EX-99.1 2 a08-21851_1ex99d1.htm EX-99.1

Exhibit 99.1

 

GRAPHIC

 

PRE-FEASIBILITY STUDY

NI 43-101 TECHNICAL REPORT,

TWANGIZA GOLD PROJECT,

South Kivu Province, Democratic

Republic of Congo

 

Prepared for Banro Corporation By:

 

MODDER House · No.1 High Road · Modder Crest Office Park

 

Moddefontein · Gauteng · South Africa

 

Telephone:+27 (0)11 608 2141 · Facsimile:+27 (0)11 608 2142

 

Website www.senet.co.za

 

Effective Date of Report: August 13, 2008

 

Contributing Engineers/Authors:

Martin Pittuck: SRK Consulting (UK) Limited

HG Waldeck: SRK (SA) (Pty) Ltd

Dr. Caroline Henderson: SRK (SA) (Pty) Ltd

John Naismith: SENET

Phil Bundo: SENET

Dermot Claffey: Knight Piésold Ltd.

Joanne Groeller: Knight Piésold Ltd

 

Qualified Persons:

Martin Pittuck, C. Eng., MIMMM

Neil Senior, MSC Mech Eng, PR Eng, Fellow of SAIMM

HG Waldeck, B.Sc(Eng), PR Eng, MBA, Fellow of SAIMM

 

 



 

TABLE OF CONTENTS

 

SUMMARY

1

1.

 

INTRODUCTION

 

6

1.1

 

Background, Scope of Work and Terms of Reference

 

6

1.2

 

Reliance on Other Experts

 

9

1.3

 

Cautionary Notes

 

9

2.

 

PROPERTY DESCRIPTION AND LOCATION

 

10

3.

 

ACCESSIBILITY, CLIMATE, LOCAL RESOURCES, INFRASTRUCTURE AND PHYSIOGRAPHY

 

16

3.1

 

Physiography

 

16

3.2

 

Current Accessibility

 

16

3.3

 

Existing Infrastructure/Local Resources

 

16

3.4

 

Climate

 

17

4.

 

HISTORY

 

17

5.

 

GEOLOGICAL SETTING

 

18

5.1

 

Regional Geology

 

18

5.2

 

Property Geology

 

19

6.

 

DEPOSIT TYPE AND DEPOSIT GEOLOGY

 

19

7.

 

MINERALIZATION

 

21

8.

 

EXPLORATIONc

 

21

8.1

 

Historical Exploration

 

21

8.2

 

Further Exploration (October 2005 – December 2006

 

23

8.2.1

 

Drilling

 

23

8.2.2

 

Soil Geochemical Programme

 

23

8.2.3

 

Trenching Programme

 

24

8.2.4

 

Prospect Scale Mapping

 

24

8.3

 

Recent Exploration (January 2006 – July 2008)

 

25

8.3.1

 

Drilling

 

25

8.3.2

 

Geophysical Exploration (LIDAR)

 

25

8.3.3

 

Additional Regional Work

 

26

9.

 

DRILLING

 

26

9.1

 

Mineralization and Results

 

26

10.

 

SAMPLING METHOD AND APPROACH

 

28

10.1

 

Soil Geochemistry

 

28

10.2

 

Trench, Channel and Grab Samples

 

28

10.3

 

Drill Core Samples

 

28

11.

 

SAMPLE PREPARATION, ANALYSES AND SECURITY

 

29

11.1

 

Introduction

 

29

 



 

11.2

 

Sample Preparation and Analysis

 

29

11.2.1

 

Assaying

 

30

11.3

 

Quality Control Procedures

 

30

11.4

 

Assessment of Quality Control Data

 

31

11.4.1

 

Certified Reference Material

 

31

11.4.2

 

Inter-Laboratory Check Assays

 

33

11.4.3

 

Duplicate Coarse Split

 

34

11.4.4

 

Blank Samples

 

36

11.4.5

 

Analytical Laboratory Quality Control

 

37

12.

 

DATA VERIFICATION

 

37

12.1

 

Database and Data Quality

 

38

12.2

 

Adit Check Sampling

 

38

12.3

 

Data Validation

 

39

13.

 

ADJACENT PROPERTIES

 

40

14.

 

MINERAL PROCESSING AND METALLURGICAL TESTING

 

40

14.1

 

Metallurgical Testwork

 

40

14.1.1

 

Background

 

40

14.1.2

 

Review of scoping study metallurgical testwork

 

41

14.1.3

 

Limitations of Scoping Study Metallurgical Results

 

42

14.1.4

 

Pre-Feasibility Study Metallurgical Testwork Sample Selection

 

43

 

14.1.4.1

Introduction

 

43

 

14.1.4.2

Sample Selection and Preparation

 

43

14.1.5

 

Metallurgical Test Program

 

45

14.1.6

 

Mineralogy

 

45

 

14.1.6.1

Oxide Mineralogy Summary

 

46

14.1.7

 

Head Grade and Specific Gravity Determination

 

46

14.1.8

 

Oxides (Main & North)

 

46

 

14.1.8.1

Transition and Fresh FP Non Refractory (Main & North)

 

47

14.1.9

 

Comminution Appraisal

 

49

 

14.1.9.1

Comminution Results of Composite Samples

 

50

 

14.1.9.2

Comminution Results of Variability Samples

 

50

14.1.1

0

  Recovery Testwork

 

51

 

14.1.10.1

Main & North Oxide Recovery Testwork

 

51

 

14.1.10.2

Transition & Fresh (Main & North) Optimisation Recovery Testwork

 

54

14.1.1

1

  Settling

 

57

15.

 

MINERAL RESOURCE AND MINERAL RESERVE ESTIMATES

 

58

15.1

 

MINERAL RESOURCE ESTIMATES

 

58

15.1.1

 

Approach

 

58

15.1.2

 

Density Determinations

 

58

 



 

 

15.1.2.1

Data Collection and Analysis

 

58

 

15.1.2.2

SRK Analysis

 

60

15.1.3

 

Descriptive Statistics of Assay Data

 

61

15.1.4

 

Geological Interpretation and Lode Identification

 

62

 

15.1.4.1

Geological Wireframes

 

62

 

15.1.4.2

Mineralisation Wireframe

 

65

15.1.5

 

Geological Block Model

 

67

15.1.6

 

Valley Fill Model

 

70

15.1.7

 

Topography, Artisanal Excavation and Oxide/Transition Sub-models

 

70

15.1.8

 

Statistical Analysis of the Mineralised Data

 

70

 

15.1.8.1

Selection Of Composite Lengths For Statistics

 

70

 

15.1.8.2

Summary Statistics and Histograms

 

71

 

15.1.8.3

High grade Capping

 

73

15.1.9

 

Geostatisical Analysis

 

74

 

15.1.9.1

Semi-Variograms

 

74

 

15.1.9.2

Block Estimation

 

76

15.1.1

0

  Block Model Definiton and Grade Estimation

 

77

 

15.1.10.1

Block Model Setup

 

77

 

15.1.10.2

Grade Estimation

 

77

 

15.1.10.3

Whittle Export

 

78

15.1.1

1

  Mineral Resource Classification

 

78

15.1.1

2

  Cut-off Grade Derivation

 

79

15.2

 

Mineral Resource Statement

 

79

15.2.1

 

Comparison to previous estimate

 

80

15.3

 

CONCLUSIONS AND RECOMMENDATIONS

 

81

15.3.1

 

Conclusions

 

81

15.3.2

 

Recommendations

 

82

15.4

 

MINERAL RESERVE ESTIMATES

 

83

16.

 

OTHER RELEVANT DATA AND INFORMATION

 

84

16.1

 

GEOTECHNICAL INVESTIGATION AND SLOPE STABILITY ANALYSIS

 

84

16.1.1

 

DEPOSIT SCALE GEOLOGY

 

84

16.1.2

 

ENGINEERING GEOLOGY

 

84

 

16.1.2.1

Transported Soils

 

84

 

16.1.2.2

Residual Soils

 

84

 

16.1.2.3

Bedrock Engineering Geology and Weathering Profile

 

86

16.2

 

MINING ASPECTS

 

88

16.3

 

GEOTECHNICAL STUDY PROGRAMME

 

89

16.3.1

 

Geotechnical Drilling

 

89

16.3.2

 

Geotechnical Logging and Rock Mass Classification

 

89

 



 

16.3.3

 

Analysis Methodology

 

91

16.4

 

RESULTS OF GEOTECHNICAL ASSESSMENT

 

93

16.4.1

 

Derivation of Rock Material and Rock Mass Properties

 

93

16.4.2

 

Estimate of Rock Mass Shear Strength Parameters

 

96

16.4.3

 

Estimate of Soil Zone Shear Strength Parameters

 

98

16.4.4

 

Structural Interpretation

 

98

16.4.5

 

Hydrogeological Factors Affecting Slope Design

 

104

16.4.6

 

Seismic Effects

 

105

16.5

 

SLOPE STABILTY ANALYSIS

 

105

16.5.1

 

Kinematic Stability Analysis of Fractures

 

105

16.5.2

 

Rock Mass Stability Analysis

 

108

16.6

 

Conclusions

 

111

16.7

 

Recommendations for Feasibility Level Work Programme

 

113

16.8

 

Mine Study

 

114

16.8.1

 

Introduction

 

114

16.8.2

 

Pit Optimization

 

114

 

16.8.2.1

Introduction

 

114

 

16.8.2.2

Resource Block Model

 

115

 

16.8.2.3

Geotechnical

 

115

 

16.8.2.4

Cost Inputs

 

115

 

16.8.2.5

Mining Costs

 

115

 

16.8.2.6

Processing and General Administration Cost

 

116

 

16.8.2.7

Mining Factors

 

116

 

16.8.2.8

Gold Price and Royalties

 

116

 

16.8.2.9

Cut off Grade Calculations

 

116

 

16.8.2.10

Whittle Results

 

117

 

16.8.2.11

Selection of Optimised Pit Shell

 

117

16.8.3

 

Practical Pit Design

 

120

16.8.4

 

Mine Production Schedule

 

126

16.8.5

 

Twangiza Mineral Reserves

 

128

16.8.6

 

Mining Operations

 

128

16.8.7

 

Mining Equipment Requirements

 

130

16.8.8

 

Mine Work Schedule

 

131

16.8.9

 

Mine Infrastructure

 

135

16.8.1

0

  Mining Manpower

 

136

16.8.1

1

  Conclusion and Recommendations

 

138

16.9

 

Process Plant

 

138

16.9.1

 

Design criteria

 

138

16.9.2

 

Ore Characteristics

 

139

 



 

16.9.3

 

Operating Schedule

 

140

16.9.4

 

Recoveries

 

140

16.9.5

 

Crushing

 

141

16.9.6

 

Milling and Classification

 

143

 

16.9.6.1    Milling

 

143

 

16.9.6.2    Classification

 

144

16.9.7

 

Trash Handling

 

145

16.9.8

 

Gravity

 

146

16.9.9

 

CIL

 

146

 

16.9.9.1    Leach and CIL

 

146

 

16.9.9.2    Interstage Screens

 

147

 

16.9.9.3    Loaded Carbon Screen

 

148

 

16.9.9.4    Tailings Dewatering

 

148

 

16.9.9.5    Cyanide Detoxification

 

149

 

16.9.9.6    Acid Wash

 

150

 

16.9.9.7    Elution

 

151

 

16.9.9.8    Electrowinning

 

151

 

16.9.9.9    Regeneration

 

153

 

16.9.9.10  Calcining & Smelting

 

154

16.9.10

 

Reagents

 

155

 

16.9.10.1    Lime

 

155

 

16.9.10.2    Cyanide

 

156

 

16.9.10.3    Caustic

 

157

 

16.9.10.4    Sodium Metabisulfite

 

157

 

16.9.10.5    Copper Sulphate

 

158

 

16.9.10.6    Hydrochloric Acid

 

158

 

16.9.10.7    Activated Carbon

 

158

 

16.9.10.8    Flocculant

 

158

 

16.9.10.9    Smelting Fluxes

 

159

 

16.9.10.10    Grinding Media

 

159

 

16.9.10.11    Mill Liners

 

159

 

16.9.10.12    Crusher Liners

 

159

16.9.11

 

Air Services

 

159

16.9.12

 

Water Services

 

160

 

16.9.12.1    Water Abstraction & Storage (AMEC)

 

160

16.9.13

 

Process Plant

 

161

 

16.9.13.1    Process Plant Summary

 

161

 

16.9.13.2    Crushing

 

164

 

16.9.13.3    Milling and Classification

 

166

 



 

 

16.9.13.4

Gravity

 

