Smelters will only pay for the contained copper as a % of the LME Copper price (the smelter will not pay 100% of the LME Copper price), so the smelter will not pay a 'premium' for any material containing native copper.
Yes - the smelter may alter the terms of the off-take agreement and this will either negatively or positively impact the NSR back to CDU
As for the smelter requiring the native copper/scrap copper to 'cool' the feed. From a smelter perspective, they will view their input from many perspectives: energy contained (if the smelter is a flash smelter), copper content (higher copper content will allow the smelter to increase unit copper production) etc.
Most smelters are optimised to run a certain feed - and this is what they pursue, blending concentrates to achieve this feed. Smelters will run the proposed concentrate specifications through value in use models in order to work out how they will benefit from the concentrate
CDU Price at posting:
$1.85 Sentiment: None Disclosure: Not Held