Ann: Phu Lon Nickel Update, Layered Massive Sulphide Intersected, page-10

There's likely to be some Pt-Pd in with the sulphides, these elements will go into the sulphide phase when it first forms. Their levels will depend on the mixing factor (R-factor) of the sulphide to silicate melts. Typically an average ultramafic liquid contains 1-2ppb of Pt, 1-2ppb of Pd, and fractions of other PGE's (Rh-Ir etc). When the first sulphides form, the PGE's partition strongly into the sulphide phase, so that a small percentage of sulphide droplets contain >99% of the PGE. So, say you have 1000 tonnes of melt (ie 1 billion grams), it contains 1 gram of Pt. If you form a sulphide segregation, almost all the PGE's end up in the sulphide. If you form 100kg of sulphide from the 1000t and that sulphide has a chance to touch every other 999,999kg of the silicates, you will have 1 gram of PGE in that 100kg of sulphide. The grade of the sulphide is 10g/t PGE.

Note, this would be a very high tenor sulphide with very efficient mixing. You'd expect that this would be very high in copper and nickel (the sulphides will steal that). Also, it assumes perfect partitioning and mixing.

The other way of achieving this is to get, say, 100,000t of silicate, and wash it over a pool of sulphide liquid, which will achieve the same result.

But the reality of a body of ultramafic like Phu Lon is that if it has a large mass of low-grade disseminated nickel, there hasn't been a lot of mixing going on. So the sulphides will be low tenor in Ni, Cu and PGE's. So, in your sulphide portion the majority of the sulphides will be expected to have 0.5-1% Ni, low Cu (0.1-0.4%?), moderate Co, and low PGE's of maybe a few 100ppb.

If this is then remobilised by shearing and metamorphic and serpentinisation processes (which cause internal deformation, metasomatic remobilisation of sulphides internally, etc; it's a mess) the tenor of the remobilised sulphides tends to be higher than the disseminated sulphides that created them; nickel and copper tenor in shear-hosted sulphides increases greatly because pentlandite, millerite, hazealwoodite are softer than pyrite and pyrrhotite, and will be moved away by shearing.

So, it's a little too early to say much prior to the assays, but in general, I would not expect that there's a lot of PGE's, and there's a high likelihood that these are low tenor nickel sulphides which have probably been upgraded by shearing. That's my prediction, and ready to be wrong.