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In the grain trade, a grain elevator is a tower containing a bucket elevator or a pneumatic conveyor, which scoops up grain from a lower level and deposits it in a silo or other storage facility. In most cases, the term "grain elevator" also covers the entire elevator complex, including receiving and testing offices, weighbridges, storage facilities etc. It may also mean organizations that operate or control several individual elevators, in different locations. In Australia the term grain elevator refers to the lifting mechanism only (see "usage" below).
Prior to the advent of the grain elevator, grain was usually handled in bags rather than in bulk (large quantities of loose grain). The elevator was invented by a merchant named Joseph Dart and an engineer named Robert Dunbar during 1842–43, in Buffalo, New York. Using the steam-powered flour mills of Oliver Evans as their model, they invented the marine leg, which scooped loose grain out of the hulls of ships and elevated it to the top of a marine tower.
Early grain elevators and bins were often constructed of framed or cribbed wood, and were prone to fire. Grain elevator bins, tanks and silos are now usually constructed of steel or reinforced concrete. Bucket elevators are used to lift grain to a distributor or consignor, from where it falls through spouts and/or conveyors and into one of a number of bins, silos or tanks in a facility. When desired, silos, bins and tanks are emptied by gravity flow, sweep augers and conveyors. As grain is emptied from bins, tanks and silos it is conveyed, blended and weighted into trucks, railroad cars or barges, and shipped to grain wholesalers, exporters and/or local end-users, such as flour mills, breweries and ethanol or alcohol distilleries.
In Australian English, the term "grain elevator" is reserved for elevator towers, while a receival and storage building or complex is distinguished by the formal term receival point or, more commonly, as a "wheat bin". Large-scale grain receival, storage and logistics operations are known in Australia as bulk handling.
In Canada, the term "grain elevator" is used to refer to a place where farmers sell grain into the global grain distribution system, and/or a place where the grain is moved into rail cars or ocean-going ships for transport. Specifically there are several types of grain elevators under Canadian law, defined in the Canadian Grain Act, Section 2.
It was both necessity and the prospect of making a lot of money that gave birth to the steam-powered grain elevator in Buffalo, New York, in 1843. Due to the completion of the Erie Canal in 1825, Buffalo enjoyed a unique position in American geography. It stood at the intersection of two great all-water routes: one extending from New York Harbor, up the Hudson River, to Albany and, beyond it, the Port of Buffalo; the other constituted by the Great Lakes, which could theoretically take boaters in any direction they wished to go (north to Canada, west to Michigan or Wisconsin, south to Toledo and Cleveland, or east to the Atlantic Ocean). All through the 1830s, Buffalo benefited tremendously from its position. In particular, it was the recipient of most of the increasing quantities of grain (mostly wheat) that was being grown on farms in Ohio and Indiana, and shipped on Lake Erie for transshipment to the Erie Canal. If Buffalo hadn't been there, or when things got backed up there, that grain would have been loaded onto boats at Cincinnati and shipped down the Mississippi River to New Orleans.
By 1842, it was clear that Buffalo's port facilities weren't keeping up. They still relied upon techniques that had been in use since the European Middle Ages: work teams of stevedores would use block and tackles and their own backs to unload or load each and every sack of grain that had been stored or was to be stored in the boat's hull. It would take several days, sometimes even a week, to service a single grain-laden boat. Grain shipments were going down the Mississippi River, not over the Great Lakes/Erie Canal system.
A merchant named Joseph Dart, Jr., is generally credited as being the one who adapted Oliver Evans' grain elevator (originally a manufacturing device) for use in a commercial framework (the transshipment of grain in bulk from lakers to canal boats), but the actual design and construction of the world's first steam-powered "grain storage and transfer warehouse" was executed by an engineer named Robert Dunbar. Thanks to the historic "Dart Elevator" (operational on 1 June 1843), which worked almost seven times faster than its non-mechanized predecessors, Buffalo was able to keep pace with — and thus further stimulate — the incredible growth of American agricultural production in the 1840s and 1850s, but especially after the Civil War, with the coming of the railroads.