167

 

16.9.13.5

Trash Removal

 

168

 

16.9.13.6

Leach & CIL

 

168

 

16.9.13.7

Tailings Dewatering

 

170

 

16.9.13.8

Cyanide Detoxification

 

170

 

16.9.13.9

Acid Wash

 

171

 

16.9.13.10

Elution

 

171

 

16.9.13.11

Electrowinning

 

172

 

16.9.13.12

Regeneration

 

173

 

16.9.13.13

Gold Room

 

174

 

16.9.13.14

Consumables

 

174

 

16.9.13.15

Air Services

 

178

 

16.9.13.16

Water Services

 

179

16.9.14

Infrastructure and Other Site Services

 

192

 

16.9.14.1

Accessibility and Transport/Logistics

 

192

 

16.9.14.2

Site Access Roads

 

193

 

16.9.14.3

Plant Site Roads

 

193

 

16.9.14.4

Security

 

194

16.9.15

Power Requirements

 

194

16.9.16

Power Supply

 

194

 

16.9.16.1

Plant Power Requirements

 

194

 

16.9.16.2

Power Distribution

 

195

16.9.17

Communications

 

196

 

16.9.17.1

External Communication system

 

196

 

16.9.17.2

Mine Communication System

 

196

16.9.18

Water Supply and Distribution

 

197

 

16.9.18.1

Water Storage and Distribution

 

197

 

16.9.18.2

Fire Water Distribution

 

197

 

16.9.18.3

Potable Water Distribution

 

197

 

16.9.18.4

Sewage Collection and Treatment

 

197

16.9.19

Fuel and Lubricant Storage and Distribution

 

197

16.9.20

Architectural Specifications

 

198

16.9.21

Workshop/Warehouse

 

198

16.9.22

Administration Building

 

198

16.9.23

Mine Dry and Canteen

 

198

16.9.24

Assay Laboratory

 

199

16.9.25

Miscellaneous Buildings

 

199

16.9.26

Accommodation Buildings

 

199

16.10

Operating Costs

 

199

 



 

16.10.1

 

Summary of Process Plant Costs

 

199

 

16.10.1.1

Basis of Estimate

 

199

 

16.10.1.2

Plant Operating and Maintenance Labour:

 

200

 

16.10.1.3

Process Plant Reagents and Consumables

 

202

 

16.10.1.4

Plant Maintenance Costs and Supplies

 

205

 

16.10.1.5

General and Administration Costs

 

205

 

16.10.1.6

Camp Food and Catering

 

207

 

16.10.1.7

Building Maintenance

 

207

 

16.10.1.8

Communication

 

207

 

16.10.1.9

Community Affairs

 

207

 

16.10.1.10

 Couriers

 

207

 

16.10.1.11

 Insurances

 

207

 

16.10.1.12

 Information Technology

 

207

 

16.10.1.13

 Head Office Costs

 

207

 

16.10.1.14

 Consultants Fees

 

207

 

16.10.1.15

 Legal and Accounting Tax Audit Fees

 

208

 

16.10.1.16

 Supplies and Spare Parts

 

208

 

16.10.1.17

 Travel and Accommodation

 

208

 

16.10.1.18

 Environment

 

208

 

16.10.1.19

 Training

 

208

 

16.10.1.20

 Recruitment

 

208

 

16.10.1.21

 Assay Costs

 

208

 

16.10.1.22

 Refining Costs

 

208

16.11 

Carbon Credits

 

208

16.12 

Capital Costs

 

209

16.12.1

 Estimate Accuracy

 

210

16.12.2

 Basis of Estimate

 

210

16.13 

Economic Model and Financial Analysis

 

212

16.13.1

 Evaluation Method

 

212

16.13.2

 Assumptions

 

212

16.13.3

 Financial Analysis Results

 

213

 

16.13.3.1

Summary of Financial Analysis

 

213

 

16.13.3.2

Project Life Cash Flow

 

214

16.14 

Sensitivity Analysis

 

216

16.14.1

 Discussion

 

218

16.15 

Tailings Dam

 

218

16.15.1

 Introduction

 

218

16.15.2

 Seismicity

 

219

16.15.3

 Geomorphology

 

220

 



 

16.16

Meteorology

 

220

16.16.1

Groundwater Elevations

 

221

16.16.2

Agriculture

 

222

16.16.3

Regional Population

 

222

16.16.4

Hunting

 

222

16.16.5

Construction material review

 

223

 

16.16.5.1

Low Permeability Material

 

223

16.16.6

Free Draining Structural Material

 

223

 

16.16.6.1

Free Draining Filter Material

 

224

16.16.7

TMF options study

 

225

16.16.8

Site Visit to Selected TMF sites

 

225

16.16.9

Environmental Appraisal

 

227

16.16.10

Data Review

 

227

16.16.11

TMF Site Selection Process

 

227

16.16.12

Preliminary Screening

 

228

 

16.16.12.1

Key Environmental Effects

 

228

 

16.16.12.2

Technical Requirements

 

228

16.16.13

Preliminary Ranking - Social, Economic and Environmental Factors

 

228

 

16.16.13.1

Location/Village

 

229

 

16.16.13.2

Catchment

 

229

 

16.16.13.3

Land Use/Ownership

 

229

 

16.16.13.4

Visibility

 

229

 

16.16.13.5

Impact on Water Supply

 

229

 

16.16.13.6

Conclusions

 

229

16.17

Tailings Delivery Options

 

230

16.17.1

Filter Cake Disposal

 

230

16.17.2

Paste/Thickened Tailings Disposal

 

232

16.17.3

Slurry Disposal

 

233

16.17.4

Ranking Study

 

234

 

16.17.4.1    Tailings Delivery System

 

235

16.17.5

TMF Embankment Cross Section

 

235

16.17.6

TMF site Technical Screening

 

236

 

16.17.6.1    Geotechnical/Geological Conditions

 

237

 

16.17.6.2    Hydrology

 

237

 

16.17.6.3    Topography

 

237

16.17.7

Operation & Development

 

237

 

16.17.7.1

Technical Assessment Ranking

 

237

16.18

Capital Expenditure Assessment Ranking

 

238

16.19

Option study conclusions

 

240

 



 

16.20

 

Option study Recomendations

 

241

17.

 

INTERPRETATION AND CONCLUSIONS

 

243

18.

 

RECOMMENDATIONS

 

249

19.

 

PROGRAMME

 

250

20.

 

REFERENCES

 

251

21.

 

DATE AND SIGNATURE PAGE

 

252

22.

 

CERTIFICATES OF QUALIFIED PERSONS

 

253

22.1

 

Neil Senior

 

253

22.2

 

Martin Pittuck

 

255

22.3

 

H.G. Waldeck

 

257

 



 

LIST OF TABLES

 

Table 1: Twangiza Mineral Resource Estimates @ 0.5 g/t Au cut-off (effective date: June 23, 2008

 

2

Table 2: Summary of Twangiza Mineral Reserves

 

3

Table 3: An economic model and financial analysis for the purposes of the Twangiza pre-feasibility study was undertaken
based on the following assumptions

 

3

Table 4: The results of the Twangiza pre-feasibility study are summarized below

 

4

Table 1-1: September 2006 Mineral Resource Estimates for Twangiza (using a 1.0 g/t Au cut-off)

 

7

Table 1-2: January 2007 Mineral Resource Estimates for Twangiza (using a 1.0 g/t Au cut-off)

 

7

Table 1-3: Twangiza Deposit Mineral Resource Estimates @ 0.5 g/t Au cut-off

 

8

Table 1-4: Twangiza Deposit Mineral Resource Estimates by material Type @ 0.5 g/t Au cut-off

 

8

Table 11-1: Statistics of Results of Standard Reference Sample Submissions

 

32

Table 11-2: Inter-laboratory Comparison – SGS vs Genalysis; July 2006

 

33

Table 11-3: Inter-laboratory Comparison – SGS vs Genalysis; November 2006

 

33

Table 11-4: Inter-laboratory Comparison – SGS vs Genalysis; February 2007

 

34

Table 11-5: Inter-laboratory Comparison – SGS vs Genalysis; June 2007

 

34

Table 11-6: Descriptive Statistics of Coarse Split Sample Pairs

 

35

Table 12-1: Data Employed in Current Mineral Resource Estimates

 

38

Table 12-2: Adit Sampling - Statistics of Composites

 

39

Table 14-1: Main Oxides Sample List

 

44

Table 14-2: North Oxides Sample List

 

44

Table 14-3: Non Refractory Sample List

 

45

Table 14-4: Oxide variability Multi Elemental Analysis

 

47

Table 14-5: Transition & Fresh FP Non Refractory Multi Elemental Analysis

 

48

Table 14-6: Comminution Index

 

49

Table 14-7: Comminution Reference

 

49

Table 14-8: Comminution Summary on Composite Samples

 

50

Table 14-9: Variability Comminution Testwork onOxide Ore

 

50

Table 14-10: Variability Comminution Testwork onTansition Ore

 

51

Table 14-11: Variablity Comminution testwork on Fresh Ore

 

51

Table 14-12: Extended Gravity Recoverable Gold Results

 

52

Table 14-13: Summary of Oxide Variability Intensive Cyanidation Results

 

52

Table 14-14: Oxide Leach variability Results Summary

 

53

Table 14-15: Summary of cyanide Destruction Results

 

54

Table 14-16: Transition and Fresh (Main & North) Gravity Testwork Summary

 

55

Table 14-17: Intensive Cyanidation Results Summary

 

55

Table 14-18: Summary of Preg-Robbing Results

 

55

Table 14-19: Grind Optimisation Results

 

56

Table 14-20: Cyanide Optimisation Results

 

56

Table 14-21: Effect of Time and Dissolved Oxygen

 

57

Table 14-22: Summary of Settling Results

 

57

Table 15-1: Relative Density Determination for All Rock Types

 

60

Table 15-2: Summary of Density Determinations for all Lithologies

 

60

Table 15-3: Summary of SRK Relative Density Values for all Material Types

 

61

Table 15-4: Summary of raw statistics per sampling phase

 

62

Table 15-5: Summary of Kriging Zones used in the latest Block Model

 

67

Table 15-6: Details of Block Model Dimensions for Geological Model

 

68

Table 15-7: Summary of Fields used for flagging different geological properties

 

68

 



 

Table 15-8: Summary of final rock codes used in the 3D model exported for PFS Pit Optimisation

 

69

Table 15-9: Summary statistics of 2 m composite

 

71

Table 15-10: Applied High-Grade Capping

 

74

Table 15-11: Search Radius for Pass 1

 

77

Table 15-12: Details of block Model Dimensions for Grade Estimation

 

77

Table 15-13: Twangiza Mineral Resource Estimates @ 0.5 g/t Au cut-off (effective date: June 23, 2008)

 

80

Table 15-14: Twangiza Mineral Resource Estimates by material Type @ 0.5 g/t Au cut-off (effective date: June 23, 2008)

 

80

Table 16-1: Depth of transported and residual soil at Twangiza

 

86

Table 16-2: Indicative Overall Slope Angles

 

90

Table 16-3: Summary of Weighted Average RMR and MRMR

 

93

Table 16-4: Table showing final average RMR, MRMR, IOSA, Intact Rock Strength (IRS) and Fracture Frequency (FF)
values derived from the borehole logging process

 

95

Table 16-5: Results of Estimates of Rock Mass Shear Strength

 

97

Table 16-6: Estimated Soil Zone shear strength parameters

 

98

Table 16-7: Main fracture sets derived from clusters of poles in stereoplots

 

104

Table 16-8: Results of Kinematic Stability Analysis for Different Pit Areas, Transition and Sulphide Zones only

 

106

Table 16-9: Results of SLIDE Limit Equilibrium Slope Stability Analysis

 

110

Table 16-10: Summary of PFS Slope Design Angles

 

112

Table 16-11: Mineral Resource Classification

 

114

Table 16-12: Whittle parameters for the Open Pit Optimization

 

116

Table 16-13: Whittle Optimization Results for Twangiza

 

118

Table 16-14: Proposed Life of Mine Schedule

 

127

Table 16-15: Summary of Twangiza Mineral Reserves

 

128

Table 16-16: Mining Equipment Requirement

 

130

Table 16-17: Schedule Working Periods

 

131

Table 16-18: Major Equipment Shift Operating Time

 

132

Table 16-19: Main Haul Road construction programme

 

136

Table 16-20: Equipment Operators

 

138

Table 16-21: Ore Characteristics

 

140

Table 16-22: Operating Schedule

 

140

Table 16-23: Recoveries

 

141

Table 16-24: Crushing

 

