Key for me is that the Mt Thirsty / Callisto Sill is a layered ultramafic intrusion (a flat lying sill) so analogous to Bushveld / Stillwater PGE deposits. In these deposits sulphide mineralisation crystallises out from the magma and settles and accumulates in layers sometimes in massive sulphide "beds" like the Merensky Reef or into more disseminated mineralisation like plat reefs, Kevitsa PNRs Lamboo.
Because, different minerals solidify at different temperatures and further because ultramafic magmas are not viscous, as each different type of mineral crystallises out the magama at roughly the same time they can settle through the magma forming layers of almost monomineralic composition which from bottom up are the first minerals to crystallise to top the last minerals to crystallise.
Layers in these types of intrusion are generally of great lateral extent and extend throughout the entire body of the sill.
Sulphides carrying Cu, Cr, Ni, Au and PGMs generally crystallise out of the magma early and therefore accumulate towards the bottom of the sill.
Its therefore a very good bet that if mineralisation is found in one part of the layered intrusion it will extend through out the sill which is why these types of deposit though rare can be absolutely humongous.
They are ore bodies with great predictable and huge continuity
Other plusses:
*With Pd>>Pt in price Callisto is better being Pd rich which it is
*The grade is economic when considering the Ni & Cu credits and maybe Co, Os, Rh- e.g. Kevitsa in Finland Reserves 179MT @ 0.22%Ni, 0.33% Cu, 0.07 g/t Au 0.08 g/t Pt 0.14 Pd & 0.011% Co see
https://www.boliden.com/globalassets/operations/exploration/mineral-resources-and-mineral-reserves-pdf/2020/resources-and-reserves-kevitsa-2020-12-31.pdf* Given we have 33m thickness of mineralisation flat lying under ~130m of barren rock (but with a Nickel-Cobalt laterite resource on top in part) gives a strip of 4:1 OVer what is probably a good substantial area for OP before needing to go underground.
Hope that goes some ways to explain why one hole has been valued so highly.
Look to enter on any weakness.
(20min delay)