Thunder Gold Corp – Tower Mountain Intrusive Complex (TMIC), Thunder Bay, Canada

The Tower Mountain property is located approximately 50 km west of Thunder Bay, Ontario, Canada. Geologically, the property is in the Archean Shebandowan Greenstone Belt, part of the Wawa Abitibi Sub-Province. Gold occurrences are well defined in a multitude of locations within the area and includes three former mines. The northeastern portion of the property is dominated by the TMIC, a multi-phase alkalic intrusion potentially coeval or slightly later than the volcanic host rocks. Alteration is dominantly propylitic (chlorite-epidote) potentially grading to carbonate-K feldspar with a late hematite overprint. Mineralization consists of broadly disseminated gold with a substantial amount of pyrite.

Our solution – 3D Induced Polarization / Resistivity exploration technique for disseminated and massive polarizable mineral occurrences

In 2021, Abitibi Geophysics was commissioned to conduct a resistivity / IP survey using its DasVision 3D IP technology. This ground and borehole distributed array system utilizes independent receivers, avoiding lengthy and troublesome wiring between receivers. Its flexible setup is practical for surveys of large systems at depths over 1000 meters while retaining good resolution and still performing well on shallower targets.

Exploring for intrusion-related gold deposits is challenging due to the complex and heterogeneous nature of these deposits. The success of 3D IP is a combination of electrode configuration, quality of the acquisition, instruments used, inversion, and geological understanding of the target. Abitibi Geophysics designed a DasVision 3D IP survey with three overlapping receiver blocks to investigate the western halo of mineralized rock abutting the TMIC.  The survey resulted in a large density of measurements to a depth of over 700 m for inversion.

Results

The inverted chargeability was recovered to better characterize the position and geometry of anomalous sources. From the resulting resistivity and chargeability model an unexplored highly prospective target was identified by the DasVision 3D IP survey. Thunder Gold’s press release of March 20, 2023, reported that the  drilling campaign intersected 941.0 g/t Au over 1.50 metres with visible gold.

“The results from the first three holes clearly demonstrate the validity of our exploration model and the validity of Induced Polarization (“IP”) as an efficient, accurate, exploration vector.” and “All three holes terminate in mineralization. This new zone, identified by geophysics, offers over 1000 metres of untested strike length and remains open in all directions.” (thundergoldcorp.com/2023/03/20)

3D Chargeability results from the DasVision 3D survey outlining the known Bench Zone at the TMIC and point to a larger extension of the zone at depth.