What is a dragline excavator and what are its primary uses?

A dragline excavator is a heavy-duty piece of equipment used for excavation in civil engineering and surface mining operations. It functions by using a large bucket suspended from a boom to dig and move material.

When was the dragline excavator invented, and what existing technologies did it challenge?

The dragline excavator was invented in 1904. It immediately presented a challenge to the established steam shovel and its later diesel and electric powered descendants, the power shovel.

How has the dragline excavator's dominance evolved over time, and what technologies have challenged or superseded it?

Dragline excavators enjoyed a period of extreme size and efficiency throughout much of the 20th century. However, they began to face competition from more efficient rotary excavators in the 1950s, and were eventually superseded by these rotary excavators in larger applications from the 1970s onwards.

What was the Big Muskie, and what were its notable specifications?

The Big Muskie was the world's largest ever walking dragline, built by Bucyrus-Erie in 1969. It measured 487 feet (148 meters) in length, weighed approximately 13,500 short tons (12,247 metric tons), and was equipped with a massive 220 cubic yard (168.2 cubic meter) bucket capable of moving 325 short tons (295 metric tons) of material per pass.

What is considered the largest walking dragline produced as of 2014, and what are its key features?

As of 2014, Joy Global's digital AC drive control P&H 9020XPC was the largest walking dragline produced. It features a bucket capacity ranging from 110 to 160 cubic yards (84 to 122 cubic meters) and boom lengths between 325 and 425 feet (99 to 130 meters), with working weights between 7,539 and 8,002 tons.

Describe the crane-based type of dragline excavator.

Crane-based draglines are typically smaller units that are based on standard lifting cranes, often with an added winch drum at the front. These machines can be temporarily dismantled for road transport and are commonly used in civil engineering for tasks like road construction, port development, pond and canal dredging, and as pile driving rigs. Manufacturers include Link-Belt and Hyster.

What are the characteristics and primary applications of the larger, site-erected dragline excavators?

The larger type of dragline excavator is erected on-site and is commonly used in strip-mining operations. Its main purpose is to remove overburden above coal deposits and, more recently, for oil sands mining. These heavy units are among the largest mobile land machines ever built, with the smallest site-erected models weighing around 8,000 tons and the largest up to 13,500 tons.

What are the main components of a dragline bucket system?

A dragline bucket system consists of a large bucket suspended from a truss-like boom or mast using wire ropes. The bucket's movement is controlled by a hoist rope, which supports the bucket and hoist-coupler assembly, and a dragrope, used to pull the bucket assembly horizontally. These ropes are powered by large diesel or electric motors.

Who is credited with inventing the dragline excavator, and for what initial project?

The dragline excavator was invented in 1904 by John W. Page. Its initial application was for digging the Chicago Canal.

How did John W. Page's involvement with draglines lead to the formation of a company?

Realizing that manufacturing draglines was more profitable than contracting, John W. Page founded the Page Engineering Company in 1912 specifically to build draglines.

What significant development did Page Engineering Company introduce regarding dragline mobility?

Page Engineering Company built its first crude walking dragline in 1923, which used legs operated by a rack and pinion system to lift and move the crane. They also developed the first diesel engines specifically for dragline applications in 1924.

What contributions did Page Engineering Company make to dragline bucket design?

Page Engineering Company invented the arched dragline bucket, a design that remains common today. They also pioneered an archless bucket design in the 1960s.

What was Monighan Machine Company's key contribution to dragline technology, and who developed it?

Monighan Machine Company, initially Monighan's Machine Works, developed the first walking mechanism for a dragline in 1913, invented by engineer Oscar Martinson and known as the Martinson Tractor. This innovation significantly improved the mobility of draglines.

How was Monighan's walking mechanism improved, and what was its impact?

In 1925, Monighan improved its walking mechanism by replacing drag chains with a cam wheel running in an oval track, providing a more efficient elliptical motion for the shoes. This improved mechanism was used until 1988 and made Monighan draglines so popular that the company name became a generic term for dragline excavators.

How did Bucyrus-Erie become involved with Monighan, and what was the outcome?

Bucyrus-Erie began purchasing shares of Monighan stock in the early 1930s with Monighan's approval. They eventually acquired a controlling interest, forming the joint company Bucyrus-Monighan, which later formally merged in 1946.

What was Ransomes & Rapier's involvement in the dragline industry?

Ransomes & Rapier initially built Marion draglines under agreement from 1924 to 1936. After this agreement ended, they began building their own dragline designs. Later, their division was sold and eventually acquired by Bucyrus.

