Blast and Vibration
Blast and vibration monitoring at Cadia is managed in accordance with the Cadia Blast and Vibration Monitoring Program, which was approved by NSW Department of Planning in June 2014.
What we monitor
Ground vibration monitoring
Airblast over pressure monitoring
Vibration monitoring is conducted using the following:
a geophone set to trigger during ground vibration events greater than 0.10mm/s
- will record peak vector sum (PVS mm/s) waveforms; and
a sound level meter or microphone as part of the blast monitor unit and set to trigger on ground vibration events -
- will record air overpressure peak (dB(Linear)) waveforms
Cadia Blasting Schedule
The mining method used at Cadia East is called panel caving, which is a natural caving method which uses ground stresses, rock structures and gravity to break the rock. While a large part of the caving process occurs naturally, some drilling and blasting through the controlled use of explosives is required to break rock for excavation.
Cadia must ensure that blasting does not exceed the relevant conditions and criteria set under the Cadia East Project Approval.
Types of blasting
Preconditioning Blasts
Preconditioning blasting involves fracturing and reducing the overall strength of the rock mass through the use of explosives. We are currently not conducting any preconditioning blasting at the Cadia East Gold Mine. We are also not planning to conduct any preconditioning blasts in the near future. If this changes, prior notice will be provided to near neighbours before blasts recommence.
Development Blasts
Typically, 60 short holes of 5 m are drilled from underground mine workings up to 1400 m below the natural ground surface. The holes are drilled in a precise pattern, filled with explosives and detonated in a controlled manner. These blasts are used in the construction/excavation of tunnels to access the ore body. Vibration from these blasts is generally not felt outside the mining area.
Underground Production Blasts
Typically, 50 short holes of 30 m are drilled in a precise pattern, filled with explosives and blasted in a controlled manner. These blasts are used to create the extraction points, known as draw bells, where underground loaders can access the broken rock from the block/panel cave mining area. These blasts are generally not felt outside the mining area.
Production blasts at Cadia East occur periodically. Ground vibration and noise from each blast is measured by Cadia's blast monitoring network and reported monthly (see Environmental Monitoring).
Cadia is not currently conducting any blasting in its Ridgeway Underground mine as it is in care and maintenance.
Other Blasting
Cadia is not currently conducting any surface blasting at our operations.
Any changes to the blasting schedule will be communicated prior to any changes taking place.
For more information on blasting schedules or blast monitoring results, please contact the Cadia Community Relations & Blasting Hotline.
Community Relations & Blasting Hotline 1800 063 043
To view the approved Cadia Vibration Monitoring Program, click on the link below:
