Piece of heavy equipment used in civil engineering and surface mining
"Dragline" redirects here. For the album by Paw, see Dragline (album).
Built by Bucyrus-Erie in 1969, Big Muskie was the world's largest ever dragline, being 487ft (148m) in length, weighing some 13,500 short tons (12,247t), and hoisting a 220cuyd (168.2m) bucket that could move 325 short tons (295t) of material at a pass.
A dragline excavator is a heavy-duty excavator used in civil engineering and surface mining. It was invented in 1904, and presented an immediate challenge to the steam shovel (and its diesel and electric powered descendant, the power shovel. Much more efficient than even the largest of the latter, it enjoyed a heyday in extreme size for most of the 20th century, first becoming challenged by more efficient rotary excavators in the 1950s, then superseded by them on the upper end from the 1970s on.
The largest ever walking dragline was Big Muskie, a Bucyrus-Erie 4250-W put online in 1969 that swung a 220cuyd (170m3), 325 ton capacity bucket, had a 310 feet (94m) boom, and weighed 13,500 tons.
The largest walking dragline produced as of 2014 was Joy Global’s digital AC drive control P&H 9020XPC, which has a bucket capacity of 110–160cuyd (84–122m3) and boom lengths ranging from 325–425ft (99–130m); working weights vary between 7,539 and 8,002 tons.[1]
Types
Draglines fall into two broad categories: those that are based on standard, lifting cranes, and the heavy units which have to be built on-site. Most crawler cranes, with an added winch drum on the front, can act as a dragline. These units (like other cranes) are designed to be temporarily dismantled and transported over the road on flatbed trailers. Draglines used in civil engineering are of this smaller, crane type. These are used for road, port construction, pond and canal dredging, and as pile driving rigs. These types are built by crane manufacturers such as Link-Belt and Hyster.
The much larger type which is erected on site is commonly used in strip-mining operations to remove overburden above coal and more recently for oil sands mining. The largest heavy draglines are among the largest mobile land machines ever built, weighing up to 13,500 tons, while the smallest and most common of the site-erected type weigh around 8,000 tons.
A dragline bucket system consists of a large bucket which is suspended from a large truss-like boom (or mast) with wire ropes. The bucket is maneuvered by means of a number of ropes and chains. The hoist rope, powered by large diesel or electric motors, supports the bucket and hoist-coupler assembly from the boom. The dragrope is used to draw the bucket assembly horizontally. By skillful maneuver of the hoist and the dragropes the bucket is controlled for various operations. A schematic of a large dragline bucket system is shown below.
History
The dragline was invented in 1904 by John W. Page (as a partner of the firm Page & Schnable Contracting) for use in digging the Chicago Canal. By 1912, Page realized that building draglines was more lucrative than contracting, so he created the Page Engineering Company to build draglines. Page built its first crude walking dragline in 1923. These used legs operated by rack and pinion on a separate frame that lifted the crane. The body was then pulled forward by chain on a roller track and then lowered again.[2] Page developed the first diesel engines exclusively for dragline application in 1924. Page also invented the arched dragline bucket, a design still commonly used today by draglines from many other manufacturers, and in the 1960s pioneered an archless bucket design. With its walking mechanism badly behind that of competitor Monighan (see below), Page updated their mechanism to an eccentric drive in 1935. This much improved mechanism gave a proper elliptical motion and was used until 1988. Page modernized its draglines further with the 700 series in 1954. Page's largest dragline was the Model 757 delivered to the Obed Mine near Hinton, Alberta in 1983. It featured a 75-yard bucket on a 298-foot boom and an operating weight of 4,500 tons. In 1988, Harnischfeger Corporation (P&H Mining Equipment) purchased Page Engineering Company.
Harnischfeger Corporation was established as P&H Mining in 1884 by Alonzo Pawling and Henry Harnischfeger. In 1914, P&H introduced the world's first gasoline engine powered dragline. In 1988, Page was acquired by Harnischfeger which makes the P&H line of shovels, draglines, and cranes. P&H's largest dragline is the 9030C with a 160-yard bucket and up to a 425-foot boom.
