ML 23812 Spring Hill Gold Project: Tats Target Round 18 Brownfields Diamond Drilling Collaborations Report

Abstract

This report presents the findings of a 414.4m drill hole (SDH25-004), drilled for PC Gold Ltd with assistance provided by the Northern Territory Government under the Resourcing the Territory Initiative, via the Geophysics and Drilling Collaborations Program, Round 18, 2025-2026. The title of the Brownfields Diamond Drilling Proposal was 'PC Gold Spring Hill Gold Project Tats Target'. The field component of the project, the drilling of Hole SDH25-004, was completed between 7th July 2025 and 13th July 2025. The hole was cored from collar, recovering HQ3-sized core throughout the hole, to 414.4m. The Drilling contractors were DDH1 from Perth, who drilled the hole as part of an ongoing core drilling contract with PC Gold Ltd. Overall the drilling went smoothly with no major delays. The hole was collared at azimuth 240 degrees True and a dip of -55 degrees. The azimuth held well throughout the hole, with the gyro reading at 414.4m of 240.53 degrees True. The hole did however rise steadily throughout, with an EoH dip of - 41.71 degrees. These features have been common to many of the holes drilled at Spring Hill by DDH1. The rationale for the Tat's Target was to test the down-plunge extensions of Vein Heaven and Steve's Gully vein systems; two vein systems identified in early modern exploration at Spring Hill that were partially defined in the early 1990s but have received little attention since. They lie to the north and west of the defined Mineral Resource at Spring Hill but show similar characteristics to the sheeted vein systems at Hong Kong and Macau that host the bulk of the currently defined Resource. The hole was targeted at a zone where they coincide with a discrete magnetic high and the northern edge of an apparent gravity low that lies beneath Spring Hill. It is thought possible that this gravity low, identified in the recent PCO gravity survey, corresponds to a small hot-late intrusive or is a southerly extension of the Prices Springs Granite. SDH25-004 was believed to have been planned to sufficient depth to identify biotite or amphibolite alteration associated with any buried intrusive, which would support the Thermal Aureole Gold / Klominski hot-late Intrusive / Sheeted Vein Type model for gold mineralisation within the PCO. While good veining density was intersected, showing that the Vein Heaven sheeted vein system persists past the previously modelled strike extent of the Vein Heaven system, the hole intersected subdued gold grades. The best mineralised intersection was over the 5m interval from 289m to 294m down hole, which averaged 5m@ 0.467g/t Au. On the positive side, enargite (Cu3AsS4), often observed on the edges of strongly mineralised zones at Spring Hill, was observed on the edges of this zone, adding weight to the conclusion that the hole lifted too much to test the mineralised sections of the Steve's Gully and Vein Heaven sheeted vein systems. In deeper parts of the hole, between 340 and 357m, biotite was found to be present, so the hole was within the biotite isograd surrounding a nearby granite, lending weight to the concept that Spring hill sheeted vein systems are related to Thermal Aureole Gold / Klominski hot-late Intrusive / Sheeted Vein Type model for Gold mineralisation within the PCO. Armed with the knowledge gained from hole SDH20-004, it is now thought most likely that there is a steeper plunge to the core of the Steve's Gully and Vein Heaven system than was anticipated, probably like the steeper plunge to the Hong Kong Zone that could be inferred following the previous Round 15 Collaboration Drillhole into the Hong Kong Deeps. The next steps for the Tats Target will be to evaluate this concept.