Lower Rainbow Valley Well Field Electrification Project in British Columbia
Operational efficiency and emission reduction are priorities at Mount Milligan Mine. As part of BC Hydro’s Industrial Energy Manager program, Mount Milligan is committed to energy conservation.
About the Lower Rainbow Valley Well Field
Mount Milligan requires use of permitted freshwater to maintain mill operations. Freshwater is sourced from surface water withdrawals from Phillip Lake and Rainbow Creek as well as withdrawals from groundwater wells. Mount Milligan operates three groundwater wells located at the Lower Rainbow Valley, pumping the water to the tailings storage facility (TSF) for storage and use. Through a Conditional Water Licence issued under the Water Sustainability Act, Mount Milligan can divert 3,860,006.4 cubic metres of groundwater annually from the three groundwater wells located at the Lower Rainbow Valley.
The Challenge: Reliance on Diesel Generated Electricity
Located 3.5 km away from the mine’s existing electrical distribution network, the Well Field did not have the infrastructure in place to operate by means of BC Hydro generated electricity. As a result, the well pumps were originally powered by electricity generated from two 500 kW diesel-fired generators (one prime, one standby). The generators were costly to operate and emitted a substantial amount of greenhouse gas emissions when compared to electricity generated by BC Hydro.
Mount Milligan Mine sought to remove the diesel-fired generators located at the Lower Rainbow Valley Well Field by extending the mine’s 25 kV overhead distribution network from the mine facility to the Well Field. In early 2020, with a financial commitment from BC Hydro’s Low Carbon Electrification Incentive Fund, Mount Milligan constructed the 3.5 km extension of the
25 kV electrical distribution network. With clean and reliable electricity available to operate the well pumps, Mount Milligan removed the diesel generators at the Lower Rainbow Valley.
Reduction in GHG Emissions and Operating Costs
Transitioning from diesel generated electricity to BC Hydro generated electricity at the Lower Rainbow Valley Well Field is estimated to reduce Mount Milligan’s carbon footprint and operational costs by:
Reducing annual operating costs by more than C$1,000,000; and
Avoiding approximately 23,000 tonnes of carbon dioxide equivalent emissions through to 2028 – equivalent to taking more than 7,000 passenger vehicles off the road for one year.