Utilize the input text as a context reference, choose the right relationship between 'Codelco' and 'copper' from the options.
Options: legal form, creator, industry, 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