That could be why their production cost was so high until after...

That could be why their production cost was so high until after they spent a majority of the $115M USD SCSN on mining and equipment improvements after the DOCA.
The recovery has been good since, they need to mine and process around 6Mt of nickel ore to produce around 15Kt of nickel concentrate so with 100Mt of JORC nickel ore reserves remaining they have around 250Kt of nickel concentrate and the lower they mine the better the grades so this will offset the additional cost of mining the deep ores.