What is the relationship between 'Codelco' and 'copper' in the context of the input sentence.
Options: product/material produced, position held, developer, director/manager

Earlier in the day, Chilean copper producer Codelco and miner Southern Copper (NYSE: SCCO - news ) saw some spread tightening, with their 2044s and 2042s quoted at 245bp and 370bp, respectively.
product/material produced