For example, NGS Super’s policy excludes investment in companies that make more than 30 per cent of their revenue from thermal coal mining.

As a result, BHP is not excluded because the $US3.5 billion it earned mining thermal coal last financial year only accounted for 6.6 per cent of its total revenue.

I can see a case being made for allowing >0, even if I don't really like it myself.

But 30% is ridiculous. It should be more like 10%, with an additional stipulation on maximum total, so a giant company like BHP which produces billions doesn't get away with it just because they also do a bunch of other stuff.