Miramar Resources Enhances Joy Helen Drill Targets After Successful Auger Drilling at Chain Pool Project, Western Australia

Auger Drilling Campaign Uncovers Significant Copper and Lead Mineralisation at Joy Helen

In May 2026, Miramar Resources conducted a reconnaissance auger drilling program at the Joy Helen prospect targeting subsurface mineralisation and alteration halos beneath soil copper-lead-silver anomalies. The campaign comprised 116 holes across 10 east-west traverses, with vertical depths ranging from 1 to 11 metres and an average depth of 4 metres. Samples were collected at 1-metre intervals and analysed for gold and a multi-element suite focusing on Sedimentary Exhalative (SEDEX) target and pathfinder elements aligned with the company’s base metal exploration strategy.

Hole CPA058 delivered the most notable intersection, recording 3 metres at 1065 ppm copper, 8429 ppm lead, and 1.8 ppm silver. Similarly, hole CPA040 showed coincident copper and lead anomalism over 2 metres with 909 ppm copper and 2974 ppm lead. Both holes are situated adjacent to residual gravity anomalies identified in the company’s recent detailed gravity survey, reinforcing their potential for deeper primary mineralisation typical of SEDEX-style deposits.

Gravity Survey and Auger Data Integration Sharpens Exploration Targeting

The recent gravity survey provided vital structural and geological context for interpreting auger drilling results. At the southern end of the survey line, several auger holes intersected elevated copper and lead values near the most significant residual gravity anomaly located just west of the historic Joy Helen workings. Central to this drill line is a zone of hard silicified dolomite, a rock type commonly linked to SEDEX mineralisation systems, which aligns directly with the gravity anomaly and represents a priority bedrock drill target that was inaccessible to shallow auger drilling.

Geochemical analysis applying the SEDEX "metal index" and "alteration index" framework from Large et al (1998) revealed an extensive alteration halo extending northeast and beyond the highest-grade mineralisation at Joy Helen. This pattern matches the peripheral mineralisation footprint characteristic of SEDEX deposits and offers a vector for locating additional high-grade mineralisation zones within the project area. The combined gravity, auger geochemistry, and geological data have significantly enhanced Miramar’s understanding of Joy Helen’s exploration potential.

New Untested Target 4 Kilometres Northwest Suggests Expansion Opportunity

Miramar identified a previously untested target approximately 4 kilometres northwest of Joy Helen exhibiting geological similarities to the main prospect. Imagery analysis indicates the presence of silicified dolomite at surface in a setting comparable to Joy Helen, with no prior systematic sampling recorded at this location. Managing Director Marion Bush stated the company is "keen to test the drill targets" and "investigating a newly identified target area 4km northwest of Joy Helen, which appears to be previously untested and could substantially increase the potential value of this project."

The company intends to advance this target through a phased exploration approach beginning with reconnaissance rock chip and soil sampling, followed by passive seismic traverses to map basement topography. Depending on initial results, a gravity survey will be conducted to identify further drill targets in this new area. This expansion strategy reflects management’s confidence in the Chain Pool Project’s prospectivity beyond historic workings and the broader Gascoyne region’s potential to host large-scale base metal deposits.

Chain Pool Project Exhibits Key Features of Significant SEDEX Deposit Systems

Joy Helen is located within Miramar’s 100%-owned Chain Pool Project in Western Australia’s Gascoyne region and hosts high-grade copper-lead-silver mineralisation with geological characteristics akin to Sedimentary Exhalative (SEDEX) deposits found in Queensland and the Northern Territory. SEDEX deposits are a major class of base metal mineralisation, typically featuring large tonnages, polymetallic primary mineralisation, and distinctive geochemical and structural signatures. Chain Pool contains essential geological ingredients for SEDEX systems, including the appropriate age, favourable lithology, structural controls, and confirmed high-grade copper-lead-silver mineralisation at Joy Helen.

The occurrence of hard silicified dolomite near gravity anomalies and elevated metal concentrations supports the SEDEX deposit model, as silicification commonly overlies SEDEX mineralisation bodies. Managing Director Marion Bush commented, "Chain Pool has all the key ingredients for a large base metal deposit, including the right age, geology and structural settings, along with direct evidence of high-grade Cu-Pb-Ag mineralisation at Joy Helen." The auger campaign results revealing widespread alteration halos and multiple elevated copper and lead zones suggest the mineralisation system extends well beyond historically mined areas, potentially indicating a large, unexplored deposit.

