Ann: Updated Maroochydore MRE, page-6

Maroochydore is a stranded deposit with significant challenges ahead of it.

Two separate processing options necessary to treat the oxide and sulphide ore. They mention these in the report but push toward the Sulphide processing operation of a concentrator which traditionally will recover just the sulphide portion of the deposit.

Traditionally oxide will be processed and mined first. The challenge Maroochydore has is the copper is hosted inside clay bearing minerals with significant acid consumption rates. Typical Heap leaches operate around 20 -50kg/t Cu produced where as Maroochydore from memory has acid consumption rates up in the 200kg/t basis. With no acid plant onsite and all acid needing to be imported this OPEX cost alone makes processing this ore a challenge as it will be a significant cost impost on the project.
If you try and process this via a tank leach process to reduce residence time and not come up against the clay issues you end up with water balance challenges when it comes to solid liquid separating the slurry from the PLS that make the size of plant large and water demand high. SRL investigated this back in the 2000s and it proved to be problematic when modelled at small scale from memory.

Processing oxide ores in a flotation concentrator is a black art. Its possible but the concentrates produced are not of the quality you get from sulphides, discounts apply as these ores need to get blended if sent for smelting. Using CPS flotation is how you can get around this but no one at CYM or Nifty have done this before so a novel challenging process that will hit alot of naysayers.

There certainly is the Copper present in the ground and with the majority of it being in oxide. Finding a breakthrouh processing solution is the challenge CYM face. Previously it was floated to do an ammonia leach instead of sulphide ore but this is quite unproven in industry and would have a lot of technical risk assocaited with it that most financiers would find it difficult to get past the independent technical reviews to provide them a mandate to finance the project.

Even though I don't hold CYM i have a passing interest in this project as I hold AIS and I would not be surprised if they took an interest in this project if something viable was able to be discovered to make it work.

Aeris Resources Limited (ASX: AIS, formerly Straits Resources Limited) holds certain rights to “buy back up to 50%” into any proposed mine development in
respect of the Maroochydore Project, subject to a payment of 3 times the exploration expenditure contribution that would have been required to maintain its interest in the project