A trommel (or trommel screen) is a rotating

A trommel (or trommel screen) is a rotating cylindrical drum with perforated holes, used to separate materials by size, common in mining, recycling, and waste management. As material is fed into the elevated, angled drum, it tumbles, allowing smaller particles to fall through the screen holes onto a conveyor below, while oversized materials travel to the end of the drum for discharge, effectively sorting items like soil, gravel, compost, or solid waste.