By-Product Credits Can Push a Silver Mine's Cash Cost Below Zero

Silver continues to experience a prolonged multi-year structural deficit, driven by strong industrial demand from the solar and electronics sectors outstripping mine supply. With spot silver assessed at $66.41 an ounce in late August, market focus is intensifying on the unique economics of polymetallic deposits where silver is extracted alongside base metals such as zinc, lead, and copper. In polymetallic mining operations, substantial revenues generated from by-product credits can exceed total operational expenditures, effectively driving the reported all-in sustaining costs (AISC) for silver below zero. This structural dynamic provides significant margin expansion and changes how capital is deployed across mining projects during commodity upcycles. Furthermore, because the vast majority of global silver production occurs as a secondary by-product rather than from primary silver mines, primary supply response remains exceptionally inelastic despite elevated price levels. As projected deficits persist, miners with existing infrastructure and polymetallic asset bases stand to capture substantial economic rents from tight metal markets.