What is the relationship between El Abra mine 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.

SANTIAGO Aug 31 A Chilean union that represents copper mine workers on Monday rejected a move to drastically cut staff at the El Abra mine owned by Freeport-McMoRan and was considering action after 700 workers had their jobs terminated at the weekend.
product_or_material_produced