Referring to metallic ores or concentrates that have been mined and perhaps crushed, but have not gone through a thermal reduction process. The metal remains chemically bound to oxygen, sulfur, or other elements. It is the baseline feedstock before being charged into a blast furnace, reverberatory furnace, or electrolytic cell.
Heard on the job
We've a stockpile of unsmelted copper sulfide waiting for the roaster to come back online.