By Andrew Todd
King River Resources has fired up a drone-borne magnetic survey over its recently acquired Mindoolah gold project in Western Australia to unveil the source of its eye-watering historical gold mineralisation with detailed new-age imaging.
The company is utilising modern exploration tech to peer beneath its early 1900’s workings at surface and define priority drill targets for first-pass drilling at the underexplored project.
The project’s allure is rooted in its high-grade history. More than a century ago, mining at Mindoolah delivered a whopping average reported head grade of 19.02 grams per tonne (g/t) gold for more than 5700 ounces from surface workings. Grades like that are rare at surface in WA and immediately flag the area as fertile ground for further gold exploration for King River.
The theory is that the old-timers only scratched the surface, chipping away at just the high-grade quartz reefs they could see, while the larger, primary structures that fed these rich veins remain hidden and untested.
King River Resources managing director Graham Gadsby said: “Historically, exploration here has relied on broad regional magnetic datasets that are heavily obscured by the nearby Weld Range formations. By utilising tight 25m spacing at low altitudes, this modern UAV program allows us to effectively map concealed structures.”
The company’s tenure covers 100 square kilometres of highly prospective greenstone in the burgeoning Murchison goldfields. Management says much of the gold structures in the lease remain underexplored and are under shallow cover, which it believes presents a compelling walk-up exploration opportunity.
The new low-level airborne survey will be flown at a tight 25-metre line spacing to generate a high-resolution magnetic map of the entire project area. This type of survey is crucial for identifying the geological architecture, including cross-cutting faults, shear zones and potential alteration, that is likely to control the obscured and underexplored gold mineralisation.
This latest geophysical campaign has built on a recent sub-audio magnetics (SAM) survey that successfully identified several new anomalies and confirmed the prospectivity of known mineralised gold trends.
The new, broader aeromagnetic data will be integrated with the detailed SAM survey results, along with all historical drilling and geological mapping, to provide a dataset for priority targeting ahead of a maiden drilling campaign.
Gold was initially discovered in the area by a prospector named Bertram. His lease, known as "Bertram's Reward," was the first to operate in the field, with underground operations in the early 1900’s coughing up grades of 11.4g/t gold from the Mindoolah main reef. The project’s other workings at the Mindeloo and Le Soleil mines turned in even better grades north of an eye-watering 30g/t gold.
Adding to the area's prospectivity, the old-timers appear to have stopped mining at around 20 metres depth due to water ingress, barely scratching the surface of what may be a much larger system.
By defining the key structural corridors and their relationship with the known high-grade mineralisation, King River believes it can uncover a significant orebody, potentially the source of the phenomenal historical grades.
The old prospectors at Mindoolah may have done the hard yards with little more than a pick and shovel. Now, armed with a century of geological understanding and cutting-edge exploration tools, King River is looking to finish the job.
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