Used mills are available for all different types of industries, such as food, chemical, environmental, pharmaceutical, mining, milling and mineral processing. Milling is utilizing complex machinery to grind and shape solid materials into a different form. Some types of mills include roll mills, ball mills, SAG mills, hammer mills, pebble mills, rod mills and vibrating mills. One of the most popular used mills is the SAG mill.

A SAG mill is a Semi-Autogenous Grinding machine that utilizes steel balls for grinding purposes. When the steel balls are filled in the drum and rotated, it causes a cascading motion within the drum which then causes the breakage of larger rocks. The inside of the drum is lined with lifting plates to carry the steel balls and larger rocks up and around the side of the SAG mill. Once they get to the top, gravity kicks in and they fall back down causing breakage of the material below. SAG mills are primarily used in the gold, copper and platinum industries. A lot of mining and milling industries have shifted their emphasis from ball mills to SAG mills due to its optimization and defined grinding ability.

Historically, used mills were ground by hand, working animals, wind or water. Today they are powered mostly by electricity. Used mills save companies an overwhelming amount of time and money due to decreased human aid. Used grinding mills can run all day and night on electricity alone. Humans cannot physically spend nearly enough time doing what a power-generated machine can do, nor can the grinding be as efficient. Used mills that are powered on electricity will get the job done faster and the grinding will be more precise.