1989-03-17_REPORT - M1977378

• Permit No: M1977378
• IBM Index Class Name: REPORT
• Doc Date: 3/17/1989
• Doc Name: Clarifications
• From: San Juan County Mining Venture
• To: MLRD
• Media Type: D
• Archive: No

EVALUATION OF FINAL PIT
SLOPE STABILITY
Table of Contents
Page
1.0 INTRODUCTION ......................................................................................... 1
2.0 CONCLUSIONS/RECOMMENDATIONS ................................................ 2
2.1 CONCLUSIONS .................................................................................. 2
2.2 RECOMMENDATIONS ..................................................................... 3
3.0 GEOLOGY AND GEOLOGIC STRUCTURE .......................................... 4
3.1 GEOLOGY ........................................................................................... 4
3.2 ROCK STRUCTURE ........................................................................... 4
3.2.1 Bench 1 Mapping ..................................................................... 4
3.2.2 Bench 2 Mapping ..................................................................... 9
4.0 PIT STABILITY EVALUATION ............................................................... 11
4.1 TECHNICAL APPROACH ................................................................. 11
4.2 PIT LAYOUT AND GEOMETRY ...................................................... 11
4.3 ASSESSMENT OF GLOBAL STABILITY ........................................ 13
4.4 EVALUATION OF STRUCTURAL DISCONTINUITIES ................ 13
4.4.1 Intermediate Scale Stability ..................................................... 16
4.4.2 Small-Scale Stability ................................................................ 19
4.5 BENCH WIDTH AND FACE ANGLE ............................................... 19
4.6 BLAST DAMAGE ............................................................................... 22
4.7 STABILITY OF TALUS MATERIAL ON THE UPPER EAST
WALL ................................................................................................... 22
REFERENCES ....................................................................................................... 23
APPENDIX A- Stereonets of Bench 1 Mapping ................................................. 24
APPENDIX B - Stereonets of Bench 2 Mapping ................................................. 28
APPENDIX C - Blasting Letter Report ............................................................... 32
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