Marion 111-M Dragline in action. (30 seconds)
In 1907, Monighan's Machine Works of Chicago became interested in manufacturing draglines when local contractor John W. Page placed an order for hoisting machinery to install one. In 1908, Monighan changed its name to the Monighan Machine Company. In 1913, a Monighan engineer named Oscar Martinson invented the first walking mechanism for a dragline.[3][4][5] The device, known as the Martinson Tractor, was installed on a Monighan dragline, creating the first walking dragline. This gave Monighan a significant advantage over other draglines and the company prospered. The cam mechanism was further improved in 1925 by eliminating the drag chains for the shoes and changing to a cam wheel running in an oval track. This gave the shoe a proper elliptical motion.[6][7] The first dragline using the new mechanism was the 3-W available in 1926. So popular were these machines that the name Monighan became a generic term for dragline. In the early 1930s, Bucyrus-Erie began purchasing shares of Monighan stock with Monighan's approval. Bucyrus purchased a controlling interest and the joint company became known as Bucyrus-Monighan until the formal merger in 1946. The first walking dragline excavator in the United Kingdom was used at the Wellingborough iron quarry in 1940.[8]
Ransomes & Rapier was founded in 1869 by four engineers to build railway equipment and other heavy works. In 1914 they started building two small Steam shovels as a result of a customer request. The rope operated crowd system they built for this was patented[9] and later sold to Bucyrus. After WWI, demand for excavators increased and in 1924 they reached an agreement to build Marion draglines from 1 to 8 cubic yards capacity. In 1927, they built Type-7 1-yard and Type-460 1.5-yard models. The deal to build Marion machines ended in 1936. R&R began building their own designs with the Type-4120 followed by the 4140 of 3.5 cubic yards. In 1958 the Ramsomes & Rapier division was sold to Newton, Chambers & Co. Ltd of Sheffield, which was combined with their NCK Crane & Excavator division. This became NCK-Rapier. The walking dragline division of NCK-Rapier was acquired by Bucyrus in 1988.
The Marion Power Shovel Company (established in 1880) built its first walking dragline with a simple single-crank mechanism in 1939. Its largest dragline was the 8950 sold to Amax Coal Company in 1973. It featured a 150-cubic yard bucket on a 310-foot boom and weighed 7,300 tons. Marion was acquired by Bucyrus in 1997.
Bucyrus Foundry and Manufacturing Company entered the dragline market in 1910 with the purchase of manufacturing rights for the Heyworth-Newman dragline excavator. Their "Class 14" dragline was introduced in 1911 as the first crawler mounted dragline. In 1912 Bucyrus helped pioneer the use of electricity as a power source for large stripping shovels and draglines used in mining. An Italian company, Fiorentini, produced dragline excavators from 1919 licensed by Bucyrus. After the merger with Monighan in 1946, Bucyrus began producing much larger machines using the Monighan walking mechanism such as the 800 ton 650-B which used a 15-yard bucket. Bucyrus' largest dragline was Big Muskie built for the Ohio Coal Company in 1969. This machine featured a 220-yard bucket on a 450-foot boom and weighed 14,500 tons. Bucyrus was itself acquired by heavy equipment and diesel engine maker, Caterpillar, in 2011. Caterpillar's largest dragline is the 8750 with a 169-yard bucket, 435-foot boom, and 8,350 ton weight.
The market for draglines began shrinking rapidly after the boom of the 1960s and 1970s which led to more mergers. P&H's acquisition of Page in 1988 along with Bucyrus' acquisition of Ransomes & Rapier in 1988 and Marion in 1997 cut the number of worldwide suppliers of heavy draglines by more than half. Today, P&H and Caterpillar are the only remaining manufacturers of large draglines.
Other manufacturers
Heavy Engineering Corporation Limited was the first Indian company to manufacture a walking dragline of 31-yard bucket capacity. HEC makes up to a 44-yard bucket. For comparison, this would be comparable to Caterpillar's Small Draglines 8000 series with a 42-yard bucket. HEC has supplied fifteen draglines to the Indian mining industry.[10]
Operation
Dragline excavator.
In a typical cycle of excavation, the bucket is positioned above the material to be excavated.Mirabediny, H.; Baafi, E. (1 January 1998). "Dragline Digging Methods in Australian Strip Mines – A Survey". Coal Operators' Conference.</ref> The bucket is then lowered and the dragrope is then drawn so that the bucket is dragged along the surface of the material. The bucket is then lifted by using the hoist rope. A swing operation is then performed to move the bucket to the place where the material is to be dumped. The dragrope is then released causing the bucket to tilt and empty. This is called a dump operation.
