samples associated with erroneous blank samples are infrequent and are reviewed prior to inclusion in the production database. No material issues with the data or the project database were identified at that time. As a result of the data verification, the QP concludes that the database is acceptable for use in mineral resource and mineral reserve estimation and can be used to support mine planning.

All drill cores and cuttings from EDR's drilling have been photographed.  Drill logs have been digitally entered into exploration database organized and maintained in Vulcan. The split core have been securely stored and are available for further checks.


Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Mineral Processing and Metallurgical Testing

13. MINERAL PROCESSING AND METALLURGICAL TESTING

13.1 Metallurgical Testing

Guanacevi has a long operating history and metallurgical recoveries are well documented. No recent testing was undertaken by Endeavour Silver. Test work conducted in 2012 is summarized in section 13.1

13.1.1 Mineralogy

Several ore and cyanide leach residues were analyzed at the University of San Luis Potosi in 2012:

  • Mill feed combined ore

  • Porvenir North ore and cyanide leach residue

  • Porvenir 2 ore and cyanide leach residue

The most abundant silver mineral was argentite (Ag2S). The less frequent minerals were stromeyerite, not specified sulfosalts, native silver and gold in various sizes and occluded in quartz or Mn-oxides. The size of silver and gold mineral grains varies from less than 1 micrometer (native gold and silver) up to 120 micrometers (Argentite) (Table 13-1). Metal sulfides were found (Pyrite, Sphalerite, Galena, and Arsenopyrite) (Table 13-2).

Table 13-1  Silver and Gold Distribution in Ore and Leach Residue Samples

Mill feed ore

Porvenir 2 ore

Porvenir 2 Leach
Residue

Porvenir 4 ore

Porvenir 4 Leach
Residue

Ag 295 gpt

Au 1.6 gpt

Au 0.30 gpt

Au 2.1 gpt

Au 0.6 gpt

Au 2.1 gpt

Ag 261 gpt

Ag 132 gpt

Ag 234 gpt

Ag 53 gpt

100% of silver as Argentite Ag2S from which 80% is liberated, size from 9 to 20 μm, and 20% is locked in quartz.

96% of silver as Argentite Ag2S from which 85% is liberated, size from 35 to 120 μm, and 15% is associated with Stromeyerite, Galena and Pyrite as particles with size <3μm; 4% of silver as Stromeyerite (Ag,Cu)2S and associated with Argentite.

100% of silver as native silver in particles smaller than <1μm.

Argentite (Ag2S) grains smaller than 10 μm and locked in Mn,Ca-oxides. Stromeyerite, (Ag,Cu)2S, particles smaller than 10 μm and locked in Mn,Ca-oxides; Ag-sulfosalts grains smaller than 10 μm and locked in Mn,Ca-oxides.

Argentite Ag2S particles smaller than 5 μm; As native gold in particles smaller than 1μm.



Endeavour Silver Corp. NI 43-101 Technical Report
Guanaceví Project Mineral Processing and Metallurgical Testing

Table 13-2  Summary of Mineralogical Analysis of Ore and Leach Residue Samples