142

Table 16-25: Milling

 

144

Table 16-26: Classification

 

145

Table 16-27: Trash Handling

 

145

Table 16-28: Gravity

 

146

Table 16-29: Intensive Cyanidation

 

146

Table 16-30: Leach and CIL

 

147

Table 16-31: Interstage Screens

 

148

Table 16-32: Loaded Carbon Screen

 

148

Table 16-33: Carbon Safety Screen

 

149

Table 16-34: Tailings Thickening

 

149

Table 16-35: Cyanide Detoxification

 

150

Table 16-36: Acid Wash

 

150

Table 16-37: Elution

 

151

Table 16-38: Electrowinning (CIL)

 

152

Table 16-39: Electrowinning (Gravity)

 

153

 



 

Table 16-40: Regeneration

 

154

Table 16-41: Calcining and Smelting

 

155

Table 16-42: Lime Slaking (Make-up, Storage and Dosing)

 

156

Table 16-43: Sodium Cyanide Make-up, Storage and Dosing

 

157

Table 16-44: Caustic Make-up, Storage and Dosing

 

157

Table 16-45: Sodium Metabisulphite Make-up, Storage and Dosing

 

158

Table 16-46: Copper Sulphate Make-up, Storage and Dosing

 

158

Table 16-47: Hydrochloric Acid

 

158

Table 16-48: Activated Carbon

 

158

Table 16-49: Flocculant

 

159

Table 16-50: High Pressure Air Services

 

160

Table 16-51: Low Pressure Air Services

 

160

Table 16-52: Water Services

 

161

Table 16-53: Soft Rock Crushing Equipment List

 

180

Table 16-54: Hard Rock Crushing Equipment List

 

181

Table 16-55: Stockpile & Reclamation Equipment List

 

182

Table 16-56: Milling 1 Equipment List

 

182

Table 16-57: Milling 2 Equipment List

 

183

Table 16-58: Milling 3 Equipment List

 

183

Table 16-59: Gravity 1 & Intensive Cyanidation Equipment List

 

184

Table 16-60: Gravity 2

 

184

Table 16-61: Gravity 3

 

184

Table 16-62: Trash Removal 1

 

184

Table 16-63: Trash Removal 2

 

184

Table 16-64: Trash Removal 3

 

185

Table 16-65: CIL 1

 

185

Table 16-66: CIL 2

 

186

Table 16-67: CIL 3

 

186

Table 16-68: Tailings Dewatering

 

187

Table 16-69: Detoxification

 

187

Table 16-70: Return Water

 

187

Table 16-71: Acid Wash

 

187

Table 16-72: Elution

 

188

Table 16-73: Electrowinning

 

188

Table 16-74: Regeneration

 

189

Table 16-75: Goldroom

 

189

Table 16-76: Cyanide & Caustic

 

189

Table 16-77: Lime

 

190

Table 16-78: Flocculant

 

190

Table 16-79: Cyanide Detox Reagents

 

190

Table 16-80: High Pressure Air Services

 

191

Table 16-81: Low Pressure Air Services

 

191

Table 16-82: Process Water

 

191

Table 16-83: Raw Water

 

191

Table 16-84: Water Treatment Plant

 

192

Table 16-85: Gland Water and Safety Showers

 

192

Table 16-86: Power Requirements

 

195

Table 16-87: Power Distribution

 

196

Table 16-88: Overall Process Costs LOM

 

199

Table 16-89: Individual Ore Operating Costs

 

200

Table 16-90: Plant Manning Requirements, Monthly Costs and LOM Costs inUS$/t

 

201

Table 16-91: LOM Consumables and Reagents Costs

 

202

Table 16-92: Power Draw Summary

 

204

 



 

Table 16-93: LOM Power Cost

 

205

Table 16-94: LOM G & A Costs

 

206

Table 16-95: Twangiza Capital Cost Estimate Summary

 

210

Table 16-96: Assumptions used in the Financial Evaluation

 

212

Table 16-97: Summary of LOM Production, Capital and Operating Costs

 

213

Table 16-98: Summary of Financial Analysis

 

213

Table 16-99: LOM Project Cash flow

 

215

Table 16-100: Gold Price Sensitivity

 

216

Table 16-101: Capex Sensitivity

 

216

Table 16-102: Operating Costs Sensitivity

 

216

Table 16-103: Fuel Price Sensitivity

 

216

Table 16-104: Meteorological Data: Twangiza Project Site

 

221

Table 16-105a: TMF Sites Environmental Impact Base Data

 

227

Table 16-105b: Environmental Assessment Scoring Criteria

 

228

Table 16-106: Preliminary Environmental Assessment

 

229

Table 16-107: Disposal System Ranking System

 

235

Table 16-108: Estimated Strength Parameters

 

235

Table 16-109: TMF Options Basic Engineering Data

 

236

Table 16-111: TMF Impact on Open Pit

 

237

Table 16-112: TMF Options Engineering Rating

 

238

Table 16-113: Unit Rates

 

238

Table 16-114: Estimated TMF Option costs for retaining 66Mt

 

239

Table 16-115: Total Option Costs (66Mt) and Ranking

 

240

Table 16-116: Price Range

 

240

Table 16-117: Overall Option Score & Ranking

 

241

Table 17-1: Mineral Resources at a cut off grade of 0.5 g/t Au

 

244

Table 17-2: Economic Model and Financial Analysis

 

245

Table 17-3: Summary of Financial Analysis

 

246

Table 17-4: Sensitivity Scenario 1 Gold Price

 

247

Table 17-5: Sensitivity Scenario 1 Capex

 

247

Table 17-6: Sensitivity Scenario 1 Operating Costs

 

247

Table 17-7: Sensitivity Scenario 1 Fuel Price

 

247

Table 17-8: Sensitivity Scenario 2 Gold Price

 

247

Table 17-9: Sensitivity Scenario 2 Capex

 

248

Table 17;10: Sensitivity Scenario 2 Operating Costs

 

248

Table 17-11: Sensitivity Scenario 2 Fuel Price

 

248

Table 17-12: Sensitivity Scenario 3 Gold Price

 

248

Table 17-13: Sensitivity Scenario 3 Capex

 

248

Table 17-14: Sensitivity Scenario 3 Operating Costs

 

248

Table 17-15: Sensitivity Scenario 3 Fuel Price

 

249

 



 

LIST OF FIGURES

 

Figure 2-1: Africa Locality Plan

 

12

Figure 2-2: Location within the Democratic Republic of Congo

 

13

Figure 2-3: Exploitation Permit Location

 

14

Figure 2-4: Map of Twangiza Property

 

15

Figure 6-1: Deposit Geology

 

20

Figure 9-1: Drill Hole Collars

 

27

Figure 11-1:Summary of returned assays per standard

 

32

Figure 11-2: XY Scatter Charts of Original Versus Coarse Duplicate Splits Submitted to SGS Mwanza (a) All Samples (b)
Original Assays between 0.5 g/t and 20.0 g/t

 

35

Figure 11-3: Plot of Absolute Percentage Difference versus Percentile Rank of Duplicate Submissions to SGS Mwanza

 

36

Figure 11-4: Submission of Blank Material (Barren Granite) during submissions to SGS Mwanza

 

37

Figure 12-1: Comparison of ACME Vancouver vs MGL Kamituga Laboratories

 

39

Figure 15-12: Cross Section (along section lines) showing digitized interpretation of oxide contacts and lithology

 

63

Figure 15-13: Screen Shot Showing 3D Plan of the Porphyry Wireframe showing boreholes and potential pit surface

 

64

Figure 15-14: Screen Shot Showing 3D Cross Section of the Porphyry Wireframe showing boreholes and pre-feasibility
design pit surface

 

65

Figure 15-15: Screen Shot displaying 3D Leapfrog interpretation of the Twangiza Orebody

 

66

Figure 15-16: Typical Plan of the Mineralised Wireframes showing boreholes, geology and fault intersections

 

67

Figure 15-17: Histogram of Sample lengths in Twangiza database

 

71

Figure 15-18: Comparative Histograms per oxidation domain

 

72

Figure 15-19: Example plot of cumulative mean and CoV for diamond drill composites in the Zone 2 Transition domain showing the significant increase in CoV beyond 20g/t assay value

 

74

Figure 15-20: Semi Variograms

 

75

Figure 15-21: Typical section through the Twangiza Main Deposit displaying classification

 

79

Figure 16-1: IBSA Chart

 

91

Figure 16-2: Graph showing range of RMR and MrMr values for different weathering zones

 

94

Figure 16-3: Graph showing variation of RMR and MRMR with different pit sectors

 

95

Figure 16-4: Fracture Infill Type and Quality, by Weathering Zone

 

99

Figure 16-5: Fracture Small-Scale Roughness, by Weathering Zone

 

100

Figure 16-6: Fracture infill/aperture thickness, by Weathering Zone

 

101

Figure 16-7: Example Stereonets from Twangiza Main and north Zones, showing wide scatter of poles for filled joints

 

103

Figure 16-8: Whittle Optimization Results for Twangiza

 

117

Figure 16-9: Outline of Whittle Pit Shell

 

119

Figure 16-10: 3-D Plan View of Selected Whittle Shells

 

120

Figure 16-11: North Final

 

122

Figure 16-12: Main Intermediate

 

123

Figure 16-13: Main Final

 

124

Figure 16-14: Section through North Final Pit

 

125

Figure 16-15: Practical Pit 3D

 

126

 



 

Figure 16-16: Practical Pit 3D showing dump positions

 

129

Figure 16-17: Twangiza Process Plant Block Flow Diagram

 

163

Figure 16-18: Map of Route Alternatives – Bukavu to Twangiza

 

193

Figure 16-19: NPV Sensitivity at 5% discount rate

 

217

Figure 16-20: IRR Sensitivity at 5% discount rate

 

217

Figure 16-21: Seismic Event Map

 

219

Figure 16-22: Seismic Map of Africa

 

220

Figure 16-23: Potential Low Permeability Earthfill evident in Road Cuttings

 

223

Figure 16-24: Feldspar Porphyry: Oxidation to approx 50 m depth

 

224

Figure 16-25: Location of Twangiza TMF Sites

 

226

Figure 16-26: Stability Results for TMF 1

 

236

 



 

LIST OF APPENDICES

 

I

Alluvial Gold Potential of the Mwana River: Preliminary Evaluation

II

Geological Mapping Report of the Twangiza Deposit

III

Significant Diamond Drill Hole Intersections

IV

Precision Control Charts of Reference Material

V

Cumulative Frequency, Log Histogram and Log Probability Graphs.

VI

Semi-Variogram Model Plots

VII

Geological Model Sections and Flitch Plans

VIII

Cross-Sections through Twangiza Deposits, with downhole geotechnical information

IX

MRMR Reports from Borehole Core Logging

X

RocLab Calculations for Rock Mass Shear Strength Estimates

XI

Stereoplots of Planar, Toppling and Wedge Failure Analysis

XII

USGS Report on 3rd February 2008 Earthquake, Lake Kivu

XIII

SLIDE Slope Stability Analysis Results

XIV

Process Diagrams

 



 

LIST OF ANNEXURES

 

A

 

Amec Pre Feasibility Tailings Dam Selection

B

 

Executive Summary of Knight Piésold Hydro Scoping EIA

C

 

Executive Summary of Knight Piésold Vancouver report

D

 

Executive Summary of SRK Environmental & Social Vol1 (Environmental)

E

 

Executive Summary of SRK Environmental & Social Vol2 (Social)

 

 

 

 

 

Full copies of above reports are available on request

 



 

LIST OF ACRONYMS

 

“Hg

 

inches of mercury

 

 

 

ANFO

 

ammonium nitrate and fuel oil

Au

 

Gold

 

 

 

CAPEX

 

capital expenditure

CIL

 

carbon-in-leach

Cil or C.I.L.

