Miners often disclose production of cathode metal. This is metal that has been electro-refined.
This is done by electrolysis (passing an electrical current though a liquid). One terminal, the anode, is made of impure metal. The metal is removed from this and deposited on the other terminal, the cathode.
This process is typically used to improve the purity of the already refined metal, after concentration, smelting and initial refining.
Electro-refining is commonly used in copper production. 99.5% pure refined copper is electro-refined to produce 99.99% pure copper cathode. This is sufficiently pure for most uses such as electrical cables.