On crane-type draglines, the bucket can also be 'thrown' by winding up to the jib and then releasing a clutch on the drag cable. This would then swing the bucket like a pendulum. Once the bucket had passed the vertical, the hoist cable would be released thus throwing the bucket. On smaller draglines, a skilled operator could make the bucket land about one-half the length of the jib further away than if it had just been dropped. On larger draglines, this is not a common practice.
Draglines in mining
Dragline excavating coal in Australia
A large dragline system used in the open pit mining industry costs approximately US$50–100 million. A typical bucket has a volume ranging from 40 to 80 cubic yards (30 to 60 cubic metres), though extremely large buckets have ranged up to 220 cubic yards (168 cubic meters).[11] The length of the boom ranges from 45 to 100 metres (148 to 328ft). In a single cycle, it can move up to 450 tons of material.
Most mining draglines are not diesel-powered like most other mining equipment. Their power consumption on order of several megawatts is so great[quantify] that they have a direct connection to the high-voltage grid at voltages of between 6.6 and 22kV. A typical[further explanation needed] dragline weighing 4000 to 6000 tons, with a 55-cubic-metre bucket, can use up to 6megawatts during normal digging operations. Because of this, many (possibly apocryphal) stories[example needed] have been told about the blackout-causing effects of mining draglines. For instance, there is a long-lived story[according to whom?] that, back in the 1970s, if all seven draglines at Peak Downs Mine (a very large BHP coal mine in central Queensland, Australia) turned simultaneously, they would black out all of North Queensland. However even now,[when?] if they have been shut down, they are always restarted one at a time due to the immense power requirements of startup.[citation needed]
"Walking" dragline animation based on Martinson's patent of 1926
In all but the smallest of draglines, movement is accomplished by "walking" using feet or pontoons, as caterpillar tracks place too much pressure on the ground, and have great difficulty under the immense weight of the dragline. Maximum speed is only at most a few metres per minute,[12] since the feet must be repositioned for each step.[13] If travelling medium distances (about 30–100km), a special dragline carrier can be brought in to transport the dragline. Above that distance, disassembly is generally required. But mining draglines due to their reach can work a large area from one position and do not need to constantly move along the face like smaller machines.
Limitations
The primary limitations of draglines are their boom height and boom length, which limits where the dragline can dump the waste material. Another primary limitation is their dig depth, which is limited by the length of rope the dragline can utilize. Inherent with their construction, a dragline is most efficient excavating material below the level of their base. While a dragline can dig above itself, it does so inefficiently and is not suitable to load piled up material (as a rope shovel or wheel loader can).
Despite their limitations, and their extremely high capital cost, draglines remain popular with many mines, due to their reliability, and extremely low waste removal cost.
Notable examples
The walking mechanism on a preserved Bucyrus-Erie 1150 dragline in the UK
This section needs expansionwith: more of the largest dragline examples, ideally in an easy to reference table as in the Power Shovel page. You can help by adding to it. (February 2024)
The coal mining dragline known as Big Muskie, owned by the Central Ohio Coal Company (a division of American Electric Power), was the world's largest mobile earth-moving machine, weighing 13,500 tons and standing nearly 22 stories tall.[14] It operated in Muskingum County, in the U.S. state of Ohio from 1969 to 1991, and derived power from a 13,800 volt electrical supply. It was dismantled for $700,000 worth of recycled metal in 1999.
The British firm of Ransomes & Rapier produced a few diesel-electric excavators rather over 1/10th its size, the largest in Europe in the 1960s at 1400-1800 tons. One, named SUNDEW, was used in a quarry from 1957 to 1974. After its working life at the first site in Rutland wrapped it walked 13 miles (21km) in 9 weeks to Corby, where it continued on till being scrapped from January to June 1987.
Smaller draglines were also commonly used before hydraulic excavators came into common use, the smaller draglines are now rarely used other than on river and gravel pit works. The small machines were of a mechanical drive with clutches. Firms such as Ruston and Bucyrus made models such as the RB10 which were popular for small building works and drainage work. Several of these can still be seen in the English Fens of Cambridgeshire, Lincolnshire and parts of Norfolk. Ruston's are a company also associated with drainage pumping engines. Electric drive systems were only used on the larger mining machines, most modern machines use a diesel-hydraulic drive, as machines are seldom in one location long enough to justify the cost of installing a substation and supply cables.
