A steam shovel is a large steam-powered excavating machine designed for lifting and moving material such as rock and soil. It is the earliest type of power shovel or excavator. Steam shovels played a major role in public works in the 19th and early 20th century, being key to the construction of railroads and the Panama Canal. The development of simpler, cheaper diesel, gasoline and electric shovels caused steam shovels to fall out of favor in the 1930s.
History
Origins and development
Grimshaw of Boulton & Watt devised the first steam-powered excavator in 1796. In 1833 William Brunton patented another steam-powered excavator which he provided further details on in 1836. The steam shovel was invented by William Otis, who received a patent for his design in 1839. His cousin, Oliver Smith Chapman, continued developing the machine after Otis's death. He obtained the patent and repurchased interests that had been sold by Mr. Otis and obtained more patents. The first machines were known as 'partial-swing', since the boom could not rotate through 360 degrees. They were built on a railway chassis, on which the boiler and movement engines were mounted. The shovel arm and driving engines were mounted at one end of the chassis, which accounts for the limited swing. Bogies with flanged wheels were fitted, and power was taken to the wheels by a chain drive to the axles. Temporary rail tracks were laid by workers where the shovel was expected to work, and repositioned as required. Steam shovels became more popular in the latter half of the nineteenth century. Originally configured with chain hoists, the advent of steel cable in the 1870s allowed for easier rigging to the winches. Later machines were supplied with caterpillar tracks, obviating the need for rails. The full-swing, 360° revolving shovel was developed in England in 1884, and became the preferred format for these machines.
Growth and uses
Expanding railway networks (in the US and the UK) fostered a demand for steam shovels. The extensive mileage of railways, and corresponding volume of material to be moved, forced the technological leap. As a result, steam shovels became commonplace. American manufacturers included the Marion Steam Shovel Company founded in 1884, the Bucyrus Company and the Erie Shovel Company, now owned by Caterpillar. The booming cities in North America used shovels to dig foundations and basements for the early skyscrapers. One hundred and two steam shovels worked in the decade-long dig of the Panama Canal across the Isthmus of Panama. Of these, seventy-seven were built by Bucyrus; the remainder were Marion shovels. These machines 'moved mountains' in their labors. The shovel crews would race to see who could move the most dirt. Steam shovels assisted mining operations: the iron mines of Minnesota, the copper mines of Chile and Montana, placer mines of the Klondike – all had earth-moving equipment. With the burgeoning open-pit mines – first in Bingham Canyon, Utah – shovels became prominent. The shovels removed hillsides. As a result, steam shovels were used globally from Australia to Russia to coal mines in China. Shovels were used for construction, road and quarry work. Steam shovels became widely used in the 1920s in the road-building programs in North America. Thousands of miles of State Highways were built in this era, together with factories and many docks, ports, buildings, and grain elevators.
Successors During the 1930s steam shovels were supplanted by simpler, cheaper diesel-powered excavating shovels that were the forerunners of those in use today. Open-pit mines were electrified at this time. Only after the Second World War, with the advent of robust high-pressure hydraulic hoses, did the more versatile hydraulic excavators take pre-eminence over the cable-hoisting winch shovels. Many steam shovels remained at work on the railways of developing nations until diesel engines supplanted them. Most have since been scrapped. Large, multi-ton mining shovels still use the cable-lift shovel arrangement. In the 1950s and 1960s, Marion Shovel built massive stripping shovels for coal operations in the Eastern US. Shovels of note were the Marion 360, the Marion 5900, and the largest shovel ever built, Marion 6360 The Captain – with a 180-cubic-yard (140 m3) bucket – while Bucyrus constructed one of the most famous monsters: the Big Brutus, the largest still in existence. The GEM of Egypt (GEM standing for "Giant Excavating Machine" and Egypt referring to the Egypt Valley in Belmont County, eastern Ohio where it was first employed), which operated from 1967 to 1988, was of comparable size. It has since been dismantled. Although these big machines are still called steam shovels, they are more correctly known as power shovels since they use electricity to power their winches.
Operation
A steam shovel consists of:
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