Pantera Minerals (ASX: PFE) has commenced its first modern drilling campaign at the 100%-owned Gillham Project in southwest Arkansas, targeting high-grade antimony and silver mineralisation beneath historic mine workings.

The programme began on August 18, with approximately 1,500 metres of diamond drilling planned across 10 holes at the Davis, Stewart and May prospects. The campaign is designed to test whether mineralisation identified through Pantera's 2026 surface exploration continues at depth, while also providing geological and structural information to guide follow-up drilling.

Surface sampling has produced high-grade results at the Stewart and May prospects, including rock chips grading up to 19.2% antimony and 63.8g/t silver. A further sample returned 7.55% antimony, 63.8g/t silver, 7.44% lead and 8.6% zinc. Pantera cautioned that the rock chip results are selective samples and should not be considered representative of average mineralisation grades or widths.

Antimony has appeared on the United States Geological Survey's critical minerals list since 2018, reflecting its use in flame retardants, ammunition, lead-acid batteries and glass. The United States has no domestic antimony mine production and meets most of its needs through imports, while China, the world's largest mined-antimony producer with roughly half of global output, imposed export controls on the metal in 2024. That supply backdrop has driven renewed interest in developing antimony sources outside China, including historic districts in the United States such as those Pantera is now testing in Arkansas.

Davis prospect

The Davis prospect provides a separate polymetallic target and contains the largest historical mine workings within the project area. Previous sampling has identified copper, zinc, lead and silver mineralisation, including a sample grading 1.96% copper and 1.465% zinc.

The current drilling is expected to provide the first known modern subsurface test of the Davis system and the broader mineralised structures beneath the historic workings.

Pantera CEO and Executive Chairman Barnaby Egerton-Warburton said the company had now moved from surface exploration to directly testing the system at depth, following the identification of high-grade rock chips, soil anomalies and historical workings.

Project scale

The Gillham Project covers approximately 5,000 acres across the Gillham East and Gillham West areas, containing more than 18 historical antimony and silver workings and mines. Historical mining largely focused on shallow and near-surface mineralisation.

Core from the new drilling will be progressively logged and submitted for assay, with results to be released as they are received and interpreted.

The assay results will be used to update Pantera's geological model and to determine potential follow-up and step-out drilling targets across the Gillham Project.