Altar - It's all about that As

Altar project, has a problem...

Come on babe, I'm about to put it down
And all that As
Go ahead and lock the door, you're about to work it out
And all that As
Won't you lead me to your whoopee spot?
Oh it don't make no sense all of that As you got
'Cause I done called it too that you see booty flu
With all that As

Oh baby all that As

Whip your hair in those stiletto heels
And all that As
I'm about to dress you up in hundred dollar bills
And all that As
Driving me crazy baby don't you pump the brakes
You better call the cops, I'm about to steal the cakes
On all the evidence they got my fingerprints
On all that As

Oh baby all that As

Or visually,

Source: 2013 technical report - Stillwater mining

This shows that there is an ~inverse ratio between As and Cu. So, high-As in the low grade (<0.4% Cu) and lowish As in the high-grade (.0.5%) core. However, we still see that concentrates produced by Altar will probably contain at least 1% As.

Why is this a problem? Penalties - here is a nice article for a few years back from International Mining (link). Highlights:

• China Imposes a limit of 0.5% As on imported base metal concentrates
• Few smelters will treat >1% As and will charge a penalty to do so (link)

It's all about that As