Mineral Hill Microhydro Power Generation Study

Award: 2016 ACEC Montana Engineering Excellence Award – Studies, Research and Consulting Engineering Services

Located just north of Yellowstone National Park, Kinross Gold Corporation’s Mineral Hill Mine near Jardine, Montana, produced gold, silver, and arsenic until in 1996 and reclamation began in 2000. The mine was comprised of a network of underground shafts tunneled into the rocky base of the nearby Mt. Palmer. As it was no longer producing metal commodities, Kinross was interested in developing a hydroelectric generating facility to offset the electrical demands of reclamation processes. They hired Morrison-Maierle to study the hydroelectric generating potential of tunnel drain water exiting the tunnel entrance, referred to as the adit. The study was also used as a scoping tool to outline project expectations and develop high-level capital costing information.

The concept was to use drain water, nearly 160-gpm, from a sealed tunnel approximately 650 feet above the mine’s administrative center. The drain water is comprised of the natural ground water that is collected in the tunnel and conveyed down the mountain to the stream discharge location. The proposed facility would be built in the administration center, existing HDPE drain piping would be used to convey the adit drain water and additional treatment process discharge waters to a turbine, and from there discharge it near Bear Creek. The proposed facility would generate approximately 16-kilowatts of power.

Morrison-Maierle determined the solution was to create an open water surface impoundment just outside of the adit seal using a pair of buried concrete tanks. The tanks would intercept the adit drain conduits and then convey water down the mountain to the turbine via a new penstock. The study determined that a skid-mounted hydroelectric generating equipment package should be developed specifically to the flow and head conditions provided by the system. The study recommends that zero-valence, ion-treated process water be introduced into the turbine tailrace for mixing with the adit drain water discharged from the turbine, and finally sent to Bear Creek via an existing conduit.