O’Callaghans
The O’Callaghan’s deposit is a tungsten, copper, lead, and zinc sulphide deposit located within the Telfer Near Mine Project on M45/203 approximately 10km south-southeast of the Telfer mine. The mineralisation occurs as a sub horizontal layer of polymetallic skarn within limestone units within the Proterozoic Puntapunta Formation from a depth of approximately 300m and is up to 60m thick.
The deposit was first discovered in 1985 and has been drilled out to a nominal 100m × 100m drill hole spacing. A small part of the deposit has been infilled to a nominal 50m × 50m drill hole spacing to test the short range geological and grade variability. A total of 184 RC and diamond drill holes have been completed for 71,700m.
- Greatland MRE: 70Mt @ 0.35% WO₃ / 0.30% Cu / 0.57% Zn / 0.28% Pb, for 246kt WO₃, 207kt Cu, 371kt Zn, and 182kt Pb.
- Globally significant deposit: One of the largest high-grade tungsten deposits worldwide, with significant copper, zinc, and lead by-products.
- Ownership & location: 100% owned by Greatland; located 10km south of the Telfer mine (M45/203).
- Confidence & drilling: Well-informed MRE supported by 71,000m of drilling from 184 RC and diamond holes, with >95% of the resource in the Indicated category.
- Historical studies: Previous owners completed technical and economic studies, including a Pre-Feasibility Study demonstrating a viable long-life mining operation.
- Mining & processing: PFS assumed long-hole open stoping with paste fill, truck haulage, standalone 2Mtpa processing facility and APT plant. Flowsheet included sequential flotation (Cu, Pb, Zn, pyrite), magnetic separation, and gravity recovery of tungsten.
- Infrastructure synergy: Strategically close to Telfer, allowing potential sharing of existing non-processing infrastructure.