Tawana Resources NL and Alliance Mineral Assets Limited are pleased to announce encouraging metallurgical test work results from the Bald Hill Lithium and Tantalum Mine in Western Australia.
Test work on ore fines delivered a series of excellent results from both fine dense media separation and flotation, highlighting the potential to increase proposed lithium production during 2018. Bald Hill remains on track to commence commissioning during Q118.
Tawana’s pre-feasibility study showed that 17.8% of lithium ore feed was reporting to fines and 10.3% of ore feed was reporting to middling concentrates. This represents 28.1% of feed containing 29.6% of the contained lithium which is not contained in the PFS production profile, highlighting the significance of the potential production increase.
Some of the highlights from the drilling include the three-stage sighter flotation test returning a recovery to concentrate level of 83%, at a concentrate grade of 4.7% Li2O from feed at P80 passing 0.212mm. DMS test work on 0.3-1mm Fines indicates a range of 71% to 91% recovery of lithium with a concentrate grades of up to 5.3% Li2O. Other assessments indicate that the fine DMS option would be a significantly lower cost, in regards to the second phase option, with the strategy working with the bulk of the combined fines and middlings. According to the company, middlings would be crushed with +1mm material and passed through a small middlings DMS whilst the 0.3-1mm will be passed through a small fine DMS. These two fractions are likely to represent about 20% of total plant feed and 24% of contained Lithium.
The results also reveal the average production rate in the PFS is approximately 150 000tpa of spodumene concentrate. Based on 70% recovery the Phase 2 DMS has the potential to increase spodumene production by 25% with a combined Phase 1 and Phase 2 DMS recovery of about 82.5%. Phase 2 DMS concentrate production would have a relatively low incremental unit cost given most costs are carried by Phase 1 operating costs, including mining, primary crushing and the bulk of the labour and general and administration costs.
Tawana Managing Director Mark Calderwood stated: “The recent test work gives great encouragement that fines and middlings from the DMS under construction can be recovered into a saleable spodumene concentrate, relatively easily. The addition of a fines circuit would increase annual production at a marginal incremental cost which should generate great returns.”