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Breaking is done with a hydraulic hammer (also known as a breaker or hoe ram), a percussion hammer fitted to an excavator that is typically used for demolishing concrete structures and is shown in Figure 23. It is used to break up rock in areas where blasting is prohibited due to environmental or other constraints. Like a ripper, a hydraulic hammer can be used in most rock types, although when sculpting a slope face, it works best in soft or moderately to highly fractured rock; existing discontinuities in the rock act as presplit lines, minimizing hammer- induced scars and fractures while creating a slope face that appears to be naturally weathered.
To allow for maximum downward pressure, the hammer is positioned perpendicular to the ground surface as shown in Figure 24. Hammering locations are spaced evenly in a grid-like fashion so that the end rock product is fractured into pieces that can be loaded and hauled. For slope excavations, the hammering angle should be not be parallel to the major discontinuity orientation, as this may cause fractures into the final slope face as Figure 25 shows.
After breaking, the excavated slope can be configured to look like a part of the natural landscape, with the addition of boulders and topsoil and reseeding with native vegetation as Figure 26 shows.