It wasn't by accident that the world's second and third grain elevators were built in Toledo, Ohio and Brooklyn, New York, in 1847. Fledgling American cities, they were connected through an emerging international grain trade of unprecedented proportions. Grain shipments from farms in Ohio were loaded onto ships by elevators at Toledo; these ships were unloaded by elevators at Buffalo that transshipped their grain to canal boats (and, later, rail cars), which were unloaded by elevators in Brooklyn, where the grain was either distributed to East Coast flour mills or loaded for further transshipment to England, the Netherlands or Germany. But this eastern flow of grain was matched by an equally important flow of people and capital in the "opposite" direction, that is, from East to West. Because of the money to be made in grain production and, of course, because of the very existence of an all-water route to get there, increasing numbers of immigrants in Brooklyn came to Ohio, Indiana and Illinois to become farmers. More farmers meant more prairies turned into farmlands, which in turn meant increased grain production, which of course meant that more grain elevators would have to be built in places like Toledo, Buffalo and Brooklyn (and Cleveland, Chicago and Duluth). It was precisely through this "feedback loop" of productivity — set in motion by the invention of the grain elevator — that America itself became an agricultural and economic colossus on the world stage: the planet's single largest producer of wheat, corn, oats and rice, a distinction it claims to this day.
In the early Twentieth Century, there was concern about monopolistic practices in the grain elevator industry, leading to testimony before the Interstate Commerce Commission in 1906. This led to several grain elevators being burned down in Nebraska, allegedly in protest.
Today, grain elevators are a common sight in the grain-growing areas of the world, such as the North American prairies. Larger terminal elevators are found at distribution centers, such as Chicago and Thunder Bay, Ontario, where grain is sent for processing, or loaded aboard trains or ships to go further afield.
Buffalo, New York, the world's largest grain port from the 1850s until the first half of the 20th century, once had the nation's largest capacity for the storage of grain in over thirty concrete grain elevators located along the inner and outer harbors. While several are still in productive use, many of those that remain are presently idle. In a nascent trend, some of the city's inactive capacity has recently come back online, with an ethanol plant started in 2007 using one of the previously mothballed elevators to store corn. In the early 20th century, Buffalo's grain elevators inspired modernist architects such as Le Corbusier, who exclaimed, "The first fruits of the new age!" when he first saw them. Buffalo's grain elevators have been documented for the Historic American Engineering Record and added to the National Register of Historic Places. Currently, Enid, Oklahoma, holds the title of most grain storage capacity in the United States.
In farming communities, each town had one or more small grain elevators that would serve the local growers. The classic grain elevator was constructed with wooden cribbing and had nine or more larger square or rectangular bins arranged in 3 × 3 or 3 × 4 or 4 × 4 or more patterns. Wooden cribbed elevators usually had a driveway with truck scale and office on one side, a rail line on the other side and additional grain storage annex bins on either side.
In more recent times with improved transportation, centralized and much larger elevators serve many farms. Some of them are quite large. Two elevators in Kansas (one in Hutchinson and one in Wichita) are half a mile long. The loss of the grain elevators from small towns is often considered a great change in their identity, and there are efforts to preserve them as heritage structures. At the same time, many larger grain farms have their own grain handling facilities for storage and loading onto trucks.
Grain elevator operators buy grain from farmers, either for cash or at a contracted price, and then sell futures contracts for the same quantity of grain, usually each day. They profit through the narrowing basis, that is, the difference between the local cash price, and the futures price, that occurs at certain times of the year.
Before economical truck transportation was available, grain elevator operators would sometimes use their purchasing power to control prices. This was especially easy since farmers often had only one elevator that was within a reasonable distance of their farm. This led some governments to take over the administration of grain elevators. An example of this is the Saskatchewan Wheat Pool. For the same reason, many elevators were purchased by cooperatives.
A recent problem with grain elevators is the need to provide separate storage for ordinary and genetically modified grain to reduce the risk of accidental mixing of the two.
In the past, grain elevators sometimes experienced silo explosions. Fine powder from the millions of grains passing through the facility would accumulate and mix with the oxygen in the air. A spark could spread from one floating particle to the other creating a chain reaction that would destroy the entire structure. (This dispersed-fuel explosion is the mechanism behind fuel-air bombs.) To prevent this, elevators have very rigorous rules against smoking or any other open flame. Many elevators also have various devices installed to maximize ventilation, safeguards against overheating in belt conveyors, legs, bearing, and explosion-proof electrical devices such as electric motors, switches and lighting.