 

carbon-in-leach leaching

CIP

 

Carbon-in-pulp

CMS

 

Carbonaceous Mudstone

 

 

 

DEM

 

Digital Elevation Model

DGPS

 

Differential Global Positioning System

DO

 

dissolved oxygen

DTM

 

Digital Terrain Model

 

 

 

EPCM

 

engineering, procurement, project and construction management

EW

 

Electrowinning

EW

 

East West

 

 

 

FP

 

Feldspar Porphyry

 

 

 

g

 

gravity constant

g

 

gram

g/mL

 

grams per millilitre

GA

 

general arrangement (drawing)

GPS

 

global positioning system

GRG

 

gravity-recoverable gold

 

 

 

h

 

hour

ha

 

hectare

HDPE

 

high density polyethylene

hrs

 

hours

HEP

 

Hydro Electric Plant

 

 

 

ILR

 

Inline Leach Reactor

InSAR

 

Interfereometric Synthetic Aperture Radar

ISO

 

International Standards Organization

 

 

 

J

 

joule

 

 

 

kg

 

kilogram

km

 

kilometre

kPa

 

kilopascal

kVA

 

kilovolt-amperes

kW

 

kilowatt

kWh

 

kilowatt-hour

 

 

 

L

 

litre

LHD

 

load-haul-dump unit

LIDAR

 

Light Detection and Ranging

 



 

m

 

metre

M

 

millions

m2

 

square metre

m3

 

cubic metre

m3/h

 

cubic metres/hour

max

 

maximum

MCC

 

Motor Control Centre

min

 

minimum

min

 

minutes

Mtpy

 

millions of tonnes per year

MW

 

megawatt

MWh

 

megawatt-hours

 

 

 

No.

 

number

NPV

 

net present value

NW

 

North West

 

 

 

ø

 

diameter

OPEX

 

operating expense

oz

 

ounce (Troy)

 

 

 

P&ID

 

piping and instrumentation drawing

Pa

 

pascal

pH

 

hydrogen ion exponent

PSD

 

particle-size distribution

PVC

 

polyvinyl chloride

 

 

 

QA

 

quality assurance

QC

 

Quality control

 

 

 

ROM

 

run of mine (ore)

RTK

 

Real Time Kinematic

 

 

 

s

 

second

SAG

 

semi-autogenous grinding

sg or SG

 

specific gravity (density)

SRTM

 

Shuttle Radar Topography Mission

 

 

 

t

 

tonne (metric)

t/h

 

tonnes per hour

t/yr

 

tonnes per year

tpa

 

tonnes per annum

tpd

 

tonnes per day

 

 

 

US¢

 

United States cents

USD

 

United States Dollars

 

 

 

V

 

volt

 

 

 

yr

 

year

 



 

SUMMARY

 

The 1,156 square kilometre Twangiza Property is located in the South Kivu Province of the Democratic Republic of the Congo (DRC), 35 kilometres west of the Burundi border and 45 kilometres to the south south west of Bukavu (Figures 2-1 and 2-2). The Twangiza Property consists of six exploitation permits, which are wholly-owned by Banro Corporation (Banro) indirectly through a Congolese subsidiary, Twangiza Mining sarl (Figures 2-3 and 2-4).

 

The Twangiza deposit is located at the hinge of the Twangiza anticline, which is underlain by mudstone, siltstones and greywackes that have been intruded along bedding planes by porphyry sills. Auriferous sulphides (pyrite and arsenopyrite) occur as dissemination and vein gangue in both the sediments and the feldspar porphyry sills. Sulphide content is greatest at the axial plane of the fold as brittle deformation is greatest due to extension forces from the folding.

 

This technical report summarizes the results of geological modelling and resource estimation of the Twangiza Main and the Twangiza North deposits, the evaluation of the Mwana River “Valley Fill” and the recently completed pre-feasibility study of the Twangiza Property.

 

The resource estimates come at the end of the fourth phase of resource drilling and sampling of the Twangiza Main and Twangiza North deposits which was completed in May 2008, and the Mwana River “Valley Fill” sampling completed in December 2006. Information regarding the evaluation of the Mwana River “Valley Fill” is set out in the September 2007 Technical Report and also in Appendix I. A copy of the September 2007 Technical Report can be obtained from SEDAR at www.sedar.com

 

The current exploration commenced in October 2005, and by May 2008, a total of 216 diamond drill holes had been completed by Banro. The programme included the extensive re-sampling of old exploration adits and resource delineation drilling on the 3.5 km north trending mining target comprising Twangiza Main and Twangiza North. Gold mineralization is hosted in sediments (mudstones and siltstones) which have been intruded by a series of feldspar porphyry sills along the hinge of a major anticlinal structure. Definition drilling continues with six diamond rigs on the property.

 

SRK Consulting (UK) Ltd. (“SRK (UK)”) has prepared an independent estimate of the Mineral Resource at Twangiza, which is set out in Table I below.

 

SRK UK undertook a site visit during April 2008 and has completed a Mineral Resource estimate based on drilling data available as at May 14, 2008. It should be noted that CME data was not provided during the data handover and has therefore not influenced this estimate. The review, analysis, interpretation and estimation has been led by Martin Pittuck, C.Eng, who is an employee of SRK and is the “qualified person” (as defined by National Instrument 43-101) for the purpose of this estimate. SRK’s Mineral Resource estimate uses the definitions and guidelines given in the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Standards on Mineral Resources and Reserves and is reported in accordance with National Instrument 43-101 requirements.

 

The effective date of the estimate is June 23, 2008 and is based on a cut-off grade of 0.5 g/t gold. The Mineral Resource is considered to have reasonable prospects for economic extraction by open pit mining and has been restricted to an optimum pit shell which uses a US$910 /oz gold price and technical and economic factors resulting from the pre-feasibility study.

 

1



 

Table 1 : Twangiza Mineral Resource Estimates @ 0.5 g/t Au cut-off (effective date: June 23, 2008)

 

Mineral Resource
Category

 

Tonnes
(Million)

 

Grade (g/t Au)

 

Gold Ounces
(Million)

 

Measured

 

16.7

 

2.59

 

1.39

 

Indicated

 

42.5

 

1.72

 

2.35

 

Measured & Indicated

 

59.2

 

1.96

 

3.74

 

Inferred

 

10.0

 

1.80

 

0.60

 

 

The Mineral Resources are found within three deposits: Twangiza Main, which contains 87% of the total Mineral Resources; Twangiza North, which contains 11% of the total Mineral Resources; and the transported Twangiza “Valley Fill” deposit, which contains 2% of the total Mineral Resources.

 

The Valley Fill Mineral Resource is currently based on Banro’s estimate which has been reviewed by SRK (UK) and which has been classified as an Inferred Mineral Resource; therefore more drilling / sampling will be required before it can be included in the mine plan.

 

This Mineral Resource estimate differs from Banro’s January 2008 estimate owing to some changes in approach. Principally, SRK (UK) has restricted the Mineral Resource to a Whittle pit shell below which the mineralization model is not considered to have reasonable prospects of economic extraction. This approach is now considered best practice and is in line with the methods used by major mining houses in their public reporting. Secondly, the cut-off grade now used is 0.5 g/t gold compared to 1.0 g/t gold previously used by Banro. This reflects economic and technical factors used in the current pre-feasibility study; however, the effect of using a lower cut-off grade has been partly offset by SRK (UK)’s slightly tighter wireframing and grade estimation parameters.

 

SRK (UK) has placed an increased emphasis on the creation of a robust geological model during the current Mineral Resource Estimate owing to variable gold recoveries in different lithological ore types. Further, the introduction of a hard / soft contact within the transitional material and a detailed review of the now substantial amount of density data has resulted in slightly lower densities being used in the weathered material compared to previous estimates.

 

The lower cut-off grade has resulted in a 10% increase in Measured and Indicated tonnage at a 13% reduced grade for a 3.5% reduction in gold content. The pit restriction has resulted in a significant reduction in Inferred Mineral Resource given that deeper areas of fresh mineralisation are now considered unlikely to be mined economically assuming a US$910 gold price.

 

A pre-feasibility study of the Twangiza Project was completed in July 2008 and the results are summarised in this report. Based on the above Mineral Resource estimates, SRK Consulting (South Africa) (Pty)Ltd, (“SRK(SA)”) estimates the following Mineral Reserves for the Twangiza pre-feasibility study: Refer Table 2 below.

 

2



 

Table 2: Summary of Twangiza Mineral Reserves

 

 

 

 

 

Tonnes

 

Grade

 

Ounces

 

Reserve Category

 

Deposit

 

(Millions)

 

(g/t Au)

 

(Million)

 

Proven;

 

Twangiza Main

 

12.55

 

2.60

 

1.273

 

 

 

Twangiza North

 

0.07

 

1.19

 

0.003

 

Total: Proven

 

 

 

15.29

 

2.60

 

1.276

 

Probable;

 

Twangiza Main

 

27.47

 

1.81

 

1.594

 

 

 

Twangiza North

 

6.13

 

2.23

 

0.440

 

Total: Probable

 

 

 

33.60

 

1.88

 

2.034

 

Total: proven and probable

 

Twangiza Project

 

48.89

 

2.11

 

3.310

 

 

There remains potential to increase the Mineral Resource contained in the Pre-Feasibility Study pit, resulting from the ongoing deposit definition drilling. It is noted that some 30 infill drillholes have been completed since data was provided to SRK (UK). The affect of adding these and reintroducing the 20 CME drillholes completed during 1997/1998 could potentially influence the optimum pitshell and increase the current Mineral Resource and Reserve. SRK(UK) would also recommend work on a number of drilling intersections in flanking structures which remain open along strike; these may add incremental oxide and transitional Mineral Resources if further drilling supports their extensions. SRK(UK) would recommend the completion of this programme to target the current Inferred Resources before commencing the Feasibility Study Resource Estimate.

 

Table 3:           An economic model and financial analysis for the purposes of the Twangiza pre-feasibility study was undertaken based on the following assumptions:

 

Parameter

 

Units

 

Assumption

 

Gold Price

 

US$/oz

 

850

 

Discount Rate

 

%

 

5%

 

Life of Mine after pre-production

 

Years

 

12

 

Oxides LoM Tonnage

 

t

 

16,729,023

 

Oxides LoM Grade

 

g/t Au

 

2.35

 

Oxides Recovery

 

%

 

89.8%

 

Transition-FP LoM Tonnage

 

t

 

6,631,919

 

Transition- FP LoM Grade

 

g/t Au

 

1.75

 

Transition- FP LoM Recovery

 

%

 

87%

 

Transition-CMS LoM Tonnage

 

t

 

8,940,654

 

Transition- CMS LoM Grade

 

g/t Au

 

2.55

 

Transition- CMS LoM Recovery

 

%

 

38%

 

Fresh- FP LoM Tonnage

 

t

 

6,456,282

 

Fresh -FP LoM Grade

 

g/t Au

 

1.51

 

Fresh-FP LoM Recovery

 

%

 

82.2%

 

Fresh- CMS LoM Tonnage

 

t

 

10,136,482

 

Fresh -CMS LoM Grade

 

g/t Au

 

1.74

 

Fresh-CMS LoM Recovery

 

%

 

54%

 

Royalty

 

%

 

n/a

 

Tax Rate

 

%

 

5 % on imports

 

 

3



 

Parameter

 

Units

 

Assumption

 

Initial Capital Costs

 

US$ 

000

 

541,202

 

Sustaining Capital

 

US$ 

000

 

39,380

 

Fixed Equipment Capital resale

 

 

%

5

%

Hydro Equipment Capital resale

 

 

%

30

%

 

Table 4:                                 The results of the Twangiza pre-feasiblity study are summarized below:

 

HEP OPTION

 

Units

 

PFS

 

Gold Annual Production- First 3 years

 

oz

 

345,125

 

Gold Annual Production- First 7 years

 

oz

 

236,144

 

Gold Annual Production- LoM

 

oz

 

195,772

 

Cash Operating Costs - First 3 years

 

US$/oz

 

212

 

Cash Operating Costs - First 7 years

 

US$/oz

 

351

 

Cash Operating Costs - LoM

 

US$/oz

 

345

 

Post Tax NPV

 

US$ million

 

352

 

IRR

 

%

 

20.5

%

Discounted Payback Period

 

years

 

2.78

 

Project net cash flow after tax and capex

 

US$ million

 

583

 

 

The results of the pre-feasibility study of the Twangiza Project are encouraging and warrant the progression of the Twangiza Project to the bankable feasibility study stage.

 

It is recommended that the exploration programme at Twangiza for the rest of 2008 should focus on the following:

 

Recommendations – Exploration

 

·                  Continue with regional exploration to define known mineralization as well as identify new targets. Continued exploration along the flanks and on the eastern limb of the Twangiza anticline may provide additional Mineral Resources where gaps currently exist inside US$ 910 /oz pit limits and where extensions to sparse intersections flanking the deposit remain untested.

 

·                  Diamond drilling to test soil geochemical anomalies in order to generate additional Indicated and Inferred Mineral Resources.

 

·                  Infill diamond drilling in the area below the adit data to a depth of  50 – 70 m below the surface where currently large portions of Indicated material rely on relatively wide spaced data. It is noted that these areas are difficult to access due to previous artisanal mining activity. Such infill drilling should strive to convert more Indicated Mineral Resource to the Measured Mineral Resource category to improve confidence in the early mine schedule affecting the project pay back period.

