Tailing/storage dams16 Sep 2021 18:45
Hi swatton.
Firstly they're a downstream storage solution and can be used in a variety of different ways, post ore mining.
Yes, they're one off purchase but like all storage devices they eventually run out of capacity.
HUM's storage dam purchase was the purpose of tighter grade control, to mitigate the effects of mining risks, similar to those they suffered in 2020. Since these dam's have been installed HUM has been mining twice as much material as what's being processed, which partly accounts for the high AISC at the start of 2021. For every tonne of ore processed, 1 tonne has been going to the storage facilities. The idea being is that you get a more accurate measure of grade, which can be drawn upon when needed. As the dams near capacity the AISC will drop away like a stone and should then be a lot less volatile than it has been historically.