Black Horse Mining Progresses Sister Rose Adit Re-establishment Amid Heavy Rainfall, Drilling to Resume in Late 2026

Black Horse Mining’s Exploration Approach and Sister Rose Adit Initiative

Black Horse Mining Ltd (ASX:BHL), based at 10 Endeavour Way, Alfredton, Victoria 3350, is focused on advancing exploration and development at its projects. The Sister Rose Adit re-establishment is a pivotal element of its current exploration program, situated within the broader underground workings that the company is systematically mapping and evaluating.

This project represents a strategic method to enhance subsurface exploration by pinpointing the Sister Rose shaft and accurately mapping historical underground workings. Upon full re-establishment of the adit and shaft location, the data will be integrated into a detailed 3D model of the underground environment. This model is expected to guide future exploration efforts and improve understanding of the project’s mineralisation potential and geometry. Managing Director David Frances emphasized the importance of this phase, stating it "will be instrumental in locating the Sister Rose shaft and accurately pinning down one end of the 3D model."

Completion of Box-Cut and Portal Excavation Despite Adverse Weather

Black Horse Mining confirmed the successful excavation and securing of the Sister Rose Adit’s box-cut and portal, marking a key milestone despite facing exceptionally high rainfall in the region. These weather challenges tested operational capabilities but did not impede the safe completion of excavation works.

Following excavation, meshing and bolting efforts are well underway to reinforce the adit’s roof and walls, ensuring structural integrity and safety. While specific timelines for these safety-critical tasks were not disclosed, the overall adit re-establishment is projected to be finished within three to four weeks from the announcement date of 24 July 2026.

Upgrading Access Tracks for Reliable All-Weather Operations

In response to recent heavy rainfall disruptions, Black Horse Mining is upgrading access tracks at the Sister Rose site to guarantee dependable all-weather access for ongoing exploration activities. This infrastructure enhancement aims to reduce future weather-related interruptions and maintain operational continuity throughout the Australian wet season.

These upgrades reflect a broader industry need for resilient infrastructure in regions prone to seasonal rainfall variability. Managing Director David Frances highlighted this commitment, stating, "significant effort is underway to upgrade access tracks so future programmes can continue uninterrupted, even after heavy rainfall events."

Temporary Drill Rig Demobilisation and Updated Drilling Timeline

Due to heavy rainfall, the company temporarily demobilised its drill rig, pausing drilling operations while restoring access to target zones. This precaution aligns with standard exploration practices prioritizing safety and site accessibility. Drilling is anticipated to recommence in September–October 2026.

The adjusted drilling schedule allows time to complete access restoration and track improvements before resuming subsurface investigations. This phased approach separates underground access works from surface drilling, potentially enhancing efficiency. Details regarding drilling targets, metres planned, or programme duration have not been disclosed, with only the expected restart timeframe provided.

3D Modelling Enhances Underground Workings Understanding and Exploration Planning

A primary goal of re-establishing the Sister Rose Adit is to facilitate precise 3D modelling of the underground workings. Locating the Sister Rose shaft and integrating spatial data will enable accurate positioning of historical underground features in three-dimensional space. This modelling is crucial for modern mineral exploration, aiding geologists in understanding mineralised zone geometry, assessing continuity, and planning targeted drilling with greater confidence.

The 3D model will serve as a foundational reference for future exploration, correlating surface geology with subsurface conditions and identifying priority investigation areas. Anchoring the model at both ends of known workings through the shaft and adit excavation enhances geometric accuracy beyond surface data alone. This approach is especially valuable in historically mined regions, reducing exploration risk by clarifying spatial relationships.

Demonstrating Operational Resilience Amid Challenging Weather

Black Horse Mining’s progress on the Sister Rose Adit re-establishment despite heavy rainfall highlights its operational resilience. The company advanced safety-critical excavation, meshing, and bolting while temporarily demobilising drilling equipment due to weather. This disciplined project management distinguishes activities that can safely continue from those requiring improved access before resuming.

The adit re-establishment is targeted for completion by mid-to-late August 2026, three to four weeks from 24 July 2026. Following this, drilling is planned to restart in September–October. This sequential methodology delivers clear milestones for shareholders and regulators, enhancing transparency on exploration progress.

Industry Trends Driving Underground Exploration and Mapping in Australia

Australian mineral exploration increasingly integrates historical mining data with modern techniques. Many prospective areas have extensive mining histories with underground workings providing direct insights into mineralisation and host rock characteristics. For companies like Black Horse Mining, accessing and mapping these workings offers a cost-effective way to reduce exploration uncertainty and focus drilling on high-probability targets.

Re-establishing historical adits and shafts combines underground engineering, geological mapping, and 3D modelling. With exploration budgets tightening and discovery rates declining globally, explorers seek to maximize information from existing assets. Black Horse Mining’s systematic approach to mapping historical workings aligns with this sector-wide trend toward efficient capital use and integrated data reliance.

Operational Risks and Considerations in Adit Re-establishment

Re-establishing historical underground adits involves inherent safety and operational risks. Excavation requires assessing ground stability, hazards from prior mining, and structural integrity. The company’s focus on meshing and bolting underscores ground stability management as a priority. Weather-related access issues have already impacted operations, prompting track upgrades, though wet season disruptions may persist.

Details on geological conditions encountered, remedial works, or costs have not been disclosed. The drill rig demobilisation due to weather highlights the susceptibility of exploration activities to seasonal rainfall, potentially affecting momentum. Successful completion depends on stable weather and effective track upgrades ensuring reliable access.

Upcoming Milestones and Investor Focus Areas

Black Horse Mining’s immediate priority is completing the adit re-establishment within the three-to-four-week window from 24 July 2026. Investors should watch for updates confirming meshing and bolting completion, successful shaft location and mapping, and availability of 3D spatial data. These will indicate adherence to schedule and provide technical foundations for drilling resumption.

Drilling restart in September–October 2026 marks the next major milestone. Market observers may look for details on drilling parameters, including hole count, locations, metres planned, and targets, to understand how spatial data from the adit will be applied. Progress on track upgrades enabling all-weather access will also be significant, signaling potential for uninterrupted future exploration despite seasonal weather challenges.