Cooling and pumping are among the largest energy consumers in deep mining, especially where access to ore demands long vertical drops and extended water loops. For a new 7 MW underground bulk air cooling (UBAC) system in Poland, mine operator Polska Grupa Górnicza and system integrator Elektrometal sought to reduce pump power, avoid extra excavation, and keep maintenance simple while ensuring a low temperature increase of the cooling medium (maintaining at 0.2°C).
The incumbent multi-vessel energy recovery approach used in similar mining operations is bulky and valve-intensive, often forcing tunnel height extensions and adding operational complexity. The project team needed a compact, reliable energy recovery device that would fit standard headings, provide operational flexibility, and deliver a fast payback.
A sustainable solution
Elektrometal selected Energy Recovery’s PX® Pressure Exchanger® for the chilled-water circuit, installing one modular train of six Pressure Exchanger units rated to 120 bar. Energy Recovery is a trusted leader in the industry, with more than 35 000 of their revolutionary PX pressure exchangers deployed throughout the world. In this application, the train transfers pressure from the high-pressure chilled-water stream to the low-pressure warm-water return, capturing energy that would otherwise be lost across a throttling valve.
Handling approximately 300 m3/h of refrigerated water, the pressure exchanger reduces the power required to pump water back to surface equipment while preserving target temperatures underground. The simple rotor design has few moving parts and no complex valve sequencing or electronic controls, which translates to high availability and zero routine maintenance. A compact footprint eases installation in constrained drifts, and the modular architecture provides operational flexibility since units can be taken offline to match lower seasonal loads while the system continues running.
Commissioning in March 2025 was seamless, with the PX train installed within the standard tunnel opening and integrated into the existing control philosophy.
“The Pressure Exchanger solution has delivered consistent, high performance while reducing cooling losses and freeing our technicians from frequent inspections,” said Piotr Cieslar, Director of Sales, Elektrometal. “Its compact footprint saved valuable underground space, and the modular train gives us flexibility as the mine evolves.”
Recovering pressure energy inside the UBAC circuit offers a practical lever to cut operating costs without compromising safety or production. Compared with bulkier multi-vessel systems, the PX train provides a smaller footprint, fewer wear components, and straightforward operation that helps operators de-risk projects and control lifecycle cost.
By providing a compact, lower-complexity alternative to traditional multi-vessel energy recovery systems, the PX solution is helping expand adoption of UBAC architectures. Its modular, maintenance-free design reduces space and operational barriers, making UBAC a more practical option for both new projects and retrofits.
Clear results
The facility is realising meaningful reductions in pumping energy and operating cost while improving system controllability and space utilisation underground.
- Energy savings: 9 GWh per year of electricity avoided.
- Cost savings: US$1.3M per year at an electricity rate of US$0.15/kWh.
- 1 MW pump avoided with the Pressure Exchanger.
Beyond the numbers, the PX train’s compact design eliminated the need for additional excavation and reduced the burden on maintenance crews compared with larger multi-vessel alternatives.
Looking ahead
As the mine advances, the PX train’s bolt-on scalability allows capacity increases or flow-path changes without major redesign. The approach provides a repeatable template for other deep mines seeking to lower energy use, avoid unnecessary excavation, and simplify operations with proven, low-maintenance equipment.
Who is Energy Recovery?
Energy Recovery designs and manufactures energy-saving technology for critical infrastructure worldwide. With more than 30 years of leadership in desalination and over 35 000 PX® Pressure Exchanger® units installed globally, the company helps customers across water and industrial applications improve reliability, reduce operating costs, and lower emissions. Headquartered in the San Francisco Bay Area, Energy Recovery provides global sales and technical support.
Author bio
David Kim-Hak, Vice President of Wastewater at Energy Recovery, brings more than six years of leadership within the company. With a background in chemical engineering and a track record of driving innovation and client-focused solutions, he has been instrumental in advancing wastewater technologies and winning global recognition for innovation in desalination.