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© SRK Consulting (SA) Ltd 2018. All rights reserved.Rock Dynamics and Applications (RocDyn-3)
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ROCKBURSTMANAGEMENTIN
DEEP SOUTHAFRICAN MINES
William Joughin
Shaun Murphy
Lindsay Linzer
Rock Dynamics and Applications © SRK Consulting (SA) Ltd 2018. All rights reserved.
RockDyn-3

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Overview
• Brief introduction to South African
deep mines
• Rockburst support systems
• Mine design
• Support design
• Seismic hazard assessment?

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Witwatersrand Goldfields

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Witwatersrand Geology

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Mining of narrow tabular reefs at depth

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Mining of narrow tabular reefs at depth
Pneumatic hand held drills
and airlegs
Scrapers pulled by winches

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Rockburst support systems (stope)
Engineered timber props (elongates)
Timber packs on gullies
Backfill

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Engineered timber props (elongates)
Backfill

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Backfill
Yielding
support
element
Yield after 2.5 event
Performance during a
seismic event
Footwall/floor
Hangingwall/roof
Total closure
(no backfill)

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Before After 2.8 event
Performance during a seismic event

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Hangingwall failure between support

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Bolts installed in 1m stope height

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High tensile steel netting
Rapid Yielding
Hydraulic Props
Extensions???

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Rockburst support systems (tunnel)

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Chain link (diamond) mesh
and lacing (de-stranded
high tensile hoist rope)

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Failed bolts
(insufficient
energy
absorption)

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Extreme damage

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Tunnel after 2.8 mag. event in
close proximity

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Tunnel support with
circular sets and foam
cement (0.3 MPa strength
– “shock absorber”)

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Tunnel support with
circular sets and foam
cement (0.3 MPa strength
– “shock absorber”)

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Mine Design (layouts)
Mined out
(green)
CLR Planned mining
Planned development
VCR Planned mining
West Section East Section

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Mine Design (limiting span – closure)
ERR = ½ 
Mo  GA

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Mine Design (sequence)

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Support Design (tunnel stress)
Similar to CRH and Martin et. al. 1999

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Support design (geological structures)
Major faults and dykes
Circular sets and
foam cement

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Map PPV due to ML = 1.9 onto
excavation surfaces
PPV
(m/s)
Wesseloo 2012
Ground motion data
Support design (PPV)

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Support design (modelling of PPV)
Malovicho & Basson, 2014
Malovicho, 2017
Adaptation of Salamon-Linkov Method

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Support design (dynamic capacity)

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Support design (dynamic capacity)

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Seismic hazard (daily)
Prediction?

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Seismic hazard (daily)
Traffic light system
Red = withdrawal?

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Acknowledgements
• AngloGold Ashanti
• Australian Centre for Gomechanics (ACG)
• New Concept Mining (NCM)
• Institute of Mine Seismology (IMS)

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