What is the relationship between Turquoise Hill Resources and gold in the context of the input sentence. Choose an answer from: 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.

July 15 (Reuters) - A project financing agreement for the underground expansion of Oyu Tolgoi, a massive copper and gold mine in Mongolia, is expected to be signed by year end, mine owner Rio Tinto (LSE: RIO.L - news ) 's Turquoise Hill Resources (Toronto: IVN.TO - news ) unit said on Wednesday.

Answer: product_or_material_produced