Ann: Ammonium Sulphate Test confirms presence of IAC REE, page-69

One big reason why extrusive rhyolites (and sediments on our new tenements) are the best hosts for IREE is that the metals are concentrated at shallower depths than granitoids (plutonic), as evidenced in our assay results. Fine-grained rhyolites and sediments weather much more evenly than granites and capture the REEs at much shallower depths. This means much lower stripping ratios so the mining economics are much better.

Granite weathered crust is mostly sandy, with high content of quartz, feldspar, and other debris, coarse particle size, poor adhesion, and strong water permeability. Rare earth ions are easy to migrate downward, and often occur in the lower part of the completely weathered layer.

On the contrary, the weathering crust of volcanic rock and shallow metamorphic tuff-tuffaceous sandstones is mostly soil-like structure, with less content of clastic particles such as quartz and feldspar, fine particle size, and poor water permeability.