Refer to the input text as context and select the correct relationship between 'El Abra mine' and 'copper' from the available options.
Options: operator, product/material produced, founded by, chief executive officer

SANTIAGO Aug 31 (Reuters) - A Chilean union that represents copper mine workers rejected a move by Freeport-McMoRan Inc to drastically cut staff at its El Abra mine and said on Monday it was considering action.
product/material produced