Avoid downtime in the crushed stone plant
When the plant stops abruptly during production, you have to start it up again with a heavy load on a conveyor belt and a crusher full of stone. It’s a huge strain on gears, motors, belts and can cost a company significant sums of money. Downtime in the crushed rock plant can be a burden not only through wear and tear and equipment that must be replaced in the plant, but also through irreversible costs due to prolonged downtime. In this text, we will look at some of the most typical reasons for production stoppages and how to avoid them.
01. Tire wear
When conveyor belts run crooked, there is a great risk of the rubber catching on the frame and starting to cut the steel profiles. Then it becomes both costly and dangerous. There are many reasons why conveyor belts can go wrong; incorrect use of tensioning stations, misaligned return rollers, sticky rollers, etc.
To avoid uneven driving, you should have a regular maintenance routine to prevent major problems. You should also consider using a belt tracker, a device that automatically centers the conveyor belt, or a guide roller that prevents the belt from slipping off the roller.
02. Metal detector and magnet
Rock bolts, blasting debris, tools and machine parts can also cause major damage to the crusher and conveyor belt.
To avoid this, it is fairly standard practice to use a metal detector. A challenge with the detector can also be that it is so sensitive that it stops the tape due to trivial objects, such as tin foil or simply too much iron in the rock masses. If this becomes a problem that leads to many stops, it may make sense to install magnets on the conveyor belt as well. A magnet for the conveyor belt will in most cases be sufficient, but if you still experience problems, it may also make sense to look at a magnetic drum.

03. Bearing failure
If you have a bearing that is too small for the task it is set for, the torque will be too great and the service life of the bearing will be drastically reduced. Incorrect lubrication can also have major consequences in the long term. For example, if you have too much lubrication on a high-speed bearing, the friction can be far too high, leading to excessive heat generation and breakdowns that reduce safety and efficiency.
To avoid bearing failure, it is important that the bearing is the right size and that lubrication and maintenance are carried out carefully.
04. Girhavari
If you have an undersized gear, the high torque will lead to excessive load, which will reduce the service life of the gear. Proper lubrication is also important. Too little oil, too much oil, the wrong type of oil. All of these things can cause major problems in the long run. It is also important to check that there is no water in the oil. This can be caused by, for example, a leaking or missing gasket on the filler plug.
To avoid overpressure, it is important that the vent plugs in the gearbox are open. Small parts often disappear, such as the cap on the vent plug in the gearbox. This can cause dust to enter the vent plug, clogging it and leading to overpressure. If the entire vent plug is missing or a tight plug has been fitted, oil may leak out into simmering rings. If the gearbox runs with overpressure and oil sweats out in the seals, there will eventually be too little oil on the gearbox, which of course leads to inadequate lubrication. Then there can be a high risk of breakdowns and downtime after a while.
05. Screen cloth
The viewing screen takes a beating when pointed stones “strut” across it day in, day out. What you want to avoid at all costs is holes in the fabric. The sieve cloth’s task is to act as a large colander that only lets through the small parts you want, and then sends the larger parts on their way. If you get a hole in your screen cloth, larger fractions will pass through and the storage piles will become contaminated. This leads to downtime as you have to replace the cloth, as well as clean and re-crush the storage pile.
There are a number of different screen fabrics to choose from, both in different thicknesses and materials. Everything from modular fabrics to finger screens, Iseflex to side-tensioned/long-tensioned fabrics, rubber, PU (polyurethane) or the traditional steel fabric. Which screen cloth is right for your work can vary based on priority, climate and cost.
06. Digitization of crushing plants
By using digital control and monitoring with sensors, rather than manual inspection, you get high-quality, real-time data on everything from power consumption to the status of the various machines in the plant. This allows you to anticipate problems before they occur. Digitizing your crusher can help you avoid downtime and surprises. Read more about digitalization of crushed stone plants here.

How much does downtime cost?
Let’s look at a practical example. Your plant produces 110 tons per hour and you charge NOK 80 per ton. If you experience downtime in your crushed rock plant, this will cost you in excess of NOK 70,000 if the downtime lasts a full working day. This is only the cost of lost production. That’s why good maintenance and preventive work is important for the environment, safety but also for sales.
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4 good reasons to use magnets over conveyor belts.
Can digitalization of crushed rock plants increase efficiency?