Hi SF2TH,
Thanks for your comments and sharing your expertise, I share your frustration with many of our fellow HotCopper pundits claims that "my preferred IAC RE punt is better than yours because mine is the only true ionic clay". As you point out no "IAC" RE deposit is purely ionic, but in my simplified understanding, a mixture of ionic adsorbed (the good stuff, only requiring desorbsion and rinsing with a moderately acidic leachate typically at pH4), colloidal (requiring partial digestion in acids of varying types at lower pH, and marginally economic) and refractory (requiring HPAL cracking, uneconomic at typical IAC grades). What is important to the economics of processing the ore is the ratio of the ionic v. colloidal v. refractory ores.
Thankfully we have been given a heads up as to the proportion of ionic v. colloidal v. refractory in Koppamurra ores by Rick Pobjoy himself in the S****head article 'Not all ionic clay rare earths deposits are created equal' , quoting R.P. "the testing indicates between 20-30% of REEs are in this adsorbed phase at Koppamurra. Including the secondary mineralised phase, 85% of mineralisation can be easily addressed at ambient temperatures and pressures." So from this statement we can infer that Koppamurra ore is 20-30% ionic, 55-65% colloidal and 15% refractory. These figures happen to map nicely across to the optimal <75 micron fraction 'magnet' RE recoveries given in the above AR3 announcement, 20% for 0.3 M MgSO4 @ pH4.0 x 0.5 hours (the ionic absorbed), 60% for 0.3 M MgSO4 @ pH1.0 x 2.0 hours (the colloidal) and the balance of 20% presumably refractory ore.
But the 'ionicness' of an IAC deposit is just one factor in it's overall economics, which include the regular mining metricise of mineralisation, grade, depth, strip ratio, location, product pricing & demand, etc. etc... so while it's a factor it's only one of many that will impact on the economic viability of a project.
Expand
