Which step uses agitation and washing to clean ore and remove fines?

• A. Screening
• B. Sizing
• C. Scrubbing
• D. Dense media separation

Answer: (C)

Scrubbing is the step that uses agitation and water to clean ore surfaces, loosening and washing away fines and adhering material like clay. The mechanical action, often inside a rotating drum or log washer, rubs the ore and breaks up surface coatings, while washing carries the loosened fines away. This cleaning improves mineral liberation and makes downstream steps—such as screening or gravity separation—more effective because the ore is genuinely cleaner and less coated with fines. Screening, in contrast, is about separating particles by size, not cleaning; sizing focuses on achieving a target particle size, and dense media separation uses a heavy liquid to separate by density rather than to wash away fines.