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

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

Abstract The Creighton Mine is a structurally complex and seismically active mining environment. Microseismic activity occurs daily and increases with depth, complicating downward mine expansion. Larger magnitude events occur less frequently but can damage mine infrastructure, interrupt operations and threaten worker safety. This thesis explores the relationships between geological structure and mining-induced seismicity through geological, seismological and numerical modelling investigations in an area known as the Creighton Deep, with concentration on the 7400 Level (2255 m). Geological features within the Creighton Deep have a reported association with seismic activity. Four families of shear zones were identified during field investigations, the most prominent striking SW and steeply dipping NW. Seismicity from 2006-2007 is analyzed. Spatial and temporal trends and seismic event parameters show little correlation to shear zone geometry. Instead, seismic event parameters correlate to spatial clusters of events. A remote cluster of events to the southwest of the excavation exhibits anomalously high seismic parameter values. This area of the mine continues to be a source of elevated seismicity. Fault plane solutions are utilized to compare shear zone geometry with active slip surfaces. Solutions for macroseismic events are inconsistent, while microseismic event focal mechanisms have similar pressure, tension and null axes. The resulting solutions do not align with shear-zone orientations. A stress inversion using microseismic focal mechanism information yields a stress tensor that is comparable to the regional stress tensor. Universal Distinct Element Code numerical models demonstrate that a yield zone exists immediately surrounding the excavation. SW-striking shear zones modify the stress field, ii
esulting in increased stress to the southeast of the excavation. These high-stress zones are areas of preferred seismic activity. Slip is induced on select SW-striking shear zones to the south of the excavation as well as localized yielding. The characteristics of mining-induced seismicity do not correlate to shear zones. Seismicity does compare to modelled stress: the yielded rock mass adjacent to the excavation has little seismicity; areas of high stress are areas of rock mass damage and dense seismic activity. It is thus proposed that seismicity in the Creighton Deep results from stress-induced rock mass degradation rather than fault-slip. iii
Page 1: THE INFLUENCES OF STRESS AND STRUCT
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 and 18: Chapter 1 Introduction 1.1 Backgrou
Page 19 and 20: Figure 1.1: Location of Sudbury and
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
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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
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located events were removed from cl
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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
Page 151 and 152:
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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Page 177 and 178:
Page 179 and 180:
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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