Ann: MYL Investor Presentation, page-32

Hi Aubin, Arsenic isn't much of a penalty dollars-wise for Ni (or Cu) concs but there is an outright rejection ceiling of 5000ppm (0.5%), which the Chinese enforce, so it's not all that material to value if you stay below that level (MgO attracts a larger penalty from memory). As mentioned, the nickel : arsenic ratio is the key to understanding if As might be a problem for the 5000ppm limit. Kambalda generally has high Ni grade going into low (c. 10 - 12%) concs. So if the recovered grade in ore is around 2% Ni, then you are only concentrating it 6 times, hence on a 1:1 scale up of arsenic with the nickel, the As grade could be 750ppm in ore. Avebury has c.1% Ni going into a high conc grade of up to 19%, hence around 330ppm and above starts to knock on the 5000ppm door.
Traders will take high As concs but at a significant discount (to blend with low As concs). I think Avebury under Oz had a life of mine offtake contract with Jinchuan so that last resort wasn't an option. Not sure if that contract has fallen away.

Cheers
KS
DYOR