Roadheader machines, also known as boom-type roadheaders are powerful machines designed for excavation, drilling, tunnelling applications, and material moving for construction projects. As a significant addition to the family of mechanical excavators, roadheaders manipulate and stabilise coal mines and other underground structures. Their mobility and automatic control elements make rock formation and creation of tunnel profiles, and various mining tasks much simpler and safer for other workers.
Most heavy equipment machines are expensive and have high maintenance costs. Unfortunately, roadheaders are not an exception. With different types of roadheader machines, operators and service technicians perform numerical tests, compare simulation results, and constantly look for techniques to improve the longevity of these machines.
In rough working environments, there is plenty of rock, dust, and debris. A combination of these elements wears down the boom-type roadheader much faster than most operators anticipate. In this comprehensive guide, our goal is to help you determine the best maintenance strategy for your machines. With a thorough overview of widely used roadheaders, and the influence of the environment on components, you will have all the data needed to find a new approach for efficient machine servicing.
How does a roadheader work?
For an untrained eye, a roadheader looks like a pretty complicated machine, but after learning about the main machine components, the control system, safety features and how the machine does its work, everything should be clear, even for complete beginners. This section covers the main parts of a roadheader and briefly explains the cutting process and the machine’s work output.
To understand what exactly a roadheader does, let’s go over the key machine components that in unison contribute to fast and productive excavation:
The cutting head is the key part of a roadheader that comes in direct contact with excavated surfaces. It is a multifunctional component that allows the attachment of different cutting tools and appendixes that ensure the desired reshaping of surfaces.
This component was developed for flexible rock cutting and mining, while different attachments make it widely applicable for construction and other projects. To keep the machine and its systems in top condition, operators and service technicians focus on the maintenance of cutting heads. The efficiency of cutting and proper fuel consumption depends on keeping them in optimal shape, as blunt tools and extensions will increase the buildup of dirt, dust, and debris that will slowly damage the rest of the machine. Proper servicing of the cutting head will result in a reduction of contaminants.
A boom is an extendable part of the machine on which the cutting head is mounted. It gives the roadheader its flexibility and accessibility to rock mass, which is essential for building safe tunnel profiles and coal mining. A skilled operator has great control of the cutting process, excavating materials with great efficiency without the constant need to move the entire machine forward. Frequent servicing, cleaning, and lubrication are necessary to keep this key component in great condition. A poorly-maintained boom can result in inaccurate cutting and danger to other employees.
Tracks or wheels
Depending on the model of your machine, a roadheader will have tracks or crawler wheels for the control of the vehicle. Here are the main differences between these systems of vehicle propulsion:
- Crawler tracks: Tracks create a more stable platform with a bigger surface area. The interconnected threads of metal stabilise the entire machine, making it slower, but easier to control in tunnels, mines, and other tight underground spaces. Tracks are less prone to wear and tear and ensure better traction on all surfaces. The biggest downside of crawler tracks is speed: while they do not depend on air pressure like wheels, a track needs more servicing: tension adjustments, lubrication, cleaning, and replacement of many interconnected parts. If one component breaks down, replacing it takes more effort than with wheels.
- Wheels: The most popular option for most vehicles, wheels have one big advantage on their side – speed. If your worksite is a construction site or a large and stable underground structure, the area will be safe enough to use roadheaders with wheels, guaranteeing their quick transportation to important areas. Wheels are less durable but easier to replace and maintain than crawler tracks.
The hydraulic system generates the force responsible for the work output of your boom and cutting head. Here is a brief overview of hydraulic components and their role in generating movement of roadheader components:
• Hydraulic pumps: a system of hydraulic pumps that push the pressurising fluid and force it to flow with bigger power with rotating components.
• Valves: After successful pressurisation, valves control the fluid flow like gates that decide when and which cylinders receive the pressurised fluid.
• Cylinders: the last step in our system, cylinders use the incoming fluid to move pistons inside the cylinder and generate mechanical force. These internal processes occur when the operator controls the boom and other mechanical components responsible for the cutting process. High-end roadheaders have control systems that allow easy customisation of cutting process parameters.
While the hydraulic system has other components, understanding the significance of the main parts will help you understand the importance of hydraulic system maintenance: cleaning, lubrication, fluid replacement, and other tasks.
Material removal systems
The main goals of heavy equipment machines are acceleration of performed tasks and increasing work output. While roadheaders are perfect for cutting through rock mass, they also need systems for excavated material removal and transportation. Fortunately, most modern roadheaders have built-in conveyors to move materials from the cutting head to a desired area in the site.
