The Pre-Screening Unit is designed to execute a first screening and thus remove the bigger pieces of material before they are processed on a screening or mixing line. It comprises a hopper section with a conveyor, a vibrating screen box equipped with self-cleaning Grizzly™ fingers, and a collection conveyor. Material is fed into the hopper and transported to the screener. The larger pieces of material float on top of the fingers, and then fall down the chute at the end of the screener to form a reject stockpile. The smaller pieces pass through the screen, are collected by a conveyor, and can then be processed.