The FMI (Freeport McMoran) Miami plant located in Arizona, USA, was designed to smelt 590,000 tpa of concentrates (165,000 tpa contained copper) and is now producing more than 200,000 tonnes of copper each year.

The ISASMELT™ furnace smelts FMI concentrates together with some purchased materials. These materials are blended in a bedding plant and transferred to concentrate feed bins. The concentrate feed, fluxes and revert material are mixed in a paddle mixer and fed to the furnace. Bath temperature is controlled using natural gas, which is injected down the lance. Process air is enriched to 50% oxygen content. The average lance life is greater than 14 days. The furnace produces a copper matte with a copper content of 60%. The matte and slag are tapped from the furnace and flow into the electric furnace for settling and separation. The slag is granulated while the matte is transferred to Hoboken converters in ladles.

Offgases from the ISASMELT™ furnace pass into a waste heat boiler, prior to passing into an electrostatic precipitator for cleaning. The cleaned gases pass to a sulphuric acid plant for capture of sulphur.