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

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

zones are planar in geometry, are of uniform strength and are laterally continuous beyond the limits of the mine, though in reality shears may be discontinuous and have variable orientations and properties. Table 4.1: Rock mass and discontinuity model properties Rock mass Properties Discontinuity Properties Property Value Property Value Range Cohesion (C) 10 MPa Cohesion (C) 0-10 MPa Friction Angle (Φ) 35° Friction Angle (Φ) 10-35° Density † (ρ) 2965 kg/m 3 Normal Stiffness †† 700,000 MPa/m Young’s Modulus (E) 35 GPa Shear Stiffness †† 99,400 MPa/m Poisson Ratio (υ) 0.263 Tensile Strength 0-10 MPa Bulk Modulus * (K) 24,613 MPa Shear Modulus * (G) 13,856 MPa σ 1 (E-W) ††† –102.7 MPa σ 3 (N-S) ††† –73.4 MPa * Calculated † Density from Tulk (2001) †† Stiffness values increased to prevent contact overlap in UDEC ††† Maximum and minimum stresses (in plane) calculated from overcoring measurements Two different approaches are used to load the model once the geometry, properties of the material and discontinuities are specified 1. A homogeneous stress field was initiated within the model and at the boundaries 2. Incremental displacements were used to synthesize tectonic loading Methods and results for both loading methods are discussed in the following sections. Boundary conditions for both models are depicted in Figure 4.5. Staged models were also created to better understand the effect of mining on the stress field and induced fault slip. This allowed the rock mass and faults to come to equilibrium without an excavation. UDEC code for the models used in this research can be found in Appendix E. 84
Figure 4.5: (A) Model for tectonic loading. North, south and eastern boundaries are constrained such that motion perpendicular to the plane is restricted. A small eastward boundary velocity, ∆v, is applied to the western model boundary. (B) A homogeneous stress field is applied at the boundaries. All sides are restrained such that motion perpendicular to the plane is restricted. 4.4 Modelling with a Homogeneous Stress Field When a homogeneous stress field is applied, boundary stresses are specified such that σ 1 is oriented east-west and σ 3 is oriented north-south. Models were initiated with internal stresses set equal to the boundary stress conditions. Three cases are presented for the same model geometry to test the sensitivity of the solution to changes in fault strength and boundary conditions. 4.4.1 Case 1: Variable fault strength parameters In the first case, all faults within the model are considered to have the same properties regardless of geology. Four fault strength conditions are tested (Table 4.2). 1) The locked condition indicates that faults are strong, healed and inactive; 2) the strong fault condition indicates that faults are strong and cohesive, yet still weaker than the rock mass; 3) the moderately strong condition implies that faults have previously slipped and have lost cohesion; 4) and lastly, the 85
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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
Page 49 and 50: 2.3.11 Late-Stage Fractures The you
Page 51 and 52: overprinting (Cochrane, 1991; Couls
Page 53 and 54: Table 2.4: Summary of Proterozoic t
Page 55 and 56: Both of these inferred stress direc
Page 57 and 58: are, at this time, in the process o
Page 59 and 60: Microseismic events of this subset
Page 61 and 62: 3.2.1.2 Seismic Energy (E o ) and S
Page 63 and 64: 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: Rock mass failure is governed by th
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 and 116: Figure 4.23: Contoured domains of s
Page 117 and 118: Figure 4.24: Fracture initiation th
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
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Cluster 1 Source Radius Asp. Radius
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Seismic Moment 10.0 9.5 9.0 8.5 8.0
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143 Peak Velocity Parameter -2.5 -2
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B.4.2 Temporal Distribution of Clus
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147 Static Stress Drop 5.0 5.5 6.0
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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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