Utilize the input text as a context reference, choose the right relationship between Glencore and mining 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.

Glencore shares posted the biggest weekly decline since the company went public in 2011 as the selloff in mining shares showed no signs of slowing.

Answer: industry