What is the relationship between Codelco and copper in the context of the input sentence. Choose an answer from: product/material produced; manufacturer; distributed by; industry; position held; original broadcaster; owned by; founded by; distribution format; headquarters location; stock exchange; currency; parent organization; chief executive officer; director/manager; owner of; operator; member of; employer; chairperson; platform; subsidiary; legal form; publisher; developer; brand; business division; location of formation; creator.

Tell me if this is incorrect, that there were negotiations going on with Codelco about maybe making some changes to the long-term contract that you have with them in respect of how the royalty is calculated to maybe give you some better predictability of what happens under highly volatile copper prices.

Answer: product_or_material_produced