Mining & Quarrying Industries

Dependable vibration monitoring

Within the coal, mining and quarrying industries, it is common for machinery to run 24/7, often under extreme environmental conditions, with high levels of dust, moisture and temperature, and in areas where access for maintenance or repair is difficult.  With machine downtime potentially costing many thousands of dollars per hour, and with machine failure representing a safety risk, it is crucial that the rotating parts of machinery (for example, motors, gearboxes, pump, screens, crushers, conveyors) are continuously monitored to warn of bearing or component wear, as part of a predictive or preventative condition monitoring programme.

Vibration monitoring is key to the success of a preventative maintenance programme.  Its use has been accepted and proven for the detection of faults that include bearing wear, misalignment of shafts and out of balance fans. 

At Hansford Sensors we offer a wide range of industrial accelerometers or vibration transmitters, designed for use throughout the mining and quarrying sectors arund the world.  These are suitable for end users, vibration analysts and OEMs.

ATEX certified solutions

Our product range includes industrial accelerometers certified to the latest ATEX (IECEx) standards (Group I Mining).  In addition, we offer products developed to operate with conveyors and other equiopment that is running at under 60Hz. In these situations a higher sensitivity sensor, for example, our 500 mV/g (HS-100 Series) can improve the signal to noise ratio and increase the capability of conducting a full data analysis. If 4-20mA vibration sensors (HS-420 Series) are installed with the signal being interfaced to a PLC (programmable logic controller) or similar system, we recommend our 0-25 mm/s RMS velocity sensor (HS-420 Series). This is a great method for monitoring ‘out of balance’ on fans. A 0-2g RMS acceleration 4-20 mA sensor (HS-422 Series) is good for providing protection on conveyors in between routine surveys.

Whether the sensors are to be installed on a crusher, screen, conveyor pulley or drive, we recommend a side-entry/low profile model. If conditions permit, top-entry can be used, but the location of the sensors may need to be reviewed to ensure debris (for example, coal falling from a conveyor) cannot damage the sensor. Our top-entry sensors can provide a cost-effective option in some applications, for example in pump rooms.

Mining is one of the harshest environments where sensors are installed so we recommend using armoured/braided cable as it has less chance of potential damage.

We also advise using 2 Pin MS connector sensors with separate IP66 2 Pin MS cable assemblies so if an urgent shutdown is needed, it is much easier and quicker to remove rather than dismount the complete sensor.  In installations where there is a strong possibility of the cables being damaged, this method would require replacement of only the cable assembly rather than the sensor. This has to be weighed up against the initial cost advantage that integral cable units have over units where a separate cable assembly needs to be purchased. The minimum IP rating for mining and quarrying applications should be IP65; for areas where sensors are submersed, IP68 units should be used.

For both online and offline applicatons we offer a full range of stainless steel enclosures, for connecting the accelerometer cables. For offline, a local switch or connection box (HS-SE/CE) is recommended, providing the facility for the data collector to be connected. If the application is for an online system, local stainless steel enclosures are available. We also offer custom-built products that have been designed for harsh conditions, and include special enclosures with fabricated roofs to provide additional protection.

HS-500 Series for maximum control of conveyors and screens

Our comprehensive family of vibration modules (HS-500 Series) has been customised to suit applications in mining and quarrying areas where vibration conveyors/screens need to be controlled.

To get the best results each sensor should be mounted as close to the components - typically a bearing - as possible, in a rigid area of the housing (for example, not on motor covers). It is also important to ensure mounting options are suitable for the environment and that installation techniques to guarantee the best readings are followed. Loose mounting or poor surface preparation will give rise to resonance or loss of high frequency data. The use of magnetic mounts or spikes may reduce the high frequency signals, but this is unlikely to cause a significant problem when trending data. Cables should be clamped to the body of each sensor with a cable tie to prevent strain and excessive movement of the cable to avoid false signals. Cables should also be fixed at suitable intervals to cable trays or other suitable supports.

Further reading:

Application note: Iron ore mining company invests in our enclosure systems

Technical article: Our latest advice on using ATEX sensors

Hansford Sensors Ltd has a wealth of experience in the design and manufacturing of industrial vibration sensors for various applications and can offer technical advice on specific applications. For further advice please consult our technical team on +44 (0) 845 680 1957 or email sales@hansfordsensors.com.