Dart Mining (ASX:DTM) plans to begin diamond drilling in October to test two deep targets at its Walwa Tin-Tantalum Project in northeast Victoria.
The targets follow Dart’s compilation and verification of 150 historical holes covering 7,672m. The database comprises 78 reverse circulation holes, 59 percussion holes, and 13 diamond holes across the Walwa mine, Mount Alwa South, and Bounce mine areas.
The first target is a potential greisen-hosted tin system above an interpreted felsic intrusion around 400–600m below surface.
The second comprises possible repetitions of shallow-dipping aplite-pegmatite dykes beneath the known mineralisation. Historical seismic work identified another four interpreted dykes measuring at least 4m thick below those previously drilled.
Chairman James Chirnside says the review has improved Dart’s understanding of the broader system.
“Review of historic exploration and mining data from the Walwa tin mine area has greatly enhanced our understanding of the tin mineralisation and has generated two high-priority drilling targets in addition to the large known tin mineralised system,” Chirnside says.
Walwa has recorded historical production of 162 tonnes of tin (Sn).
Historical estimates include 8.64 million tonnes (Mt) @ 0.163% Sn and 50 parts per million (ppm) tantalum pentoxide (Ta₂O₅), alongside a selective ‘higher-grade’ zone of 993,000 tonnes @ 0.38% Sn and 55ppm Ta₂O₅.
Neither estimate was prepared under the JORC Code, and Dart Mining is not treating the figures as current mineral resources or ore reserves.
Historical drilling included 5.1m @ 0.34% tin oxide (SnO₂) from 7.5m and 6.1m @ 0.58% SnO₂ from 35.1m in hole DDH2.
Limitations in the dataset include the absence of downhole surveys, quality-assurance and quality-control records, and sample-recovery information. Assays for 24 shallow percussion holes are also missing.
The October program will test deeper stacked dykes, possible feeder structures, and greisen zones above the interpreted intrusion.
Write to France Pinzon at Mining.com.au
Images: Dart Mining
