Undervalued?, page-34

I understand that. That doesn't answer a key question though in considering an impairment reversal, which is:

"what would the deprecIated carrying amount have been had no impairment ever taken place?" You can't reverse more than that value regardless of the valuation of the business or CGU. What I'm suggesting is that due to mining activities and time a fair chunk of that value wouldn't be available for reversal. How much we don't know as it's not disclosed and depreciation would've been a combination of UOP (no doubt largely on reserves with no or limoted resources) and straight line. I'd like to know that value.

Technically speaking if there is a reversal they don't have a choice and would have to book it, if the indicators that gave rise to that impairment subsequently reversed. Whether they do and their auditors force them to is a different matter however.