Upcoming Bedrock Drilling to Target Deeper Mineralisation Zones

Miramar is planning its inaugural dedicated bedrock drilling campaign at Joy Helen, using reverse circulation (RC) and/or diamond drilling to test targets identified from the auger program and gravity survey. The hard silicified dolomite zone west of historic workings, inaccessible to auger drilling, is designated as the priority target for deeper exploration. This area coincides with significant gravity residual anomalies and elevated surface copper-lead values, making it the main focus for initial drilling.

Alongside bedrock drilling, the company will undertake a passive seismic HVSR (Horizontal-to-Vertical Spectral Ratio) survey to better define basement topography and fault structures within the prospect. This geophysical method is valuable for understanding deeper structural controls on mineralisation and pinpointing additional drill targets. Combining drilling with advanced geophysical techniques reflects Miramar’s systematic approach to delineating the geometry and grade distribution of the copper-lead-silver mineralisation at Chain Pool.

Historic Joy Helen Workings Represent Limited Portion of Mineralisation

The historic Joy Helen workings are the only documented mining activity at Chain Pool and serve as the main reference for the prospect’s mineralisation characteristics. However, the recent auger drilling campaign identified significant copper and lead anomalies extending well beyond these workings, indicating that historic mining accessed only a small part of a much larger mineralised system. The presence of extensive alteration halos and widespread geochemical anomalies suggests mineralisation persists across a substantially larger area.

Managing Director Marion Bush emphasized, "This auger drilling campaign was a cost effective and efficient way to further test the potential scale of the mineralisation and alteration outside the main workings at Joy Helen. These new results suggest that the opportunity at Chain Pool could be much larger than indicated by the historic Joy Helen workings." The geochemical footprint from the auger program confirms that metal-bearing zones and alteration features extend significantly in all directions from historic workings, implying a larger primary mineralisation body at depth.

Gidji Joint Venture Project Advances Towards Development Potential

In addition to Chain Pool, Miramar is progressing exploration at the Gidji Joint Venture project, where all drilling data is under review by a resource geologist. The assessment focuses on identifying potential shallow gold resources near the Goldfields Highway, a key infrastructure corridor in Western Australia’s established mining region. The proximity to existing transport infrastructure enhances development feasibility and reduces capital costs for mine access.

Depending on the geologist’s assessment, the company plans to advance Gidji towards potential development, including applying for a Mining Lease. This dual-project strategy combines copper-lead-silver exploration at Chain Pool with gold resource development at Gidji, both situated in established Western Australian mining regions with supportive infrastructure and regulatory frameworks.

Cost-Effective Auger Drilling Provides Valuable Exploration Data

Miramar’s auger drilling campaign at Joy Helen was a cost-efficient method for rapidly assessing subsurface geology over a broad area while generating geochemical data to guide more costly bedrock drilling. Completing 116 holes averaging 4 metres depth across 10 traverses, the company achieved broad coverage with modest expenditure, collecting samples at 1-metre intervals for multi-element analysis. This approach enabled the identification of primary drill targets prior to committing to RC or diamond drilling.

The program’s success in detecting coincident copper-lead anomalies, mapping extensive alteration halos, and confirming hard silicified dolomite in geological positions consistent with the SEDEX model demonstrates its effectiveness. The company described the campaign as "a cost effective and efficient way to further test the potential scale of the mineralisation," highlighting the value of integrating auger geochemistry with gravity survey data and geological mapping to develop a robust targeting framework for deeper mineralisation at Joy Helen and new prospects.

Weathered Dolerite Dyke Encountered in Eastern Survey Area

During the auger campaign, several holes on the eastern survey traverses intersected a weathered dolerite dyke from the 755 million-year-old Mundine Well Suite. These intersections showed anomalous copper and titanium values interpreted as resulting from elemental enrichment through weathering rather than primary mineralisation. This distinction is important as it demonstrates the company’s ability to differentiate between primary SEDEX-related metal concentrations and secondary enrichment from post-mineralisation alteration.

Recognizing that copper and titanium anomalies in the dolerite are weathering-related prevented misinterpretation of background geochemical noise as economic mineralisation. This analytical rigor enhances confidence in positive results from other holes, such as CPA058 and CPA040, which display geochemical signatures and spatial relationships with gravity anomalies consistent with genuine SEDEX mineralisation.