Uncertainty Remains as Miramar Starts Shallow Drilling at Chain Pool SEDEX Prospect

Reviving a 60-Year-Old High-Grade Base Metals Target

Miramar Resources Limited (ASX:M2R) has turned the page on more than six decades of dormancy at its Chain Pool Project in Western Australia, commencing auger drilling at the Joy Helen copper-lead-silver prospect. This marks the first active drilling since rotary air blast holes were completed in 1964, reigniting interest in a site that boasts historic workings and exceptionally high-grade mineralisation.

The Joy Helen prospect is notable for its SEDEX (Sedimentary Exhalative) style mineralisation extending over at least 300 metres of strike, with Miramar’s recent rock chip sampling confirming and expanding the known base metal footprint. Samples have returned standout grades including 54.5% lead, 7.23% copper, and up to 73.48g/t silver, underscoring the prospect’s potential to host significant mineralisation beneath shallow cover.

Miramar’s Managing Director, Marion Bush, emphasised the strategic value of this drilling campaign, noting that the auger rig will test three main carbonate alteration halos identified through soil sampling. These halos are geochemical footprints typical of SEDEX deposits, where mineralisation often occurs near surface, making auger drilling an efficient first-pass tool. The program plans approximately 100 shallow vertical holes, aiming to reach depths between 2 and 20 metres, with assay results expected to guide subsequent drilling phases such as aircore or reverse circulation (RC).

Historic Data and Geological Analogues Support Exploration Model

Joy Helen’s mineralisation is hosted in silicified dolomite breccia of the Middle Proterozoic Irregully Formation, with historic shafts and pits revealing lead grades as high as 35% over 2.4 metres and chip samples hitting 23.6% lead alongside significant silver and copper. A 1964 drilling campaign intersected copper and lead mineralisation up to 1.6% and 13.7% respectively, but no systematic exploration has occurred since.

Miramar’s Technical Director Allan Kelly highlighted the geological parallels between Joy Helen and the renowned Lady Loretta SEDEX deposit in Queensland. Both feature zoned carbonate alteration halos adjacent to major growth faults, which are considered key vectors to mineralisation. Soil geochemistry at Chain Pool mirrors this zonation, reinforcing the prospectivity of the area. Moreover, a historic rock chip sample from the nearby Barlee Range Nature Reserve suggests the mineralised system could extend over at least 1 kilometre, with potential parallel zones identified through grid soil sampling due to folding effects.

Chain Pool’s Strategic Location and Diverse Mineralisation Styles

The Chain Pool Project sits at the geological boundary between the Durlacher Supersuite granite and the Edmund Basin, hosts to various mineralisation styles including SEDEX Pb-Zn-Ag, Mississippi Valley Type (MVT) Pb-Zn, and mafic intrusion-hosted Ni-Cu-Co-PGE sulphides. This diversity enhances the exploration upside beyond the Joy Helen prospect alone.

Miramar’s exploration push at Chain Pool follows a series of strategic moves including the recent $1.49 million capital raise that supports accelerated drilling programs across its portfolio. The company has been actively mobilising its drilling team and securing approvals, positioning itself to unlock value from its WA-focused base metals and gold assets. This drilling campaign is a critical step in translating historical data and recent geochemical anomalies into a coherent mineral resource model.

With assay results pending, the market will be watching closely how Miramar’s auger drilling at Chain Pool progresses and whether it can delineate a coherent, high-grade mineralised system worthy of follow-up aircore or RC drilling. The project’s location in the Gascoyne region, combined with its geological setting and historical data, offers a compelling case for discovery potential in a relatively underexplored part of Western Australia.

This drilling initiative builds on the company’s recent efforts to advance the Chain Pool SEDEX prospect, as detailed in the prior mobilisation of drilling team and drilling approval announcement, underscoring Miramar’s commitment to unlocking value from this high-grade base metals project.