Ensuring electrical safety in underground mining

The shaft tower is required to take the miners up and down the shaft. The drive is a large electric motor powered by a frequency converter. To ensure maximum security, the IT system is used as the network system here. It is monitored via an ISOMETER®.

Ventilation of underground mines is a crucial criterion for their operational safety. An interruption to the ventilation is potentially life-threatening for the miners, includes an increased fire risk and failure of the production system. This means continuous residual current monitoring using RCMS is vital, as it detects any hazardous changes to the power supply immediately.

Drainage of underground mines is incredibly important. Any interruption to the drainage system increases the risks of shafts filling up with water and people being put in danger. From this perspective, continuous monitoring with ISOMETER®s or RCMS residual current monitoring systems is essential. They immediately recognise hazardous changes in the power supply.

Electric motors are generally employed for conveyor belts used in mining, which are driven by soft starters or frequency converters. However, these generate critical harmonic vibrations and DC currents which would not normally be present in the feeding AC system. With regular RCD or simple insulation monitors (e.g. 3 lamp method or 2 voltmeter process), this cannot be monitored with the requisite precision. There is a need for modern monitoring equipment which can recognise and report these problems quickly. Some standards even require a quick shutdown, which can be achieved using Bender insulation monitoring devices.

Mining vehicles are electrically powered. These cordless vehicles need monitoring of the earthing conductor in the cable (pilot wire monitoring). For this application, Bender offers a range of monitoring options, depending on the requirements for wire monitoring or fault current/earth conductor monitoring.