 

·                  Close spaced drilling clusters or crosses in three or four parts of the deposit to confirm short scale continuity of the mineralisation and to allow a conditional simulation to be completed if necessary.

 

·                  The Valley Fill Mineral Resources are currently classified as Inferred Mineral Resources, therefore more drilling / sampling will be required before it can be included in the mine plan.

 

·                  Geotechnical drilling to better assess pit slope stabilities for the proposed open pits.

 

4



 

·                  Complete sterilization investigation at preferred tailings site location and undertake complete geotechnical assessment.

 

·                  Complete geotechnical site investigation on preferred process plant location and other infrastructure sites (i.e. hydro electric facility, access roads, haul roads, waste dumps, and accommodation village).

 

Recommendations – Other

 

·                  Refine the geological model and update the resource model, and subsequently convert the mineral resources to mineral reserves on completion of optimized pit designs.

 

·                  Compilation of the geological and sampling database into a secure database system and move away from storage of files in Microsoft Excel.

 

·                  Update historical drill logs and complete basic recoding of historical logs where possible using the current protocols. The aim of this programme would be to ensure all data captured from diamond core drilling is in one format.  Attention should be paid to the critical factors for the Mineral Resource model including rock types, oxidation codes, weathering and hardness. The updated data should be integrated into the database so all data is accessible from one location where possible.

 

·                  Inclusion of the 20 CME boreholes (drilled 1997 /1998) not used in the current estimates.

 

·                  Onsite review of the geological wireframes by site geologists. The rock type field is extremely important at Twangiza in the estimating the recoverable resources, due to the variable recoveries within the transitional and fresh rock for porphyry and carbonaceous metasediments.

 

·                  Extension of the geological wireframes and interpretations beyond the current pit design. The current porphyry wireframes lie mainly within the current pit limits. A syncline to the east of the Twangiza Anticline has been noted from deposit scale mapping. Interpretations should be extended to confirm the location of the hinge zone for the syncline as it could impact on the pit slope design.

 

·                  Introduction of dates into the capture of quality control which will aid reviews across multiple standards. Current investigations are live and problems should be addressed at the time, but will help aid in monthly / quarterly reviews.

 

·                  To date the focus of the sampling has been for resource estimation purposes based only on gold assays inside the mineralised zones. Other factors such as sulphur levels in the waste rocks will be important and should be modelled in the Feasibility Study.

 

·                  Completion of a feasibility study to provide increased confidence on the economic viability of the Twangiza Project.  For completion of the feasibility study, the following will need to be undertaken in addition to the infill drilling:

 

·                  Additional metallurgical testwork to further define the chemical and physical characteristics of the various ore material types in order to optimise plant recoveries and further define the processing plant flowsheet.

 

·                  Undertake a bankable feasibility study on the hydroelectric potential for the Twangiza Project.

 

·                  Further define access and transportation routes.

 

·                  Complete a bankable feasibility Environmental and Social Impact Assessment for the Twangiza Project.

 

·                  Further define capital and operating costs and reduce contingency costs.

 

5



 

1.              INTRODUCTION

 

1.1                     Background, Scope of Work and Terms of Reference

 

The 1,156 square kilometre Twangiza Property is located in the South Kivu Province of the Democratic Republic of the Congo (DRC), 35 kilometres west of the Burundi border and 45 kilometres to the south south west of Bukavu (Figures 2-1 and 2-2). The Twangiza Property consists of six exploitation permits, which are wholly-owned by Banro Corporation indirectly through a Congolese subsidiary, Twangiza Mining sarl (Figures 2-3 and 2-4).

 

The Twangiza Property is located in the northern half of the Great Lakes sub-province of High Africa, one of the world’s principal Precambrian orogenic-metallogenic provinces. Minière des Grande Lacs (MGL) began exploration for in-situ resources in 1957. Work followed the occurrence of alluvial gold deposits upstream from the Mwana River to the present day Twangiza deposits (Figure 8-1). MGL tested the Twangiza Property through 8,323.1 metres of trenching and 13,207 metres of adits on seven levels, collecting a total of 17,804 samples. In 1996, Banro Resource Corporation (now Banro Corporation) (hereafter Banro) acquired control of the Twangiza Property and, in the following year, undertook an exploration program of geological mapping, surveying, data verification, airborne geophysical surveying, diamond drilling and resource modelling that was completed in 1998. Work included 10,490 line kilometres of airborne geophysics, 2,161 surface samples, 1,613 adit samples from 16 adits, 8,577 drill core samples from 9,122 metres of diamond drilling and 162 density tests.

 

Shortly after the completion of the 1997-1998 Exploration Program, President Laurent D. Kabila issued presidential decrees which caused the expropriation of the Twangiza Property from Banro. Banro initiated arbitration proceedings against the Government of the DRC seeking compensation for the expropriation of Banro’s assets. On April 19, 2002, the Government of the DRC signed a settlement agreement with Banro. The agreement called for, among other things, Banro to hold a 100% interest in the Twangiza Property under a revived mining convention that is renewable in 2027 for another 25 years.

 

No exploration work was carried out on the Twangiza Property between 1998 and October 2005, but artisanal mining occurred on the main deposit depleting over 3 million tonnes of ore from the area of the southern part of the deposit.

 

In mid-September 2005, the Congolese authorities gained control of the Twangiza area. Banro mobilized and commenced a simultaneous program of field camp construction and exploration in October 2005. The objectives of this exploration programme were:

 

·                  Elevating the Inferred Resources to the higher confidence category;

·                  Testing the extensions of the known Twangiza mineralization; and

·                  Locating and assessing new mineralized zones.

 

The exploration programme included gridding, soil geochemical sampling, mapping of artisanal workings and trenching. In February 2006 a helicopter supported diamond drilling program involving 2 portable CS1000 rigs was initiated. In July 2006 two additional rigs were mobilized to expedite the phase I and II drilling programs.

 

Mineral resource estimation was undertaken in September 2006 following the successful completion of 33 diamond drill holes (Phase I). The mineral resource estimates from this preliminary work, which are set out in Table 1-1 below, gave a clear scope and direction to the project.

 

6



 

Table 1-1: September 2006 Mineral Resource Estimates for Twangiza (using a 1.0 g/t Au cut-off)

 

Category

 

Tonnage
 (Mt)

 

Grade (g/t
Au)

 

Metal 
(Mg Au)

 

Au
(Moz)

 

Measured

 

4.80

 

3.50

 

16.80

 

0.54

 

Indicated

 

16.79

 

2.75

 

46.16

 

1.48

 

Measured and Indicated

 

21.60

 

2.92

 

62.96

 

2.02

 

Inferred

 

62.34

 

1.93

 

120.62

 

3.88

 

 

At the end of the 2006 field season, an additional 38 drill holes (Phase II) were also completed at Twangiza and a resource update was initiated and completed in January 2007. Table 1-2 summarizes the results of the mineral resource estimates for the Twangiza Property undertaken in January 2007.

 

Table 1-2: January 2007 Mineral Resource Estimates for Twangiza (using a 1.0 g/t Au cut-off)

 

Category

 

Tonnage
 (Mt)

 

Grade (g/t
 Au)

 

Metal
 (Mg Au)

 

Au
(Moz)

 

Measured

 

9.93

 

2.99

 

29.68

 

0.96

 

Indicated

 

29.30

 

2.18

 

63.88

 

2.05

 

Measured and Indicated

 

39.23

 

2.39

 

93.56

 

3.01

 

Inferred

 

42.12

 

1.85

 

77.79

 

2.50

 

 

In December 2006 an extensive program of “Valley Fill” evaluation was initiated at the Mwana River Valley, and by the end of the December 2006 field season, 44 “Valley Fill” samples had been collected from the Mwana River valley. Resource Evaluation was initiated and completed in January 2007 for the Mwana River “Valley Fill”. A separate report on the evaluation methodology and estimates of the Mwana River “Valley Fill” is attached as Appendix I. The Inferred Mineral Resource reported from the “Valley Fill” material at a 1.0 g/t Au cut-off is 0.132 million ounces of gold (0.985 million tonnes grading 4.16 g/t Au).

 

The measured and indicated resource update released in June 2007 gave the following estimates: 45.97 Mt at a mean grade of 2.13 g/t Au containing 3,146,200 ounces of gold.

 

Banro announced a further resource update in January 2008 following the completion of some infill drilling on the Twangiza Main and North deposits as follows :

 

·                  Measured Resource of 1.315 million ounces based on 14.510 million tonnes, grading at 2.82 g/t Au, using a cut-off grade of 1.0 g/t Au.

·                  Indicated Resource of 2.558 million ounces based on 39.119 million tonnes, grading at 2.03 g/t Au, using a cut-off grade of 1.0 g/t Au.

·                  Inferred Resource of 2.705 million ounces of gold, based on 46.188 million tonnes, grading 1.82 g/t Au, using a cut-off grade of 1.0 g/t Au.

 

In July 2008, SRK (UK) completed a resource update at Twangiza using two hundred and sixteen core holes totaling 48,087 metres completed as part of the recent drilling and the historical adit and trench data. Drilling is still continuing.

 

Tables 1-3 and 1-4 below summarize the current mineral resource estimates for Twangiza using a 0.5 g/t Au cut-off (with an effective date of June 23, 2008).

 

7



 

Table 1-3: Twangiza Deposit Mineral Resource Estimates @ 0.5 g/t Au cut-off

 

Mineral Resource Category

 

Tonnes (Million)

 

Grade (g/t Au)

 

Ounces (Million)

 

Measured

 

16.7

 

2.59

 

1.39

 

Indicated

 

42.5

 

1.72

 

2.35

 

Measured & Indicated

 

59.2

 

1.96

 

3.74

 

Inferred

 

10

 

1.80

 

0.6

 

 

Table 1-4: Twangiza Deposit Mineral Resource Estimates by Material Type @ 0.5 g/t Au cut-off

 

 

 

Measured

 

Indicated

 

Inferred

 

Mineral
Resource
Category

 

Tonnes
(Million)

 

Grade
(g/t
Au)

 

Ounces
(Million)

 

Tonnes
(Million)

 

Grade
(g/t
Au)

 

Ounces
(Million)

 

Tonnes
(Million)

 

Grade
(g/t
Au)

 

Ounces
(Million)

 

Oxide

 

11.3

 

2.76

 

1.01

 

5.2

 

2.00

 

0.33

 

2.1

 

1.29

 

0.09

 

Transitional

 

5.3

 

2.25

 

0.38

 

16.3

 

1.94

 

1.02

 

2.8

 

1.75

 

0.16

 

Sulphide

 

0.1

 

1.15

 

0.00

 

21.0

 

1.47

 

1.00

 

4.1

 

1.53

 

0.20

 

Total

 

16.6

 

 

 

1.39

 

42.5

 

 

 

2.35

 

9.0

 

 

 

0.45

 

* Valley Fill

 

 

 

 

 

 

 

 

 

 

 

 

 

0.99

 

4.16

 

0.132

 

 

Tonnage rounded to the nearest ’000 and ounces rounded to the nearest ’00.

 


* Resources quoted at 1.0 g/t

 

All fieldwork undertaken since Banro’s 1997-1998 Exploration Programme has been determined to be compliant with National Instrument 43-101 (hereafter NI 43-101).

 

On the basis of its findings to date, Banro decided to go beyond the completed preliminary economic assessment (“scoping study”) and undertake a pre-feasibility study (“PFS”) of the gold deposits found at Twangiza.

 

In April 2007, SENET was appointed by Banro the principal engineering company to compile the preliminary assessment report in accordance with NI 43-101.  As a result, SENET undertook a technical visit to the DRC from 4 May 2007 to 8 May 2007.  The objectives of the visit were to inspect the site of the Twangiza deposits as well as the surrounding infrastructure and to assess the available information and data pertaining to Twangiza.  After completion of this preliminary assessment in July 2007, SENET was appointed by Banro to proceed to the level of pre-feasibility study and to report this in accordance with NI 43-101. SENET undertook a further technical visit from 06 June 2008 to 10 June 2008 with the objective of assessing the site layout, access routes and required access infrastructure upgrades required.

 

Part of SENET’s responsibilities was the oversight of the metallurgical testwork, preliminary process plant design, infrastructural needs and the overall capital and operating costs for the project.  In addition, SENET has liaised with Banro, SRK Consulting (UK) Limited (Cardiff office in the United Kingdom), SRK Consulting (SA) (Johannesburg office in South Africa) Knight Piesold Ltd. (Vancouver office in Canada) SGS Lakefield (Johannesburg office in South Africa) and F.H. Bertling Logistics (PTY) Ltd (Johannesburg South Africa) for the inclusion of mineral resource estimates, the mining study, power plant information, metallurgical testwork and Transport Logistics, respectively.

