My interpretation:
58% of the gold can go straight to leaching.
The remaining 42% gets flotated first, then to leaching.
Flotation won't recover all the remining gold. Some will still get thrown away.
A higher gold:not-gold ratio lowers the cost of isolating the gold.
The "excellent" result is still measured in grammes per tonne! There's still a lot of not-gold to get rid of.
