Ann: Bonanza Grade Platinum Intersection at Phoenix Platinum Zone, page-135

Hi Carillon - sounds like you have experience with PGM deposits.
since the announcement i have been reading a bunch of papers trying to understand whats going on here and as far as i can tell this is not some type of reef deposit. reefs are formed from massive magma chambers that sprawl out laterally over wide areas.
this paper has a pretty neat definition of what Alaskan-type intrusion are, i quote: "The Ural-Alaskan type complexes consist of km-scale, intrusive bodies of dunite, chromitite, wehrlite, clinopyroxenite, amphibole **bro, and hornblendite arranged in a broad concentric zoning. They are believed to have been emplaced as sub-vertical pipe-like bodies" ..."these complexes were products of syn-subduction igneous activity at the root of island-arcs, possibly representing the feeder pipes of andesitic volcanoes."
From what I can tell there is a lot of debate in geological community about the origins of these types of deposits. Alaskan type Pt deposits through secondary mineralisation like alluvial 'placer' deposits were of importance before 1924. From my research it turns out Fifield has been extensively studied in geology circles. as SRL have pointed out the area was a large source of Pt back in the day but only from secondary sources of the platinum at or near-surface. only now do we have the will to assay deep looking for the primary source. exciting times!
ps. the drill holes are angled at 60 degrees from vertical making the 129g/t find ~220m below surface.
Happy to be corrected in any of this information - disclosure i'm an engineer not a geologist. Cheers