What were some key contributions and notable machines from the Marion Power Shovel Company?

The Marion Power Shovel Company built its first walking dragline in 1939 using a simple single-crank mechanism. Its largest dragline was the 8950, sold in 1973, which featured a 150-cubic yard bucket on a 310-foot boom and weighed 7,300 tons.

What were some of Bucyrus Foundry and Manufacturing Company's early contributions to dragline technology?

Bucyrus entered the dragline market in 1910 by acquiring manufacturing rights for the Heyworth-Newman dragline excavator. They introduced the 'Class 14' dragline in 1911, the first crawler-mounted dragline, and helped pioneer the use of electricity for large stripping shovels and draglines in 1912.

How did the market for large draglines consolidate in the late 20th century?

The market for large draglines experienced significant consolidation due to mergers and acquisitions. Key events included P&H's acquisition of Page in 1988, Bucyrus' acquisition of Ransomes & Rapier in 1988, and Bucyrus' acquisition of Marion in 1997, which reduced the number of major worldwide suppliers for heavy draglines by more than half.

Who are the primary manufacturers of large draglines today?

As of the information provided, P&H (Harnischfeger Corporation) and Caterpillar are the only remaining manufacturers of large draglines.

Which Indian company manufactures walking draglines, and what is their capacity?

Heavy Engineering Corporation Limited (HEC) is the first Indian company to manufacture walking draglines, producing models with bucket capacities up to 44 yards, comparable to Caterpillar's 8000 series.

Describe the typical operational cycle of a dragline excavator.

In a standard excavation cycle, the dragline positions its bucket above the material, lowers it, and then uses the dragrope to pull the bucket along the surface. The hoist rope then lifts the bucket, after which the machine swings to the dumping location. Finally, the dragrope is released, allowing the bucket to tilt and empty its contents.

How could the bucket be 'thrown' on crane-type draglines, and why is this less common on larger machines?

On crane-type draglines, the bucket could be 'thrown' by winding up the jib and releasing a clutch on the drag cable, causing the bucket to swing like a pendulum. Releasing the hoist cable at the right moment would then propel the bucket forward. This technique allowed the bucket to land further than if simply dropped, but it is not a common practice on larger draglines.

What is the approximate cost and typical capacity of a large dragline system used in open-pit mining?

A large dragline system for open-pit mining can cost approximately US$50 to $100 million. Typical bucket volumes range from 40 to 80 cubic yards (30 to 60 cubic meters), with boom lengths from 148 to 328 feet (45 to 100 meters).

How are large mining draglines typically powered, and what are their significant power demands?

Unlike most other mining equipment, large mining draglines are not usually diesel-powered. Their substantial power consumption, on the order of several megawatts, requires a direct connection to the high-voltage grid, typically between 6.6 and 22 kV.

What kind of stories circulate regarding the power consumption of mining draglines?

Due to their immense power demands, there are apocryphal stories about the effects of mining draglines on local power grids. One such tale suggests that if all seven draglines at the Peak Downs Mine in Queensland, Australia, were activated simultaneously, they could cause a blackout across all of North Queensland. While likely apocryphal, it illustrates the immense power demands of these machines.

How do large draglines typically move, and why is this method preferred over tracks?

Most large draglines move by 'walking' using feet or pontoons. This method is preferred over caterpillar tracks because tracks would place too much pressure on the ground under the immense weight of the dragline, and tracks have great difficulty supporting such heavy loads.

What are the limitations regarding the speed and travel distance for walking draglines?

Walking draglines have a very slow maximum speed, typically only a few meters per minute, as their feet must be repositioned for each step. For medium distances (about 30-100 km), a special carrier can be used for transport; beyond that, disassembly is usually required.

What are the main operational limitations of dragline excavators?

The primary limitations of draglines are their boom height and length, which restrict where they can dump waste material, and their digging depth, limited by the length of rope they can utilize. They are most efficient when excavating material below the level of their base.

In what type of excavation is a dragline most efficient, and what tasks are they not well-suited for?

Draglines are most efficient when excavating material below the level of their base. While they can dig above themselves, it is inefficient, and they are not suitable for loading piled-up material, unlike rope shovels or wheel loaders.

Despite their limitations and high cost, why do mines continue to use draglines?

Draglines remain popular in many mines due to their reliability and the exceptionally low cost associated with removing waste material compared to other methods.

What happened to the Big Muskie after its operational life?