An operator’s cabin is a space where a designated worker interacts with electrical components, the automatic control system and its parameters. As a designated space for a specialised worker, it has a medical kit, tools for fixing and maintenance, an equipment manual, and safety equipment.
Roaheaders are always in contact with rocks, dust, debris, and other materials that contaminate the engine compartment, hydraulic system, and even the air in the operator’s cabin. Ventilation systems aim to create a safe working environment for an operator, as well as maximise the efficiency of the machine by reducing wear and tear to other components. Ventilation systems are maintained through constant monitoring, cleaning, and replacement of roadheader filters.
Rock cutting process
The rock-cutting process has many tangibles affecting the task, but the core principles can be divided into three simple steps:
- Rock surface penetration. The operator controls the cutting head, bringing it into contact with the targeted surface. For effective excavation, the appropriate tools and attachments are chosen to achieve the desired result with minimal accumulation of waste.
- Rock fragmentation. The excavated rock is crumbled into smaller pieces for easier transportation.
- Material transportation. Extracted materials travel through conveyors or other material removal systems for quick disposal or storage for specific use cases
The complexity of rock cutting comes from choosing the right tools and rock-cutting parameters to influence and break down the surface in a perfect way without compromising the stability of the underground structure. Roadheaders are the perfect tools for the job, as their different types and cutting head attachments are perfect for mining and tunnelling.
While each machine has different combinations of components, here we have the main types of roadheaders that are used in most cases of mining, rock cutting and landscaping, as well as the classification of machines based on their unconfined compressive strength.
For the most popular one, the boom-type roadheader, its most dominant part is the boom – a massive extendable part that swivels and pivots for accurate and flexible control of the cutting head. A skilled operator understands the control system and knows how to manoeuvre the machine for safe cutting and mining while ensuring the safety of other workers.
The extendable crane is retractable at will, to reach and process the rock mass at the most optimal angles. Thanks to the boom’s length and efficient control, a boom-type roadheader is a perfect machine for mining and tunnelling applications. Compared to other types, these machines have more flexible cutting heads, as the boom allows it to reach the right angles to transform the rock face without moving the entire machine forward.
Many construction projects and tunnelling applications would not be achieved without the help of a boom-type roadheader. It is one of the best tools for achieving stability in underground structures while maintaining exemplary speed and precision.
During operation, the main components of a boom-type roadheader suffer a lot of wear and tear. To keep the machine at its peak value and efficiency, the maintenance plan for this equipment should focus on servicing, repairs, and lubrication of the boom, the cutting heads, and the motor that generates the work output for cutting.
Longitudinal Cutter Roadheader
For longitudinal cutter roadheaders, the secret is the new approach to a controlled machine rotation. Unlike with the boom type roadheader, its cutting head rotates parallel to the longitudinal axis. These parameters make it one of the best tools for mining, where its structure is perfect for efficient rock processing.
With a consistent pattern for cutting and transforming the surface, the longitudinal cutter roadheader is perfect for perpendicular cutting. For specific situations, the speed of their cutting process is unmatched. Widely used for coal mining and precise forming of underground structures.
While working with the longitudinal cutter, the operator can transform the rock surface, excavate, and transport the extracted materials without moving the base of the equipment. Cutting heads are the main components that need the most maintenance, but don’t forget to check up on the hydraulic system to keep the machine accurate and stable
Transverse cutter roadheader
The transverse cutter roadheader controls the cutting head perpendicular to the axis of the machine. They allow a more consistent formation of the surface and are better at manipulating softer materials in coal mines and underground structures.
With a focus on precision and stability, transverse cutter roadheaders focus on accuracy and selective cutting, aiming to only process the desired materials without too much effect on brittle surroundings. Expertise in soft material excavation makes transverse cutters the optimal choice for less stable underground structures.
Transverse cutter roadheaders cause less vibration in the operated environment, which indirectly protects and reduces maintenance costs for all heavy equipment on the site. They are very good at transforming the rock face into a specific desired shape, an essential feat for tunnelling applications in unstable areas.
When speed is the name of the game, no equipment matches the raw work output of a full-face roadheader. With a cutting head as wide as your entire machine, this beast can excavate and transport massive amounts of rock and other materials and reshape the underground structure at a rapid pace.
Full-face roadheaders are perfect for tunnelling applications in safe spaces where extra power does not cause safety concerns. With newer models that include a powerful control system, the operator can control the boom to set the perfect width and excavate the material with unmatched efficiency.