Grain elevators in small Canadian communities often had the name of the community painted on two sides of the elevator in large block letters, with the name of the elevator operator emblazoned on the other two sides. This made identification of the community easier for rail operators (and, incidentally, for lost drivers and pilots). The old community name would often remain on an elevator long after the town had either disappeared or been amalgamated into another community; the grain elevator at Ellerslie, Alberta, remained marked with its old community name until it was demolished, which took place more than twenty years after the village had been annexed by the City of Edmonton.
One of the major historical trend in the grain trade has been the closure of many smaller elevators, and the consolidation the grain trade to fewer places and among fewer companies. For example, in 1961 there were 1642 "country elevators" (the smallest type) in Alberta, holding 3,452,240 tonnes (3,397,720 long tons; 3,805,440 short tons) of grain. By 2010 there were only 79 remaining "primary elevators" (as they are now known), holding 1,613,960 tonnes (1,588,470 long tons; 1,779,090 short tons).
The City of Buffalo is not only the birthplace of the modern grain elevator, but has the world's largest number of extant examples. A number of the city's historic elevators are clustered along "Elevator Alley," a narrow stretch of the Buffalo River immediately adjacent to the harbor. The alley runs under Ohio Street and along Childs Street in the city's First Ward neighborhood.
In the early pioneer days of Western Canada's Prairie towns, when a good farming spot being settled, many people wanted to make money by building their own grain elevators, this brought in droves of private grain companies. Towns boasted dozens of elevator companies which all stood in a row along the railway tracks. If a town was lucky enough to have two railways, it was to be known as the next Montreal. In many elevator rows there would be two or more elevators of the same company. Small towns bragged of their large elevator rows in promotional pamphlets to attract settlers. With so much competition in the 1920s consolidation began almost immediately and many small companies were merged or absorbed into larger companies.
In the mid-1990s with the cost of grain so low many private elevator companies once again had to merge. This time causing thousands of "prairie sentinels" to be torn down. Because so many grain elevators have been torn down, Canada has only two surviving elevator rows, one located in Warner, Alberta, and the other in Inglis, Manitoba. The Inglis elevator row has been protected as National Historic Sites of Canada, while the Warner elevator row remains unprotected.
During the Battle of Stalingrad, one particularly well-defended Soviet strong point was known simply as "the Grain Elevator" and was strategically important to both sides.
[File:Graincoop.JPG|thumb|Historic Cooperative Elevator, a row of corrugated steel hopper bottom bins on the left and cribbed annex bins on the right, Crowell, Texas]]
Buffalo, New York
Given a large enough suspension of combustible flour or grain dust in the air, a significant explosion can occur. A famous historical example of the destructive power of grain explosions is the 1878 explosion of the Washburn "A" Mill in Minneapolis, Minnesota, which killed eighteen, leveled two nearby mills, damaged many others and caused a destructive fire that gutted much of the nearby milling district. (The Washburn "A" mill was later rebuilt and continued to be used until it was shut down in 1965.) Another example occurred in 1998, when the DeBruce grain elevator in Wichita, Kansas exploded and killed seven people. The most recent example is an explosion on October 29, 2011 at the Bartlett Grain Company in Atchison, Kansas. The death toll was 6 people. Two more men received severe burns, but the remaining four were not hurt.
Almost any finely-divided organic substance becomes an explosive material when dispersed as an air suspension; hence, a very fine flour is dangerously explosive in air suspension. This poses a significant risk when milling grain to produce flour, so mills go to great lengths to remove sources of sparks. These measures include carefully sifting the grain before it is milled or ground to remove stones which could strike sparks from the millstones, and the use of magnets to remove metallic debris able to strike sparks.
The earliest recorded flour explosion took place in an Italian mill in 1785, but there have been many since. The following two references give numbers of recorded flour and dust explosions in the USA in 1994 and 1997. In the ten-year period up to and including 1997, there were 129 explosions.
During the sixth season of the History Channel series Ax Men, one of the featured crews takes on the job of dismantling the Globe Elevator in Wisconsin. This structure was the largest grain storage facility in the world when it was built in the 1880s.
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