After operating from 1969 to 1991, the Big Muskie was dismantled in 1999. It was sold for its recycled metal, generating approximately $700,000.

What was the status of dragline production in Europe during the 1960s, and what is an example?

The British firm Ransomes & Rapier produced some of the largest diesel-electric excavators in Europe during the 1960s, weighing between 1400-1800 tons. An example named 'SUNDEW' operated from 1957 to 1974 before being scrapped in 1987.

What is the current role of smaller draglines compared to their past usage?

Smaller draglines were commonly used before the advent of hydraulic excavators. Today, they are rarely used except for specific tasks like river and gravel pit works, as they were often mechanically driven with clutches, unlike modern diesel-hydraulic machines.

Has the fundamental technology of draglines changed significantly over time?

The basic mechanical technology and control functions of draglines have remained relatively unchanged for nearly 100 years. However, advances such as hydraulic and electro-hydraulic controls (including joysticks), simulation software for training, and ongoing research into automation systems are being pursued.

What research is being conducted regarding the automation of draglines?

Researchers at CSIRO in Australia have been developing automation technology for draglines since 1994. This includes systems like cruise control and Digital Terrain Mapping, with proof-of-concept successes such as dragline swing cruise control.

Why has simulation software been developed for dragline operators?

Since draglines are large, complex, and very expensive machines, training new operators can be challenging. Mining simulator software has been developed, similar to flight simulators for pilots, to help new operators learn how to control these machines effectively.

What is UDD technology in draglines, and how does it differ from standard systems?

UDD stands for Universal Dig-Dump. This technology represents a significant change, using four ropes (two hoist and two drag) instead of the standard two ropes. This allows for greater control over picking up and dumping the bucket, potentially increasing productivity.

What is the ongoing debate within the mining industry regarding UDD draglines?

While UDD machines generally offer higher productivity than standard draglines, they often come with greater mechanical issues. Consequently, there is ongoing debate within the mining industry about whether the improvements offered by UDD justify their increased costs and potential complexities.

What are some alternative heavy machinery used in mining excavation besides draglines?

Other significant excavation machines used in mining include bucket wheel excavators, bucket chain excavators, and power shovels (which include earlier steam shovels).

How does the dragrope function in controlling the dragline bucket?

The dragrope is a critical component used to draw the bucket assembly horizontally along the material to be excavated. By skillfully maneuvering both the dragrope and the hoist rope, the operator can precisely control the bucket's actions for various digging and dumping operations.

What was the impact of major acquisitions on the number of heavy dragline suppliers?

The acquisitions of companies like Page, Ransomes & Rapier, and Marion by larger manufacturers significantly reduced the number of worldwide suppliers for heavy draglines, cutting the number by more than half.

What specific limitations related to dumping material do draglines face?

Draglines are limited in where they can dump waste material primarily by their boom height and boom length. These factors dictate the maximum reach and elevation at which the excavated material can be deposited.

How does a dragline's efficiency relate to the level of the material being excavated?

A dragline is most efficient when excavating material below the level of the machine's base. This allows the bucket to be effectively filled and swung without excessive strain or inefficiency.

What is the historical significance of the name 'Monighan' in relation to draglines?

Due to the popularity and widespread use of their walking dragline machines, the name 'Monighan' became a generic term used to refer to dragline excavators in general.

What pioneering role did Bucyrus play regarding power sources for large mining equipment?

In 1912, Bucyrus was instrumental in pioneering the use of electricity as a power source for large stripping shovels and draglines used in mining operations.

Which major company acquired Bucyrus, and when?

Bucyrus, the heavy equipment and diesel engine maker, was acquired by Caterpillar in 2011.

What patent did Ransomes & Rapier develop that was later sold to Bucyrus?

Ransomes & Rapier patented a rope-operated crowd system for steam shovels, which they later sold to Bucyrus.

What was the purpose of the Martinson Tractor developed by Monighan's engineer?

The Martinson Tractor, invented by Oscar Martinson, was the first walking mechanism developed for a dragline. It allowed the machine to move by lifting and repositioning its body, significantly improving its mobility.

When and where was the first walking dragline excavator used in the United Kingdom?

The first walking dragline excavator in the United Kingdom was used at the Wellingborough iron quarry in 1940.

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What is a Dragline Excavator?

Definition

A dragline excavator is a heavy-duty piece of equipment utilized extensively in civil engineering and surface mining. Invented in 1904, it emerged as a significant advancement over the steam shovel and its successors, offering superior efficiency, particularly in large-scale operations.

