A roadheader is a machine that gets no easy treatment, as it operates in confined underground workings, in dust, moisture and under heavy loads. Failures are therefore part of every roadheader’s working life. Some of them do not appear without warning – they are preceded by a series of signals that can easily be underestimated or missed in the rush of daily operation.
In this article, we have gathered an overview of the 6 most common roadheader faults, prepared on the basis of the day-to-day experience of our service department. We have illustrated them with photographs and comments, so that you can understand their causes and potentially avoid the same type of failure. Enjoy the read!
Two categories of roadheader faults
When roadheader failures are viewed as a whole, they can be divided into two types:
- The first is natural operational wear – these are machine components that simply reach the end of their service life and need to be replaced.
- The second, and much more common, is faults caused by neglect or incorrect machine operation – usually resulting from overly aggressive work at the face of the heading and delayed or neglected roadheader inspections.
For each of the faults described below, we will indicate which type we are dealing with, because this affects both the repair approach and the method of prevention.
1. Picks and pick holders – when the operator drives too close to the face
Type: operator error / neglect
Pick holders are the components that secure tangential picks to the cutting head body. As a rule, they should not cut the rock themselves – that is the job of the picks. However, when the roadheader operator drives too close to the face of the heading, the rock is no longer cut only by the picks and begins to slide over the holders.
In the photographs below, taken from one of hundreds of such cases, the characteristic abrasion marks on the holder surfaces are clearly visible – and the clearly visible hardfacing marks show that the holders had already been refurbished before.
Most common causes of this type of fault
The most common culprit is insufficient distance between the cutting head and the face during operation, as well as delayed replacement of worn tangential picks. A blunt pick no longer cuts the rock effectively, so the operator – wanting to maintain the previous production rate – decides to increase the pressure of the cutting head against the face.
As a result, the rock begins to load the pick holders, which leads to their rapid damage.
How can this be prevented?
- Regularly inspect the condition of the tangential picks and replace them before they become completely blunt.
- Maintain the correct cutting head pressure against the face.
- Do not hardface severely worn pick holders – internal stresses in the metal will cause cracking, even if the holder walls are still relatively thick and appear to be in acceptable condition.
2. Roadheader gearboxes – operation without oil
Type: neglect
Roadheader gearboxes – including travel gearboxes, cutting head gearboxes and slewing gearboxes – can operate for years without major problems, but on one condition: they need to be properly maintained.
In the photographs below, we show three different symptoms of the same neglect: a damaged Goetze sliding seal in the loading table gearbox, which led to oil leakage and contamination entering the gearbox, a sheared brake shaft and a worn spline in the travel gearbox. Each of these faults looks different, but they all have the same root cause.
Why does this type of failure occur?
Gearbox operation without oil, with oil contaminated by water, or simply without regular inspections and oil changes will inevitably end in a serious failure. The first signs of seal damage and oil leakage should be treated as a signal for immediate action, not as something to postpone until the next inspection. A worn spline and a sheared shaft, in turn, are the result of long-term overloading of the connection, which progresses faster when the entire system is poorly lubricated.
How can premature gearbox wear and damage be prevented?
- Change the gearbox oil systematically and check its quality – the presence of water or contamination immediately disqualifies the oil from further use.
- Regularly inspect the condition of the seals – an oil leak visible from the outside is the last moment for a relatively inexpensive repair.
- Do not ignore elevated gearbox temperature during operation – it is one of the first warning signs of lubrication problems.
3. Hydraulic and water systems – cooling, spraying and lubrication
Type: neglect / operational wear
This is the most case-rich section of the entire article – and for good reason. The hydraulic system, water system and lubrication system are three interconnected installations, and neglecting them has consequences that go far beyond the fault itself.
The photographs show seized components of the central lubrication pump – excavated material entered the grease and literally ground the pump’s precision components from the inside – a worn water pump valve with clear evidence of a lack of clean water in the system, damaged ITP curtain components, and the most telling case: a leaking water jacket on the cutting head motor, 230 kW, with a clearly visible “repair” made by mine personnel using two-component adhesive.
The same motor also shows flattening of the housing, indicating long-term operation of the cutting head in an extremely low position. This triggered a domino effect – starting with material fatigue, which led to leakage and, ultimately, to an unsuccessful temporary repair and damage to the motor itself.
Why does this happen?
Each of these faults has its own mechanism, but they share at least one common cause: leakage in the system that was overlooked or underestimated during inspection. Dirty water and contaminated grease act like an abrasive paste inside the systems, while insufficient cooling of the cutting head motor leads to overheating. A temporary repair instead of proper servicing is a direct path to a much more serious failure and a more expensive service job.
How can this type of fault be prevented?
- Regularly check the tightness of the central lubrication system, water system and hydraulic system.
- Replace hydraulic oil and filters according to the schedule – do not wait for visible signs of deterioration.
- Treat the first signs of oil or water leakage seriously.
