Discrepancy in Mindoolah Mining Records Raises Questions Over Unreported Gold Stockpiles

Historic Mining Records Mask Potential Gold Inventory

King River Resources Ltd (ASX:KRR) has uncovered a striking discrepancy at its Mindoolah Gold Project in Western Australia’s Murchison Province. Modern LiDAR and volumetric surveys reveal that over one million tonnes of material were physically excavated from historic pits, yet only about 11% of this volume was officially recorded as ore mined between 1986 and 1989. This gap suggests either substantial gold-bearing stockpiles remain on site or historical throughput was significantly underreported.

The company’s detailed volumetric survey identified approximately 467,659 m³ of stockpiled material across key tenements, translating to an estimated 746,000 tonnes. When combined with the volume of open-pit voids, the total excavated material exceeds one million tonnes, far surpassing the 38,589 tonnes documented in official production reports. At the reported historical grade of 2.44 g/t Au, this could represent an unaccounted ~23,500 ounces of gold, though this remains to be validated by forthcoming drilling.

Reassessing Geological Controls and Drilling Strategies

Beyond the stockpile volumes, King River Resources is revisiting the fundamental geology of Mindoolah. The largest pit at the Excelsior Prospect has never been drilled at depth or tested with the correct orientation, leaving a substantial volume of mineralisation unassessed. Similarly, at the Cundy and Bertram’s prospects, structural mapping indicates that high-grade lodes run in orientations previously unrecognised by historical drilling and pit designs, effectively necessitating a geological 'reset' for the project.

This fresh interpretation aligns with selective grab samples returning high-grade gold values, such as 10.0 g/t Au at Excelsior and 31.7 g/t Au at Bertram’s. However, King River cautions that isolated high-grade samples are not representative of average grades and will be part of a systematic evaluation.

The company’s approach builds on its earlier acquisition and exploration activities, including deploying digital mapping and geophysics, as outlined in its April 2026 update, where it emphasized leveraging modern technologies to unlock high-grade targets digital mapping and drilling plans.

June Drilling and Geophysical Campaigns Target Stockpiles and Structural Intersections

King River Resources is advancing rapidly, with a systematic drilling program scheduled to commence in June 2026, aiming to test the grade distribution and economic viability of the vast stockpiles. Complementing this, a high-resolution magnetic survey, delayed but now rescheduled for early June, will refine structural targets beneath key pits, including Excelsior and Mindoolah Main Reef.

Site preparation completed earlier this year has improved accessibility and cleared historical waste dumps, setting the stage for efficient exploration. The integration of LiDAR-derived digital terrain models with geophysical data is expected to enhance targeting accuracy for deep-seated mineralisation.

This exploration strategy follows King River’s earlier deployment of cutting-edge geophysical and digital mapping technologies, which laid the groundwork for this focused drilling and target refinement high-tech exploration.

Multiple Prospects Show Untapped Potential

Each key prospect within Mindoolah presents distinct opportunities. Excelsior, the largest historic open pit, remains underexplored at depth and along structurally significant orientations. Mindoolah Main Reef’s historic underground workings reported impressive grades averaging 11.4 g/t Au, yet east-west drilling remains sparse.

Bertram’s Prospect features structural complexities with mineralisation focused along reverse faults and dyke intrusions, where historical drilling likely underestimated true widths due to suboptimal orientations. Cundy’s open pit and associated stockpiles exhibit limonitic alteration indicative of gold mineralisation but lack systematic sampling. Le Soleil’s historic mining was selective and shallow, with no drilling beneath the pit floor, leaving its depth potential untested.

The company’s comprehensive approach to reassessing these prospects, combined with the volumetric survey findings, signals a potential redefinition of Mindoolah’s scale and value.