As always the devil will be in the details.
At what price will it kick in?
Will it be adjusted to inflation?
Will it be after expenses are deducted?
I personally don't like windfall taxes as the way I see it the government wont be there to help us out if the gold price falls too low so why do they deserve a share when the price goes too high. That being said I think this is already discounted in our share price and so I will be holding on.