On November 6, 2025, the U.S. Interior Department added copper, silver and lead to its final critical minerals list, among 10 new entries. All three are main metals of a polymetallic deposit, where the USGS vein model places them in zones around a single intrusion. Silver shows how closely these metals are linked. The USGS says U.S. silver is "primarily obtained as a byproduct from lead-zinc, copper, and gold mines", and six smaller metals on the infographic reach the market the same way.