Excavating machinery is earthmoving equipment that uses a bucket to excavate materials above or below the machine's bearing surface and load them into transport vehicles or unload them at a stockpile. The materials excavated are mainly soil, coal, silt, and pre-loosened rock and ore. Excavating machinery is divided into two categories: single-bucket excavators and multi-bucket excavators.
The earliest excavators were dredgers powered by human or animal power, used for dredging deep riverbeds. Their bucket capacity was generally no more than 0.2–0.3 cubic meters. Between 1833 and 1836, the American Otis designed and manufactured the first steam-powered, iron-wood hybrid, semi-rotary, rail-mounted single-bucket excavator, with a productivity of 35 meters per hour, but it was not adopted due to poor economics. In the 1870s, improved steam shovels were formally produced and used in open-pit mining stripping. In 1880, the first semi-rotary steam shovels based on tractor chassis appeared.