After speedy removal on desired tunnel sections, full-face roadheaders have developed conveyor systems to transport the excavated rock and other materials as quickly as possible, making sure that the cutting head only comes in touch with unprocessed surfaces. If a designated technician has determined that the structure is safe enough for heavy-duty work, a full-face roadheader is the right machine for the job. However, keep in mind that large-scale rock cutting creates a lot more dust, debris, and other contaminants. For servicing, full-face roadheaders need extra attention and maintenance for the air filtering system to keep the operator safe, prevent damage to other components, and maximise the efficiency of fuel consumption.
These are the most common types of roadheaders for mining, tunnel processing, landscaping, and construction. Keep in mind that the market is full of unique machines that fit specific use cases, but understanding the differences between these 4 categories will help you understand the structure of any developed roadheader.
Sorting of compressive strength
Roadheader machines are also often categorised by their compressive strength. Roadheaders that weigh up to 25–30 tonnes and have compressive strength of no more than 70 MPa are classified as light.
For example, longitudinal cutter roadheaders usually fall into this category, as compressive strength is not as important as flexibility and manoeuvrability for this machine.
In the middle tier, we have medium-strength equipment with weights ranging from 30 to 50 tonnes and compressive cutting power in the range of 90–100 MPa. Depending on the model, longitudinal cutter, transverse cutter, and boom-type roadheaders are most likely to be classified as medium machines.
For heavy-duty equipment, we have roadheaders that go as heavy as 45 tonnes and up, with the threshold for compressive strength at 150 MPa. Big boom type or transverse cutter roadheaders have models that fall into this category. Meanwhile, most full-face roadheaders are classified as mostly heavy-duty machines.
What is a roadheader used for?
This section describes the most popular use cases for roadheaders and the most suitable type for the described task. Keep in mind that all cases and models are different, so make sure to read the manufacturer’s manual to learn the strengths and limits of our vehicle.
Tunnelling and excavation
The first roadheaders were built for tunnelling applications and excavation. Thanks to the rotation of cutting heads and their parameters, the machine generates enough power to break down surrounding soil and rock surfaces. With precise mining and cutting, a road header expands the underground space without causing too much damage to its stability.
For tunnelling and excavation, the best type of machine is the boom-type roadheader. The extendable boom creates more distance between the workers and a processed surface, making the task a lot safer. Full-face roadheaders can also be effective when the structure is safe enough to push the limits of speed and work output efficiency.
After using roadheders for excavation of materials, make sure to inspect and service the main components regularly and clean the machine to remove any contaminants.
Roadheaders have also been successfully used in mining thanks to their ability to remove and handle materials with great efficiency. For example, in underground structures full of rich materials, the expansion of the area only occurs after the removal of valuable resources. Roadheaders work the surface and use different cutting head attachments for better preservation of materials in a preferred form.
Accuracy and precision are the keys to excellence in underground mining. The best machine that meets these requirements is the longitudinal cutter roadheader. It can work a big surface and pick out and mine valuable resources without moving or causing extra damage to the surface with too much power.
If your roadheader is primarily used for mining, make sure to pay extra attention to the state of the cutting head. If not replaced in time, the damaged components will lose accuracy and may cause damage to the processed surface.
Rock reinforcement procedures strengthen fragile underground structures by installing bolts for rock stability. Boom-type roadheaders often have complementary tools for rock reinforcement, and the impressive manoeuvrability of the boom and attached cutting heads creates a perfect combination for ensuring stability.
Navigation and headings
In mining and tunnelling applications, headings are special small tunnels that are built to improve the airflow or to explore further underground surfaces. To create and navigate in these structures longitudinal and other compact roadheaders are your best options for the job. Remember – the key here is to reach further rock surfaces without disrupting the rest of the underground construction.
Roadheader longevity: how long does a roadheader last?
On average, a roadheader’s lifespan can range from 5000 to 25000 hours, or even exceed this limit if the machine receives proper care. Of course, the application of a roadheader for specific projects, its weight and power, and other factors can affect this data. For more accurate predictions, check out these parameters in the manufacturer’s manual.
The estimated operation hours can be cut short if the machine is not kept in optimal condition. Roadheader owners who cut maintenance costs usually end up paying a lot more for replacement parts. Below are the main criteria that affect roadheader longevity. Study them to better understand the optimal maintenance strategy for your heavy equipment machines.
A well-structured maintenance plan is the most important tool for keeping your roadheader in top condition. With a strict schedule and an appropriate protocol for damage control, your machine can even exceed the estimated operation hours.
