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.

Mining and trading firm Glencore (Xetra: A1JAGV - news ) has seen its share value drop by more than half in the past 12 months, with a 43.4% plunge since May.

Answer: industry