When I spoke to Greg Myles in March . He said they were using a Ni cutoff of 0.25%, but they believed the real financially optimised cutoff was 0.21%. That fits exactly with your comment re-getting it all.
The key will be the metal prices applying.
so here's something Courtesy of Vitamin D on MLX
https://seekingalpha.com/news/3371128-copper-prices-poised-go-on-steroids-citi-analysts-say
Copper prices poised to go 'on steroids,' Citi analysts say
Jul. 18, 2018 12:44 PM ET|By:
Carl Surran, SA News Editor
“
Prepare for a decade of Dr. Copper on steroids,” as the metal’s slump amid a deepening global trade conflict offers a long-term buying opportunity, Citigroup analysts say.
However, note the caveat at the bottom of the article. No-one liked it when I mentioned it before.