Use of Vibration monitoring at Telfer Mine

All rights reserved Newcrest Mining Ltd 1
Use of
Vibration Monitoring and
Modelling
at Telfer Mine
David Duke
Principal Drill and Blast Engineer

Summary of presentation
•Newcrest Mining overview
•Telfer Open Pit overview.
•Process for vibration control
•Modification process
•Influence on control

Use of Vibration Monitoring and Monitoring at Telfer
Modelling is undertaken for the following purposes;
1. Modelling for blast design process
• Hybrid vibration model design for burden and offset
2. Modelling for vibration limitations
• Self imposed limits on infrastructure and geotechnical issues.
This presentations will focus on the vibration limitations.
The hybrid vibration model will be discussed at a Workshop this
evening due to time limitations.

Telfer Overview
•Large Gold-Copper orebody
•Commenced Open pit in 2003, Mill
2004 and UG in 2006
•Reef and stock works domains in
weakly metamorphosed Proterozoic
sediments that have be deformed by
folding and faulting.
•Reserves onsite will sustain mining to
2023 for the Open pit and 2017 for the
UG
•Milling 20Mtpa through twin train
circuits
•Grades open pit down to 0.5g/t AU and
UG 1.0g/t AU

Telfer - Plan
Mining stages
indicating vibration
control areas
4
7
7W
3
1km

Telfer - Cross Section

Reasons for the program
•Initial work was carried out to understand blasting design
• Assessment for burden and spacing detonator delay timing
• Near field monitoring conducted to evaluate constants for Hybrid
Vibration model
• This work was then utilised for wall control blast optimisation
•Vibration modelling work then used for to allow mining to;
• Enable bigger blasts
• Protection of Pit/UG isolation plugs – ST3
• Protection of Comms tower and UG offices/workshop/power station
– ST4
• Current – reassessment of ST7 mining – high risk to infrastructure
• Portal, Shaft, vent fans, offices, workshops

Critical Infrastructure
•I30 Plug, 5094 Plug, VR2D, VR2D
•Decline, portal etc

Critical areas
4
7
7W
3

Stage 7– Nearby Infrastructure
280m

Stage 7– Nearby Infrastructure
Decline Portal
100m
Shotcrete plant
80m

• Standard formula
Issues
• K and B – long or short term averaging
• Q - based on weight (MIC) not energy release (MJ/ms)
• R – Sophistication of distance, frequency attenuation
.

Trial Blasts
•Require monitoring at different distances and utilising difference sensors
to ensure data is reliable on frequency attenuation
• Near field utilising high frequency sensors
• Far field utilising lower frequency sensors

5300-020 Production
42ms/109ms highly unconfined shot

5300-021 Trim shot
109ms / 42ms with 67 on buffer row

Frequency analysis
•Frequency analysis allowed understanding of transmission of shock
through ground.
• Benefits to allow blasting closer to structure though MIC higher
Slower timing long delays at back Faster timing throughout the shot

Displacement
•Displacement is a function of time and PPV – not just PPV.
•This is critical when blasting near infrastructure onsite.
•Offsite environmental requires compliance to the PPV level.

Explosive
Density
g/cc
Energy
MJ/kg
VOD
m/s
Hole
mm
Charge
kg/m
Total
MJ / m MJ/ms
ANFO 0.8 3.7 4200 102 6.5 24.2 102
T2030 1.1 3.3 3150 102 9.0 29.7 93
T2040 1.3 3.2 2900 102 10.6 34.0 99
T2070 1.1 2.6 4500 102 9.0 23.4 105
T2000 1.25 2.5 4500 102 10.2 25.5 115
Emulsion 1.1 2.8 5000 229 45.3 126.9 634
MJ/ms analysis of explosives

Priming location – Effect on MJ/ms
5m
3m
5m
2m
2m
10m
2m
3m 8m
Center Bottom Nonel Det
Electronic Det
Dt = 5/5000
= 1ms
MJ/ms = 1260
Dt = 8/5000
= 1.6 ms
MJ/ms = 787
Dt = 3/5000
= 0.6ms
MJ/ms = 2100
Dt = 10/5000
= 2ms
MJ/ms = 630

Vibration control - D&B process
•Embedding the system of vibration control at Telfer to ensure use and
compliance.
Design
blast
JK 2D
Simulation
Blast
Approval
Signoff by
RM and MM
Drilled
survey
and
QA/QC
JK 2D
Simulation
on actuals
Comparison
of MIC and
explosives
used
Blast
Actual PPV
compared to
analysis
Database
and sent
report
Monthly
evaluation
Modify
K and b
values

JK 2D Process
•Critical to the evaluation of the MIC of the blast utilised in the Blast
approval.

Video of trim blast
5228-012

Review blast against MIC
• Comparison of MIC and
vibration result
• Need to understand why
there is differences.
• Is it confinement, rock type,
structure
• Does the MIC comply to Blast
approval levels calculated

Blast Approval
• Entire section devoted
to PPV checks against
site limitation.
• Needs considerable
signoff to approve blast

Vibration Analysis

K and B Analysis
• Monthly analysis
• Blast location
• Explosive type
• Monitoring location
• Need to change for
each blast is extreme
accuracy is needed.

K and B Analysis
Stage 3 K B
Vertical 120 -1.1
N/S 458 -1.45
E/W 500
Stage 4
N/S 700 -1.35
E/W 400 -1.28
Stage 7
East 512 -1.52
West 307 -1.24
3
7
4

Effect on Blast – Structural direction
K indicates the confinement
in a blast
B indicates the attenuation
characteristics of the rock

Learnings –
•Understanding of geotechnical and geology.
• Rock properties and structural information critical.
•Assessment of vibration critical to design of blasts
• Undertake trials both near field and far field.
• Include frequency analysis – timing to limit distance
• Review site K and b values on a regular basis and update model.
• Assess structural integrity and consider frequency/displacement.
•Criteria to control
• Blast packet design and planning
• Explosive energy released – Not just MIC
• Consider priming location, consider MJ/ms,
• Initiation point and direction of blasting influence
• Delay timing changes at back of shots greatly influenced wall control
• Use of blast analysis software has been critical.

Summary – How to make the system work
•Training, Education and Knowledge.
• Ensure the technical team understands
•Get ownership from Technical team
• Enviros, Geotechs or D&B?
•Embed the modelling system into D&B Approvals
Getting it right – What cost and what benefit?
• Investment - $60,000, time 2-3 months part time
• Return and benefits – Bigger shots, more ore, better walls, $$$$$

Thankyou all
Questions?

Use of Vibration monitoring at Telfer Mine

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