In the context of the input sentence, determine the relationship between 'Chuquicamata' and 'copper'.
Options: operator, position held, brand, product/material produced

SANTIAGO, July 28 World no.1 copper miner Codelco halted operations Tuesday at its key Chuquicamata mine as a week-long contract workers' strike intensified, chief executive Nelson Pizarro said.
product/material produced