title of the thesis - Department of Geology - Queen's University

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$Fayek & Kyser 2000 uraninite fractionations.pdf - Queen's University$

Damage zones produced using maximum stress and differential stress outline similar areas of fracture initiation. Areas of active excavation during the 2006-2007 time period as well as a zone of high-stress between the Return Air Raise Shear Zone and Plum Shear Zone are identified as areas of possible fracture initiation under both maximum stress and differential conditions. This demonstrates that fracturing of intact rock is a possible mechanism for seismicity to the south of the excavation where seismicity is observed, but the crack coalescence threshold is not surpassed. Fracture contours identify the area south of the excavation as a region that is in a state of damage but not yield (Fig. 4.24). This is a lower state of degradation than was found in Chapter 3 using seismic source parameters, where the rock mass to the south of the excavation was hypothesized to be in post-peak conditions. Figure 4.24 shows that cracking is not possible immediately to the north and south of the excavation, based on the final state of models produced for Case 1 (Φ=30 o , C=0 MPa). This is because yielding has already occurred and high stress cannot be accommodated by the disintegrated rock mass in this state. UDEC code and routines can be found in Appendix E. 100
Figure 4.24: Fracture initiation thresholds mapped using maximum and differential stress conditions. 4.7 Modelling Summary and Discussion The distribution of stress on the 7400 Level in Creighton Mine is strongly dependent on both the excavation geometry and the strength of the discontinuities. UDEC models demonstrate that cohesion and the friction angle of the discontinuities modify the flow of stress around the excavation. Faults must have sufficiently low friction values for shear slip to occur. Under the current stress field, faults must have some residual friction as low values produced unrealistic stress distributions. Models demonstrate that stress is substantially reduced in a yield zone adjacent to an excavation. Tensile and shear failure associated with the yield zone is directly incurred by the presence of the excavation. Diederichs (2003) states that this is an area of tensile fracture accumulation and 101
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THE INFLUENCES OF STRESS AND STRUCT
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esulting in increased stress to the
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Table of Contents Abstract.........
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4.6.1 Fracture Reactivation........
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List of Figures Figure 1.1: Locatio
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Figure 3.23: Preliminary stress inv
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Figure B11: Events between Jan 1, 2
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List of Tables Table 2.1: Geologica
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Chapter 1 Introduction 1.1 Backgrou
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Figure 1.1: Location of Sudbury and
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Chapter 2 Geological Assessment of
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ack breccia and sediments later dep
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Murray Fault, the principal fault o
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2.2 Local Geology of Creighton Mine
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B West East B’ Figure 2.4B: Longi
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Table 2.2: Fault systems within the
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Table 2.3: Summary of Fault Charact
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Figure 2.6: (A) Damage to shotcrete
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Figure 2.7: (A) The 1290 Shear Zone
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Figure 2.8: Images of (A) the 400-E
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Figure 2.9: (A) Photograph of the c
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Figure 2.10 (A) Shear foliation, in
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Figure 2.11: Thin sections of the F
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(Fig. 2.12B). Reduction of quartz g
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2.3.11 Late-Stage Fractures The you
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overprinting (Cochrane, 1991; Couls
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Table 2.4: Summary of Proterozoic t
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Both of these inferred stress direc
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are, at this time, in the process o
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Microseismic events of this subset
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3.2.1.2 Seismic Energy (E o ) and S
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3.2.1.4 Stress Parameters Stress pa
