@Mike Street Re: Let me see if I understand this.
"Greens may want to present this as a subsidy, but as the article clearly says, it is a reduction in the amount of extra taxes they would otherwise have paid on income from extraction"
It has nothing to do with Greens, or any type of environmental, political or other persuasion - it is a subsidy in as far as it is an assistance, a help, to the sector (which is what a subsidy is). Whether that is good, or bad, thing is entirely another matter.
"Now, you might believe that paying 25% income tax is equivalent to a government subsidy to you of 75%, but the rest of us believe that it amounts to a 25% tax, not a 75% subsidy. It depends on whether you think all your money belongs to the state or not."
That's not what is happpening here. Here there is a tax levy - and a reduction (or subsidy) is being make on that fiscal requirement, e.g. like being part of a group liable for 25% income tax but you receiving a 10% allowance or subsidy due to certain circumstances - the comparison group is not that of those pay zero tax (and hence you being now a 15% tax payer) but the group you are part of (and so you have a subsidy of 10%). Whether you believe that the tax is a fair rate is, again, nothing to do with whether you receiving assistance is a subsidy or not against the norm of your taxation group.