Technological Context

While initially dominant, the dragline's reign, especially in extreme sizes, began to face challenges from more efficient rotary excavators starting in the 1950s, eventually being superseded in the upper echelons of size and capability from the 1970s onward.

Scale and Impact

The sheer scale of some draglines is astounding. For instance, the 'Big Muskie', built in 1969, was the world's largest ever dragline, demonstrating the immense capacity and engineering prowess associated with this class of machinery.

Types of Draglines

Crane-Based Draglines

Many draglines are essentially standard lifting cranes modified for dragline work. These units typically feature an added winch drum at the front. They are designed for easier dismantling and transportation, making them suitable for various civil engineering tasks such as road construction, port development, pond and canal excavation, and pile driving.

Heavy, Site-Erected Draglines

The larger category of draglines are massive machines built on-site. These are predominantly used in extensive strip-mining operations, primarily for removing overburden above coal seams and, more recently, in oil sands extraction. These giants represent some of the largest mobile land machines ever constructed.

Historical Development

Origins and Early Innovations

The dragline excavator was invented in 1904 by John W. Page. Initially involved in the Chicago Canal project, Page later founded the Page Engineering Company to focus on dragline manufacturing. Early walking mechanisms, like the Martinson Tractor patented in 1913-1914, were developed by Monighan Machine Company, leading to the first true walking draglines.

Manufacturer Evolution

Key manufacturers like Page, Monighan, Bucyrus-Erie, Harnischfeger (P&H), Marion Power Shovel Company, and Ransomes & Rapier played pivotal roles. Mergers and acquisitions shaped the industry, with Bucyrus eventually acquiring Ransomes & Rapier and Marion, and Harnischfeger acquiring Page. Today, P&H and Caterpillar remain the primary manufacturers of large draglines.

UK Introduction

The United Kingdom saw its first walking dragline excavator deployed in 1940 at the Wellingborough iron quarry. Later, machines like the Ransomes & Rapier 'SUNDEW' demonstrated impressive mobility, walking significant distances between work sites.

Operational Mechanics

The Excavation Cycle

The standard dragline operation involves a cyclical process: the bucket is positioned, lowered, and then dragged along the material surface using the dragrope. Subsequently, the hoist rope lifts the bucket. A swing operation repositions the bucket over the dump site, where releasing the dragrope allows the bucket to tilt and discharge its load.

Advanced Techniques

On smaller draglines, a technique called 'throwing' could be employed. By utilizing pendulum motion and releasing the hoist cable, operators could extend the bucket's reach significantly beyond its normal drop distance, a maneuver requiring considerable skill.

Walking Mechanism

Larger draglines move using a 'walking' mechanism, employing large feet or pontoons. This method avoids the excessive ground pressure associated with tracks and is essential for supporting the immense weight of these machines. Movement is slow, typically only a few meters per minute, requiring careful repositioning for each step.

Draglines in Mining

Economic Scale

Large dragline systems represent substantial investments, often costing tens to hundreds of millions of US dollars. Despite the high capital expenditure, their efficiency in moving vast quantities of material contributes to a remarkably low cost per ton of waste removed, making them indispensable for many large-scale open-pit mines.

Power Requirements

Unlike most mining equipment, large draglines are typically powered by direct high-voltage electrical connections (6.6 to 22 kV) due to their immense power demands, often reaching several megawatts during operation. Startup procedures require careful management to avoid grid instability.

Operational Context

In Australia, large draglines operating at mines like Peak Downs have historically required sequential startups due to their power draw. Their extensive reach allows them to work large areas from a single position, minimizing the need for frequent relocation compared to smaller machinery.

Operational Constraints

Reach and Depth

The primary limitations of draglines are dictated by their boom height and length, which constrain the maximum height at which waste material can be dumped. Similarly, the length of the ropes limits the achievable digging depth.

Above-Grade Excavation

While draglines can excavate material above their base level, this is done inefficiently. They are not suited for loading stockpiled material, unlike rope shovels or wheel loaders, which are designed for such tasks.

Notable Examples

Big Muskie

Owned by American Electric Power, the Bucyrus-Erie 4250-W 'Big Muskie' was the world's largest mobile earth-moving machine. Operating from 1969 to 1991 in Ohio, it weighed approximately 13,500 tons, stood nearly 22 stories tall, and featured a 220 cubic yard bucket. It was dismantled in 1999.

