AuKing Mining Ltd (ASX:AKN) has delivered copper recoveries up to 90% from further metallurgical test-work on ore from Onedin deposit at its Koongie Park Project in Western Australia’s Halls Creek region.
The focus of the latest round of testing has been on the near-surface oxide materials that appear to be dominated by iron oxide/hydroxide due to the heavy weathering profile of the mineralised zone.
The latest test-work has identified:
- Excellent copper recoveries up to 90% from certain ores utilising ammonia leaching.
- Copper and zinc recoveries are not generally affected by particle size.
- In zones of greater iron concentration, copper recoveries improve over time.
- Higher-grade zinc zones are amenable to ammonia leaching, whereas in the lower-grade zinc zones, the mineral is observed to be locked in the weathered iron lattice and more difficult to recover.
- Heap leaching appears to be the most likely metallurgical recovery process for these Onedin materials.
“Earlier in the year, when we identified this heavy level of iron concentration especially in the mineralised oxide zone at Onedin, the ability to achieve economic-scale recoveries appeared challenging,” AuKing chief executive officer Paul Williams said.
“However, this latest program appears to provide AuKing with a sound basis to move into the more substantial test-work activities with a pretty clear processing pathway in mind.
"Of course, there still needs to be more detailed assessment of the treatment solutions across the entire Onedin deposit, but we are now well-placed to proceed with that work.
“As noted previously, the ability to establish a processing solution for Onedin can be an important contributor to the overall Koongie Park development strategy.”
Koongie Park project location featuring key deposits and prospects.
Forward plan
The test results show inconsistency across the mineralised oxide and transition zones at Onedin.
For future detailed test-work, AuKing plans to create a metallurgical solution that has more consistent results.
Also, in the transition ore zone at Onedin, there appears to be very high carbonate content. While this was predicted, future tests will address the optimal recovery processes for material that is heavily dominated by carbonates.
AuKing is planning a major test-work program, which is expected to be implemented shortly.