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

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

energy (McGarr et al., 1975). Stiff and strong materials such as dykes have been linked to higher rates of seismicity (Gay et al, 1984). The pre-mining stress tensor can be altered significantly in disturbed ground (Jager and Ryder, 1999). Rates of seismicity in South African gold mines are noted to be higher when the rock mass contains significant structure such as faults, dykes and bedding (Durrheim et al, 2006). Faults can provide the large slip surfaces necessary to produce large magnitude events when affected by mining activity (Durrheim et al, 2006). Many large events occur in proximity to both faults and the advancing excavation face (Gay, 1984). There exists a need for a better understanding of the relationship between structure, stress and seismicity (Kaiser et al., 2005). This relationship is crucial for seismic hazard assessment and mitigation, re-entry protocols, improved mine design, planning of mine geometry, and adequate support design. Creighton Mine is used as a study site to explore possible relationships between structure and seismicity. Creighton Mine, located west of Sudbury, Ontario (Fig. 1.1), is a nickel and copper mine operated by Vale Inco. Mining-induced seismicity is a normal part of the mining process at Creighton and occurs regularly as the rock mass adjusts to stresses imposed by blasts, development and rock extraction. The mine hosts numerous shear zones, making it the ideal candidate for studying the relationship between shear zones or local rock anisotropies and seismicity. Large magnitude events in the mine are commonly attributed to fault slip without verification. Seismicity related to shear zones in Creighton Mine as well as interactions between structures are not well understood. Seismicity is frequently linked to geological structure only after large events occur (Kaiser et al., 2005). 2
Figure 1.1: Location of Sudbury and Creighton Mine in Ontario and within the Sudbury Basin. Creighton Mine experiences increasing seismicity with depth as the mine is being deepened to 10,000 feet (3048 m; Vale Inco). Events in Creighton Mine are closely monitored by an array of uniaxial and triaxial accelerometers to observe trends and prevent injury. Dense clusters of microseismic events occur to the south of the 400 Orebody, the main orebody in the lowermost levels Creighton Mine, where important infrastructure (ventilation and refuge stations, for example) exists. To investigate the relationship between structure and seismicity, geological investigations, seismological studies and numerical modelling focusing on shear zones were carried out for the lower portion of the Creighton Deep, which extends from the 6600 foot level (2012 m, 6600L) to the bottom of the mine. Joint characteristics are not considered in this study. For further information the reader is referred to Coulson (1996). Studies were conducted for levels on and below 7400 feet (2255 m), with emphasis on the 7400 Level (7400L). The results of these studies are presented in this thesis. 3
Page 1 and 2: THE INFLUENCES OF STRESS AND STRUCT
Page 3 and 4: esulting in increased stress to the
Page 5 and 6: Table of Contents Abstract.........
Page 7 and 8: 4.6.1 Fracture Reactivation........
Page 9 and 10: List of Figures Figure 1.1: Locatio
Page 11 and 12: Figure 3.23: Preliminary stress inv
Page 13 and 14: Figure B11: Events between Jan 1, 2
Page 15 and 16: List of Tables Table 2.1: Geologica
Page 17: Chapter 1 Introduction 1.1 Backgrou
Page 21 and 22: Chapter 2 Geological Assessment of
Page 23 and 24: ack breccia and sediments later dep
Page 25 and 26: Murray Fault, the principal fault o
Page 27 and 28: 2.2 Local Geology of Creighton Mine
Page 29 and 30: B West East B’ Figure 2.4B: Longi
Page 31 and 32: Table 2.2: Fault systems within the
Page 33 and 34: Table 2.3: Summary of Fault Charact
Page 35 and 36: Figure 2.6: (A) Damage to shotcrete
Page 37 and 38: Figure 2.7: (A) The 1290 Shear Zone
Page 39 and 40: Figure 2.8: Images of (A) the 400-E
Page 41 and 42: Figure 2.9: (A) Photograph of the c
Page 43 and 44: Figure 2.10 (A) Shear foliation, in
Page 45 and 46: Figure 2.11: Thin sections of the F
Page 47 and 48: (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
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Table 3.1: Event characteristics in
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Table 3.3: Summary of relevant para
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) Damage Zone The rock mass in the
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quadrants of dilatation and compres
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Figure 3.12: Lower hemisphere equal
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mechanism shows that over 57% of th
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Figure 3.16: Classification of prin
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Figure 3.18: Contoured P-axis, B-ax
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Figure 3.20: Distribution of double
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This parameter reflects the magnitu
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Figure 3.23: Preliminary stress inv
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Figure 3.25: Equal area stereonet s
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Figure 3.27: (A) Maximum principal
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4.2 Numerical Methods Phase 2 and U
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Stress-strain relationships are use
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Rock mass failure is governed by th
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Figure 4.5: (A) Model for tectonic
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The zero cohesion and low friction
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Figure 4.9: Model of yielding for C
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Figure 4.11: Model of differential
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Figure 4.14: Model of maximum stres
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stress field model. There is little
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clustering are indications of rock
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Figure 4.23: Contoured domains of s
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Figure 4.24: Fracture initiation th
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seismic Cluster 1, which correspond
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contains energetic events and is no
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preferentially oriented fracture pl
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methodologies employed are of value
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References Alcott, J. M., Kaiser, P
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Galkin, V., Mungall, J. (2005). Str
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Mungall, J. E., & Hanley, J. J. (20
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Appendix A Geological Maps and Samp
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A.2 Level Plans with Sample Locatio
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Figure A3: 7400 Level, modified for
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Figure A5: 7680 Level, modified for
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Figure A7: 7940 Ramp, modified from
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MICROSEISMIC EVENTS Source Radius A
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2006 Event Frequency with Depth 600
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B.2 Spatial Distribution of Seismic
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Figure B11: Events between Jan 1, 2
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Page 153 and 154:
Page 155 and 156:
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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