Technological advances
The basic mechanical technology of draglines, unlike that of most equipment used in earth-moving, has remained relatively unchanged in design and control functions for almost 100 years. Some advances, however, have been made (such as hyraulic, then electro-hydraulic, controls (including joysticks) and using simulation software to train new operators), are being pursued (such as improved automation systems), or are arguable as a step forward (as is "universal dig-dump" (UDD)):
Automation
Researchers at CSIRO in Australia have a long-term research project[15] into automating draglines. Mining automation teams at QCAT, a CSIRO division; have been developing the automation technology since 1994. Automated systems include cruise control and Digital Terrain Mapping. Working solutions include the proof-of-concept dragline swing cruise control on a Tarong BE1370.[16]
Simulation software
Since draglines are typically large, complicated and very expensive, training new operators can be a tricky process. In the same way that flight simulators have developed to train pilots, mining simulator software has been developed to assist new operators in learning how to control the machines.
UDD
UDD stands for universal dig-dump. It represents the first fundamental change to draglines for almost a century, since the invention of the 'miracle hitch'. Instead of using two ropes (the hoist rope and the drag rope) to manipulate the bucket, a UDD machine uses four ropes, two hoist and two drag. This allows the dragline operator to have much greater selectivity in when to pick up the bucket, and in how the bucket may be dumped. UDD machines generally have higher productivity than a standard dragline, but often have greater mechanical issues. Within the mining industry, there is still much debate as to whether UDD improvements justify their costs.
Excavators are heavy construction equipment primarily consisting of a boom, dipper, bucket and cab on a rotating platform known as the "house" - although the largest form ever, the dragline excavator, eliminated the dipper in favor of a line and winch.
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.
Big Brutus is the nickname of the Bucyrus-Erie model 1850-B electric shovel, which was the second largest of its type in operation in the 1960s and 1970s. Big Brutus is the centerpiece of a mining museum in West Mineral, Kansas, United States where it was used in coal strip mining operations. The shovel was designed to dig from 20 to 69 feet down to unearth relatively shallow coal seams, which would themselves be mined with smaller equipment.
The Silver Spade was a giant power shovel used for strip mining in southeastern Ohio. Manufactured by Bucyrus-Erie, South Milwaukee, Wisconsin, the model 1950-B was one of two of this model built, the other being the GEM of Egypt. Its sole function was to remove the earth and rock overburden from the coal seam. Attempts to purchase and preserve the shovel from Consol to make it the centerpiece of a mining museum exhibit for $2.6 million fell short, and the shovel was dismantled in February 2007.
A bucket-wheel excavator (BWE) is a large heavy equipment machine used in surface mining.
Marion Power Shovel Company was an American firm that designed, manufactured and sold steam shovels, power shovels, blast hole drills, excavators, and dragline excavators for use in the construction and mining industries. The company was a major supplier of steam shovels for the construction of the Panama Canal. The company also built the two crawler-transporters used by NASA for transporting the Saturn V rocket and later the Space Shuttle to their launch pads. The company's shovels played a major role in excavation for Hoover Dam, the Holland Tunnel and the extension of the Number 7 subway line to Main Street in Flushing, Queens.
Big Muskie was a dragline excavator built by Bucyrus-Erie and owned by the Central Ohio Coal Company, weighing 13,500 short tons (12,200 t) and standing nearly 22 stories tall. It mined coal in the U.S. state of Ohio from 1969 to 1991. It was dismantled and sold for scrap in 1999.
A landship is a large land vehicle that travels exclusively on land. Its name is meant to distinguish it from vehicles that travel through other mediums such as conventional ships, airships, and spaceships.
Bucyrus-Erie was an American surface and underground mining equipment company. It was founded as Bucyrus Foundry and Manufacturing Company in Bucyrus, Ohio, in 1880. Bucyrus moved its headquarters to South Milwaukee, Wisconsin, in 1893. In 1927, Bucyrus merged with the Erie Steam Shovel Company to form Bucyrus-Erie. In 1997, it was renamed Bucyrus International, Inc. In 2010 the enterprise was purchased by Caterpillar in a US$7.6 billion transaction that closed on July 8, 2011. At the time of its acquisition, the Bucyrus product line included a range of material removal and material handling products used in both surface and underground mining.
