In most underground mines, the largest consumer of energy is the ventilation system. Vital for providing essential fresh air to miners, ventilation systems have traditionally been very static; fans are set to run continuously 24 hours a day, 7 days a week. As well as preventing the build-up of dangerous levels of diesel equipment gases (CO, NOx) and diesel particulate matters (DPM) underground, they also evacuate respirable dust and the noxious gases associated with extracting ore and other waste chemicals.
The Goldcorp Éléonore gold mine has a fresh air capacity of more than 900 kcfm (425 m3/s). The principal ventilation system consists of two Howden Alphair 12300-AMF-6600 exhaust axial fans with a nominal power of 2,000 HP (1,471 KWh) each, configured in parallel. There is also an exploration shaft that has two Howden Alphair 11200-AMF-6600 main intake fans with a nominal power of 750 HP (551.62 KWh), again configured in parallel. The mine also has over 140 auxiliary and booster fans operated in conjunction with seven dampers and air regulators, and a heating system fuelled by propane.
Goldcorp commissioned us to provide them with a control system that would provide safe, efficient ventilation while reducing energy demands and costs.
We set out to create an automated system covering all the ventilation equipment in the Éléonore mine, including the main fans, underground auxiliary fans and airflow regulators. 30 Ventilation Monitoring Stations (VMS) were installed to determine the quantity and quality of fresh air at various points underground. Each VMS includes one flow sensor and three gas sensors, to detect CO, NOx and C3H8, and is an integral part of the VentSim™ CONTROL system.
A mine-wide tracking system was installed to detect the presence of vehicles and personnel underground. Each of the 144 vehicles was fitted with a Radio Frequency Identification (RFID) tag that indicates its position in the mine and whether the engine is operating. Everyone working underground was also given a unique RFID tag that connects to one of 254 zonebased Access Points.
The tracking data is transmitted from these Access Points to the control room on the surface through a hybrid fiber optic network. There is currently between 60% and 70% wifi coverage in the mine, with plans for 100% coverage during full production. The data from the RFID tags provides enhanced safety and management of the movement of vehicles and personnel, as well as Ventilation on Demand (VOD).
The data from the tracking system allows ventilation requirements for each zone to be calculated by the VOD logic software. This information is then used to automatically modify the speed of each of 140 underground auxiliary fans, to ensure that each zone of the mine receives enough fresh air.
The control system in the Éléonore mine can be easily expanded as the mine grows in size, to maintain adequate, safe ventilation in every part of the workings as new areas and levels are opened up.