Byrock Copper-Gold Targets Explained

Key Concepts

• Aircore Drilling: A type of drilling used to test the tops of targets, particularly under shallow cover.
• Porphyry Systems: Large, intrusive igneous bodies that can host significant mineral deposits, often containing copper and gold.
• Airborne Magnetic Surveys (Air Mag): Geophysical surveys flown from an aircraft to measure variations in the Earth's magnetic field, used to identify geological structures and potential mineralized zones.
• Ground Gravity Surveys: Geophysical surveys conducted on the ground to measure variations in the Earth's gravitational field, also used for geological interpretation.
• Soil Geochemistry: Analysis of soil samples to detect the presence of indicator elements that may be associated with underlying mineralization.
• Induced Polarization (IP) Surveys: Geophysical surveys that measure the electrical properties of the subsurface, useful for detecting disseminated sulfides.
• Alteration Textures: Changes in the mineralogy and texture of rocks due to hydrothermal processes, indicative of proximity to mineralizing systems.
• Veining: The presence of mineral-filled fractures in rocks, often associated with ore deposits.
• Metal Sulfides: Minerals containing metals combined with sulfur, such as chalcopyrite (copper sulfide).
• McArthur Arc: A significant geological province in Australia known for hosting major porphyry copper-gold deposits.
• Northparkes and Cadia: Major porphyry copper-gold mines located within the McArthur Arc.

Brock Drill Program: Initial Exploration and Target Delineation

The Brock drill program represents a crucial initial drilling phase for the project, building upon extensive prior exploration work. This earlier work included:

• Airborne Magnetic Surveys (Air Mag): Large-scale regional surveys were conducted, followed by detailed magnetic modeling to interpret structural settings.
• Ground Gravity Surveys: Collection of ground gravity data to further refine geological understanding.
• Soil Geochemistry: Analysis of soil samples to identify potential geochemical anomalies.
• Trial Induced Polarization (IP) Surveys: Limited IP surveys were carried out to delineate the specific targets that are now being tested by the current drill program.

The speaker has recently returned from the site where the drill program has commenced, indicating a high level of excitement.

Identification of High-Priority Targets

Seven high-priority targets have been identified through the aforementioned exploration efforts. These targets are characterized by:

• Magnetic Signatures: They exhibit magnetic anomalies, described as "magnetic porphyry-looking targets."
• Structural Setting: Their location within a northwestern segment of the McArthur Arc is considered significant, a segment that has not been previously interpreted as such. The project is believed to be situated under shallow cover.
• Similarities to Known Deposits: The geophysical footprints of these targets bear strong resemblances to those observed at major porphyry systems like Northparkes, specifically referencing E26.

Target T47: A Key Focus

Target T47 is highlighted as a significant large intrusive body. Historical exploration in 1978 by CRA identified the correct type of intrusive rocks in an old drill hole at T47. However, no further work was conducted at this location since then. The current understanding of porphyry systems in Australia, particularly within the McArthur Arc, has advanced considerably since 1978. Notably, major discoveries like Cadia and Northparkes were made after this initial drill hole at T47. The current program sees similarities between the geophysical signatures of T47 and these major porphyry systems.

Aircore Drilling Methodology and Expected Outcomes

The current drill program is employing an aircore rig to test the tops of these seven highest-priority targets. The methodology involves drilling a "fence line of holes" to assess the shallow portions of the identified targets. The key outcomes and indicators being sought from the assay results include:

• Alteration Textures: Evidence of alteration textures that suggest proximity to a porphyry system.
• Veining: Any indication of mineralized veining within the drill core.
• Metal Sulfides: Ideally, the presence of copper sulfides, such as chalcopyrite.
• Geochemical Anomalies: Gold anomalies in the bottom-of-hole samples.

Significance of Positive Results and Future Outlook

While the presence of these indicators is not guaranteed, obtaining evidence of a processed porphyry system underneath the cover would be a significant validation. The company believes that if their interpretation of the northwestern extension of the McArthur Arc is correct, it could represent a major discovery. The ongoing drill program means that significant news flow is anticipated in the near future.

Conclusion and Key Takeaways

The Brock drill program is a critical first step in exploring a project situated in a potentially significant, underexplored northwestern segment of the McArthur Arc. The program is systematically testing seven high-priority targets identified through a comprehensive suite of geophysical and geochemical surveys. The aircore drilling is designed to detect indicators of porphyry systems, such as alteration, veining, and metal sulfides, at the shallow tops of these targets. Positive results would strongly support the company's hypothesis of a major discovery, with considerable news flow expected as assay results become available.