3D and 2D radars for open pit slope monitoring Albert Cabrejo, - PowerPoint PPT Presentation

3D and 2D radars for open pit slope monitoring Albert Cabrejo, Product Manager (GroundProbe)

Acknowledgments From GroundProbe: • Patrick Bellett – Principal Scientist • David Noon – VP Sales & Operations From LisaLabs • Davide Leva – Principal Scientist • Carlo Rivolta - CEO

Introduction and Background • Real Aperture Radar (RAR) vs Synthetic Aperture Radar (SAR) • Radar dimensionality – 3D and 2D radars 3D-RAR 2D-SAR 2D-RAR Tactical (targeted) and strategic (broad area) Safety-critical and background monitoring Rapid-brittle and slow-ductile failures Bench-scale, multi-bench scale, total slope failures All radars (3D-RAR, 2D-SAR and 2D-RAR) are capable to monitor all these combinations Each has particular strengths and trade-offs as well • Balanced comparison of 3D-RAR, 2D-SAR and 2D-RAR • Co-authors (Drs Bellett, Leva and Rivolta)

MONITORING STRATEGIES EFFECTIVE USES OF SLOPE STABILITY RADAR

Monitoring Strategies • Monitor known risks and hazards • Highly mobile Targeted • Flexible positioning Monitoring • Safety-critical for small/large rapid- brittle failures • Find new risks and hazards • Often left at crest or mid-slope Broad Area • Longer term Monitoring monitoring • Safety-critical and background for large slow failures

Targeted and Broad Area Monitoring Systems 3D Real Aperture Radar (RAR) 2D Synthetic Aperture Radar (SAR) 2D Real Aperture Radar (RAR) Dish antenna Small antennas on rail Long antennas Pencil beam – small spot on the wall Vertical beam – thin stripe on wall Vertical beam – thin stripe on wall Scans a spot in azimuth and elevation Each stripe segmented by range Each stripe segmented by range Each spot is also sliced in range Fixed view forward Rotates the stripe in azimuth (fast) Highest confidence for targeted area Longest range Broadest area covered per unit of time Highest resolution

3D Radar sees the world in 3D 3D-RAR and generates a radar 3D DTM Elevation° Azimuth°

3D Radar sees the world in 3D 3D-RAR and generates a radar 3D DTM and projects naturally to front view Elevation° Azimuth°

3D-RAR with native front view visualisation

3D-RAR with native 3D visualisation Photograph draped over 3D radar DTM

3D-RAR with native 3D visualisation Deformation image draped over 3D radar DTM

3D-RAR with native 3D visualisation Photograph & deformation image draped over 3D radar DTM

2D-RAR Long antennas Thin, tall, vertical stripe ~0.5 ° wide and ~60 ° tall

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2D Radar with natural plan view image eg. SSR-FX: 60/180 degrees in 2 minutes Azimuth pixels ~ 0.125°/0.5° Range pixels ~ 0.67 m

Broad area monitoring in Plan view 180 ° 180 °

Broad area monitoring in Plan view

Broad area monitoring in Plan view

2D-SAR eg. SSR-SARx bench-scale at 4.5km range Small antennas Horizontal translation The 2D-SAR generates a broad beam that synthesizes narrow beams in a fixed field of view.

Long range monitoring 2D-SAR Tuesday, December 01, 2015 – Commercial in Confidence – 27

Long range monitoring 2D-SAR 2mm over 14 days 5mm over 14 days Tuesday, December 01, 2015 – Commercial in Confidence – 28

Periodic monitoring with 2D-SAR 2 nd periodical check 6-15 september 2015 •

Periodic monitoring with 2D-SAR 1 st PC 2 nd PC Permanent 5mm 60mm monitoring

Conclusions  3D and 2D radars can be used for targeted and broad area monitoring – but each has a strength:  For targeted monitoring of known high risk areas…  3D-RAR provides high confidence for targeted monitoring  Front-view display - users can tactically view the slope as if looking from front-on.  For very broad area monitoring to detect new risk areas …  2D-RAR provides very broad angle coverage quickly  Plan-view display - users can strategically view the slope with reference to other mine geospatial maps (eg. aerial photograph, mine plan, hazards map).

Conclusions  For very long range monitoring …  2D-SAR provides up to 4.5km range over a fixed angle of view  For monitoring slopes with very slow rates of movements…  2D-SAR hardware is easy to relocate and geo-reference so small movements in-between monitoring periods can be measured.  For some mines, an integrated solution using some or all of the available radar monitoring technologies (3D-RAR, 2D- SAR and 2D-RAR) together with non-radar monitoring technologies will provide the most comprehensive monitoring strategy

Safety first Customer focus Innovative solutions Honesty and integrity People matter