A cross-gallery tomographic survey in the New England Antimony Mine

Abstract

The aim of a cross-gallery seismic experiment in the Hillgrove Antimony-Gold Mine (New South Wales) was to find out whether variations in seismic velocities could be related to a known shear zone containing mineralised gold. A further objective was to test simple means of S-wave generation and recording. Using the impact of a 4.5 kg sledge hammer as seismic source, seismic signals containing frequencies above 500 Hz could be produced. P-waves were best recorded on horizontal-component geophones for horizontal impact. Most P-wave onset could be picked with a precision of 0.1 milliseconds. S-waves showed best up on vertical-component recordings of vertical impact shots. However, their onset cannot be easily picked with the same precision as those of P-waves. The resulting P-wave tomogram indicates significant velocity variations. That a straight correlation with the known geology is not possible indicates that the zone of mineralisation is too narrow to be resolved by our experiment.