We are developing an Airborne Induced Polarisation system capable of detecting sulphide and other mineral deposits at depths up to 150 m, which is currently being field tested by sponsor Source Geophsiscs.
Project dates: 2011-2016
Key people: Professor James Macnae
Grants and funding: AMIRA International project P1036, P1036a, P1036b (in circulation)
Partners: Industry partner sponsors of the AMIR project: Anglo American (Spectrem Air), Abitibi Geophysics, BHP Billiton, Outer-Rim Developments, Teck-Cominco
The aim of this project is to deliver technology for Airborne Induced Polarisation (AIP) measurements and interpretation. Proprietary studies in the mid 2000’s using available software (program ArjunaAir from P223e and code from the CEMI consortium) independently suggested that porphyries should be detectable to 150 m depth using B field data collected at low frequencies, provided that a transmitter dipole moment exceeded 1 MAm2 and that B field noise levels could be kept below 10 pT at later delay times, or E field measurements be made with sub mV/m accuracy. Since then, theoretical studies by Marchant at UBC, Viezzoli at Aarhus, Kratzer and Macnae at RMIT, and others have confirmed earlier suggestions by Smith and Klein. For example, that AIP may be feasible using dB/dt measurements in limited circumstances
Stages 1 and 2 of P1036 developed key hardware to measure B and E fields, and provide the necessary corrections for rotation noise (changes in coupling to the Earth’s magnetic field that have limited useful AEM to frequencies at or above 25 Hz)). The project has achieved 3 pT noise levels on airborne B field data, with usable 8.33 Hz excitation, and has every prospect of reducing noise levels by an order of magnitude or more. The hardware developments to date thus have met the design specifications of sensitivity for the IP effect in porphyries within 150 m of surface. Airborne hardware suitable for AIP surveying is being constructed by P1036 project sponsor Outer-Rim Developments
The opportunity exists for additional sponsors to join Stage 3 of the P1036b project which will focus on the development of processing and interpretation tools for the hardware already developed. Sponsors will have the opportunity to obtain exclusivity for commercial surveys during the project and for a period after commercial flying commences.