The capex figure was thrown out there by Barry in one of the recent interviews (can't quite remember the one).
MetalsX pegged Nifty's ASIC between $1.60 USD and $1.91 USD for copper cathode, so I believe this figure to be conservative.
Additionally their estimated pre-production capital was between $40 - $60m. We currently have ~$52m.
Regarding the future plans to expand CYM from 20ktpa to 40ktpa and 60ktpa, I believe this has been stated by Barry in interviews as well. Logically, it makes sense given the proximity of Nifty to relatively high grade deposits.