 

8



 

In order to verify and refine the findings of the completed preliminary assessment report, the engineering performed in preparing this pre-feasibility study was used to further define the mineral resources, determine ore reserves, mining plans and costs, transport and infrastructure costs, beneficiation plant capital and operational costs, marketing and sales, financing arrangements and cover the environmental and social impact assessments required.

 

This technical report summarizes the results obtained from the July 2008 re-modelling and grade estimation of the Twangiza mineralization, as well as the recently completed pre-feasibility study of the Twangiza Project.

 

The “qualified persons” (within the meaning of NI 43-101) for the purposes of this report are Neil Senior of SENET, HG Waldeck of SRK (SA) and Martin Pittuck of SRK (UK).  Mr. Senior is reviewer of the report based on visits to the project site by SENET personnel during 2007 to review the infrastructure and access to the site, together with local and regional facilities. Mr. Anthony Evans, Mr. John Naismith and Mr. Sven Bambus all in the employment of SENET have been to Twangiza. Mr Waldeck has visited Twangiza where he reviewed site conditions for the purposes of doing the mine planning with specific focus on access to site, topography and potential waste dump site locations. Mr. Pittuck has visited Twangiza where he was involved in inspection of the drilling and sampling, review of storage and sample preparation, inspection of core, outcrop and geological interpretations.

 

1.2                     Reliance on Other Experts

 

Not applicable.

 

1.3                     Cautionary Notes

 

This report contains forward-looking statements.  All statements, other than statements of historical fact, that address activities, events or developments in respect of which it is believed, expected or anticipate will or may occur in the future (including, without limitation, statements regarding estimates and/or assumptions in respect of production, revenue, cash flow and costs, estimated project economics, mineral resource and mineral reserve estimates, potential mineralization, potential mineral resources and mineral reserves, projected timing of possible production and exploration and development plans and objectives) are forward-looking statements.  These forward-looking statements reflect current expectations or beliefs based on information currently available.  Forward-looking statements are subject to a number of risks and uncertainties that may cause the actual results of Banro to differ materially from those discussed in the forward-looking statements, and even if such actual results are realized or substantially realized, there can be no assurance that they will have the expected consequences to, or effects on Banro.

 

Factors that could cause actual results or events to differ materially from current expectations include, among other things: uncertainty of estimates of capital and operating costs, production estimates and estimated economic return; the possibility that actual circumstances will differ from the estimates and assumptions used in the pre-feasibility study of the Twangiza project; failure to establish estimated mineral resources or mineral reserves; fluctuations in gold prices and currency exchange rates; inflation; gold recoveries being less than those indicated by the metallurgical testwork carried out to date (there can be no assurance that gold recoveries in small scale laboratory tests will be duplicated in large tests under on-site conditions or during production); changes in equity markets; political developments in the DRC; lack of infrastructure or permits and approvals; unavailability of plant, equipment or labour; inability to retain key management and personnel; changes to regulations or policies affecting Banro’s activities; uncertainties relating to the availability and costs of financing needed in the future; the uncertainties involved in interpreting drilling results and other geological data; and the other risks disclosed under the heading “Risk

 

9



 

Factors” and elsewhere in Banro’s annual information form dated March 28, 2008 filed on SEDAR at www.sedar.com and on EDGAR at www.sec.gov.  Any forward-looking statement speaks only as of the date on which it is made and, except as may be required by applicable securities laws, any intent or obligation to update any forward-looking statement, whether as a result of new information, future events or results or otherwise, is disclaimed.  Although it is believed that the assumptions inherent in the forward-looking statements are reasonable, forward-looking statements are not guarantees of future performance and accordingly undue reliance should not be put on such statements due to the inherent uncertainty therein.

 

The mineral resource and mineral reserve figures referred to in this report are estimates and no assurances can be given that the indicated levels of gold will be produced.  Such estimates are expressions of judgment based on knowledge, mining experience, analysis of drilling results and industry practices.  Valid estimates made at a given time may significantly change when new information becomes available.  While it is believed that the resource and reserve estimates included in this report are well established, by their nature resource and reserve estimates are imprecise and depend, to a certain extent, upon statistical inferences which may ultimately prove unreliable.  If such estimates are inaccurate or are reduced in the future, this could have a material adverse impact on Banro.

 

Due to the uncertainty that may be attached to inferred mineral resources, it cannot be assumed that all or any part of an inferred mineral resource will be upgraded to an indicated or measured mineral resource as a result of continued exploration.  Confidence in the estimate is insufficient to allow meaningful application of the technical and economic parameters to enable an evaluation of economic viability worthy of public disclosure, except in certain limited circumstances set out in National Instrument 43-101.  Inferred mineral resources are excluded from estimates forming the basis of a feasibility study.

 

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

 

The pre-feasibility study of the Twangiza project summarized in this report is preliminary in nature.  There is no certainty that the conclusions reached in the pre-feasibility study will be realized.  Actual results may differ significantly.

 

The United States Securities and Exchange Commission (the “SEC”) permits U.S. mining companies, in their filings with the SEC, to disclose only those mineral deposits that a company can economically and legally extract or produce.  Certain terms are used in this report, such as “Measured”, “Indicated”, and “Inferred” “Resources”, that the SEC guidelines strictly prohibit U.S. registered companies from including in their filings with the SEC.  U.S. investors are urged to consider closely the disclosure in the Company’s Form 40-F Registration Statement, File No. 001-32399, which may be secured from the Company, or from the SEC’s website at http://www.sec.gov/edgar.shtml.

 

2.              PROPERTY DESCRIPTION AND LOCATION

 

The 1,156 square kilometre Twangiza Property is made up of six exploitation permits and is located in the South Kivu Province of the Democratic Republic of the Congo (“DRC”), 35 kilometres west of the Burundi border and 45 kilometres to the south of Bukavu (Figures 2-1, 2-2, 2-3 & 2-4).

 

In January 1996, Banro Resource Corporation’s (now Banro Corporation, “Banro”) wholly owned subsidiary, African Mineral Resources Inc. (“AMRI”), in conjunction with its jointventure partner Mines D’Or du Zaire (“MDDZ”), completed the purchase of the outstanding privately held shares of La Societé Minière et Industrielle du Kivu SARL (“SOMINKI”). The joint venture partners controlled 72% (AMRI - 36%, MDDZ - 36%) of

 

10



 

SOMINKI, with the remaining 28% held by the Government of Zaire (DRC). Banro subsequently acquired MDDZ’s 36% interest in SOMINKI in December 1996. SOMINKI, a privately owned company, was formed in 1976 as a result of the amalgamation of nine companies including Compagnie Minière Zairoses Des Grand Lacs (“MGL”), and held 10 mining permits covering an area of 238 square kilometres and 47 mining concessions covering 10,034 square kilometres.

 

In early 1997, Banro, SOMINKI and the government of the DRC ratified a new 30 year mining convention that provided for SOMINKI to transfer its gold assets to a newly created company. Societé Aurifère du Kivu et du Maniema, SARL (“SAKIMA”) was incorporated to acquire the assets of SOMINKI as stipulated in the new mining convention. In addition to this asset transfer, the new mining convention included a ten year tax moratorium from the start of commercial production, the ability to export all gold production, the ability to operate in US currency, the elimination of import duties and title confirmation for all of the concessions.

 

The new mining convention provided for Banro to control 93% of SAKIMA with the remaining 7% held by the Government of the DRC as a net carried interest.

 

In July 1998, President Laurent D. Kabila issued presidential decrees which, amongst other things, effectively expropriated SAKIMA’s gold assets (Banro, 1998a). As a result of these actions, Banro initiated arbitration proceedings against the Government of the DRC seeking compensation for the expropriation of the Banro’s gold assets (Banro, 1998b).

 

In April 2002, the Government of the DRC formally signed a settlement agreement with Banro. The agreement called for, among other things, Banro to hold a 100% interest in the Twangiza Property under a revived mining convention which expires in March 2027 (subject to extension under the new Mining Code).

 

11



 

Figure 2-1:  Africa Locality Plan

 

 

12



 

Figure 2-2:  Location within the Democartic Republic of Congo

 

 

13



 

Figure 2-3:  Exploitation Permit Location

 

 

14



 

Figure 2-4:  Map of Twangiza Property

 

 

15



 

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

 

3.1                     Physiography

 

The Twangiza Property is located on the western edge of the African Rift Valley. The area is mountainous with deeply incised valleys. Elevation ranges from 1500 metres to 2400 metres above sea level. Vegetation is typically alpine grassland, with groves of cypress and eucalyptus.

 

Due to its location within the western arm of the rift system the property is subject to Seismic Activity. 48 earthquakes were recorded within 100km of the Twangiza project site between 1977 and January 2008, with Richter magnitudes up to 5.4M.

 

3.2                     Current Accessibility

 

Bukavu, the capital city of South Kivu Province is some 45 kilometres north of theTwangiza Property. Bukavu has an international airport, Kavumu. There are commercial flights between Bukavu and Goma (North Kivu), Kindu (Maniema), Nairobi — Kenya, Mwanza – Tanzania. There are two commercial ferries on Lake Kivu between Goma - North Kivu and Bukavu that run daily.

 

Bukavu is a one hour drive from Bukavu airport using  road which is in poor ondition. The prefered means of access to Bukuva is via Kemembe Airport in Rwanda which is a one hour drive away including border crossing time.

 

The Twangiza Property can be accessed by travelling some 55km on the recently upgraded N2 road and then 30km on a smaller road to the camp; the latter will need to be upgraded in order to transport heavy goods to site. Access by road takes two or three hours depending on the season.

 

The journey time is 2 hours during the dry season and extends to 3 hours under wet conditions. The property is also serviced by a helicopter and the journey between Bukavu and Twangiza is some eighteen minutes.

 

Until October 2005 there were no Congolese authorities, Local Government Administrator, police and/or integrated national army in control of the Twangiza area. The above mentioned government authorities were installed in late September 2005 which resulted in increased security of the area. Banro mobilized field staff to Twangiza in mid- October 2005.

 

3.3                     Existing Infrastructure/Local Resources

 

The Twangiza Property is remotely located and no ready supply of exploration services or equipment is available. The local workforce consists primarily of subsistence farmers and artisanal miners. The country does have a long history of mining and a reasonably qualified workforce could be developed from other areas.

 

Until October 2005 there were no Congolese authorities, Local Government Administrator, police and/or integrated national army in control of the Twangiza area. The above mentioned government authorities were installed in late September 2005 which resulted in increased security in the area.

 

16



 

No exploration or mining infrastructure was located on the Twangiza Property until Banro mobilized field staff and established an exploration camp on the property in mid-October 2005.

 

3.4                     Climate

 

The climate can be classified as tropical to sub-tropical.

 

The climate is further characterized by a Wet Season, from September to April, and a dry season, from May and August. Due to the limited metrological data available for Twangiza, AMEC have reviewed data from adjacent metrological stations at Confomeka, Bukavu, Tshibinda and Kailo, and estimate the average annual rainfall as 1,796mm. A maximum of 242mm is expected to fall during December and a minimum of 35mm during July. A report by CEMIC (2005a) indicates that annual rainfall at Twangiza Mine varies between 1500 and 1750mm.  Rainfall occurs as soft lengthy rain in mid to late afternoons as well as short violent thunderstorms.

 

Temperatures vary from below 10ºC in the evenings to between 15ºC to 25ºC during the day. The hottest temperatures occur during April and May, and the lowest temperatures occur during January.

 

Additional Information regarding accessibility, climate, local resources, infrastructure and physiography is set out in the technical report of Michael B. Skead dated March 30. 2006 and entitled “NI 43-101 Technical Report Twangiza Project, South Kivu Province, Democratic Republic of the Congo”. A copy of the said report can be obtained from SEDAR at www.sedar.com.

 

4.              HISTORY

 

This section summarises only the work completed on the Twangiza Deposit and does not cover work completed on other deposits within the Twangiza license area.

 

History of past exploration activity on the Twangiza Property was originally summarised in the technical report of CME Consulting Ltd. dated April 30, 2003 and entitled “Review and Mineral Resource Update of the Twangiza Property, Kivu Province, Democratic Republic of the Congo” (the “2003 CME Report”). A copy of the said report can be obtained from SEDAR at www.sedar.com.

