Before going to Kotzebue, Obama went to Dillingham, home to one of the world's largest sockeye salmon fisheries, where residents are fighting the Pebble Mine copper and gold project that has been proposed by Northern Dynasty Minerals Ltd .
Refer to the input text as context and select the correct relationship between 'Pebble Mine' and 'copper' from the available options.
Options: product/material produced, position held, legal form, chief executive officer