Southern African mines will soon begin the transition from diesel-driven to battery-powered drill jumbos, with the introduction of the world’s first highly-automated underground electric drill rig by Sandvik Mining & Rock Technology, according to the mining OEM.
Saltiel Pule, Sandvik Mining & Rock Technology’s Business Line Manager for Underground drilling in southern Africa, says the Sandvik DD422iE rig has already seen enthusiastic take-up in mining countries with strict anti-pollution regulations such as Canada, with the innovation having been in development for the past three years.
“The key benefits of the battery concept in underground drill rigs are zero emissions and much less heat, making for safer and healthier working conditions,” Pule said. “There are many other advantages to this technology, however, including increased drilling productivity, reduced operating costs and better energy efficiency.”
One of the first mines to have received the DD422iE was the all-electric Borden mine in Ontario, Canada. Since then, Barrick has trialled a unit at its Hemlo underground mine, also in Ontario.
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 delivers exact control of the tramming speed, according to Sandvik.
“The rig only needs to be connected to mains power during the actual drilling, at which point the electric motor is connected onto hydraulic pumps,” Pule says.
Improved drilling power of up to 20% is achieved by an active power compensation system which draws reserve power from batteries during peak loads, according to Sandvik. Battery charging is carried out during those phases of the drilling cycle when power intake is low, such as during boom movements. There is, therefore, no waiting time to charge up batteries.
In pursuit of zero-harm safety standards, the unit uses sodium nickel chloride technology – regarded as one of the safest battery systems for underground conditions.
Sandvik also offers a battery rental option to customers, taking responsibility for battery inspection and maintenance, as well as responsible disposal at the end of battery’s life, the company says.
“The battery therefore becomes an operational cost for the mine, rather than a capital expense,” Pule says. “This option also gives the customer the certainty of predictable operating costs while adopting a new technology.”
In addition to zero emissions and less heat generation, the electric drill rig produces less noise, making communication easier and working conditions less stressful, Sandvik added. There is a reduced risk of fire, as there are no fuels exposed to hot surfaces – as can happen with diesel engines.
“The range of indirect savings that customers achieve when they move from diesel to electric includes lower ventilation costs underground, no need for diesel storage and diesel pipelines, and more control over operating costs,” Pule says.