An almond furnace is an early type of refining hearth designed to recover residual metals from sweepings, cinders, and slag. Operators would load the waste material into the furnace and heat it until the trapped metal melted and separated from the non-metallic impurities. It was commonly used in historic mints and silver refineries to minimize material loss.
Heard on the job
The assay report shows enough silver left in the sweepings to justify running them through the almond furnace.