Mining

Electrical Safety for Underground Mining

Head Frame and Hoist

The hoist must take the equipment and miners up and down the shaft and bring ore to the surface for processing. The drive used on the hoist is a large electric motor powered by a frequency converter. The floating or high-resistance grounding system is used as the dominant grounding system to ensure maximum security. Bender manufactures the ISOMETER® for optimal electrical safety in underground mining.

Ventilation

Ventilation of underground mines is crucial for safe operation. An interruption to the ventilation is potentially life-threatening. It can also create the potential for a build-up of gasses creating a fire hazard and loss of production due to mandatory evacuation. This means continuous ground-fault monitoring using RCMS is vital. Insulation resistance monitoring provides early detection of insulation breakdown and can assist in preventative maintenance planning.

Drainage

Drainage of underground mines is essential. Any interruption to the drainage system increases the risks of shafts filling up with water ruining equipment, and people being put in danger. From this perspective, continuous insulation monitoring with ISOMETER®s or RCMS residual current monitoring systems (ground-fault monitors) is essential. Early detection of insulation degradation can help prevent prolonged and unnecessary downtime. Where portable trash pumps or submersible pumps are handled, additional safety precautions should be taken by installing Bender Lifeguard units for personnel protection.

Conveyor Belts

Electric motors are generally employed for conveyor belts used in mining, driven by soft starters or frequency converters. However, these often generate harmonics and DC currents which would typically not be present in an AC system. With regular ground-fault protection or simple insulation monitors (e.g. 3 lamp method or 2 voltmeter process), these circuits cannot be monitored and adequately protected. These specialized applications require more modern monitoring equipment which can recognize and report insulation breakdown and leakage current to ground quickly. Some standards even require a quick shutdown, which can be achieved via ground-fault monitoring devices.

Mobile Equipment and Movable Substations

Mining equipment is typically electrically powered. The trailing cables powering these vehicles need monitoring. The monitoring ensures proper bonding of the equipment to prevent hazardous shock potential on the frame. For these applications, Bender offers a range of monitoring options, depending on the requirements for pilot-wire (ground-check) monitoring, ground-fault current protection, or ground conductor monitoring. If the equipment being powered is DC, the ISOMETER range of products can be applied.

Substations feeding power to moveable and mobile loads are often required to be resistance grounded. Some standards require continuous monitoring of the neutral grounding resistor. The Bender RC48N and NGRM700 are ideal choices for this protection. Outgoing trailing cables can be monitored with an RC48C ground-fault ground-continuity monitor.

Continuity of Service
Control fault current and have alarm-only operation on the first ground-fault.

Ease of Retrofit
Ability to easily and cost-effectively upgrade older equipment.

Improved Safety
Reduces potential for shock and arc flash hazard. Arc flash is reduced by as much as 95%. Automatic fault location at feeders and loads can eliminate the need to open doors on energized equipment during troubleshooting.

Reduces Maintenance Costs
Accuracy of detection leads to a decrease in maintenance costs and the need for human interaction with the system.

Downloads

NameCategorySizeLanguageTimestampD-/B-Number
Electrical safety - Product overview Product Overviews 4.8 MB EN2024/03/0505.03.2024
2020 Guidelines (US) Technical Information 1.9 MB EN2020/06/1515.06.2020
Mining Market Segment Brochures 2.6 MB EN2021/08/2626.08.2021
Bender Industry Application Market Segment Brochures 19.1 MB EN2022/08/1919.08.2022

Products

Measuring and monitoring relays

RC48C
RC48C

Trailing cable protection, ground-fault ground-check monitor

Resistance Grounded Systems (HRG/LRG)

LINETRAXX® NGRM700

Monitor for use in high-resistance grounded systems

Measuring and monitoring relays

RC48C
RC48C

Trailing cable protection, ground-fault ground-check monitor

Details

Resistance Grounded Systems (HRG/LRG)

LINETRAXX® NGRM700

Monitor for use in high-resistance grounded systems

Details