A deposit carrying several economic metals at once, most often some combination of zinc, lead, copper, silver and gold.
A mineral deposit containing economically significant quantities of two or more metals, such as copper-gold, zinc-lead-silver, or cobalt-nickel. Polymetallic deposits offer revenue diversification but require more complex metallurgy and processing.
By-product credits can make or break a polymetallic project, and they introduce exposure to metals the company may never mention in its marketing. They are also why equivalence grades exist, and why those grades need reading carefully.
108 terms have their own page: the definition, why it matters to an investor, where it shows up in practice, and the mistake people make with it.