If all servicing tasks are structured and enforced at appropriate time intervals, the main equipment components will never reach total equipment failure. Even better, a timely repair will stop the faulty part from damaging and affecting the functionality of other pieces.
Cleaning is the foundation of all maintenance procedures. If a roadheader does not receive regular cleaning, its components will start deteriorating much faster.
Last, but not least – the quality of maintenance. Operators and equipment managers track the state of all machine components, either manually, or with the help of heavy equipment software. Quality servicing procedures use appropriate liquids for fuel and lubrication, especially for parts that come in contact with the most contaminants.
Workplace conditions can throw your whole maintenance plan out of the window if you don’t take their effects seriously. For example, if the underground area has a lot more rocks and rough surfaces, the roadheader’s cutting heads and their attachments will need replacement much sooner.
Environmental conditions are another key factor that often gets overlooked, especially when talking about coal mining and tunnelling. While the machine will not be under heavy rain, the excessive moisture in underground structures can lead to rust on important roadheader parts.
If a roadheader is used outside, for example, on a construction site, the environment becomes an even bigger enemy. Rain, snow, floods, or extreme temperatures create dangerous conditions where unattended roadheader can reach total breakdown.
Now that we have a general sense of how to maintain a roadheader, let’s establish maintenance frequency. Scheduled servicing is the way to go, as it instils strict guidelines for equipment management. When it comes to roadheader servicing, it is always better to do too much than not enough. That being said, with a machine that is in contact with so many abrasive materials, daily servicing tasks will never be overkill. Below you can observe popular servicing strategies and a basic template for a maintenance schedule.
Roadheader model quality
Not all roadheaders are created equal. Since the first roadheader patent in the late 40s, this piece of heavy equipment has come a long way in functionality and flexibility. If you have a new, high-end roadheader, chances are your servicing tasks will be greatly simplified with the assistance of sensors and the automatic control system warning the operator about any unexpected damages.
That being said, a newer roadheader will be more efficient and last longer, but only if you take care of its servicing needs. A better model will have a whole set of electrical components that will need skilled electricians for proper servicing.
While not a very influential criterion, the experience of an operator reduces the mistakes they make during operation hours. When a person operating the equipment undergoes proper training and follows the manufacturer’s recommendations, the performed tasks will be more accurate, and the damage to machine components stays minimal.
Workload intensity can ruin all longevity estimates. If your roadheader is performing heavy-duty work and stays in contact with rocks and heavy materials for hours on end, the machine will break down a lot faster unless it receives extra servicing.
The recommended maintenance framework
For roadheaders, and many other heavy equipment machines, a maintenance schedule helps us minimise equipment breakdown and massive costs of repairs. Below is a framework for a maintenance plan, brought to you with the help of experts at Frontu.
Daily maintenance procedures happen once or twice a day, usually before a roadheader’s operator starts their shift. The process begins with a quick overview of an entire machine and the search for obvious signs of critical damage. Then, the next step is cleaning the boom and cutting heads, before moving to other main parts, such as the engine, air filters, wheels, and tracks.
After these procedures, an operator or an assigned technician checks all fluid levels and lubricates moving parts. In the end, a last checkup of all safety features is completed and the shift begins.
Every week, a designated worker performs a closer inspection of all visible components, looking for damaged parts, blunt tools, and other signs of damage that might have been missed during daily inspections and inspects the functionality of the hydraulic system.
Next, an assigned electrician checks the manufacturer’s guidelines and inspects the control system, tests energy consumption, plus looks for damages in all electrical components. Then, any signs of gradual damage are documented, and the equipment manager orders the most suitable replacement parts ahead of time.
Monthly maintenance procedures start with another thorough checkup on the roadheader and any signs of damage. After that comes the inspection of components that are never exposed to environmental factors. Here an assigned worker checks the engine compartment, and cooling components, and schedules the replacement of important parts.
Seasonal and annual maintenance
This section covers a deep dive into the state of all machine components and the scheduling of additional procedures if the need arises. Seasonal and annual maintenance tasks also cover plans for any changes in servicing for the future. Here an experienced equipment manager tracks the average breakdown time for roadheader components to predict and prepare for damages in the future.
Roadheaders provide great assistance in digging, transforming, and excavating all kinds of surfaces. Their biggest strength is best utilised for underground projects like mining and tunnelling, but without proper maintenance, these machines break down fast. In this guide, we covered the functionality of roadheader machines, their types, and depreciation factors that will help you build a servicing plan for the future.