 

Initial work programs within the Twangiza Property consisted of alluvial mining for tin and gold as early as the 1930’s along prominent rivers and creeks. Gold mining activities occurred within the Twangiza, Bugoy-Kashwa and Mufwa Regions. Tin mining was undertaken in the Kashwa, Kilungutwe-Mutshege-Tshigui, Gombo-Kashangwa-Muduwe, Sasa-Mikuba and Kasika-Lugulu Regions by Mines des Grandes Lacs  (MGL).

 

MGL is the first recorded company to engage in exploration and alluvial mining in the Twangiza area. MGL began exploration for in-situ resources in 1957. Work followed the occurrence of alluvial gold deposits upstream from the Mwana River to the present day Twangiza deposit. MGL tested the Twangiza deposit through 8,200 metres of trenching and 12,100 metres of adits (20 metre by 20 metre grid) on seven levels (Levels 2100 to Level 2220). A total of 17,400 samples were collected at two metre intervals from both the trenches and adits and analyzed for gold by fire assay at MGL’s analytical laboratory in Kamituga.

 

In 1974 to 1976, Charter Consolidated Limited (“Charter”) undertook an evaluation program of the Twangiza Area in order to verify the results obtained by MGL and to look for possible extensions of the deposit. Soil sampling at 25 metre intervals along 100 metre spaced lines was conducted over a 4.6 square kilometre area. The southern limit of the 2.3 kilometre long grid was located 500 metres north of the Twangiza deposit. Anomalous soil samples were

 

17



 

followed up by 11 pits, six trenches and five adits. Work also included the resampling of three MGL adits (Levels 2100, 2130, and 2220) and metallurgical studies.

 

From 1982 to 1984, SOMINKI undertook a feasibility study which was completed by ABAY, a Belgian consulting company. Their study pertained to the exploitation and treatment of the ore by either the Merrill-Crowe method or the carbon-in-pulp method.

 

In 1988 the Northern Queensland Company assessed the deposit and generated some financial models, but was unable to proceed due to internal problems. Based on the findings of the studies conducted by both Charter and ABAY-SOMINKI, a report was prepared by Billiton in 1989 for SOMINKI and submitted to the Ministry of Planning for tax exoneration purposes.

 

In 1997, Banro consolidated the information base through a data compilation program, which included the MGL adit and trench assay plan maps. From August 15, 1997, to April 15, 1998, Banro undertook a field exploration program, which was managed by CME & Company (CME). Work included:

 

·                  topographical surveying (31.65 sq. kilometres),

·                  LANDSAT acquisition and interpretation,

·                  helicopter-supported magnetic airborne surveying (10,490 line-kilometres),

·                  geological mapping and rock sampling of the Twangiza Area (2,161 samples),

·                  geological mapping and channel sampling of 16 adits (1,613 samples),

·                  diamond drilling (20 holes, 9,122 metres, 8,577 samples),

·                  density testing, and

·                  petrographic studies.

 

Banro’s ongoing exploration work which includes a rigorous quality control programme has broadly confirmed lengths and gold grades reportedly intersected during historical exploration. Therefore, SRK considers the historical data to be valid for use in the Mineral Resource estimate.

 

5.              GEOLOGICAL SETTING

 

5.1                     Regional Geology

 

The Twangiza Property is located in the northern half of the Great Lakes sub-province of High Africa, one of the world’s principal Precambrian orogenic-metallogenic provinces. It consists of five spatial trends that were built during seven cycles. The oldest trend in the province is represented by the 2.2 Ga Transvaal sediments. The youngest trend is the Katangian geosyncline formed more than 500 Ma ago.

 

The Great Lakes sub-province extends 1,500 kilometres in a north-south direction from lake Victoria to Kolwezi; and 500 kilometres east-west between the Congo and Luala Rivers and the Great Lakes. The oldest rocks of the Kivu-Maniema Region are sediments belonging to the Ruzizian Series (Bontemps, 1983). These sediments were folded during the Ruzizian Orogeny (2.1 Ga) and intruded by granitic stocks localized in anticlinoria and gneissic and migmatitic contacts. A phase of erosion and sedimentation deposited shale, conglomerate, quartzite and sandstone belonging to the Burundian Series which was deformed during the Kibarian/Burundian Orogeny (1.3 Ga). Calc-alkaline granites were again intruded in anticlinoria.

 

The Kivu-Maniema Region is predominately underlain by Precambrian schists intruded by granites. Metabasites interbedded with schists and dolerite occur along the periphery of the batholiths and stocks. Most of the tin, tungsten and columbite-tantalite deposits of the region

 

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are related to post-tectonic granitic batholiths and stocks, while the gold deposits occur in the synclinoria between the granites. One of the tin mineralisation belts is located to the western side of the province. The belt extends from Tshamaka through Punia- Kalima-Moga and south to Kampene. An eastern tin belt follows the contact of the Kasese batholith in the Lulingu and Ona Districts.

 

A west-northwest trending gold belt that connects Kima with Shabunda occurs between the tin belts. The gold belt separates into two branches with the eastern branch passing through the Lugushwa and Kamituga Districts and the western branch bifurcating southeast of the batholith into the Namoya District. Just west of the Great Lakes is a very long and narrow gold belt, which trends east-west in its northern portion, in the Kilo-Moto Area, near the Congo/Sudan border and then south along the Great Lakes to Katanga. The Twangiza deposit is located within this belt.

 

5.2                     Property Geology

 

The Mufwa-Bugoy-Twangiza Area is divided geologically into three parts, the Kaziba Area, the Twangiza-Bugoy Area and the Birala-Tshondo-Mufwa Area. The Kaziba Area is characterized by a sequence of sedimentary rocks deformed to a composite syncline trending northwest-southeast. The stratigraphic section is composed, from bottom to top of a base conglomerate then black shale passing up into an interlayered sequence of shale, quartzite and conglomerate.

 

The Twangiza-Bugoy Area is underlain by a sedimentary sequence of shale, mudstone, siltstone, minor greywacke and arkose, and intraformational conglomerate. The succession is bounded by conglomerate formations on the east and west sides. This sequence was folded into a composite anticline (Twangiza Anticline) then intruded by intermediate to mafic sills and modified by sub-parallel shear zones and numerous faults.

 

6.              DEPOSIT TYPE AND DEPOSIT GEOLOGY

 

The type of magmatic-hydrothermal mineralisation at Twangiza occurs within magmatic provinces best known for tungsten and/or tin mineralisation.

 

This deposit type contains a metal suite that includes a combination of bismuth, tungsten, arsenic, tin, molybdenum, tellurium and antimony, and contrasts with that found in the more widely-developed gold-rich porphyry copper deposits. They are located on cratonic margins, or within continental collisional settings, and are related to felsic domes, stocks and plutons of intermediate oxidation state (both magnetite and ilmenite series).

 

Many significant deposits of this type recognised around the world including, Kidston, Vasilkovskoye, Donlin Creek and Muruntau.

 

The Twangiza deposit is a structurally and lithologically controlled hydrothermal gold deposit. The primary control is structure, which is related to the axis of the Twangiza Anticline with secondary control related to lithological units and contacts.

 

The Twangiza deposit is comprised of a relatively unaltered, folded sedimentary sequence of mudstone, siltstone and greywacke intruded by an intercalated sequence of stratiform albitedolomite and chlorite-actinolite-carbonate altered dioritic – gabbroic sills.

 

Intrusions into this sedimentary pile were relatively passive and probably a shallow level event that had minimal structural and metamorphic effect on the surrounding sediments. The intrusive sills pinch and swell along bedding causing minor bedding displacement. Contact metamorphism consisted of bleaching and silicification along narrow widths of the contacts.

 

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The intrusive sills are mapped as having two different phases, a mafic porphyry phase and a feldspar porphyry phase.

 

The albite-dolomite altered phase of the feldspar porphyry gives the sills a more brittle character and coupled with the hydrothermal alteration of the immediate overlying sediments, the continued folding of the rock units developed extensive fracturing and brecciation on the upper intrusive/sediment contacts.

 

During the folding, two stress regimes further fractured the anticline structure. One stress regime involved radial fracturing perpendicular to bedding and striking along the anticline axis with the maximum intensity within the axial plane zone. The second regime is represented by the east-west trending left-lateral faults dissecting the anticline into larger blocks with variable vertical and horizontal throw. Alteration and auriferous hydrothermal fluids are directed by east-west faults, and bedding planes. As a result, some auriferous zones at the Twangiza Main deposit occur as crescent-shaped sheets or lenses of mineralisation located preferentially in the upper side of the sills, in the anticline, these are in turn crosscut by mineralised veins or veinlets. The mineralisation can be considered as a stockwork that is most intense at the axial plane of the anticline where the densest pattern of fractures occur and at the junction of the east-west faults. The mineralisation tends to gradually diminish down dip along the limbs. A schematic illustration of the mineralisation is provided in figure 5-1

 

Figure 6-1: Deposit Geology

 

 

FIGURE 3. SCHEMATIC CROSS-SECTION SHOWING PRINCIPAL FEATURES OF THE TWANGIZA MINERALIZATION

 

In the Twangiza North deposit the mineralisation is concentrated in feldspar porphyrys of the unfolded limb which have been prefentially fractured internally along their contact. This results in a sharper mineralised boundary than that seen at Twangiza Main.

 

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7.              MINERALIZATION

 

Gold mineralisation encountered in the Twangiza Deposit occurs within albite-carbonate-quartz sulphide veining and associated pyrite and arsenopyrite disseminations in both the feldspar porphyry sills and the sedimentary rocks near the axial plane of the Twangiza Anticline.

 

Mineralisation styles can be summarised as:

 

·                  small to medium quartz veins and micro-breccia intrude the rocks with low percentages of pyrite and general paucity of arsenopyrite,

·                  small to medium quartz-pyrite-arsenopyrite (partly as massive sulphides) veins and breccia intrude often forming the centre with gangue in the selvages; and

·                  medium to large ankerite/dolomite dominated veins with variable amounts of sulphides and quartz.

 

8.              EXPLORATION

 

The exploration on the Twangiza Property has been divided into historical exploration and that carried out from October 2005 to July 2008 (recent exploration).

 

8.1                     Historical Exploration

 

There have been three historical major field exploration programs during the historic exploration (i.e. pre-2000) on the Twangiza Property.

 

The first was between 1957 and 1966 by MGL and consisted of the driving of approximately 12,100 metres of adits and 8,200 metres of trenches at the Twangiza deposit. A total of 17,400 samples were collected at two metre intervals from both the trenches and adits.

 

Secondly, from 1974 to 1976, Charter Consolidated Limited undertook an evaluation program of the Twangiza Area in order to verify the results obtained by MGL and to look for possible extensions of the deposit. Soil sampling was conducted over a 4.6 square kilometre area to the north of the Twangiza deposit. Anomalous soil samples were tested by 11 pits, 6 trenches and 5 adits. Work also included the re-sampling of three MGL adits (Levels 2100, 2130, and 2220).

 

The third historical program was undertaken by Banro between August 15, 1997 and April 15, 1998 within the Twangiza Area. The program was managed by CME and consisted of:

 

·                  Topographical surveying (31.65 square kilometres)

 

·                  LANDSAT acquisition and interpretation – completed during 1997 by R. Eyers of the Remote Sensing Group at Imperial College London. High Resolution digital satellite imagies for an area covering 60,000 square kilometre between latitude 2°30’S and 4°30’S and longitude 26°30’E and 29°30’E were created. Results indicated the Twangiza Property lies on a complex north-south trending structure composed of a number of curvilinear segements which trend toward northwest –southeast orientations away from the axis.

 

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·                  Helicopter-supported magnetic airborne surveying (10,490 line-kilometres) – Conducted during 1997 – 1998 exploration prgrammes by High Sense Geophysics (now Fugro geophysics) of Harare, Zimbabwe. The survey provide high resolution magnetic maps, used to define anomaly definition, detailed structural evaluation and identification of lithological trends in a digital format. The investigation covered five of the six Twangiza permit areas (PE40, PE41, PE42, PE43, PE44), and were based on a 200 metre spacing orientated at 045° and tie-lines at 135° at a spacing of 2,000 metres. The results confirmed the Twangiza deposit is characterised by a high magnetic field adjacent to a large low magnetic anomaly in the north and a smaller low anomaly to the southwest. The magnetic lows probably represent an underground intrusive which provided the fluid and/or heating source for the gold mineralisation and the porphyry sills found at the Twangiza deposit.