Modern Giants

Contemporary large draglines include Joy Global's P&H 9020XPC (up to 160 cu yd bucket, 425 ft boom, ~8,000 tons) and Caterpillar's 8750 (169 cu yd bucket, 435 ft boom, 8,350 tons). These machines continue the legacy of immense scale in mining operations.

Key Specifications Table

Machine Name / Model	Manufacturer	Approx. Weight (tons)	Bucket Capacity (cu yd)	Boom Length (ft)	Year Introduced / Operational
Big Muskie (4250-W)	Bucyrus-Erie	13,500 - 14,500	220	450 - 487	1969
Marion 8950	Marion Power Shovel Co.	7,300	150	310	1973
Caterpillar 8750	Caterpillar	8,350	169	435	(Post-2011 acquisition)
P&H 9020XPC	Joy Global (P&H)	7,539 - 8,002	110 - 160	325 - 425	(Circa 2014)
Page Model 757	Page Engineering	4,500	75	298	1983
SUNDEW	Ransomes & Rapier	1,400 - 1,800	(Not specified)	(Not specified)	1957

Technological Advancements

Automation Initiatives

Research into automating draglines has been ongoing, notably by CSIRO in Australia since 1994. Developments include cruise control systems and digital terrain mapping, aiming to enhance efficiency and safety in mining operations.

Simulation Software

To address the complexity and cost of training operators on these massive machines, sophisticated mining simulator software has been developed. These simulators provide a safe and effective environment for learning machine control, analogous to flight simulators for pilots.

Universal Dig-Dump (UDD)

The Universal Dig-Dump (UDD) system represents a significant change in dragline mechanics, utilizing four ropes (two hoist, two drag) instead of the traditional two. This allows for greater control over bucket manipulation and dumping, potentially increasing productivity, though often accompanied by greater mechanical complexity.

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References

Digging big â the worldâs biggest draglines Mining Technology, July 6, 2014

"Maid Marian's journey becomes a 'drag'" The Daily Gleaner (10 October 2008) accessed 1 November 2008]

CSIRO research project

A full list of references for this article are available at the Dragline excavator Wikipedia page

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Important Notice

This page was generated by an Artificial Intelligence and is intended for informational and educational purposes only. The content is derived from publicly available data and may not be exhaustive or entirely up-to-date.

This is not professional engineering or safety advice. The information provided should not substitute for consultation with qualified professionals, adherence to manufacturer specifications, or compliance with relevant safety regulations in the operation of heavy machinery. Always consult official documentation and expert advice for specific applications.

The creators of this page are not responsible for any errors or omissions, or for any actions taken based on the information provided herein.

Giants of Earthmoving

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What is a Dragline Excavator? ℹ️

🏗️ Definition

⚙️ Technological Context

⚖️ Scale and Impact

Types of Draglines 🧩

🕹️ Crane-Based Draglines

🏭 Heavy, Site-Erected Draglines

Historical Development 📜

💡 Origins and Early Innovations

🤝 Manufacturer Evolution

🇬🇧 UK Introduction

Operational Mechanics 🔄

⛏️ The Excavation Cycle

🚀 Advanced Techniques

🚶 Walking Mechanism

Draglines in Mining ⛰️

💰 Economic Scale

⚡ Power Requirements

🇦🇺 Operational Context

Operational Constraints ⚠️

📏 Reach and Depth

⬆️ Above-Grade Excavation

Notable Examples 👑

🇺🇸 Big Muskie

⚙️ Modern Giants

📊 Key Specifications Table

Technological Advancements 💡

🤖 Automation Initiatives

🎮 Simulation Software

🔧 Universal Dig-Dump (UDD)

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What is a Dragline Excavator?

Definition

Technological Context

Scale and Impact

Types of Draglines

Crane-Based Draglines

Heavy, Site-Erected Draglines

Historical Development

Origins and Early Innovations

Manufacturer Evolution

UK Introduction

Operational Mechanics

The Excavation Cycle

Advanced Techniques

Walking Mechanism

Draglines in Mining

Economic Scale

Power Requirements

Operational Context

Operational Constraints

Reach and Depth

Above-Grade Excavation

Notable Examples

Big Muskie

Modern Giants

Key Specifications Table

Technological Advancements

Automation Initiatives

Simulation Software

Universal Dig-Dump (UDD)

Teacher's Corner

True or False?

Test Your Knowledge!

Gamer's Corner

Discover other topics to study!

References

Feedback & Support

Disclaimer

Important Notice