Eldorado Gold has confirmed it is testing Newtrax’s environmental monitoring platform and ventilation on demand (VoD) solution at the Olympias mine in Greece.

Mine ventilation represents the single largest electrical load at the Olympias mine and, in response to the EU energy crisis and Eldorado’s own Energy and Carbon Management System, the company has been aggressively advancing VoD implementation at the Greek operation.

The benefits associated with VoD include:

• Targeted air circulation and improved air quality as the working environment is upgraded as fresh air is distributed through the mine in a manner that ensures workers’ health and safety;
• Right-sizing fans to provide the required volumetric flow rates (from a static to a dynamic and intelligent air supply leading to a reduction of the total required airflow within a mine);
• Improving energy efficiency and power consumption – by reducing the total airflow, energy can be saved in disproportionately high amounts due to the cubic relationship between volume flow and fan power; and
• Enabling the production and development activities at the lower levels of the mine.

To obtain the immediate benefits of VoD, the Olympias mine operations team implemented a manual solution during 2022, where the team adjusts ventilation fan operations each day based on the daily mine plan. As part of this, variable speed drives were applied to many of the fans to allow air flow adjustments to meet operational needs with minimum electricity consumption. This process is being carried out via the control room on surface, with a SCADA system used to disconnect fans that are not planned to be used during the day.

This transition saw ventilation fan consumption decrease from about 620 kWh/mth of electricity consumption per kW of installed fan capacity to about 377 kWh/mth of electricity consumption per kW of fan capacity, representing a 40% decrease in energy consumption, according to Simon Hille, SVP, Technical Services and Operations. At the end of 2022, the mine had 3.1 MW of installed ventilation capacity.

“This 40% reduction represents about 9,051 MWh/y of electricity savings and about 3,800 t/y of GHG emission reductions (utilising the updated emissions factor of 0.42 t CO2e/MWh),” he told IM.

While manual VoD has been very effective, automated VoD will further decrease energy consumption and eliminate the many worker hours required to implement VoD on a daily basis, according to Hille.

This is where the company brought in Newtrax, part of Sandvik Mining and Rock Solutions, to implement an automated VoD system.

The Olympias mine will be the first Newtrax installation utilising LTE as the communications medium versus low frequency radio (leaky feeder) utilised previously, according to Eldorado. LTE was installed in August 2022 with the help of Cosmote.

The automated platform will also leverage data from the existing Micromine fleet management system and RFID-based employee location tags provided by Newtrax. Ventilation will then be provided by surface fans with higher ventilation capacities.

Olympias already uses Accutron Technology to monitor air flow velocity and Trolex technology to monitor mine air quality, according to Hille.

In addition to the VoD benefits, the Newtrax technology will improve mine safety (mine evacuation and rescue) as well as improve productivity by allowing mine supervision to have a better understanding of resource locations for improved decision making, the company says.

“Technology and connectivity are the key parameters for VoD to operate effectively,” Hille said. “Automated employee and equipment geo-location is necessary as it helps adjust ventilation delivery to different areas by effectively shutting down entire areas and thus reducing the overall ventilation demands. This requires smooth connectivity with the LTE across the mine site.”

Last month, Newtrax installed five Bluetooth low energy (BLE) devices on select mobile machinery to test system connectivity. Once troubleshooting is complete and communication is established between the underground fans and Newtrax BLE devices, full-sized implementation will be considered with equipment procurement, installation and commissioning to be done by end of Q1 (March quarter) 2024.

On top of this, Eldorado Gold is evaluating non-diesel powered equipment for all new equipment purchases and, in some cases, as an alternative to equipment rebuilds.

“The mine ventilation benefits of equipment electrification are included in the evaluation of that equipment,” Hille said.