Definition: Unroller, also known as a "mud roller" or "crackling roller," is a type of equipment used in construction and mining to break up and remove large amounts of rock, sand, gravel, or other materials from excavated areas. These machines are typically used on large-scale projects such as mining operations, quarrying, and road construction. The unroller works by creating a frictional force between the material being broken, which can be either small particles like sand or rocks or