Spectral Time Domain IP - Factors Affecting Data Information Content and Applicability to Geological Characterization

A DCIP survey with different timing settings, electrode arrays, cable spreads and waveforms (50% and 100% duty cycle waveform) were carried out over the Liikavaara deposit in northern Sweden. All the measured data were inverted using AarhusInv. Measured data with 100% duty cycle waveform, which is much faster than the conventional 50% duty cycle waveform, present significant improvements in the quality of IP-data. It was also attempted to increase the data quality by separating current and potential cables.

Tau and C parameters from time domain IP were compared in different time bases and spreads. These two parameters appear to be sensitive to the duration of current injections in which; decreasing the time base causes diminished anomalies in Tau and partly in C. Although measurement with separated spreads improved the data quality, it did not have any significant effect on these two parameters. Moreover correlation of sulphide content matched well with the inverted models, which confirms the applicability of the DCIP method in mineral exploration.