- Never allow the roadheader to operate unless the cooling system is fully functional and leak-tight.
4. Loading table faults – table plates and gathering arms
Type: operator error
The loading table is the first area reached by the material cut by the roadheader cutting head, which is why it operates under constant mechanical load. The photographs show a bent and worn gathering star which, instead of efficiently moving the excavated material onto the conveyor, was fighting oversized pieces of rock.
Why does this happen?
Excessive cutting advance causes the detached rock fragments to become simply too large. When the boom is in an extremely low position, they may additionally become wedged in the space between the cutting head motor housing and the loading table. In such a situation, the gathering arms no longer transport the material efficiently; instead, they struggle against it. This quickly leads to deformation and accelerated wear of the gathering stars and the roadheader loading table.
How can this situation be prevented?
- Adjust the position of the cutting head boom and the cutting speed to the hardness of the rock being excavated.
- Avoid keeping the boom in extremely low positions for prolonged periods when working with harder or more compact excavated material.
- Regularly inspect the condition of the gathering stars / gathering arms – their deformation is visible to the naked eye and is a clear signal to intervene before the loading table gearbox is damaged.
5. Chain conveyor – broken chain and damaged shafts
Type: operator error / neglect
The chain conveyor is the only route for transporting excavated material from the face to the rear of the roadheader, so when it stops, the entire machine stops. The photographs show two related types of damage: a ruptured return shaft and a visibly stretched and worn conveyor chain.
This is a good example of a domino effect – one-sided seizure of the return shaft bearing caused uneven loading of the chain on one side, which directly accelerated its wear.
What causes this type of fault?
When inspection of the drive system is postponed for too long, shaft seal failure is often the first problem to occur, allowing water and contamination from the face to enter the bearings. This leads to bearing seizure and increased load on the chain, which in turn may result in chain elongation or breakage, shaft rupture or damage to the shaft teeth.
The entire chain conveyor system also wears faster when oversized pieces of excavated material block the conveyor and generate excessive loads.
How can this be prevented?
- Regularly inspect the condition of the drive shaft bearings and seals – increased temperature and louder operating noise are the first indicators of an approaching failure.
- Regularly check the chain tension and adjust it in accordance with the manufacturer’s recommendations.
- Adjust the cutting rate so that the material reaching the conveyor is not made up of oversized lumps.
- Treat the conveyor drive and chain as an interconnected system – a fault in one area affects the entire assembly.
6. Torn cables and hoses, and other operational oversights
Type: maintenance neglect
Electrical cables and hydraulic hoses are basic components that can easily be overlooked during everyday roadheader operation – until something gets torn off. And this happens regularly, because they operate in a confined, uneven excavation, under constant vibration and with a continuous risk of mechanical snagging.
The same applies to other roadheader accessories and auxiliary components, which may not attract much attention during daily operation. The photographs show a particularly telling case of a roadheader travel motor with a sheared drive shaft caused by what seemed to be a minor oversight.
The mounting bolts of the travel motor regularly loosen due to vibration during roadheader operation. If even one of them is not properly tightened, the motor shaft is no longer coaxial with the travel gearbox, which causes it to crack or become detached. The result of this fault is a travel system failure and forced downtime for servicing.
Causes of this type of failure
Many such cases result from natural material fatigue caused by long-term vibration and impacts – in these situations, the human factor is relatively limited. However, a significant number of failures are still the result of missing routine inspections or carrying them out only superficially.
How can such failures be prevented?
- Carefully inspect the condition of cables, hoses and their mountings as part of every routine service check.
- Regularly tighten the bolts securing auxiliary equipment, especially travel motors – this is literally a few dozen minutes of work that can prevent many hours of downtime.
- Replace cables and hoses with visible mechanical damage without delay – a damaged hydraulic or water hose is, above all, a serious safety risk for the roadheader operator and the rest of the crew.
Do you have a roadheader and need technical support?
If your roadheader shows any of the symptoms described above, or has simply been through years of intensive operation without a comprehensive inspection, use the support of Minostar specialists.
As a company with over 12 years of experience, we offer professional overhauls, modernisations and repairs of roadheaders. Our offer also includes the supply of high-quality spare parts for roadheaders, available from our on-site stock.
Spare parts for mining roadheaders
At our company, you will find a field service team ready to go underground at the mine, spare parts from our own warehouse and many years of experience in roadheader diagnostics and repairs. And if the machine requires more than a basic repair, our proprietary RESTART programme can restore it to full technical working order.
See how the Minostar RESTART program works!
Most common causes of mining roadheader failures – summary
Looking at these six main categories of faults, it is difficult not to notice a common denominator. Only a small proportion of roadheader failures result from unavoidable operational wear – the vast majority are the consequence of postponed inspections, ignored early warning signs and errors in day-to-day operation.
Most of the situations we have presented can be avoided by following the recommended service intervals and using common sense.
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