The highwall is the unexcavated face of exposed rock (overburden, ore or coal) in a surface mine.

The working faces of a mine are cut away into benches. Benches are used in open pit mining to control the depth of the blast holes, the slope of the pit walls, and the dangers of highwall surfaces. The benches are basically the flat part of each step; in an open pit mine the steps are part of the staircase type of design that starts from the surface and goes down to the bottom of the pit. Benches can be used as haul roads to accommodate material handling equipment

Figure: Benches as not only safety measures in the mine, but also provide working space and roads for equipment during the life of the mine.

On the edge of each bench or at the edge of a dumping point, a berm is typically constructed by piling dirt and rock. Berms are important for safety, and are commonly required by governments to be at least half as tall as the wheels of the largest machine at the location being mined.

Figure: Berms are required safety structures used to keep equipment and personnel from getting dangerously close to the highwall.