Page 65 and 66: located events were removed from cl
Page 67 and 68: Figure 3.7: Detected seismicity cor
Page 69 and 70: Table 3.1: Event characteristics in
Page 71 and 72: Table 3.3: Summary of relevant para
Page 73 and 74: ) Damage Zone The rock mass in the
Page 75 and 76: quadrants of dilatation and compres
Page 77 and 78: Figure 3.12: Lower hemisphere equal
Page 79 and 80: mechanism shows that over 57% of th
Page 81 and 82: Figure 3.16: Classification of prin
Page 83 and 84: Figure 3.18: Contoured P-axis, B-ax
Page 85 and 86: Figure 3.20: Distribution of double
Page 87 and 88: This parameter reflects the magnitu
Page 89 and 90: Figure 3.23: Preliminary stress inv
Page 91 and 92: Figure 3.25: Equal area stereonet s
Page 93 and 94: Figure 3.27: (A) Maximum principal
Page 95 and 96: 4.2 Numerical Methods Phase 2 and U
Page 97 and 98: Stress-strain relationships are use
Page 99 and 100: Rock mass failure is governed by th
Page 101 and 102: Figure 4.5: (A) Model for tectonic
Page 103 and 104: The zero cohesion and low friction
Page 105 and 106: Figure 4.9: Model of yielding for C
Page 107 and 108: Figure 4.11: Model of differential
Page 109 and 110: Figure 4.14: Model of maximum stres
Page 111 and 112: stress field model. There is little
Page 113 and 114: clustering are indications of rock
Page 115: Figure 4.23: Contoured domains of s
Page 119 and 120: seismic Cluster 1, which correspond
Page 121 and 122: contains energetic events and is no
Page 123 and 124: preferentially oriented fracture pl
Page 125 and 126: methodologies employed are of value
Page 127 and 128: References Alcott, J. M., Kaiser, P
Page 129 and 130: Galkin, V., Mungall, J. (2005). Str
Page 131 and 132: Mungall, J. E., & Hanley, J. J. (20
Page 133 and 134: Appendix A Geological Maps and Samp
Page 135 and 136: A.2 Level Plans with Sample Locatio
Page 137 and 138: Figure A3: 7400 Level, modified for
Page 139 and 140: Figure A5: 7680 Level, modified for
Page 141 and 142: Figure A7: 7940 Ramp, modified from
Page 143 and 144: MICROSEISMIC EVENTS Source Radius A
Page 145 and 146: 2006 Event Frequency with Depth 600
Page 147 and 148: B.2 Spatial Distribution of Seismic
Page 149 and 150: Figure B11: Events between Jan 1, 2
Page 155 and 156: Cluster 1 Source Radius Asp. Radius
Page 157 and 158: Seismic Moment 10.0 9.5 9.0 8.5 8.0
Page 159 and 160: 143 Peak Velocity Parameter -2.5 -2
Page 161 and 162: B.4.2 Temporal Distribution of Clus
Page 163 and 164: 147 Static Stress Drop 5.0 5.5 6.0
Page 165 and 166: B.4.3 Temporal Distribution of Clus
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151 Static Stress Drop 4.0 4.5 5.0
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Frequency-Magnitude Relation for Cl
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P-axis B-axis T-axis 155 Fault Plan
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P-axis B-axis T-axis Fault Plane 1
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D.1.1: Case 1 Models Figure D1: Cas
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Figure D3: Case 1, elastic models s
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A B C D Figure D5: Case 1, plastic
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A B C D Figure D7: Case 1, plastic
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D.1.2: Case 2 Models A B C D Figure
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D.1.3: Case 3 Models A B C Figure D
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D1.4 Tectonic Loading Models Figure
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D.2 Discussion of Phase 2 Models El
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Staged models were created in which
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Figure D17 (A) Elastic model showin
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Figure D19 (A) Elastic model showin
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• Similar damage zones surroundin
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; ;================================
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change jmat=1 range 0,1564.64 0,156
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crack (845.579,718.676) (787.063,57
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;===plum=== crack (0,355.2371429) (
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crack (866.14,726.44) (838.2,737.61
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crack (838.2,737.616) (815.848,771.
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crack (815.848,771.144) (815.848,78
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;===== define sub block ===========
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E.9 S3:S1 Model for fracture reacti
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yval= abs(z_syy(zi)) xyval= abs(z_s
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and rearranged to , (Equation F4) .
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Such that , (Equation F19) I is the
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title of the thesis - Department of Geology - Queen's University

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