The successful maiden reverse circulation (RC) drilling program at Critical Resources Ltd (ASX:CRR)'s Amoco Gold-Antimony Project in the Armidale region of New South Wales has validated the company’s exploration model, confirming the presence of a substantial mineralised orogenic system. This first round of drilling has outlined broad zones of hydrothermal alteration and strong pathfinder anomalies, providing a solid technical foundation for advancing exploration at Amoco.
Petrological studies of surface rock samples show that the mineralisation at Amoco shares key characteristics with the well-known Hillgrove antimony-gold system. Detailed petrographic analysis of drill samples is now underway to help vector towards potential higher-grade zones within the system. Earlier surface sampling at Amoco returned assays of up to 17.9 g/t gold and 0.7% antimony, and the maiden drilling has highlighted broad mineralisation consistent with a large orogenic gold-antimony system.
Amoco maiden RC drill program with rock samples and major/minor interpreted fault structures (black dashed lines), gold-in-soil contours green (0.5-1 ppb Au) orange (1-2 ppb Au) red (2-3.5 ppb Au) and pink (3.5-21 ppb Au).
Amoco is strategically located about 19km south-east of Larvotto Resources’ Hillgrove Antimony-Gold Project and roughly 14km east of Koonenberry Gold’s Enmore Gold Project, within the fertile New England Fold Belt of NSW, a region with a strong antimony-gold production history and recent exploration success.
Permitting is progressing with the NSW Resource Regulator to allow extended drilling across an approximately 2-kilometre gold-in-soil anomaly. Ongoing work, including further petrographic analysis and structural mapping, is expected to guide the next phase of exploration at the project.
“The confirmation of a substantial orogenic system at Amoco validates our geological model and exploration approach,” Critical Resources managing director Tim Wither said. “The presence of features consistent with Hillgrove-style mineralisation, together with strong pathfinder anomalism and extensive alteration, provides a solid foundation for continued work. We remain focused on systematically advancing our Halls Peak projects in the highly prospective New England Fold Belt, aiming to unlock significant value for our shareholders through targeted exploration.”
Technical and exploration update
Since starting work at Amoco, CRR has progressed the project through geochemical surveys, mapping and a maiden reverse circulation (RC) drilling program.
The initial RC drilling has validated the company’s exploration strategy and geological model, confirming a substantial, fault-controlled orogenic system with strong multi-element anomalism, including gold up to 0.38 g/t Au, silver up to 22.7 g/t Ag, antimony up to 133 ppm Sb, copper up to 0.27%, lead up to 0.46% and zinc up to 0.85%.
Drilling highlights include:
- 1m @ 0.38 g/t Au, 22.7 g/t Ag from 36m (ARC-012)
- 3m @ 0.22 g/t Au, 6.4 g/t Ag, 0.32% Pb, 103 ppm Sb from 21 m, including 1m @ 0.32 g/t Au, 10.1 g/t Ag, 0.46% Pb, 133 ppm Sb from 21 m, within 22 m of hydrothermal alteration from 21–42m (ARC-005)
- 1m @ 0.21 g/t Au from 63 m (ARC-011)
- 1m @ 0.20 g/t Au, 22.2 g/t Ag, 0.17% Cu, 0.34% Pb, 61 ppm Sb, 0.85% Zn from 13m (ARC-004)
Key geological observations are:
- Anomalous arsenic up to 7,020 ppm (0.7%) As, coupled with relatively low base metals (Pb up to 0.46%, Zn up to 0.85%, Cu up to 0.27%), sulphide mineralogy and quartz textures consistent with an orogenic gold system.
- Structurally controlled, hydrothermally emplaced quartz–sulphide mineralisation up to 22 m wide downhole (ARC-005), with open epithermal textures observed.
- Mineralisation hosted in fault-brecciated, fine-grained sedimentary rocks that are intensely altered by heat and fluid flow, typical of orogenic systems capable of hosting high-grade mineralisation.
- The results collectively confirm a substantial orogenic system with strong pathfinder anomalism at Amoco, supporting the company’s exploration model and providing a solid basis for further work.
Next steps
- Petrographic study: Additional petrological work will be carried out on fresh rock samples from the recent drilling. This work will draw on specialist expertise in Hillgrove-style mineral systems to refine the understanding of mineralisation and guide follow-up exploration.
- Target refinement: Ongoing structural mapping and detailed geochemical analysis will focus on identifying and ranking potential feeder zones – areas considered most likely to host higher-grade mineralisation, supported by surface rock samples up to 17.9 g/t Au and 0.7% Sb.
- Follow-up drilling: Planning has commenced for the next phase of drilling, which will be directed at the most prospective structural corridors and surface anomalies defined to date, with the aim of expanding known mineralisation and improving geological understanding.
Permitting for drilling over the secondary gold-in-soil anomaly is progressing with the NSW Resource Regulator. Subject to approval, the next drilling phase will also test deeper targets and potential feeder structures highlighted by ongoing technical work.