Electric drill rig set to transform mining

A transition from diesel-driven to battery-powered drill rigs is expected across Southern African mines, with the introduction of a highly-automated underground electric drill rig.

The innovation has been in development for the past three years and, accoding to Sandvik Mining & Rock Technology, the company’s new DD422iE rig has already seen enthusiastic take-up in mining countries with strict anti-pollution regulations.

The key benefits of the battery concept in underground drill rigs are said to include:

• Zero emissions
• Less heat
• Safer and healthier working conditions owing to lower noise levels and reduced risk of fire
• Increased drilling productivity
• Reduced operating costs
• Better energy efficiency
• Less noise

The Sandvik DD422iE’s electric driveline, with an electric motor mechanically connected to axles for high torque and high efficiency, allows the rig to tram independently between working areas. The unit’s high-precision inverter is designed to deliver exact control of the tramming speed.

The company explains that the rig needs to be connected to mains power only during the actual drilling, at which point the electric motor is connected onto hydraulic pumps. Improved drilling power of up to 20% is said to be achieved by an active power compensation system which draws reserve power from batteries during peak loads. Battery charging is done during those phases of the drilling cycle when power intake is low, such as during boom movements, reducing the waiting time to charge up batteries.

The unit uses sodium nickel chloride technology, which is regarded as the safest battery system for underground conditions. The company offers a battery rental option to customers, taking responsibility for battery inspection and maintenance, as well as responsible disposal at the end of the battery’s life.

This option means that the battery becomes an operational cost for the mine, rather than a capital expense and aims to give customers the certainty of predictable operating costs while adopting a new technology.