Poseidon Nickel (ASX: POS) has reported a maiden resource estimate of 675kt grading 0.92% nickel and 683 ppm cobalt for the Silver Swan Tailings dam located at its Black Swan project in Western Australia.
Along with the JORC 2012-compliant MRE, metallurgical test-work was also carried out on four composites selected to represent the four quadrants of the SST dam, which yielded positive results including:
- Ni-recovery of 48% to a rougher flotation concentrate;
- Fe: MgO ratio >10:1;
- excellent repeatability in the results between the composites tested; and
- detailed mineralogy confirmed nickel (primarily as pentlandite) and iron sulphides (pyrrhotite / pyrite) reported to flotation concentrate, while rejecting the majority of the MgO.
Test work underway to blend open-pit ore with tailings product
The company notes that the results supported the concept of co-processing SST with Black Swan Disseminated (BSD) open-pit ore to increase the Fe: MgO ratio, thereby improving product marketability.
“Combining the Silver Swan tails with the Black Swan disseminated ore feed significantly improves the saleability of the Black Swan concentrate product”
The results had revealed that a low proportion of SST was required to be co-processed; and there would be opportunity to improve on the Fe:MgO ratio further by incorporating a cleaner flotation stage.
Consequently, detailed test work is underway to optimise the SST blend, and test the optimal blend ratio with appropriate proportions of the Silver Swan and Golden Swan massive sulphides.
Results support bankable feasibility study
The company noted that the results would support a bankable feasibility study on restarting the Black Swan Concentrator at the 1.1Mpta production rate, due to various positive factors including:
- The SST are already at required grind size for flotation;
- There is low OPEX to reclaim and co-process; and
- The measured resource provides six-years-plus of mining inventory for blending
Water-access agreement to complement production restart
POS reports that it has inked a five-year agreement with Norton Gold Fields Pty Ltd to access large standing water reserves at its Golden Cities and Mulgarrie open cut mines. The access to water would utilise Poseidon’s existing 24km Federal Pit pipeline infrastructure.
The agreement also complements the proposed restart at Black Swan Concentrator and facilitates the potential to ramp-up to nameplate throughput (2.2 Mtpa), subject to availability of ore feed and market conditions.
Poseidon Nickel Managing Director and CEO Peter Harold said: “The Silver Swan Tailings are a low cost, high Fe: MgO ratio ore feed for our “Fill The Mill” strategy.
Combining the Silver Swan tails with the Black Swan disseminated ore feed significantly improves the saleability of the Black Swan concentrate product and will assist with our discussions with potential off-takers as we progress toward a production restart.”
Images: Poseidon Nickel Ltd