Altitude Pushes Byrock Targets Forward, Nilpinna Drilling in Motion

Key Concepts

• Porphyry Systems: Geological formations associated with the emplacement of igneous intrusions, often hosting valuable mineral deposits like copper and gold.
• Geochron Date: A radiometric dating technique used to determine the absolute age of rocks.
• Intrusive Rock: Igneous rock that formed from magma that cooled and solidified beneath the Earth's surface.
• Porphyry Copper Deposit: A type of copper deposit associated with porphyry intrusions.
• McQuarie Arc: A geological province in New South Wales, Australia, known for its mineral potential.
• Air Core Drilling: A type of drilling used for shallow exploration, typically to depths of 20-30 meters, to collect samples of unconsolidated material.
• Ground Gravity Work: A geophysical survey method that measures variations in the Earth's gravitational field to infer subsurface geological structures.
• Magnetics Survey (Mag Survey): A geophysical survey that measures variations in the Earth's magnetic field to identify magnetic minerals and geological structures.
• Heavy Mineral Sands (HMS): Sedimentary deposits containing a high concentration of dense, valuable minerals such as zircon, ilmenite, rutile, and monazite.
• Zircon: A zirconium silicate mineral, often used in ceramics and as a refractory material, and a valuable component of heavy mineral sands.
• Titanium Minerals: Minerals containing titanium, such as ilmenite (iron titanium oxide) and rutile (titanium dioxide), used in pigments, alloys, and other industrial applications.
• Loxene: Likely a misspelling or colloquial term for rutile or another titanium mineral.
• Ilmenite: An iron titanium oxide mineral, a primary ore of titanium.
• Rutile: A titanium dioxide mineral, a valuable source of titanium.
• Facies Map: A geological map that shows the distribution of different rock types or sedimentary environments.
• Paleo Beach Line: The ancient shoreline of a former body of water, often associated with the concentration of heavy minerals.
• Resource Definition: The process of determining the quantity and quality of a mineral deposit.
• Metallurgy: The science and technology of extracting metals from their ores.
• Permitting: The process of obtaining official approval to undertake a project, especially in mining.

Buck Project: Porphyry Exploration

The Buck project is targeting porphyry systems through new air core (AC) surveys and ground gravity work. Several indicators suggest its potential for hosting the same types of porphyry systems found at Northparkes and Cadia:

• Rock Age: Geochron dating from 1978 drill holes indicates a Benam age of 430 million years, suggesting the presence of rocks of the correct age for porphyry formation.
• Intrusive Rock Type: Previous drilling has identified the correct type of intrusive rock, specifically a more felsic type, which is characteristic of porphyry systems.
• Porphyry-Indicative Veining: One drill hole encountered a porphyry-style vein, suggesting the presence of a porphyry system in the area.
• Geophysical Signatures: Magnetic surveys reveal large, blocky intrusive bodies with smaller, pipelike features ("pencil porphyry" type), which are indicative of porphyry styles seen in the G9 Volcanic Belt and the Molong Volcanic Belt near Cadia.

A key difference at Buck is the shallow cover, estimated at 40 to 100 meters. This limited exploration and may have prevented the area from being recognized as part of the Macquarie Arc. The dual AC and gravity program is expected to provide definitive answers.

Target Prioritization and Drilling Program

The exploration team has systematically narrowed down potential targets:

• Initial Identification: 39 pipelike features were initially identified.
• Selection for Gravity: 19 of these were selected for gravity surveys based on size, depth, logistical feasibility, and magnetic/gravity responses.
• Selection for AC Drilling: This was further reduced to nine targets for AC drilling.
• First Pass Program: Seven targets are planned for the initial drilling program.

Key Drilling Targets:

• T47 Target Area: This area features a larger intrusive body and a cluster of targets (P2, P1, P37, and P38) located around its periphery, suggesting a potential porphyry cluster.
• Beyond Shear Zone: Targets P28 and P7 are located on the other side of a major shear zone, allowing for testing of different parts of the system.

The first seven ranked targets are scheduled for drilling in November.

High-Grade Sample Results and Heavy Mineral Sands Exploration

The representativeness of high-grade surface grab and pan concentrate samples is discussed:

• Nature of Samples: These are not representative of drill hole grades but are crucial for understanding the mineral assemblage and the breakdown of heavy mineral components.
• Indicator of Prospectivity: A high percentage of "trash" minerals (e.g., magnetite, goethite) with few valuable heavy minerals indicates a less prospective area.
• Positive Findings: The grab samples revealed a good heavy mineral sands (HMS) assemblage, including high-value zircon and titanium minerals like rutile, ilmenite, and loxene (likely rutile). Zircon content reached up to 35% in some samples.

Air Core Program for HMS:

The AC program will target areas beneath these surface samples, focusing on magnetic features that could represent ancient beach strands where heavy minerals might have accumulated.

• Drilling Depth: AC drilling will extend to approximately 20 to 30 meters.
• Objective: To identify valuable heavy minerals near the surface, as this is a bulk commodity and shallow deposits are quicker and cheaper to exploit.
• Outcomes: The program aims to obtain initial grade information, build a facies map to understand the paleo beach line and high-energy beach front zones, and clarify the nature of the magnetic features.

The speaker emphasizes that mineral exploration, particularly with AC drilling, is often about defining the most prospective zones by understanding geological processes like paleo beach line formation and high-energy beach environments that concentrate heavy minerals.

Timeline to Resource and Development

The timeline to resource definition and potential development for a heavy mineral sands deposit is presented as relatively quick:

• Resource Drill Out: A resource drill-out for an HMS deposit can be completed in a matter of weeks once a high-grade zone is identified.
• Current AC Program: The ongoing AC program involves 4,000 meters of drilling, expected to take two to two and a half weeks. This could potentially define the start of a small resource.
• Reconnaissance Nature: The current program is described as reconnaissance, covering large areas for facies mapping and targeting magnetic features.
• Metallurgy and Permitting: Resource definition through to potential development involves about a year or two of metallurgical work and permitting.
• Permitting Speed: Permitting for HMS projects is generally quicker than for other commodities because processing does not involve chemicals, relying instead on water and gravity recovery.
• Processing and Transport: Heavy mineral concentrates are processed using water and gravity and then trucked to a major railway line, located a couple of hours drive west, for transport to Adelaide or Darwin.