 

·                  Geological mapping and rock sampling of the Twangiza area (2,161 samples) – was completed during the 1997 – 1998 exploration programme and covered a 38 square kilometre area extending 2.6 kilometres south and 5.2 kilometres north of the Twangiza deposit. The regional mapping is bounded to the east and west by north – south trending conglomerates. Grab samples and channel samples were taken and after sample preperation at Banro’s on site Sample Preparation Laboratory (Prep Lab) were sent to Acme Analytical Laboratory in Vancouver, Canada for analysis

 

·                  geological mapping and channel sampling of 16 adits (1,613 samples) – covering Detailed of the southern portion of the Twangiza area previously worked by an artisan mining operation. Grab samples and channel samples were taken and after sample preperation at Banro’s on site Sample Preparation Laboratory (Prep Lab) were sent to Acme Analytical Laboratory in Vancouver, Canada for analysis.

 

·                  Petrographic studies – Completed by Dr J. F. Harris of Vancouver Petrographics Ltd, based on polished and thin sections using samples collected during the 1997 – 1998 exploration programme. Investigation observed that native gold occurs in veins against pyrite crystals and fine grained gold occurs at the boundary of sulphides or along fractues within sulphide grains.

 

·                  “diamond drilling” (20 holes, 9,122 metres, 8,577 samples, HQ and NQ diamond drilling) was completed between September 4 1997 and March 9 1998, covering an area of some 800 m strike length of mineralisation within the hinge of the Twangiza Anticline using different orientations. Due to the extreme topogrpahy at Twangiza an A-Star 350 B2 helicopter was utilised for moving drilling rigs, materials and personnel from site to site. Drilling was performed by Rosond International Limited of South Africa utilizing two longyear 38 drill rigs with a maximum potential depth of 600 m. All drillhole collars were surveyed using a Sokkia SET4100 Total Station, with dips and azimuth at surface setup using handheld compasses. Downhole surveying of all holes was completed using a Sperry Sun Single Shot instrument which recorded both azimuth and dip.

 

·                  Density testing, - performed on behalf of Banro by CME in 1998 on a variety of rock types that make up the Twangiza deposit. The purpose of the study was to assign rock densities to specific lithological and mineralogical units for inclusion into the resource estimates. A total of 165 bulk density determinations were undertaken by CME.

 

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8.2       Further Exploration (October 2005 – December 2006)

 

Banro resumed its exploration programme at Twangiza after the Congolese government had established control and authority in the area in October 2005.

 

8.2.1       Drilling

 

The aim of this drilling was to convert the remaining Inferred Mineral Resources into Indicated and Measured categories and to identify additional Inferred Mineral Resources. A total of 17,037.34 metres of PQ, HQ and NQ diamond drilling involving 71 holes were completed between February and December, 2006. Drilling tested the 800 metre long zone of mineralisation within the hinge of the Twangiza Anticline and soil geochemical anomalies to the north. A total of 48 resource holes were initially drilled at 40 m centres to infill the holes drilled in 1997/98 with the objective of upgrading the Inferred Mineral Resources to the high confidence Measured and Indicated Mineral Resources. In addition, 23 exploration holes were drilled to test the geochemical anomaly to the north and east of the main Twaniza deposit.

 

An A-Star 350 B2 helicopter (owned and operated by Wilddog Helicopters) was used for the moving of drills, materials and personnel from site to site. The diamond drilling was performed by Geosearch International Limited of South Africa utilizing three portable CS1000 and a Longyear 38 drill rigs with a maximum depth capability of 600 metres.

 

All drill holes collars were surveyed with Real Time DGPS equipment. Drillholes collar azimuths were established at surface by using hand held compasses. Down-hole surveying of drill holes utilized a Reflex Single Shot or Flexit instrument, which measures both azimuth and dip. All drill holes were oriented. Orientation was carried out by the “Spear” method or other gravity-based Ezy Mark system.

 

The majority of drill holes an azimuth of between 70 - 80° at dips of between 50 – 55°. A portion of the programme has been drilled in the opposite direction on an azimuth of 260° to improve the definition of the 3D wireframes.

 

8.2.2       Soil Geochemical Programme

 

A soil geochemical programme designed to test the immediate northern, eastern, western and southern extension of the known Twangiza resource was completed in 2006. The 7 km soil geochemical grid had its base line orientated along the hinge of the anticline at 350º. Soil sampling was undertaken at 40 m intervals on lines spaced at 80 m.

 

The baseline origin for the soil geochemical grid was pegged at UTM coordinate of 9682698.2N / 693500.5E, which corresponds to a local grid coordinate of 10000N/20000E (Figure 5). The soil geochemical grid was initially surveyed using compass, tape and ranging rod method. All sample points are peg with a wooden peg with local grid co-ordinates clearly labelled on each peg. All sample points are subsequently surveyed in using a Trimble Differential GPS. The survey used the WGS-84 zone 35 south coordinate system.

 

The base line is 7 kilometres long and orientated at 350º with cross-lines spaced at 80 metres intervals each being 2 kilometres long. The soil geochemical grid was surveyed using differential GPS. Soil geochemical samples are taken at 40 metre intervals along cross-lines and sent to the Banro sample preperation facility before being dispatched to the laboratoy. At the end of December 2006 field work, a total of 275.44 line kilometres had been cut and a 6,589 soil geochemical samples collected and sent for analysis

 

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Gold-in-soil geochemical results outlined an 800 metres long and 450 metres wide, +100 ppb gold in soil anomaly to the immediate north of Twangiza Main deposit. The anomaly splits into three roughly parallel trends to the south of the Lukungurhi workings. A 1.5 km long, 80 metre to 160 metre wide north-northwest trending +100 ppb Au soil anomaly occurs to the south of the Lukugurha artisanal workings.

 

8.2.3       Trenching Programme

 

A trenching programme was initiated to test the gold-in-soil geochemical anomalies and the continuity of mineralisation on the northern extension of the Twangiza main deposit, as well as, the southern and northern extensions of the Lukungurhi workings. Trenches were located to the north of the baseline origin and were oriented at 080°.

 

The lithological units encountered in the trenches are intensely weathered with limonite staining occurring predominantly in the sediments and feldspar porphyries where mineralised. Kaolinite is the dominant weathering product in the feldspar porphyries.

 

Hydrothermal silicification is mainly encountered at the contacts between feldspar porphyry the sediments. Silicification is usually intense at the contacts and decreases away from the contact into the wall rock. Sampling was completed lithologically by floor channelling with the maximum sample length being 1 m and 0.3 m minimum length. Samples were cut from grooves of 10 cm wide and to a depth of 5 cm.

 

A total of 785 channel samples were collected from 1,159 m of trenching.

 

Trench sampling was carried out by channelling a sample along the floor of the trench. Each channel is approximately 10 centimetres wide and 3 to 5 centimetres deep. Sample intervals were determined by geological features. In homogeneous rock, the maximum sample interval was 1 metre. The minimum sample interval employed is 0.3 m. Veins, altered zones, or distinct geological units were sampled so that the contacts were a standard 2 cm within the sample boundaries. Sample weights varied between 3 and 6 kilograms.

 

8.2.4       Prospect Scale Mapping

 

A detailed mapping project was carried out in the Twangiza artisanal workings in order to gain a better understanding of the geological and mineralisation controls and to verify and compliment the diamond drilling data. The study reviewed all aspects of the geology including lithology, structure and alteration (Appendix II).

 

Structural mapping at the Twangiza main deposit (workings, trenches and road cuts) demonstrate that the bedding in the Twangiza workings strikes dominantly NW-SE. The intersection of bedding planes indicated an anticlinal fold axis plunging 37º to 120º. The few quartz veins measured from the workings are either oblique or cross cut bedding with a NW and EW trend.

 

The Lukungurhi artisanal working is located approximately 1.5 kilometres north of the Twangiza deposit and measures about 600 metres in strike length and on average 70 metres wide. The axis of the workings is orientated at 350°. Work carried out during 2005 included trenching, geological/structural mapping of trenches and artisanal pits as well as rock chip/channel sampling. Two trenches TWT 3 and TWT 4 located respectively at the southern and northern extensions of the workings were excavated to test the continuity of the Lukungurhi mineralisation.

 

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Structural mapping from trenches and artisanal workings reveal the bedding is dominantly North - South. Limonite-quartz veins within the porphyries have a dominantly East orientation of 080º/71º strike dip right. Kaolinite alteration is the product of intense weathering of feldspars in both the feldspar porphyry and mafic intrusives. Further mapping and trenching was completed at artisanal workings in the vicinity, notably at Kashegeshe, Muhona and Bugoy.

 

8.3       Recent Exploration (January 2007 – July 2008)

 

8.3.1       Drilling

 

The aim of the recent drilling was to convert the remaining Inferred Mineral Resources into Indicated and Measured categories and to identify additional Inferred Mineral Resources particularly at Twangiza North.

 

A total of 23,873.12 metres of PQ, HQ and NQ diamond drilling in 100 holes was completed between February 2006 and May 2007.  Drilling tested the 800 metre long zone of mineralisation within the hinge of the Twangiza Anticline and Twangiza North soil geochemical anomalies. A total of 61 resource holes were drilled at 40 m centres to infill the holes drilled in 1997/98 with the objective of upgrading the Inferred Mineral Resources to the higher confidence Measured and Indicated Resources. In addition, 39 exploration holes were drilled to test the Twangiza Northeochemical anomaly.Four drill rigs were deployed at the Twangiza property, with two additional rigs  mobilized in 2008.

 

The remainder of the programme between May 2007 and May 2008 consisted of a total of 24,231.3 metres of PQ, HQ and NQ diamond drilling involving 116 holes. The focus of the drilling was to infill the drilling grids and potential resources within the Twangiza Noth area of the deposit. 98 holes were drilled at 40 m centres to infill the holes drilled in 2006 / early 2007 in the Twangiza North deposit versus 18 holes in Twangiza Main during the period.

 

An A-Star 350 B2 helicopter (owned and operated by Wilddog Helicopters) was used for the moving of drills, materials and personnel from site to site. The diamond drilling was performed by Geosearch International Limited of South Africa utilizing three portable CS1000 and a Longyear 38 drill rigs with a maximum depth capability of 600 metres.

 

All drillhole collars were surveyed with Real Time DGPS equipment. Drillhole collar azimuths were established at surface by using hand held compasses. Down-hole surveying of drill holes utilized a Reflex Single Shot or Flexit instrument, which measures both azimuth and dip. All drill holes were oriented. Orientation was carried out by the “Spear” method or other gravity-based Ezy Mark system.

 

The majority of the drilling in the programme have been drilled to the East on an azimuth of betweem 70 - 80° at dips of between 50 –55°. A portion of the programme has been drilled in the opposite direction on an azimuth of 260° to improve the definition of the 3D wireframes (significant intersections are highlighted in Appendix III).

 

8.3.2       Geophysical Exploration (LIDAR)

 

LIDAR, airborne magnetic and radiometric surveys were also completed over the entire Twangiza property; several promising new targets were identified for follow-up work. LIDAR (Light Detection and Ranging) is an optical remote sensing technology and has been used to create accurate images and surfaces of the topography, which historically have been difficult to accurately survey

 

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8.3.3       Additional Regional Work

 

2007 also saw Banro begin exploration of the Twangiza property outside the main trend. The company established a new exploration camp at the major artisanal site at Mufwa, situated 13 kilometres northwest of the Twangiza Main deposit, and initiated field work in other target areas including the promising artisanal workings at Tshondo. Additional rigs are being mobilized to Twangiza so this new prospect can also be drilled during the coming months once groundwork has been completed.

 

9.     DRILLING

 

The aim of the recent drilling is to convert the remaining Inferred Resources into Indicated and Measured categories and to identify additional Inferred Resources. A total of 55,817.04 metres of PQ, HQ and NQ diamond drilling involving 247 holes was completed between February 2006 and July 2008 (Figures 9-1). Drilling tested the 800 metre long zone of mineralization within the hinge of the Twangiza Anticline and Twangiza North mineralisation. One hundred and eight (108) holes totaling 28,195.52 metres were completed at Twangiza Main; holes were drilled at 40 m centres to infill the holes drilled in 1997/98 with the objective of upgrading the Inferred Resources to the higher confidence Measured and Indicated Resources. A total of 27,621.52 metres from 139 exploration and resource holes were drilled at Twangiza North. Drill core data for holes TDD001 to TDD216 (216 holes) of the current drilling were employed in the mineral resource estimates discussed in section 15 of this report. Assay results for an additional 30 holes were reported in Banro’s July 31, 2008 press release which are included in Appendix IIIb.

 

9.1       Mineralization and Results

 

Appendix III attached to this report is a table of significant intersections from the diamond drilling programme. Individual sample grades were not capped and intercepts are down-hole lengths as such composite results are presented over core length and true widths.

 

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Figure 9-1:           Drill Hole Collars

 

 

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