Permanent blast monitoring for Fimiston open pit surface blasts was established in 1993 as part of the noise and vibration monitoring program established by KCGM. Ground vibration and airblast overpressure are monitored using Texcel ATM Blast Monitors. There are six monitors permanently installed at sites between the Open Pit and the City of Kalgoorlie-Boulder.
The trigger levels for the Fimiston blast monitors are set at 1 mm/sec for vibration and 114 dB(L) for overpressure. If either of these levels are reached then a result is recorded for the blast event. Ministerial conditions for blast overpressure are set at 125 dB(L) for any one blast, and 120 dB(L) for not more than one in any ten consecutive blasts.
The permanent blast monitoring network was extended by KCGM in 1998 under the direction of experts who assisted with the planning, installation and commissioning of the sites.
Surface ground vibration generated by Mt Charlotte operations are also monitored using Texcel ATM Blast Monitors. There are eight monitors permanently installed at locations around Mt Charlotte. Data from these monitors are used to manage and minimise potential impacts.
KCGM uses this information to re-design the blast and to ensure that the design, which produces the lowest vibrations, is selected. Special explosives and detonators have been manufactured for Mt Charlotte to help minimise blast vibration.