Sharper Grades Confirm Mangaroon’s Corridor of Opportunity

Key Concepts

• Mingabar Shear Zone: A large, crustal-scale structure within a greenstone belt, now confirmed as mineralized with gold.
• Composite Samples: Combining multiple sample intervals (e.g., 3m, 4m) for analysis, which can be less reliable than 1m splits.
• Lithostructural Settings: The geological context – rock types (lithos) and structural features – influencing gold deposition.
• Corridor of Opportunity: A defined area within the Mingabar Shear Zone identified as highly prospective for gold mineralization.
• Greenstone Belt: A zone of ancient, altered volcanic and sedimentary rocks, often associated with significant mineral deposits.

Increased Gold Grades and Expanded Scale at Mingabar

The recent drilling program has demonstrated a significant increase in gold grades, particularly from samples at Hole Two and, notably, Midnight Star North, located approximately 5 kilometers north of Cullins. A 3-meter composite sample from Midnight Star North yielded “quite significant gold,” substantially expanding the known scale of mineralization. This is a key development as previous drilling focused on a very limited area around Cullins dating back to the 1980s. The increase in grade isn’t limited to new locations; overall grades across most holes have also improved.

Challenges and Insights from Composite Sampling

The speaker acknowledges the inherent difficulties with composite sampling methods, stating, “the only thing worse than a 3 meter comp is a 4 meter comp.” While necessary for efficient gold exploration, composite samples are less reliable than 1-meter splits taken directly from the drill core. The comparison between composite results and the higher confidence 1-meter splits underscores the potential for composites to be “dangerous” in interpretation, but simultaneously reinforces the presence of high-grade gold across a considerable area. This highlights the robustness of the system despite sampling limitations.

The Mingabar Shear Zone: A Major Mineralized Structure

The Mingabar Shear Zone is described as a “very large crustal scale structure,” reaching up to 1.5 to 2 kilometers in width and extending over 80 kilometers in strike length within the surrounding greenstone belt. Around the Cullins-Mingabar trend, the structure exhibits bending and interaction with different rock types. The confirmation of “thick and good gold intercepts” along this structure confirms that the Mingabar Shear Zone is a “mineralized” and “well-endowed” geological feature. Critically, almost no prior gold exploration has been conducted along the vast majority of this zone, making it a highly prospective area. The initial drilling at Cullins in the 1980s represented the first exploration within the Mingabar structure itself.

Defining a “Corridor of Opportunity”

The recent results have led the new Chief Geologist, Jamie Robinson, to define a “corridor of opportunity” within the Mingabar Shear Zone. This corridor is understood to contain fluid pathways, and the current focus is on identifying specific locations within the structure where gold deposition is occurring. The strategy involves targeted drilling to pinpoint these areas of gold concentration.

Drilling Program Success Metrics and Future Exploration

The primary measure of success for future drill programs remains “more and better” drill intercepts – thicker and/or higher-grade gold mineralization than previously encountered. However, the focus is expanding beyond individual intercepts to encompass the overall scale of the system. Confirmed gold at Cullins and Midnight Star, coupled with interesting copper-gold-bismuth mineralization at Midday Moon, necessitates testing additional targets within the identified corridor.

Specifically, exploration will focus on understanding different “lithostructural settings” within the corridor. This involves analyzing the interplay between rock types (lithos) and structural features to refine targeting. The ultimate goal is to improve the understanding of the gold system to design more effective and efficient follow-up drill programs, ultimately leading to resource definition and potential discovery. The speaker emphasizes the importance of continuously improving the geological model to optimize drilling efforts.

Notable Quote

“The only thing worse than a 3 meter comp is a 4 meter comp.” – Speaker, highlighting the challenges of composite sampling.

Technical Terms

• Custal Scale Structure: A geological feature extending deep into the Earth's crust.
• Greenstone Belt: An area of ancient, altered volcanic and sedimentary rocks, often associated with mineral deposits.
• Lithos: Refers to the rock types present in a geological setting.
• Strike Length: The distance over which a geological feature (like a shear zone) extends in a specific direction.
• Bismuth: A metallic element often found associated with gold and copper mineralization.