Utilize the input text as a context reference, choose the right relationship between Escondida mine and Copper from the options. Options: 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.

Copper is selling for around $2.47 a pound, not far off a six-year low, while BHP's output will also fall next year due to lower grades at its Escondida mine in Chile.

Answer: product_or_material_produced