The service life of the hammers in rotary crushers for limestone is 80–120 thousand tonnes, depending on the hardness of the raw material, particle size and moisture content. The service life can be extended by adjusting the clearance, using chrome-plated hammers and replacing them in good time. The figures given are for the PF-1214, PF-1315 and PF-1520 models.
According to the official specifications of rotary crusher manufacturers, a set of working hammers is sufficient to process between 80,000 and 120,000 tonnes of medium-hardness limestone; this figure represents an engineering reference range derived from the results of trial operations at in Central and Eastern Europe during the period 2024–2025.
The key parameter affecting the service life of the set is the hardness of the limestone on the Mohs scale; at a hardness of 3 to 4—which corresponds to standard construction limestone—the performance remains within the specified engineering reference range. At hardness levels above 4, the service life is reduced by 30–45 per cent, according to actual data from quarries in the Krasnodar Krai obtained in 2025. The second significant factor is the particle size distribution of the feedstock; when feeding pieces up to 500 mm in size, the service life is reduced by 18–22 per cent compared with processing raw material of a fraction size up to 300 mm. These figures are based on the official specifications of major Chinese and European manufacturers of crushing equipment
Regular adjustment of the clearance between the bits and the deflector plates every 1,500 operating hours increases the overall service life of the set by 22–27 per cent, according to actual data from mining sites in the Siberian region. A third effective method is the use of bits with a chromium-based alloy overlay; such sets have a service life that is 40–50 per cent longer service life than standard carbon steel hammers, according to the manufacturers’ official specifications. It is also worth noting that the timely replacement of worn hammers before they reach critical wear—70 per cent of their original thickness—helps to prevent rotor overload and furtherfurther wear to adjacent components of the crusher’s structure
The table below sets out the current specifications for rotary crusher models with a capacity of between 150 and 350 tonnes per hour, which are most commonly used for processing limestone
| Crusher model | Number of tickets included | The weight of one bill was kg | Limestone reserves (tonnes) | Data source |
| PF-1214 | 4 | 112 | 80000-90000 | Official specifications |
| PF-1315 | 6 | 135 | 95000-110000 | Actual test data |
| PF-1520 | 6 | 187 | 105000-120000 | Scope of the Engineering Reference |
First question: how does the moisture content of limestone affect the service life of the hammers? When the moisture content of the raw material exceeds 8 per cent, the service life of a set is reduced by 15–20 per cent. This is due to the raw material sticking to the rotor elements and increased friction during crushing. The second question is: can a single set of hammers be used to crush rock types other than limestone, such as granite, basalt and other hard rocks? In such cases, the service life of the hammers is reduced by 60–70 per cent; therefore, using standard sets designed for limestone to process hard rocks is not economically viable. Third question: how often should the condition of the hammers be checked? It is recommended to measure the thickness of the hammers every 200 operating hours, which allows for timely planning of replacements and avoids unplanned downtime of the crushing plant. These recommendations are set out in the official operating manuals of most manufacturers of gyratory crushers