A power shovel, also known as a motor shovel, stripping shovel, front shovel, mining shovel or rope shovel, is a bucket-equipped machine usually powered by steam, diesel fuel, gasoline or electricity and used for digging and loading earth or fragmented rock and for mineral extraction. Power shovels are a type of rope/cable excavator, where the digging arm is controlled and powered by winches and steel ropes, rather than hydraulics like in the modern hydraulic excavators. Basic parts of a power shovel include the track system, cabin, cables, rack, stick, boom foot-pin, saddle block, boom, boom point sheaves and bucket. The size of bucket varies from 0.73 to 53 cubic meters.
Sundew was a large electrically powered dragline excavator used in mining operations in Rutland and Northamptonshire in the United Kingdom.
Ransomes & Rapier was a major British manufacturer of railway equipment and later cranes, from 1869 to 1987. Originally an offshoot of the major engineering company Ransome's it was based at Waterside Works in Ipswich, Suffolk.
Ruston-Bucyrus Ltd was an engineering company established in 1930 and jointly owned by Ruston & Hornsby based in Lincoln, England, and Bucyrus-Erie based in South Milwaukee, Wisconsin, the latter of which had operational control and into which the excavator manufacturing operation of Ruston & Hornsby was transferred. The Bucyrus company proper, from which the Bucyrus component of the Ruston-Bucyrus name was created, was an American company founded in 1880, in Bucyrus, Ohio.
Marion 6360, also known as The Captain, was a giant power shovel built by the Marion Power Shovel company. Completed in 1965, it was one of the largest land vehicles ever built, exceeded only by some dragline and bucket-wheel excavators. The shovel originally started work with Southwestern Illinois Coal Corporation, but the owners were soon bought out by Arch Coal. Everything remained the same at the mine except for the colors which were changed to red, white, and blue.
The Ursa Major at Black Thunder Coal Mine, Wyoming, is the largest dragline excavator currently in use in North America and the third largest ever built. It is a Bucyrus-Erie 2570WS model and cost US$50 million. The Ursa Major was one of five large walking draglines operated at Black Thunder, with the next two largest in the dragline fleet being Thor, a B-E 1570W - which has a 97.5-metre (320 ft) boom and a 69-cubic-metre (2,400 cu ft) bucket - and Walking Stick, a B-E 1300W with a 92-metre (302 ft) boom and a 34-cubic-metre (1,200 cu ft) bucket.
P&H Mining Equipment sells drilling and material handling machinery under the "P&H" trademark. The firm is an operating subsidiary of Joy Global Inc. In 2017 Joy Global Inc. was acquired by Komatsu Limited of Tokyo, Japan, and is now known as Komatsu Mining Corporation and operates as a subsidiary of Komatsu.
Joy Global Inc. was a company that manufactured and serviced heavy equipment used in the extraction and haulage of coal and minerals in both underground and surface mining. The company had manufacturing facilities in Alabama, Pennsylvania, Texas, Wisconsin, Australia, Canada, China, France, South Africa, Poland and the United Kingdom. In 2017, Joy Global was acquired by Komatsu Limited and was renamed Komatsu Mining Corp.
NCK, started as a subsidiary of Newton, Chambers & Company, a large engineering company based in Sheffield, England. They produced the range of agricultural equipment, skimmers, excavators, cranes and draglines that were renowned for high quality and long life, typically over 20 years. Many NCK machines continue to operate worldwide.
The term walking excavator may apply to two different forms of heavy equipment, the historic walking power shovel or dragline excavator that began to appear already early in the 20th century, or the contemporary version of all-terrain excavator popularly known as a spider excavator.
A bucket chain excavator (BCE) is a piece of heavy equipment used in surface mining and dredging. BCEs use buckets on a revolving chain to remove large quantities of material. They are similar to bucket-wheel excavators and trenchers. Bucket chain excavators remove material from below their plane of movement, which is useful if the pit floor is unstable or underwater.
↑ "Dragline Automation"Dr Jonathan Roberts CSIRO (11 December 2009) accessed 19 December 2011
K. Pathak, K. Dasgupta, A. Chattopadhyay, "Determination of the working zone of a dragline bucket – A graphical approach", Doncaster, The Institution of mining engineers, 1992.
Peter Ridley, Peter Corke, "Calculation of Dragline bucket pose under gravity loading", Mechanism and machine theory, Vol. 35, 2000.
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