Utilize the input text as a context reference, choose the right relationship between Debswana 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.

If that is the case, there is little purpose in bringing all four existing mining companies together with the ZMDC in an attempt to form a local Debswana and exploit the diamonds on site.
industry