Shallow excavations up to 6 meters deep are commonly used for site investigations and surveys to study subsurface composition and structure. Excavations less than 2 meters are done by hand, between 2-4 meters use a wheeled backhoe, and 4-6 meters use a hydraulic excavator. Deeper excavations over 6 meters use drilling rig machines, which allow extraction of soils and rocks to greater depths in a faster, easier manner compared to other methods, though they require more skilled labor and are louder.